fix: locale format and translation updates

New Crowdin updates

.github/ISSUE_TEMPLATE/bug_report.yml

@@ -0,0 +1,123 @@
+name: Bug Report
+description: Report a bug or unexpected behavior
+title: "[Bug]: "
+labels: ["bug"]
+body:
+  - type: markdown
+    attributes:
+      value: |
+        Thanks for taking the time to report a bug! Please fill out the form below.
+
+  - type: checkboxes
+    id: checklist
+    attributes:
+      label: Checklist
+      description: Please confirm the following before submitting
+      options:
+        - label: I have searched existing issues and this bug hasn't been reported yet
+          required: true
+        - label: I am using the latest version of SpotiFLAC (Stable Version)
+          required: true
+
+  - type: textarea
+    id: description
+    attributes:
+      label: Bug Description
+      description: A clear and concise description of what the bug is
+      placeholder: Describe the bug...
+    validations:
+      required: true
+
+  - type: textarea
+    id: steps
+    attributes:
+      label: Steps to Reproduce
+      description: Steps to reproduce the behavior
+      placeholder: |
+        1. Go to '...'
+        2. Click on '...'
+        3. See error
+    validations:
+      required: true
+
+  - type: textarea
+    id: expected
+    attributes:
+      label: Expected Behavior
+      description: What did you expect to happen?
+      placeholder: Describe what you expected...
+    validations:
+      required: true
+
+  - type: textarea
+    id: actual
+    attributes:
+      label: Actual Behavior
+      description: What actually happened?
+      placeholder: Describe what actually happened...
+    validations:
+      required: true
+
+  - type: input
+    id: version
+    attributes:
+      label: App Version
+      description: Which version of SpotiFLAC are you using? (Check in Settings > About)
+      placeholder: "e.g., v2.2.0"
+    validations:
+      required: true
+
+  - type: dropdown
+    id: platform
+    attributes:
+      label: Platform
+      description: Which platform are you using?
+      options:
+        - Android
+        - iOS
+    validations:
+      required: true
+
+  - type: input
+    id: device
+    attributes:
+      label: Device & OS Version
+      description: What device and OS version are you using?
+      placeholder: "e.g., Samsung Galaxy S24, Android 14"
+    validations:
+      required: true
+
+  - type: dropdown
+    id: download-service
+    attributes:
+      label: Download Service
+      description: Which download service were you using when the bug occurred?
+      options:
+        - Tidal
+        - Qobuz
+        - Amazon Music
+        - Deezer (search only)
+        - Not applicable
+    validations:
+      required: true
+
+  - type: textarea
+    id: logs
+    attributes:
+      label: Logs / Screenshots
+      description: |
+        If applicable, add logs or screenshots to help explain your problem.
+        
+        **To get logs:**
+        1. Go to Settings > Options > Detailed Logging (turn ON)
+        2. Reproduce the bug
+        3. Go to Settings > Logs
+        4. Tap Share button to export logs
+      placeholder: Paste logs or drag & drop screenshots here...
+
+  - type: textarea
+    id: additional
+    attributes:
+      label: Additional Context
+      description: Any other context about the problem
+      placeholder: Add any other context...

.github/ISSUE_TEMPLATE/config.yml

@@ -0,0 +1,8 @@
+blank_issues_enabled: false
+contact_links:
+  - name: README
+    url: https://github.com/zarzet/SpotiFLAC-Mobile#readme
+    about: Check the README for setup instructions and FAQ
+  - name: Extension Development Guide
+    url: https://zarz.moe/docs
+    about: Documentation for building SpotiFLAC extensions

.github/ISSUE_TEMPLATE/download_issue.yml

@@ -0,0 +1,111 @@
+name: Download Issue
+description: Report issues with downloading specific tracks or albums
+title: "[Download]: "
+labels: ["download-issue"]
+body:
+  - type: markdown
+    attributes:
+      value: |
+        Having trouble downloading a specific track or album? Please provide details below.
+
+  - type: checkboxes
+    id: checklist
+    attributes:
+      label: Checklist
+      description: Please confirm the following before submitting
+      options:
+        - label: I have tried downloading with a different service (Tidal/Qobuz/Amazon)
+          required: true
+        - label: I am using the latest version of SpotiFLAC (Stable Version)
+          required: true
+
+  - type: dropdown
+    id: issue-type
+    attributes:
+      label: Issue Type
+      description: What kind of download issue are you experiencing?
+      options:
+        - Track not found on service
+        - Wrong track downloaded
+        - Download fails/errors
+        - Metadata incorrect
+        - Audio quality issue
+        - Other
+    validations:
+      required: true
+
+  - type: input
+    id: spotify-url
+    attributes:
+      label: Spotify URL
+      description: The Spotify URL of the track/album you're trying to download
+      placeholder: "https://open.spotify.com/track/..."
+    validations:
+      required: true
+
+  - type: input
+    id: track-info
+    attributes:
+      label: Track Info
+      description: Artist name and track title
+      placeholder: "Artist - Track Title"
+    validations:
+      required: true
+
+  - type: dropdown
+    id: download-service
+    attributes:
+      label: Download Service
+      description: Which service did you try to download from?
+      options:
+        - Tidal
+        - Qobuz
+        - Amazon Music
+        - All services
+    validations:
+      required: true
+
+  - type: dropdown
+    id: search-service
+    attributes:
+      label: Search Service
+      description: Which search service are you using?
+      options:
+        - Spotify
+        - Deezer
+    validations:
+      required: true
+
+  - type: textarea
+    id: description
+    attributes:
+      label: Description
+      description: Describe the issue in detail
+      placeholder: |
+        What happened? What did you expect?
+        If wrong track was downloaded, what track was downloaded instead?
+    validations:
+      required: true
+
+  - type: input
+    id: version
+    attributes:
+      label: App Version
+      description: Which version of SpotiFLAC are you using?
+      placeholder: "e.g., v2.2.0"
+    validations:
+      required: true
+
+  - type: textarea
+    id: screenshots
+    attributes:
+      label: Screenshots / Logs
+      description: |
+        If applicable, add screenshots or logs.
+        
+        **To get logs:**
+        1. Go to Settings > Options > Detailed Logging (turn ON)
+        2. Try downloading the track again
+        3. Go to Settings > Logs
+        4. Tap Share button to export logs
+      placeholder: Drag & drop screenshots or paste logs here...

.github/ISSUE_TEMPLATE/extension_feature_request.yml

@@ -0,0 +1,117 @@
+name: Extension API Feature Request
+description: Request new API features or capabilities for extension development
+title: "[Extension API]: "
+labels: ["enhancement", "extension-api"]
+body:
+  - type: markdown
+    attributes:
+      value: |
+        Thanks for helping improve the SpotiFLAC Extension API! 
+        This form is for extension developers who need new features or capabilities that don't exist yet.
+
+  - type: checkboxes
+    id: checklist
+    attributes:
+      label: Checklist
+      description: Please confirm the following before submitting
+      options:
+        - label: I have read the [Extension Development Guide](https://github.com/zarzet/SpotiFLAC-Mobile/blob/main/docs/EXTENSION_DEVELOPMENT.md)
+          required: true
+        - label: I have searched existing issues and this API feature hasn't been requested yet
+          required: true
+
+  - type: textarea
+    id: extension_goal
+    attributes:
+      label: What are you trying to build?
+      description: Describe the extension or feature you're developing
+      placeholder: "I'm building an extension that downloads from [service name] / provides metadata from [source]..."
+    validations:
+      required: true
+
+  - type: textarea
+    id: current_limitation
+    attributes:
+      label: Current API Limitation
+      description: What's missing or limiting in the current extension API?
+      placeholder: |
+        The current API doesn't support:
+        - [missing feature 1]
+        - [missing feature 2]
+        
+        This prevents me from...
+    validations:
+      required: true
+
+  - type: textarea
+    id: proposed_api
+    attributes:
+      label: Proposed API / Feature
+      description: Describe the API or feature you'd like to see added
+      placeholder: |
+        I would like to have:
+        - A new function `api.newFeature()` that does X
+        - A new manifest field `newOption` that enables Y
+        - Access to Z capability...
+    validations:
+      required: true
+
+  - type: textarea
+    id: use_case
+    attributes:
+      label: Use Case Example
+      description: Provide a code example of how you would use this feature
+      placeholder: |
+        ```javascript
+        // Example usage in extension code
+        function download(request, progressCallback) {
+          const result = api.proposedFeature(params);
+          // ...
+        }
+        ```
+    validations:
+      required: false
+
+  - type: dropdown
+    id: api_category
+    attributes:
+      label: API Category
+      description: What category does this feature fall under?
+      options:
+        - HTTP/Network API
+        - File System API
+        - Storage API
+        - FFmpeg/Audio Processing
+        - Manifest Options
+        - Runtime Functions
+        - UI Integration
+        - Authentication
+        - Other
+    validations:
+      required: true
+
+  - type: dropdown
+    id: priority
+    attributes:
+      label: How critical is this for your extension?
+      options:
+        - Blocker - Cannot build my extension without this
+        - High - Major functionality depends on this
+        - Medium - Would significantly improve my extension
+        - Low - Nice to have
+    validations:
+      required: true
+
+  - type: textarea
+    id: workaround
+    attributes:
+      label: Current Workaround
+      description: Are you using any workaround currently? If so, describe it.
+      placeholder: "Currently I'm working around this by..."
+
+  - type: textarea
+    id: additional
+    attributes:
+      label: Additional Context
+      description: Add any other context, links to similar APIs, or examples from other platforms
+      placeholder: "Similar feature in other platforms: ..."

.github/ISSUE_TEMPLATE/feature_request.yml

@@ -0,0 +1,66 @@
+name: Feature Request
+description: Suggest a new feature or improvement
+title: "[Feature]: "
+labels: ["enhancement"]
+body:
+  - type: markdown
+    attributes:
+      value: |
+        Thanks for suggesting a feature! Please fill out the form below.
+
+  - type: checkboxes
+    id: checklist
+    attributes:
+      label: Checklist
+      description: Please confirm the following before submitting
+      options:
+        - label: I have searched existing issues and this feature hasn't been requested yet
+          required: true
+
+  - type: textarea
+    id: problem
+    attributes:
+      label: Problem / Motivation
+      description: Is your feature request related to a problem? Please describe.
+      placeholder: "A clear description of what the problem is. Ex: I'm always frustrated when..."
+    validations:
+      required: true
+
+  - type: textarea
+    id: solution
+    attributes:
+      label: Proposed Solution
+      description: Describe the solution you'd like
+      placeholder: A clear description of what you want to happen...
+    validations:
+      required: true
+
+  - type: textarea
+    id: alternatives
+    attributes:
+      label: Alternatives Considered
+      description: Describe any alternative solutions or features you've considered
+      placeholder: Other approaches you've thought about...
+
+  - type: dropdown
+    id: category
+    attributes:
+      label: Category
+      description: What category does this feature fall under?
+      options:
+        - UI/UX Improvement
+        - Download Feature
+        - New Service Integration
+        - Metadata/Tagging
+        - Performance
+        - Settings/Configuration
+        - Other
+    validations:
+      required: true
+
+  - type: textarea
+    id: additional
+    attributes:
+      label: Additional Context
+      description: Add any other context, mockups, or screenshots about the feature request
+      placeholder: Add any other context or screenshots...

.github/workflows/release.yml

@@ -93,11 +93,12 @@ jobs:
           # Accept licenses
           yes | $ANDROID_HOME/cmdline-tools/latest/bin/sdkmanager --licenses || true
 
-          # Install NDK (required for gomobile)
-          $ANDROID_HOME/cmdline-tools/latest/bin/sdkmanager "ndk;25.2.9519653" "platforms;android-34" "build-tools;34.0.0"
+          # Install NDK r27d LTS (required for 16KB page size support on Android 15+)
+          # Platform android-36 and build-tools 36.0.0 for targetSdk 36 (Android 16)
+          $ANDROID_HOME/cmdline-tools/latest/bin/sdkmanager "ndk;27.3.13750724" "platforms;android-36" "build-tools;36.0.0"
 
           # Set NDK path
-          echo "ANDROID_NDK_HOME=$ANDROID_HOME/ndk/25.2.9519653" >> $GITHUB_ENV
+          echo "ANDROID_NDK_HOME=$ANDROID_HOME/ndk/27.3.13750724" >> $GITHUB_ENV
 
       - name: Install gomobile
         run: |
@@ -144,7 +145,7 @@ jobs:
           keyStorePassword: ${{ secrets.KEYSTORE_PASSWORD }}
           keyPassword: ${{ secrets.KEY_PASSWORD }}
         env:
-          BUILD_TOOLS_VERSION: "34.0.0"
+          BUILD_TOOLS_VERSION: "36.0.0"
 
       - name: Rename APKs
         run: |
@@ -344,6 +345,8 @@ jobs:
             CHANGELOG="See CHANGELOG.md for details."
           else
             echo "Found changelog content"
+            # Remove trailing --- separator if present (CHANGELOG uses --- between versions)
+            CHANGELOG=$(echo "$CHANGELOG" | sed '/^---$/d')
           fi
 
           # Save to file for multiline support

.gitignore

@@ -6,6 +6,8 @@ Thumbs.db
 .idea/
 .vscode/
 *.iml
+.cursorignore
+.cursorrules
 
 # Kiro specs (development only)
 .kiro/
@@ -13,6 +15,9 @@ Thumbs.db
 # Reference folder (development only)
 referensi/
 
+# Documentation (development only, published separately)
+docs/
+
 # Old spotiflac_android folder (moved to root)
 spotiflac_android/
 
@@ -50,3 +55,20 @@ ios/.symlinks/
 ios/Flutter/Flutter.framework/
 ios/Flutter/Flutter.podspec
 android/app/libs/gobackend-sources.jar
+
+# Extension folder
+extension/
+
+# Agent instructions
+AGENTS.md
+
+# Temp/misc
+nul
+
+# Log files
+*.log
+hs_err_*.log
+flutter_*.log
+
+# Development tools
+tool/

CHANGELOG.md

@@ -1,5 +1,876 @@
 # Changelog
 
+## [3.1.1] - 2026-01-17
+
+### Added
+
+- **Lyrics Caching**: Lyrics are now cached for 24 hours to reduce API calls and improve performance
+  - Thread-safe cache with automatic expiration
+  - Cache key based on artist, track, and duration
+  - Log indicator shows "(cached)" when lyrics are served from cache
+
+- **Lyrics Duration Matching**: Improved lyrics accuracy with duration-based matching
+  - Compares track duration with lrclib.net results
+  - 10-second tolerance to handle version differences (radio edit, remaster, etc.)
+  - Prioritizes synced lyrics over plain text when duration matches
+  - Falls back gracefully if no duration match found
+
+- **Deezer Cover Art Upgrade**: Cover art from Deezer CDN now automatically upgraded to maximum quality
+  - Detects Deezer CDN URLs (`cdn-images.dzcdn.net`)
+  - Upgrades cover resolution to 1800x1800 (max available)
+  - Works alongside existing cover upgrade
+
+- **Live Search for Extensions**: Search-as-you-type functionality for extension search
+  - 800ms debounce delay to prevent excessive API calls
+  - Minimum 3 characters required before searching
+  - Concurrency control to prevent race conditions in extension runtime
+  - Queues pending searches if a search is already in progress
+
+- **Russian Language Support**: Added Russian (Русский) translation - 99% complete
+  - Translated via Crowdin community contributions
+  - Covers all UI elements, settings, and error messages
+
+### Fixed
+
+- **ISRC Index Race Condition**: Fixed repeated index rebuilding during parallel downloads
+  - Added per-directory build lock using `sync.Map` and `sync.Mutex`
+  - Double-check locking pattern ensures index is built only once
+  - Significantly improves performance during CSV import with many tracks
+
+- **Queue Tab Scroll Exception**: Fixed Flutter rendering exception with NestedScrollView
+  - Disabled Material 3 stretch overscroll indicator that caused `_StretchController` assertion
+  - Wrapped NestedScrollView with ScrollConfiguration to prevent `setState during build` errors
+  - Issue was especially noticeable during rapid queue updates (CSV import)
+
+- **CSV Import**: Fixed CSV export not being parsed correctly
+  - Added support for `Artist Name(s)` header (with parentheses)
+  - Added support for `Track URI` header for track IDs
+  - Added `artists` and `track_id` as alternative header names
+  - Now correctly parses "Liked Songs" and playlist exports
+
+---
+
+## [3.1.0] - 2026-01-16
+
+### Added
+
+- **Recent Access History**: Quick access to recently visited content when tapping the search bar
+  - Shows recently visited artists, albums, playlists, and downloaded tracks
+  - Merged view combining navigation history and download history
+  - Tap to quickly navigate back to previously accessed content
+  - X button to remove individual items from history
+  - "Clear All" button to clear entire history
+  - Persists across app restarts (stored in SharedPreferences)
+  - Max 20 items stored, sorted by most recent
+  - Multi-language support (Artist/Album/Song/Playlist labels localized)
+
+- **Artist Screen Redesign**
+  - Full-width header image (380px) with gradient overlay
+  - Artist name displayed at bottom of header with text shadow
+  - Monthly listeners count display (formatted with compact notation)
+  - "Popular" section showing top 5 tracks with download status indicators
+  - Dynamic download button states (queued, downloading, completed)
+  - Header image and top tracks fetched from extension metadata
+  - Image alignment set to top-center to show faces properly
+
+- **Extension Store Update Badge**: Badge indicator on Store tab icon showing number of available updates
+  - Users can see extension updates are available without opening Store tab
+  - Badge shows count of extensions with updates
+
+- **Extension Compatibility Warning**: Warning badge for extensions requiring newer app version
+  - Extensions with `minAppVersion` higher than current app show warning label
+  - Label displays "Requires vX.X.X+" to encourage users to upgrade
+  - Users can still install the extension (not blocked)
+
+- **Year in Album Folder Name** ([#50](https://github.com/zarzet/SpotiFLAC-Mobile/issues/50)): New album folder structure options with release year
+
+  - `Artist / [Year] Album`: Albums/Coldplay/[2005] X&Y/
+  - `[Year] Album Only`: Albums/[2005] X&Y/
+  - Year extracted from release date metadata
+  - Matches desktop SpotiFLAC folder structure
+
+- **Extension Album/Playlist/Artist Support**: Extensions can now return albums, playlists, and artists in search results
+
+  - Search results now properly separated into Albums, Playlists, Artists, and Songs sections
+  - Albums, playlists, and artists show chevron icon (navigate to detail) instead of download button
+  - Tap album/playlist to view track list and download
+  - Tap artist to view their albums/discography
+  - New `getAlbum()`, `getPlaylist()`, and `getArtist()` extension functions
+  - New `ExtensionAlbumScreen`, `ExtensionPlaylistScreen`, and `ExtensionArtistScreen` for fetching content from extensions
+  - YouTube Music extension updated with album/playlist/artist support
+
+- **Odesli (song.link) Integration for YouTube Music Extension**
+  - New `enrichTrack()` function to fetch ISRC and external service links
+  - Uses Odesli API to convert YouTube Music tracks to Deezer/Tidal/Qobuz
+  - Enables built-in service fallback for high-quality audio downloads
+  - Extension version updated to 1.4.0 with `api.song.link` and `odesli.io` network permissions
+- **Download Cancel**: Canceling a download now stops in-flight built-in provider downloads (Tidal/Qobuz/Amazon) and clears backend progress tracking.
+
+### Changed
+
+- **Search Bar Behavior**: Tapping search bar now immediately moves it to top position
+  - Logo and subtitle hide when search bar is focused
+  - Recent access history appears in the content area below
+  - More space for recent items, not blocked by keyboard
+
+### Fixed
+
+- Fixed search source chips still referencing removed badge props.
+- Fixed extension artist album metadata to preserve provider IDs and cover URLs for correct navigation.
+- Fixed extension playlist fetch to populate provider IDs and reject disabled extensions.
+- Fixed extension collection screens calling setState after dispose during async loads.
+- Fixed URL handler responses to include provider IDs for extension albums and artists.
+- Fixed YTMusic extension not extracting album name and duration from search results.
+  - Album name is now extracted from flexColumns/subtitle when linked to album browseId.
+  - Duration is now extracted from fixedColumns/flexColumns in addition to existing sources.
+- Fixed "Separate Singles" setting not working ([#54](https://github.com/zarzet/SpotiFLAC-Mobile/issues/54)) - singles were going to Albums folder.
+  - Root cause: `albumType` was not being extracted from Deezer API during metadata enrichment.
+  - Deezer track responses now correctly include `album_type` (single/ep/album/compilation).
+  - Track creation now preserves `albumType` and `source` fields throughout download flow.
+- Fixed PageView overscroll at edges (BouncingScrollPhysics → ClampingScrollPhysics)
+- Fixed settings item highlight on swipe (highlightColor: Colors.transparent)
+- Fixed extension duplicate load error (skip silently instead of throwing error)
+- Fixed keyboard appearing when swiping between tabs (unfocus on page change)
+- Removed "Free"/"API Key" badges from search source selector
+- Fixed cancel action briefly resuming downloads in the queue UI after ~1 second.
+- Fixed cancelled downloads being marked as failed when the backend returns after cancellation.
+- Fixed cancel triggering provider fallback (cancel now stops the download flow immediately).
+- Fixed stale ISRC cache returning deleted files after cancel.
+- Fixed search results mixing extension and built-in artists when using default provider.
+- Fixed audio files opening with non-music apps by passing audio MIME type on open.
+- Fixed album artist showing null/blank by normalizing empty metadata and using artist fallback for tags.
+- Fixed `use_build_context_synchronously` lint warnings in `home_tab.dart`
+- Fixed `unnecessary_underscores` lint warnings in error widget callbacks
+- Fixed duplicate artist entries in recent history (recording now only happens in screen's initState)
+- **Go Backend: Missing `item_type` and `album_type` fields**
+  - Added `ItemType` and `AlbumType` fields to `ExtTrackMetadata` struct
+  - Fixed `CustomSearchWithExtensionJSON` - now includes `item_type` and `album_type` in response
+  - Fixed `HandleURLWithExtensionJSON` - now includes `item_type` and `album_type` for tracks
+  - Fixed `GetAlbumWithExtensionJSON` - now includes `item_type` and `album_type` for album tracks
+  - Fixed `GetPlaylistWithExtensionJSON` - now includes `item_type` and `album_type` for playlist tracks
+- **Album/Playlist Track Thumbnails**: Tracks inside albums/playlists now use album/playlist cover as fallback when no individual cover exists
+- **YouTube Music Extension getArtist**: Fixed `getArtist()` function not being registered in extension, causing artist pages to fail with "returned null" error
+- **Recent Access UI**: Fixed recent access list disappearing when keyboard is dismissed - now stays visible until user presses Back button
+- **Extension Artist Top Tracks**: Fixed top tracks not appearing when opening artist from extension search results
+  - YT Music extension `getArtist()` now returns `top_tracks` array with up to 10 popular songs
+  - Go backend `GetArtistWithExtensionJSON` now forwards `top_tracks`, `header_image`, and `listeners` to Flutter
+  - `ExtensionArtistScreen` now parses and passes top tracks to `ArtistScreen`
+  - `ArtistScreen` with `extensionId` skips metadata fetch, uses extension data only (fixes "Rate Limited" errors)
+- **Search Bar Unfocus**: Fixed search bar not unfocusing when tapping outside - now properly dismisses keyboard and unfocus when tapping anywhere outside the search field
+- **Keyboard Appearing on Settings Navigation**: Fixed keyboard randomly appearing when returning from Settings sub-pages (e.g., Appearance) - now uses `FocusManager.instance.primaryFocus?.unfocus()` for more aggressive unfocus
+- **Recent Access Artist Navigation**: Fixed opening artist from recent access using wrong screen - now correctly uses `ExtensionArtistScreen` for extension artists (YT Music, etc.) instead of trying to fetch from API
+
+### Extensions
+
+- **YouTube Music Extension**: Updated to v1.5.0
+  - `getArtist()` now returns `top_tracks` array with popular songs
+  - Added `header_image` and `listeners` to artist response
+- **Web Extension**: Updated to v1.6.0
+
+### Localization
+
+- **Multi-Language Support**: App now supports multiple languages with community contributions via Crowdin
+  - Available languages: English, Indonesian (Bahasa Indonesia)
+  - More languages coming soon with community translations
+  - Contribute translations at [Crowdin](https://crowdin.com/project/spotiflac-mobile)
+- Added new localization strings for recent access types:
+  - `recentTypeArtist` - "Artist" / "Artis"
+  - `recentTypeAlbum` - "Album" / "Album"
+  - `recentTypeSong` - "Song" / "Lagu"
+  - `recentTypePlaylist` - "Playlist" / "Playlist"
+  - `recentPlaylistInfo` - "Playlist: {name}"
+  - `errorGeneric` - "Error: {message}"
+
+---
+
+## [3.0.0] - 2026-01-14
+
+### Extension System (Major Feature)
+
+SpotiFLAC 3.0 introduces a powerful extension system that allows third-party integrations for metadata, downloads, and more.
+
+#### Extension Store
+
+- Browse and install extensions directly from the app
+- New "Store" tab in bottom navigation
+- Browse by category: Metadata, Download, Utility, Lyrics, Integration
+- Search extensions by name, description, or tags
+- One-tap install, update, and uninstall
+- Offline cache for browsing without internet
+
+#### Web Extension
+
+- Available in Extension Store - install and enable in Settings > Extensions
+- Metadata provider using web player API
+- Download tracks from Daily Mix, Discover Weekly, and other personalized playlists
+- Useful when official API is rate-limited or unavailable
+
+#### Extension Capabilities
+
+- **Custom Search Providers**
+- **Custom URL Handlers**
+- **Custom Thumbnail Ratios**: Square (1:1), Wide (16:9), Portrait (2:3)
+- **Post-Processing Hooks**: Extensions can process downloaded files
+- **Quality Options**: Extensions can define custom quality settings
+
+#### Extension APIs
+
+- Full HTTP support: GET, POST, PUT, DELETE, PATCH
+- Persistent cookie jar per extension
+- Browser-like polyfills: `fetch()`, `atob()`/`btoa()`, `TextEncoder`/`TextDecoder`, `URL`/`URLSearchParams`
+- Storage API for persistent data
+- File API for file operations
+- HMAC-SHA1 utility for cryptographic operations
+
+#### Security
+
+- Sandboxed JavaScript runtime (goja)
+- Permission-based access control
+- Network domain whitelisting
+- Improved credential encryption with per-installation random salt
+
+### Added
+
+- **Album Folder Structure Setting**: Option to remove artist folder from album path
+
+  - `Artist / Album` (default): `Albums/Artist Name/Album Name/`
+  - `Album Only`: `Albums/Album Name/`
+
+- **Separate Singles Folder**: Organize downloads into Albums/ and Singles/ folders
+
+  - Based on `album_type` from metadata
+  - Toggle in Settings > Download > Separate Singles Folder
+
+- **Year in Album Folder Name**: New album folder structure options with release year
+
+  - `Artist / [Year] Album`: Albums/Coldplay/[2005] X&Y/
+  - `[Year] Album Only`: Albums/[2005] X&Y/
+  - Year extracted from release date metadata
+  - Matches desktop SpotiFLAC folder structure
+
+- **Parallel API Calls**: Download URL fetching now uses parallel requests
+  - Tidal: All 8 APIs requested simultaneously, first success wins
+  - Qobuz: Both APIs requested simultaneously, first success wins
+  - Significantly reduces download URL fetch time
+
+### UI/UX Improvements
+
+- **Swipeable History Filters**: History tab now supports swipe gestures between All, Albums, and Singles filters
+
+  - Swipe left/right to switch between filter tabs
+  - Filter chips sync with swipe position
+  - Smooth edge-to-edge transition: swipe past Singles to go to Store, swipe past All to go to Home
+  - Natural gesture feel - drag connects to parent navigation
+
+  - **Improved File Open Intent**: Play button in History now correctly opens music players only
+  - Added proper MIME type (`audio/flac`, `audio/mpeg`, etc.) when opening downloaded files
+  - Prevents system from showing unrelated apps in the "Open with" dialog
+
+### Fixed
+
+- **Fixed Tab Edge Overscroll**: Home and Settings tabs now stop at edges instead of bouncing into empty space
+
+- **Fixed Extension Duplicate Load Error**: Extension loading now silently skips already-loaded extensions instead of throwing error
+
+- **Fixed Settings Item Highlight on Swipe**: Settings items no longer highlight when swiping at page edge
+
+- **Fixed Keyboard Appearing on Tab Switch**: Keyboard now auto-dismisses when swiping between tabs
+
+- **Removed Search Source Badges**: Removed "Free" and "API Key" labels from provider selector in Options
+
+- **Back Gesture Freeze on Android 13+**: Fixed app freeze when using back gesture in settings
+
+  - Added `PopScope` with `canPop: true` to all settings pages
+  - Changed navigation to use `PageRouteBuilder` with proper slide transition
+
+- **Bottom Overflow in Folder Organization Dialog**: Fixed overflow in portrait and landscape mode
+
+  - Made dialog scrollable with max height constraint
+
+- **Japanese Artist Name Order**: Fixed artist mismatch for Japanese names
+
+  - "Sawano Hiroyuki" vs "Hiroyuki Sawano" now correctly matches
+
+- **Multi-Artist Matching**: Fixed artist mismatch for collaboration tracks
+
+  - "RADWIMPS feat. Toko Miura" now matches when service only shows "Toko Miura"
+
+- **Max Resolution Cover Download**: Fixed cover not upgrading to max resolution on mobile
+
+  - Mobile now correctly upgrades 300x300 → 640x640 → max resolution (~2000x2000)
+
+- **EXISTS: Prefix in File Path**: Fixed "File not found" error in metadata screen
+
+  - Duplicate detection prefix now stripped before saving to history
+
+- **Extension Search Result Parsing**: Fixed "cannot unmarshal array" error
+
+  - Go backend now handles both array and object formats from extensions
+
+- **Store Tab Unmount Crash**: Fixed "Using ref when widget is unmounted" error
+
+- **Duplicate History Entries**: Fixed duplicate entries when re-downloading same track
+
+  - Detects existing entries by track ID, Deezer ID, or ISRC
+
+- **Permission Error Message**: Fixed download showing "Song not found" when actually permission error
+
+  - Now shows proper message: "Cannot write to folder, check storage permission"
+
+- **Android 13+ Storage Permission**: Fixed storage permission not working on Android 13+
+  - Now requests both `MANAGE_EXTERNAL_STORAGE` and `READ_MEDIA_AUDIO`
+
+### Changed
+
+- **Extension Manifest**: New `file` permission required for file operations
+  ```json
+  "permissions": {
+    "network": ["api.example.com"],
+    "storage": true,
+    "file": true
+  }
+  ```
+
+### Technical
+
+- Go backend: Simplified parallel download result handling in Tidal/Qobuz
+- Go backend: Removed unused functions and fixed bit shifting warnings
+- Release workflow: Fixed duplicate `---` separator in release notes
+
+---
+
+## [3.0.0-beta.2] - 2026-01-13
+
+### Added
+
+- **Album Folder Structure Setting**: Option to remove artist folder from album path
+  - New setting in Download Settings when "Separate Singles Folder" is enabled
+  - `Artist / Album` (default): `Albums/Artist Name/Album Name/`
+  - `Album Only`: `Albums/Album Name/`
+  - Requested by user who prefers flat album organization
+
+### Fixed
+
+- **Back Gesture Freeze on OnePlus/Android 13+**: Fixed app freeze when using back gesture in settings
+
+  - Added `PopScope` with `canPop: true` to all settings pages
+  - Changed navigation to use `PageRouteBuilder` with proper slide transition
+  - Fixes predictive back gesture conflict on devices with gesture navigation
+  - Affected pages: Download, Appearance, Options, Extensions, About, Logs, Extension Detail
+
+- **Extension Search Result Parsing**: Fixed "cannot unmarshal array into Go value" error
+
+  - Go backend now handles both array and object formats from extensions
+  - Extensions returning `[{track}, {track}]` now work correctly
+  - Extensions returning `{tracks: [...], total: N}` still work as before
+
+- **Max Resolution Cover Download**: Fixed cover not upgrading to max resolution on mobile
+
+  - Added missing `spotifySize300` constant (300x300 size code)
+  - Mobile now correctly upgrades 300x300 → 640x640 → max resolution (~2000x2000)
+  - Added `_upgradeToMaxQualityCover()` helper in Flutter for M4A conversion path
+  - Go backend `cover.go` now directly replaces URL without HEAD verification
+
+- **Extension Search Provider Reset**: Fixed search provider not resetting to default when disabled
+
+  - `copyWith` in `AppSettings` couldn't set `searchProvider` to `null`
+  - Added `clearSearchProvider` boolean parameter to properly clear the value
+  - Settings menu now correctly switches back to default provider
+
+- **Extension Disabled Search Fallback**: Fixed error when extension is disabled but still called
+
+  - `_performSearch` now checks if extension is still enabled before calling custom search
+  - Automatically falls back to Deezer search if extension was disabled
+  - Clears `searchProvider` setting if extension no longer available
+
+- **Store Tab Unmount Crash**: Fixed "Using ref when widget is unmounted" error
+
+  - Added `mounted` check after async operation in `_initialize()`
+  - Prevents crash when navigating away from Store tab during initialization
+
+- **EXISTS: Prefix in File Path**: Fixed "File not found" error in metadata screen after download
+
+  - Duplicate detection was adding `EXISTS:` prefix to file paths
+  - Prefix now stripped before saving to download history
+  - Legacy history items with prefix are handled gracefully
+
+- **History Error Badge**: Fixed error badge showing on history items even when file exists
+
+  - `queue_tab.dart` now strips `EXISTS:` prefix before checking file existence
+  - File open and delete operations also use cleaned path
+
+- **Extension Artist URL Handler**: Fixed artist pages showing "0 releases" from extensions
+
+  - Extension `fetchArtist` now returns correct format: `{ type: "artist", artist: { albums } }`
+  - Go backend `HandleURLWithExtensionJSON` now includes albums in artist response
+  - Added `AlbumType` field to `ExtAlbumMetadata` struct
+
+- **Extension Artist Name in Logs**: Fixed empty artist name in extension track logs
+
+  - Now uses `firstArtist` + `otherArtists` instead of deprecated `artists.items`
+  - Logs correctly show "Fetched track: {title} by {artist}"
+
+- **Japanese Artist Name Order**: Fixed artist mismatch for Japanese names with different order
+
+  - "Sawano Hiroyuki" vs "Hiroyuki Sawano" now correctly matches
+  - Added `sameWordsUnordered` check to both Tidal and Qobuz artist matching
+  - Handles Japanese name order (family name first) vs Western name order (given name first)
+
+- **Multi-Artist Matching**: Fixed artist mismatch for collaboration tracks
+
+  - "RADWIMPS feat. Toko Miura" now matches when Qobuz/Tidal only shows "Toko Miura"
+  - Split artists by separators (`, `, `feat.`, `ft.`, `&`, `and`, `x`)
+  - Match if ANY expected artist matches ANY found artist
+
+- **Cover Download Logging**: Improved cover download logs for debugging
+  - Shows original URL, upgrade steps, and final URL
+  - Displays estimated resolution based on file size
+  - Logs now appear in Settings > Logs via GoLog
+
+---
+
+## [3.0.0-beta.1] - 2026-01-13
+
+### Security
+
+- Improved extension sandbox security
+- Improved credential encryption with per-installation random salt
+
+### Changed
+
+- **Extension Manifest**: New `file` permission required for file operations
+  ```json
+  "permissions": {
+    "network": ["api.example.com"],
+    "storage": true,
+    "file": true
+  }
+  ```
+  Extensions that need to download files must declare `"file": true` in manifest.
+
+### Fixed
+
+- Extension packages now preserve directory structure (subdirectories supported)
+- Back gesture freeze in settings pages on Android gesture navigation
+
+---
+
+## [3.0.0-alpha.4] - 2026-01-12
+
+### Added
+
+- **Extension Store**: Browse and install extensions directly from the app
+
+  - New "Store" tab in bottom navigation
+  - Browse extensions by category (Metadata, Download, Utility, Lyrics, Integration)
+  - Search extensions by name, description, or tags
+  - One-tap install and update
+  - Offline cache for browsing without internet
+  - Extensions hosted at github.com/zarzet/SpotiFLAC-Extension
+
+- **Custom URL Handler for Extensions**: Extensions can now register custom URL patterns
+
+  - Handle URLs from YouTube Music, SoundCloud, Bandcamp, etc.
+  - Manifest config: `urlHandler: { enabled: true, patterns: ["music.youtube.com"] }`
+  - Implement `handleUrl(url)` function in extension to parse and return track metadata
+  - SpotiFLAC automatically routes matching URLs to the appropriate extension
+  - Supports share intents and paste from clipboard
+
+- **Artist URL Handler Support**: Extensions can now return artist data from URL handlers
+
+  - Added `type: "artist"` handling in track_provider.dart
+  - Navigate to artist screen with albums list from extension
+
+- **HMAC-SHA1 Utility**: New `utils.hmacSHA1(key, message)` function for extensions
+  - Enables TOTP generation and other cryptographic operations
+  - Returns byte array for flexible use
+
+### Fixed
+
+- **Extension Store Refresh**: Store tab now properly refreshes after uninstalling an extension
+  - "Installed" badge correctly updates to "Install" button
+
+### Documentation
+
+- Updated `docs/EXTENSION_DEVELOPMENT.md`:
+  - Added Custom URL Handler section with examples
+  - Added `handleUrl` function documentation
+  - Added URL pattern examples for YouTube, SoundCloud, Bandcamp
+  - Added `utils.hmacSHA1` documentation with TOTP example
+
+### Extensions
+
+- **Web Extension** (example): New extension for metadata via web API
+  - Supports personalized playlists (Daily Mix, Discover Weekly, Release Radar, etc.)
+  - Search, album, playlist, track, and artist fetching
+  - Available in Extension Store (3.0.0-alpha.4)
+
+---
+
+## [3.0.0-alpha.3] - 2026-01-12
+
+### Added
+
+- **Separate Singles Folder**: Option to organize downloads into Albums/ and Singles/ folders
+  - Based on `album_type` from metadata
+  - Toggle in Settings > Download > Separate Singles Folder
+  - Singles saved to `{output}/Singles/`, albums to `{output}/Albums/`
+- **Browser-like Polyfills**: New global APIs for easier library porting
+  - `fetch()` - Browser-compatible HTTP API with `json()`, `text()`, `arrayBuffer()` methods
+  - `atob()` / `btoa()` - Global Base64 encoding/decoding
+  - `TextEncoder` / `TextDecoder` - UTF-8 text encoding classes
+  - `URL` / `URLSearchParams` - URL parsing and manipulation classes
+  - Makes porting browser libraries (like `youtubei.js`) much easier
+
+### Performance
+
+- **Parallel API Calls**: Download URL fetching now uses parallel requests
+  - Tidal: All 8 APIs requested simultaneously, first success wins
+  - Qobuz: Both APIs requested simultaneously, first success wins
+  - Significantly reduces download URL fetch time
+
+### Fixed
+
+- **Duplicate History Entries**: Fixed duplicate entries when re-downloading same track
+  - Detects existing entries by track ID, Deezer ID, or ISRC
+  - Replaces existing entry and moves to top of list
+  - Auto-deduplicates existing history on app load
+- **Extension Search Fallback**: Fixed error when extension is disabled but still called for search
+  - Now checks if extension is still enabled before calling custom search
+  - Auto-resets search provider to default if extension was disabled
+- **Permission Error Message**: Fixed download showing "Song not found" when actually a permission error
+  - Now shows proper message: "Cannot write to folder, check storage permission"
+  - Added `permission` error type detection in backend
+- **Android 13+ Storage Permission**: Fixed storage permission not working on Android 13+
+  - Android 13+ now requests both `MANAGE_EXTERNAL_STORAGE` and `READ_MEDIA_AUDIO`
+  - `MANAGE_EXTERNAL_STORAGE` opens Settings (system-level, persists across app data clear)
+  - `READ_MEDIA_AUDIO` shows dialog (app-level, resets on app data clear)
+  - Proper permission check before showing "granted" status
+
+---
+
+## [3.0.0-alpha.2] - 2026-01-12
+
+### Added
+
+- **Full HTTP Method Support**: New shortcut methods for all common HTTP verbs
+  - `http.put(url, body, headers)` - PUT requests
+  - `http.delete(url, headers)` - DELETE requests
+  - `http.patch(url, body, headers)` - PATCH requests
+  - `http.clearCookies()` - Clear all cookies for the extension
+- **Persistent Cookie Jar**: Each extension now has its own cookie jar
+  - Cookies automatically stored from `Set-Cookie` headers
+  - Cookies automatically sent with subsequent requests to same domain
+  - Useful for APIs requiring session cookies (YouTube, etc.)
+- **Multi-Value Header Support**: Response headers now return arrays for multi-value headers
+  - `Set-Cookie` and other headers with multiple values returned as arrays
+  - Single-value headers still returned as strings for convenience
+- **Generic HTTP Request Method**: New `http.request()` for full HTTP control
+  - Supports all HTTP methods (GET, POST, PUT, DELETE, PATCH, etc.)
+  - Single options object for cleaner API: `http.request(url, { method, body, headers })`
+- **Response Helper Properties**: HTTP responses now include convenience properties
+  - `response.ok` - true if status code is 2xx
+  - `response.status` - alias for `statusCode`
+
+### Fixed
+
+- **User-Agent Header Respect**: Custom `User-Agent` headers are now respected
+  - Previously, extension-provided User-Agent was overwritten
+  - Now only sets default User-Agent if extension doesn't provide one
+- **HTTP POST Body Auto-Stringify**: `http.post()` now automatically stringifies objects to JSON
+  - Previously, passing an object as body resulted in `[object Object]`
+  - Now objects and arrays are automatically JSON.stringify'd
+  - String bodies still work as before (no double-encoding)
+
+### Documentation
+
+- Updated `docs/EXTENSION_DEVELOPMENT.md`:
+  - Added complete HTTP API documentation with all methods
+  - Added Cookie Jar documentation
+  - Added `http.put()`, `http.delete()`, `http.patch()`, `http.clearCookies()` docs
+  - Added YouTube Music / Innertube API example with custom User-Agent
+  - Added common domain lists for YouTube, SoundCloud, Bandcamp
+  - Improved HTTP API documentation with response properties
+
+---
+
+## [3.0.0-alpha.1] - 2026-01-11
+
+#### Extension System
+
+- **Custom Search Providers**: Extensions can now provide custom search functionality
+  - YouTube, SoundCloud, and other platforms via extensions
+  - Custom search placeholder text per extension
+  - Configurable thumbnail aspect ratios (square, wide, portrait)
+- **Extension Upgrade System**: Upgrade extensions without losing data
+  - Preserves extension settings and cached data during upgrades
+  - Version comparison prevents downgrades
+  - Auto-detects upgrades when installing same extension
+- **Custom Thumbnail Ratios**: Extensions can specify thumbnail display format
+  - `"square"` (1:1) - Album art style (default)
+  - `"wide"` (16:9) - YouTube/video style
+  - `"portrait"` (2:3) - Poster style
+  - Custom width/height override available
+
+### Added
+
+- **Track Source Tracking**: Tracks now remember which extension provided them
+  - `Track.source` field stores extension ID
+  - `TrackState.searchExtensionId` for current search context
+  - Enables extension-specific UI customization
+- **Extension Upgrade API**: New methods for extension management
+  - `upgradeExtension(filePath)` - Upgrade existing extension
+  - `checkExtensionUpgrade(filePath)` - Check if file is an upgrade
+  - `RemoveExtensionByID` - Remove extension by ID
+- **iOS Extension Support**: Added missing iOS method handlers
+  - `upgradeExtension` - Upgrade extension from file
+  - `checkExtensionUpgrade` - Check upgrade compatibility
+- **Extension Documentation**: Comprehensive extension development guide
+  - Thumbnail ratio customization documentation
+  - Extension upgrade workflow documentation
+  - New troubleshooting entries for common issues
+
+### Changed
+
+- **Version Bump**: 2.2.7 → 3.0.0-alpha.1 (major version for extension system)
+- **Build Number**: 49 → 50
+- **Extension Manager**: Improved upgrade detection in `LoadExtensionFromFile`
+  - Auto-detects if installing same extension with higher version
+  - Calls `UpgradeExtension` automatically for seamless upgrades
+
+### Fixed
+
+- **Extension `registerExtension`**: Fixed global `extension` variable not being set
+  - Extensions can now access their own functions via `extension.functionName()`
+  - Required for `customSearch` and other provider functions
+- **Custom Search Empty Results**: Fixed error when extension returns null
+  - Now returns empty array instead of error
+  - Prevents crash when no results found
+- **Mutex Crash on Upgrade**: Fixed "Unlock of unlocked RWMutex" crash
+  - Removed `defer m.mu.Unlock()` when manual unlock is used
+  - Proper lock handling in upgrade flow
+- **Duplicate Error Messages**: Fixed extension install errors showing twice
+  - Added `clearError()` method to extension provider
+  - Improved PlatformException parsing to remove "null, null" artifacts
+- **Extension Images Field**: Fixed thumbnails not showing in search results
+  - Added `Images` field to `ExtTrackMetadata` struct
+  - Renamed `GetCoverURL` to `ResolvedCoverURL` (gomobile conflict)
+
+### Technical
+
+- **Go Backend Changes**:
+  - `go_backend/extension_manager.go`: Added `compareVersions()`, `UpgradeExtension()`, `CheckExtensionUpgradeJSON()`
+  - `go_backend/extension_providers.go`: Added `Images` field, `ResolvedCoverURL()` method
+  - `go_backend/extension_manifest.go`: Added `ThumbnailRatio`, `ThumbnailWidth`, `ThumbnailHeight` to `SearchBehaviorConfig`
+  - `go_backend/exports.go`: Added `RemoveExtensionByID`, `UpgradeExtensionFromPath`, `CheckExtensionUpgradeFromPath`
+- **Flutter Changes**:
+  - `lib/models/track.dart`: Added `source` field
+  - `lib/models/track.g.dart`: Updated for `source` field
+  - `lib/providers/track_provider.dart`: Added `searchExtensionId`, updated `_parseSearchTrack` with source parameter
+  - `lib/providers/extension_provider.dart`: Added `SearchBehavior.getThumbnailSize()`, `clearError()`
+  - `lib/screens/home_tab.dart`: Dynamic thumbnail size based on extension config
+  - `lib/screens/settings/extensions_page.dart`: Improved error handling
+  - `lib/services/platform_bridge.dart`: Added `upgradeExtension()`, `checkExtensionUpgrade()`, `removeExtension()`
+- **iOS Changes**:
+  - `ios/Runner/AppDelegate.swift`: Added `upgradeExtension`, `checkExtensionUpgrade` handlers
+- **Android Changes**:
+  - `android/app/src/main/kotlin/com/zarz/spotiflac/MainActivity.kt`: Already had upgrade methods
+
+---
+
+## [2.2.8] - 2026-01-12
+
+### Added
+
+- **Multi-Select Batch Delete**: Long-press tracks in History to enter selection mode
+  - Select multiple tracks at once
+  - "Select All" and "Delete Selected" actions
+  - Modern Material 3 bottom action bar (slides up from bottom)
+  - Works in both grid and list view modes
+- **History Filter Tabs**: Filter history by All/Albums/Singles
+  - Album = tracks where album has >1 track in history
+  - Single = tracks where album has only 1 track in history
+  - Filter chips show counts for each category
+- **Album Grouping View**: When "Albums" filter is selected, tracks are grouped by album
+  - Album cards displayed in 2-column grid with cover art and track count badge
+  - Tap album to open dedicated album detail screen
+  - Album detail shows all downloaded tracks from that album
+  - Multi-select delete support within album view
+  - Auto-navigates back when album has <2 tracks remaining
+
+### Changed
+
+- **Issue Templates**: Updated version confirmation checkbox to specify "(Stable Version)"
+
+---
+
+## [2.2.7] - 2026-01-11
+
+### Added
+
+- **CSV Import Metadata Enrichment**: Tracks imported from CSV now automatically fetch metadata from Deezer
+  - Cover art, duration, track/disc number fetched via ISRC lookup
+  - Fallback to text search (artist + track name) when ISRC not found in Deezer
+  - Progress dialog shows enrichment status during import
+  - Ensures downloaded files have proper cover art and metadata
+- **Deezer Metadata Support**: Enhanced metadata viewer for Deezer tracks
+  - "Open in Deezer" button for Deezer-sourced tracks (opens app or web)
+  - Displays "Deezer ID" instead of "Spotify ID" when applicable
+- **Smart Tag Injection**: Filename format editor intelligently handles separators
+  - Auto-detects if " - " is needed between tags
+  - Prevents double separators or missing spaces
+- **Dynamic Source Info**: Search source selector now shows helpful context
+  - "No login required" for Deezer
+  - "Requires credentials" for Spotify
+
+### Changed
+
+- **UI Modernization**: Major UI consistency updates across the app
+  - **Unified App Bars**: Home, History, and Settings now share identical behavior
+    - Lowered expanded header for easier one-handed reachability
+    - Dynamic title text scaling (20px to 34px)
+  - **Appearance Settings**: Completely redesigned appearance page
+    - New "Theme Preview" card showing visualizing current theme
+    - Modern color palette picker replacing old color dots
+    - Clean, grouped layout
+    - "AMOLED Dark" switch is now hidden when using Light Mode
+  - **App Logo**: Refined logo style on Home and About screens
+    - Inverted colors: Filled primary color circle with on-color icon
+    - Removed padding for a cleaner, bolder look
+  - **Material 3 Switches**: Added checkmark icon to active switches
+- **UI Modernization (Global)**: Complete design refresh for a cleaner, modern look
+  - **Rounded Corners**: Standardized 16px radius for all cards, buttons, and input fields
+  - **Transparent Elements**: Applied subtle transparency to input fields and containers using `surfaceContainerHighest`
+  - **Consistent Buttons**: Unified button styling across the app (pill shape, 16px radius)
+- **Options Settings Redesign**: improved layout and usability
+  - **Search Source Priority**: Moved "Search Source" section to the very top for quick access
+  - **Compact Source Selector**: Redesigned provider toggle (Deezer/Spotify) to be compact and consistent
+  - **Credentials Workflow**: Reorganized Custom Credentials settings; toggle now auto-prompts if credentials missing
+  - **Modern Credentials Dialog**: Totally redesigned input dialog for Spotify Client ID/Secret
+- **Filename Format Editor 2.0**:
+  - **Modern Sheet UI**: Replaced legacy dialog with a clean, full-width bottom sheet
+  - **Tag Chips**: Added clickable chips ({artist}, {title}) for one-tap insertion
+  - **Smart Formatting**: Automatically injects separators (" - ") when adding tags for faster editing
+
+### Fixed
+
+- **CSV Import Missing Cover Art**: Fixed tracks from CSV having no cover art in download history
+  - Cover URL now properly fetched from Deezer during enrichment
+  - Falls back to text search when ISRC lookup fails
+- **CSV Import Missing Duration**: Fixed duration showing 0:00 for CSV-imported tracks
+  - Duration now fetched from Deezer metadata during enrichment
+- **Disc Number Not Displayed**: Fixed disc number not showing in track metadata screen
+  - Changed condition from `discNumber > 0` to `discNumber > 0`
+  - Now displays disc 1 instead of hiding it
+- **Download History Using Wrong Track Data**: Fixed history using original CSV data instead of enriched data
+  - Now uses `trackToDownload` (enriched) instead of `item.track` (original)
+
+### Technical
+
+- Updated `lib/services/csv_import_service.dart`:
+  - Added `_enrichTracksMetadata()` with ISRC lookup + text search fallback
+  - Added progress callback for UI feedback
+- Updated `lib/screens/home_tab.dart`:
+  - Added progress dialog during CSV enrichment
+- Updated `lib/providers/download_queue_provider.dart`:
+  - Uses enriched track data for download history
+- Updated `lib/screens/track_metadata_screen.dart`:
+  - Show disc number when > 0 (was > 1)
+- Updated `go_backend/metadata.go`:
+  - Added `TotalSamples` to `AudioQuality` struct for duration calculation
+- Updated `go_backend/exports.go`:
+  - `ReadFileMetadata` now returns duration calculated from FLAC stream info
+- Updated `AppTheme` with new `InputDecorationTheme` and `ButtonTheme` definitions
+- Refactored `DownloadSettingsPage` to use new `_showFormatEditor` with cursor-aware capabilities
+- Optimized various dialogs to use `showModalBottomSheet` with `isScrollControlled` for better keyboard handling
+
+---
+
+## [2.2.6] - 2026-01-11
+
+### Fixed
+
+- **Release Mode Logging**: Flutter app logs now properly captured in release builds
+  - Previously only Go backend logs appeared when "Detailed Logging" was enabled
+  - Now both Flutter and Go logs are captured in release mode
+  - Bypasses Logger package which filters logs in release mode
+
+### Added
+
+- **Detailed Deezer Search Logging**: Better debugging for search issues
+  - Logs API URLs, response counts, and errors
+  - Helps diagnose geo-restriction and API issues
+  - Detects Deezer API error responses
+
+### Changed
+
+- **Home Screen Logo**: Replaced music note icon with app logo
+  - Uses `assets/images/logo.png`
+  - Rounded corners (24px radius)
+  - Fallback to music note icon if logo fails to load
+- **About Page Logo**: Removed shadow/border from logo
+  - Cleaner appearance without background container
+- **About Page Icon Alignment**: Icons now aligned with contributor avatars
+  - DoubleDouble and DAB Music icons use 40x40 area
+  - Text now properly aligned with contributor items
+
+## [2.2.5] - 2026-01-10
+
+### Added
+
+- **In-App Log Viewer with Go Backend Logs**: Complete logging system for debugging
+  - Go backend logs now captured and displayed in app
+  - Circular buffer stores up to 500 log entries
+  - Real-time polling (500ms) for Go backend logs
+  - Logs include timestamp, level, tag, and message
+  - "Go" badge indicates logs from backend
+- **Detailed Logging Toggle**: Control logging in Settings > Options > Debug
+  - Disabled by default for performance
+  - Errors are always logged regardless of setting
+  - Enable before reproducing bugs for detailed logs
+- **Log Issue Summary**: Automatic detection of common issues in logs
+  - ISP Blocking detection with affected domains
+  - Rate limiting detection
+  - Network error detection
+  - Track not found detection
+  - Shows suggestions for each issue type
+- **ISP Blocking Detection**: Detects when ISP blocks download services
+  - DNS resolution failure detection
+  - Connection reset/refused detection
+  - TLS handshake failure detection
+  - HTTP 403/451 blocking page detection
+  - Suggests VPN or DNS change (1.1.1.1 / 8.8.8.8)
+
+### Fixed
+
+- **Artist Profile Placeholder**: Shows person icon when artist has no profile image
+  - Validates image URL before loading
+  - Fallback icon on load error
+- **Latin Extended Character Detection**: Fixed wrong track downloads for Polish, Czech, French, Spanish songs
+  - Characters like Ł, ę, ć, ñ, é now correctly treated as Latin script
+  - Previously treated as "different script" causing false matches
+  - Affects both Tidal and Qobuz search
+
+### Changed
+
+- **Log Screen UI Improvements**:
+  - Copy button moved to app bar (left of menu)
+  - Removed redundant info card
+  - Cleaner interface
+- **Issue Templates Updated**: Instructions for enabling detailed logging before submitting bug reports
+
+### Technical
+
+- New file: `go_backend/logbuffer.go` with circular buffer and GoLog function
+- Updated `go_backend/httputil.go` with ISP blocking detection
+- Updated `go_backend/tidal.go` and `go_backend/qobuz.go` with `isLatinScript()` function
+- Updated `lib/utils/logger.dart` with Go log polling
+- Updated `lib/screens/settings/log_screen.dart` with issue summary
+- Added method channel handlers for logging in Android and iOS
+- New error type: `isp_blocked` for ISP blocking errors
+
+---
+
 ## [2.2.0] - 2026-01-10
 
 ### Fixed

README.md

@@ -1,11 +1,12 @@
 [![GitHub All Releases](https://img.shields.io/github/downloads/zarzet/SpotiFLAC-Mobile/total?style=for-the-badge)](https://github.com/zarzet/SpotiFLAC-Mobile/releases)
-[![VirusTotal](https://img.shields.io/badge/VirusTotal-Safe-brightgreen?style=for-the-badge&logo=virustotal)](https://www.virustotal.com/gui/file/cb87d23fc9fd4a6f0a7b2b934773029c7e7ab25101dfce503e68e9c9e8921fca/)
+[![VirusTotal](https://img.shields.io/badge/VirusTotal-Safe-brightgreen?style=for-the-badge&logo=virustotal)](https://www.virustotal.com/gui/file/e1c527eacb6f5ce527af214a75aab8da060c2afc629825fff24af858439e7e6b)
+[![Crowdin](https://img.shields.io/badge/HELP%20TRANSLATE%20ON-CROWDIN-%2321252b?style=for-the-badge&logo=crowdin)](https://crowdin.com/project/spotiflac-mobile)
 
 <div align="center">
 
 <img src="icon.png" width="128" />
 
-Get Spotify tracks in true FLAC from Tidal, Qobuz & Amazon Music — no account required.
+Download music in true lossless FLAC from Tidal, Qobuz & Amazon Music — no account required.
 
 ![Android](https://img.shields.io/badge/Android-7.0%2B-3DDC84?style=for-the-badge&logo=android&logoColor=white)
 ![iOS](https://img.shields.io/badge/iOS-14.0%2B-000000?style=for-the-badge&logo=apple&logoColor=white)
@@ -23,37 +24,60 @@ Get Spotify tracks in true FLAC from Tidal, Qobuz & Amazon Music — no account
   <img src="assets/images/4.jpg?v=2" width="200" />
 </p>
 
-## Metadata Source
+## Search Source
 
-SpotiFLAC supports two metadata sources for searching tracks:
+SpotiFLAC supports multiple search sources for finding music metadata:
 
-| Source | Pros | Cons |
-|--------|------|------|
-| **Deezer** (Default) | No developer account needed, rate limit per user IP | Slightly less comprehensive catalog |
-| **Spotify** | More comprehensive catalog, better search results | Requires developer API credentials to avoid rate limiting |
+| Source | Setup |
+|--------|-------|
+| **Deezer** (Default) | No setup required |
+| **Extensions** | Install additional search providers from the Store |
 
-### Using Spotify
-To use Spotify as your search source without hitting rate limits:
-1. Create a Spotify Developer account at [developer.spotify.com](https://developer.spotify.com)
-2. Create an app to get your Client ID and Client Secret
-3. Go to **Settings > Options > Spotify API > Change from Deezer to Spotify > Input Custom Credentials**
-4. Enter your Client ID and Secret
-5. Change **Search Source** to Spotify
+## Extensions
+
+Extensions allow the community to add new music sources and features without waiting for app updates. When a streaming service API changes or a new source becomes available, extensions can be updated independently.
+
+### Installing Extensions
+1. Go to **Store** tab in the app
+2. Browse and install extensions with one tap
+3. Or download a `.spotiflac-ext` file and install manually via **Settings > Extensions**
+4. Configure extension settings if needed
+5. Set provider priority in **Settings > Extensions > Provider Priority**
+
+### Developing Extensions
+Want to create your own extension? Check out the [Extension Development Guide](https://zarz.moe/docs) for complete documentation.
 
 ## Other project
 
 ### [SpotiFLAC (Desktop)](https://github.com/afkarxyz/SpotiFLAC)
-Get Spotify tracks in true FLAC from Tidal, Qobuz & Amazon Music for Windows, macOS & Linux
+Download music in true lossless FLAC from Tidal, Qobuz & Amazon Music for Windows, macOS & Linux
+
+## FAQ
+
+**Q: Why is my download failing with "Song not found"?**  
+A: The track may not be available on Tidal, Qobuz, or Amazon Music. Try enabling more download services in Settings > Download > Provider Priority, or install additional extensions from the Store.
+
+**Q: Why are some tracks downloading in lower quality?**  
+A: Quality depends on what's available from the streaming service. Tidal offers up to 24-bit/192kHz, Qobuz up to 24-bit/192kHz, and Amazon up to 24-bit/48kHz. The app automatically selects the best available quality.
+
+**Q: Can I download playlists?**  
+A: Yes! Just paste the playlist URL in the search bar. The app will fetch all tracks and queue them for download.
+
+**Q: Why do I need to grant storage permission?**  
+A: The app needs permission to save downloaded files to your device. On Android 13+, you may need to grant "All files access" in Settings > Apps > SpotiFLAC > Permissions.
+
+**Q: Is this app safe?**  
+A: Yes, the app is open source and you can verify the code yourself. Each release is scanned with VirusTotal (see badge at top of README).
 
 [![Ko-fi](https://img.shields.io/badge/Ko--fi-Support%20Me-FF5E5B?style=for-the-badge&logo=ko-fi&logoColor=white)](https://ko-fi.com/zarzet)
 
 ## Disclaimer
 
-> **iOS Support**: This app is primarily tested on Android. iOS support is experimental and may have bugs — the developer is too poor to afford an iPhone for proper testing. If you encounter issues on iOS, please report them!
-
 This project is for **educational and private use only**. The developer does not condone or encourage copyright infringement.
 
-**SpotiFLAC** is a third-party tool and is not affiliated with, endorsed by, or connected to Spotify, Tidal, Qobuz, Amazon Music, or any other streaming service.
+**SpotiFLAC** is a third-party tool and is not affiliated with, endorsed by, or connected to Tidal, Qobuz, Amazon Music, Deezer, or any other streaming service.
+
+The application is purely a user interface that facilitates communication between your device and existing third-party services.
 
 You are solely responsible for:
 1. Ensuring your use of this software complies with your local laws.

android/app/build.gradle.kts

@@ -46,7 +46,7 @@ android {
     defaultConfig {
         applicationId = "com.zarz.spotiflac"
         minSdk = flutter.minSdkVersion
-        targetSdk = 34
+        targetSdk = 36
         versionCode = flutter.versionCode
         versionName = flutter.versionName
         multiDexEnabled = true

android/app/src/main/kotlin/com/zarz/spotiflac/DownloadService.kt

@@ -15,6 +15,9 @@ import androidx.core.app.NotificationCompat
 /**
  * Foreground service to keep downloads running when app is in background.
  * This prevents Android from killing the download process or throttling network.
+ * 
+ * Note: Android 15+ (API 35+) has a 6-hour timeout for dataSync foreground services.
+ * The service will be stopped automatically after 6 hours of cumulative runtime in 24 hours.
  */
 class DownloadService : Service() {
     
@@ -106,6 +109,19 @@ class DownloadService : Service() {
     
     override fun onBind(intent: Intent?): IBinder? = null
     
+    /**
+     * Called when the foreground service timeout is reached (Android 15+, API 35+).
+     * dataSync services have a 6-hour limit in a 24-hour period.
+     * We must call stopSelf() within a few seconds to avoid a crash.
+     */
+    override fun onTimeout(startId: Int, fgsType: Int) {
+        // Log the timeout for debugging
+        android.util.Log.w("DownloadService", "Foreground service timeout reached (6 hours limit). Stopping service.")
+        
+        // Gracefully stop the service
+        stopForegroundService()
+    }
+    
     private fun createNotificationChannel() {
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
             val channel = NotificationChannel(

android/app/src/main/kotlin/com/zarz/spotiflac/MainActivity.kt

@@ -117,6 +117,13 @@ class MainActivity: FlutterActivity() {
                             }
                             result.success(null)
                         }
+                        "cancelDownload" -> {
+                            val itemId = call.argument<String>("item_id") ?: ""
+                            withContext(Dispatchers.IO) {
+                                Gobackend.cancelDownload(itemId)
+                            }
+                            result.success(null)
+                        }
                         "setDownloadDirectory" -> {
                             val path = call.argument<String>("path") ?: ""
                             withContext(Dispatchers.IO) {
@@ -151,8 +158,9 @@ class MainActivity: FlutterActivity() {
                             val spotifyId = call.argument<String>("spotify_id") ?: ""
                             val trackName = call.argument<String>("track_name") ?: ""
                             val artistName = call.argument<String>("artist_name") ?: ""
+                            val durationMs = call.argument<Int>("duration_ms")?.toLong() ?: 0L
                             val response = withContext(Dispatchers.IO) {
-                                Gobackend.fetchLyrics(spotifyId, trackName, artistName)
+                                Gobackend.fetchLyrics(spotifyId, trackName, artistName, durationMs)
                             }
                             result.success(response)
                         }
@@ -161,8 +169,9 @@ class MainActivity: FlutterActivity() {
                             val trackName = call.argument<String>("track_name") ?: ""
                             val artistName = call.argument<String>("artist_name") ?: ""
                             val filePath = call.argument<String>("file_path") ?: ""
+                            val durationMs = call.argument<Int>("duration_ms")?.toLong() ?: 0L
                             val response = withContext(Dispatchers.IO) {
-                                Gobackend.getLyricsLRC(spotifyId, trackName, artistName, filePath)
+                                Gobackend.getLyricsLRC(spotifyId, trackName, artistName, filePath, durationMs)
                             }
                             result.success(response)
                         }
@@ -218,6 +227,12 @@ class MainActivity: FlutterActivity() {
                             }
                             result.success(null)
                         }
+                        "hasSpotifyCredentials" -> {
+                            val hasCredentials = withContext(Dispatchers.IO) {
+                                Gobackend.checkSpotifyCredentials()
+                            }
+                            result.success(hasCredentials)
+                        }
                         "preWarmTrackCache" -> {
                             val tracksJson = call.argument<String>("tracks") ?: "[]"
                             withContext(Dispatchers.IO) {
@@ -284,6 +299,370 @@ class MainActivity: FlutterActivity() {
                             }
                             result.success(response)
                         }
+                        // Log methods
+                        "getLogs" -> {
+                            val response = withContext(Dispatchers.IO) {
+                                Gobackend.getLogs()
+                            }
+                            result.success(response)
+                        }
+                        "getLogsSince" -> {
+                            val index = call.argument<Int>("index") ?: 0
+                            val response = withContext(Dispatchers.IO) {
+                                Gobackend.getLogsSince(index.toLong())
+                            }
+                            result.success(response)
+                        }
+                        "clearLogs" -> {
+                            withContext(Dispatchers.IO) {
+                                Gobackend.clearLogs()
+                            }
+                            result.success(null)
+                        }
+                        "getLogCount" -> {
+                            val count = withContext(Dispatchers.IO) {
+                                Gobackend.getLogCount()
+                            }
+                            result.success(count.toInt())
+                        }
+                        "setLoggingEnabled" -> {
+                            val enabled = call.argument<Boolean>("enabled") ?: false
+                            withContext(Dispatchers.IO) {
+                                Gobackend.setLoggingEnabled(enabled)
+                            }
+                            result.success(null)
+                        }
+                        // Extension System methods
+                        "initExtensionSystem" -> {
+                            val extensionsDir = call.argument<String>("extensions_dir") ?: ""
+                            val dataDir = call.argument<String>("data_dir") ?: ""
+                            withContext(Dispatchers.IO) {
+                                Gobackend.initExtensionSystem(extensionsDir, dataDir)
+                            }
+                            result.success(null)
+                        }
+                        "loadExtensionsFromDir" -> {
+                            val dirPath = call.argument<String>("dir_path") ?: ""
+                            val response = withContext(Dispatchers.IO) {
+                                Gobackend.loadExtensionsFromDir(dirPath)
+                            }
+                            result.success(response)
+                        }
+                        "loadExtensionFromPath" -> {
+                            val filePath = call.argument<String>("file_path") ?: ""
+                            val response = withContext(Dispatchers.IO) {
+                                Gobackend.loadExtensionFromPath(filePath)
+                            }
+                            result.success(response)
+                        }
+                        "unloadExtension" -> {
+                            val extensionId = call.argument<String>("extension_id") ?: ""
+                            withContext(Dispatchers.IO) {
+                                Gobackend.unloadExtensionByID(extensionId)
+                            }
+                            result.success(null)
+                        }
+                        "removeExtension" -> {
+                            val extensionId = call.argument<String>("extension_id") ?: ""
+                            withContext(Dispatchers.IO) {
+                                Gobackend.removeExtensionByID(extensionId)
+                            }
+                            result.success(null)
+                        }
+                        "upgradeExtension" -> {
+                            val filePath = call.argument<String>("file_path") ?: ""
+                            val response = withContext(Dispatchers.IO) {
+                                Gobackend.upgradeExtensionFromPath(filePath)
+                            }
+                            result.success(response)
+                        }
+                        "checkExtensionUpgrade" -> {
+                            val filePath = call.argument<String>("file_path") ?: ""
+                            val response = withContext(Dispatchers.IO) {
+                                Gobackend.checkExtensionUpgradeFromPath(filePath)
+                            }
+                            result.success(response)
+                        }
+                        "getInstalledExtensions" -> {
+                            val response = withContext(Dispatchers.IO) {
+                                Gobackend.getInstalledExtensions()
+                            }
+                            result.success(response)
+                        }
+                        "setExtensionEnabled" -> {
+                            val extensionId = call.argument<String>("extension_id") ?: ""
+                            val enabled = call.argument<Boolean>("enabled") ?: false
+                            withContext(Dispatchers.IO) {
+                                Gobackend.setExtensionEnabledByID(extensionId, enabled)
+                            }
+                            result.success(null)
+                        }
+                        "setProviderPriority" -> {
+                            val priorityJson = call.argument<String>("priority") ?: "[]"
+                            withContext(Dispatchers.IO) {
+                                Gobackend.setProviderPriorityJSON(priorityJson)
+                            }
+                            result.success(null)
+                        }
+                        "getProviderPriority" -> {
+                            val response = withContext(Dispatchers.IO) {
+                                Gobackend.getProviderPriorityJSON()
+                            }
+                            result.success(response)
+                        }
+                        "setMetadataProviderPriority" -> {
+                            val priorityJson = call.argument<String>("priority") ?: "[]"
+                            withContext(Dispatchers.IO) {
+                                Gobackend.setMetadataProviderPriorityJSON(priorityJson)
+                            }
+                            result.success(null)
+                        }
+                        "getMetadataProviderPriority" -> {
+                            val response = withContext(Dispatchers.IO) {
+                                Gobackend.getMetadataProviderPriorityJSON()
+                            }
+                            result.success(response)
+                        }
+                        "getExtensionSettings" -> {
+                            val extensionId = call.argument<String>("extension_id") ?: ""
+                            val response = withContext(Dispatchers.IO) {
+                                Gobackend.getExtensionSettingsJSON(extensionId)
+                            }
+                            result.success(response)
+                        }
+                        "setExtensionSettings" -> {
+                            val extensionId = call.argument<String>("extension_id") ?: ""
+                            val settingsJson = call.argument<String>("settings") ?: "{}"
+                            withContext(Dispatchers.IO) {
+                                Gobackend.setExtensionSettingsJSON(extensionId, settingsJson)
+                            }
+                            result.success(null)
+                        }
+                        "searchTracksWithExtensions" -> {
+                            val query = call.argument<String>("query") ?: ""
+                            val limit = call.argument<Int>("limit") ?: 20
+                            val response = withContext(Dispatchers.IO) {
+                                Gobackend.searchTracksWithExtensionsJSON(query, limit.toLong())
+                            }
+                            result.success(response)
+                        }
+                        "downloadWithExtensions" -> {
+                            val requestJson = call.arguments as String
+                            val response = withContext(Dispatchers.IO) {
+                                Gobackend.downloadWithExtensionsJSON(requestJson)
+                            }
+                            result.success(response)
+                        }
+                        "removeExtension" -> {
+                            val extensionId = call.argument<String>("extension_id") ?: ""
+                            withContext(Dispatchers.IO) {
+                                Gobackend.removeExtensionByID(extensionId)
+                            }
+                            result.success(null)
+                        }
+                        "cleanupExtensions" -> {
+                            withContext(Dispatchers.IO) {
+                                Gobackend.cleanupExtensions()
+                            }
+                            result.success(null)
+                        }
+                        // Extension Auth API methods
+                        "getExtensionPendingAuth" -> {
+                            val extensionId = call.argument<String>("extension_id") ?: ""
+                            val response = withContext(Dispatchers.IO) {
+                                Gobackend.getExtensionPendingAuthJSON(extensionId)
+                            }
+                            if (response.isNullOrEmpty()) {
+                                result.success(null)
+                            } else {
+                                result.success(response)
+                            }
+                        }
+                        "setExtensionAuthCode" -> {
+                            val extensionId = call.argument<String>("extension_id") ?: ""
+                            val authCode = call.argument<String>("auth_code") ?: ""
+                            withContext(Dispatchers.IO) {
+                                Gobackend.setExtensionAuthCodeByID(extensionId, authCode)
+                            }
+                            result.success(null)
+                        }
+                        "setExtensionTokens" -> {
+                            val extensionId = call.argument<String>("extension_id") ?: ""
+                            val accessToken = call.argument<String>("access_token") ?: ""
+                            val refreshToken = call.argument<String>("refresh_token") ?: ""
+                            val expiresIn = call.argument<Int>("expires_in") ?: 0
+                            withContext(Dispatchers.IO) {
+                                Gobackend.setExtensionTokensByID(extensionId, accessToken, refreshToken, expiresIn.toLong())
+                            }
+                            result.success(null)
+                        }
+                        "clearExtensionPendingAuth" -> {
+                            val extensionId = call.argument<String>("extension_id") ?: ""
+                            withContext(Dispatchers.IO) {
+                                Gobackend.clearExtensionPendingAuthByID(extensionId)
+                            }
+                            result.success(null)
+                        }
+                        "isExtensionAuthenticated" -> {
+                            val extensionId = call.argument<String>("extension_id") ?: ""
+                            val isAuth = withContext(Dispatchers.IO) {
+                                Gobackend.isExtensionAuthenticatedByID(extensionId)
+                            }
+                            result.success(isAuth)
+                        }
+                        "getAllPendingAuthRequests" -> {
+                            val response = withContext(Dispatchers.IO) {
+                                Gobackend.getAllPendingAuthRequestsJSON()
+                            }
+                            result.success(response)
+                        }
+                        // Extension FFmpeg API
+                        "getPendingFFmpegCommand" -> {
+                            val commandId = call.argument<String>("command_id") ?: ""
+                            val response = withContext(Dispatchers.IO) {
+                                Gobackend.getPendingFFmpegCommandJSON(commandId)
+                            }
+                            if (response.isNullOrEmpty()) {
+                                result.success(null)
+                            } else {
+                                result.success(response)
+                            }
+                        }
+                        "setFFmpegCommandResult" -> {
+                            val commandId = call.argument<String>("command_id") ?: ""
+                            val success = call.argument<Boolean>("success") ?: false
+                            val output = call.argument<String>("output") ?: ""
+                            val error = call.argument<String>("error") ?: ""
+                            withContext(Dispatchers.IO) {
+                                Gobackend.setFFmpegCommandResultByID(commandId, success, output, error)
+                            }
+                            result.success(null)
+                        }
+                        "getAllPendingFFmpegCommands" -> {
+                            val response = withContext(Dispatchers.IO) {
+                                Gobackend.getAllPendingFFmpegCommandsJSON()
+                            }
+                            result.success(response)
+                        }
+                        // Extension Custom Search API
+                        "customSearchWithExtension" -> {
+                            val extensionId = call.argument<String>("extension_id") ?: ""
+                            val query = call.argument<String>("query") ?: ""
+                            val optionsJson = call.argument<String>("options") ?: ""
+                            val response = withContext(Dispatchers.IO) {
+                                Gobackend.customSearchWithExtensionJSON(extensionId, query, optionsJson)
+                            }
+                            result.success(response)
+                        }
+                        "getSearchProviders" -> {
+                            val response = withContext(Dispatchers.IO) {
+                                Gobackend.getSearchProvidersJSON()
+                            }
+                            result.success(response)
+                        }
+                        // Extension URL Handler API
+                        "handleURLWithExtension" -> {
+                            val url = call.argument<String>("url") ?: ""
+                            val response = withContext(Dispatchers.IO) {
+                                Gobackend.handleURLWithExtensionJSON(url)
+                            }
+                            result.success(response)
+                        }
+                        "findURLHandler" -> {
+                            val url = call.argument<String>("url") ?: ""
+                            val response = withContext(Dispatchers.IO) {
+                                Gobackend.findURLHandlerJSON(url)
+                            }
+                            result.success(response)
+                        }
+                        "getURLHandlers" -> {
+                            val response = withContext(Dispatchers.IO) {
+                                Gobackend.getURLHandlersJSON()
+                            }
+                            result.success(response)
+                        }
+                        "getAlbumWithExtension" -> {
+                            val extensionId = call.argument<String>("extension_id") ?: ""
+                            val albumId = call.argument<String>("album_id") ?: ""
+                            val response = withContext(Dispatchers.IO) {
+                                Gobackend.getAlbumWithExtensionJSON(extensionId, albumId)
+                            }
+                            result.success(response)
+                        }
+                        "getPlaylistWithExtension" -> {
+                            val extensionId = call.argument<String>("extension_id") ?: ""
+                            val playlistId = call.argument<String>("playlist_id") ?: ""
+                            val response = withContext(Dispatchers.IO) {
+                                Gobackend.getPlaylistWithExtensionJSON(extensionId, playlistId)
+                            }
+                            result.success(response)
+                        }
+                        "getArtistWithExtension" -> {
+                            val extensionId = call.argument<String>("extension_id") ?: ""
+                            val artistId = call.argument<String>("artist_id") ?: ""
+                            val response = withContext(Dispatchers.IO) {
+                                Gobackend.getArtistWithExtensionJSON(extensionId, artistId)
+                            }
+                            result.success(response)
+                        }
+                        // Extension Post-Processing API
+                        "runPostProcessing" -> {
+                            val filePath = call.argument<String>("file_path") ?: ""
+                            val metadataJson = call.argument<String>("metadata") ?: ""
+                            val response = withContext(Dispatchers.IO) {
+                                Gobackend.runPostProcessingJSON(filePath, metadataJson)
+                            }
+                            result.success(response)
+                        }
+                        "getPostProcessingProviders" -> {
+                            val response = withContext(Dispatchers.IO) {
+                                Gobackend.getPostProcessingProvidersJSON()
+                            }
+                            result.success(response)
+                        }
+                        // Extension Store
+                        "initExtensionStore" -> {
+                            val cacheDir = call.argument<String>("cache_dir") ?: ""
+                            withContext(Dispatchers.IO) {
+                                Gobackend.initExtensionStoreJSON(cacheDir)
+                            }
+                            result.success(null)
+                        }
+                        "getStoreExtensions" -> {
+                            val forceRefresh = call.argument<Boolean>("force_refresh") ?: false
+                            val response = withContext(Dispatchers.IO) {
+                                Gobackend.getStoreExtensionsJSON(forceRefresh)
+                            }
+                            result.success(response)
+                        }
+                        "searchStoreExtensions" -> {
+                            val query = call.argument<String>("query") ?: ""
+                            val category = call.argument<String>("category") ?: ""
+                            val response = withContext(Dispatchers.IO) {
+                                Gobackend.searchStoreExtensionsJSON(query, category)
+                            }
+                            result.success(response)
+                        }
+                        "getStoreCategories" -> {
+                            val response = withContext(Dispatchers.IO) {
+                                Gobackend.getStoreCategoriesJSON()
+                            }
+                            result.success(response)
+                        }
+                        "downloadStoreExtension" -> {
+                            val extensionId = call.argument<String>("extension_id") ?: ""
+                            val destDir = call.argument<String>("dest_dir") ?: ""
+                            val response = withContext(Dispatchers.IO) {
+                                Gobackend.downloadStoreExtensionJSON(extensionId, destDir)
+                            }
+                            result.success(response)
+                        }
+                        "clearStoreCache" -> {
+                            withContext(Dispatchers.IO) {
+                                Gobackend.clearStoreCacheJSON()
+                            }
+                            result.success(null)
+                        }
                         else -> result.notImplemented()
                     }
                 } catch (e: Exception) {

crowdin.yml

@@ -0,0 +1,19 @@
+files:
+  - source: /lib/l10n/arb/app_en.arb
+    translation: /lib/l10n/arb/app_%locale%.arb
+    languages_mapping:
+      locale:
+        # Short codes for single-variant languages
+        de: de
+        es: es
+        fr: fr
+        hi: hi
+        id: id
+        ja: ja
+        ko: ko
+        nl: nl
+        pt: pt
+        ru: ru
+        # Full codes for Chinese variants
+        zh-CN: zh_CN
+        zh-TW: zh_TW

go_backend/amazon.go

@@ -2,8 +2,10 @@ package gobackend
 
 import (
 	"bufio"
+	"context"
 	"encoding/base64"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io"
 	"net/http"
@@ -25,10 +27,9 @@ type AmazonDownloader struct {
 }
 
 var (
-	// Global Amazon downloader instance for connection reuse
 	globalAmazonDownloader *AmazonDownloader
 	amazonDownloaderOnce   sync.Once
-	amazonRateLimitMu      sync.Mutex // Mutex for rate limiting
+	amazonRateLimitMu      sync.Mutex
 )
 
 // DoubleDoubleSubmitResponse is the response from DoubleDouble submit endpoint
@@ -53,17 +54,14 @@ func amazonArtistsMatch(expectedArtist, foundArtist string) bool {
 	normExpected := strings.ToLower(strings.TrimSpace(expectedArtist))
 	normFound := strings.ToLower(strings.TrimSpace(foundArtist))
 
-	// Exact match
 	if normExpected == normFound {
 		return true
 	}
 
-	// Check if one contains the other
 	if strings.Contains(normExpected, normFound) || strings.Contains(normFound, normExpected) {
 		return true
 	}
 
-	// Check first artist (before comma or feat)
 	expectedFirst := strings.Split(normExpected, ",")[0]
 	expectedFirst = strings.Split(expectedFirst, " feat")[0]
 	expectedFirst = strings.Split(expectedFirst, " ft.")[0]
@@ -78,17 +76,14 @@ func amazonArtistsMatch(expectedArtist, foundArtist string) bool {
 		return true
 	}
 
-	// Check if first artist is contained in the other
 	if strings.Contains(expectedFirst, foundFirst) || strings.Contains(foundFirst, expectedFirst) {
 		return true
 	}
 
-	// If scripts are different (one is ASCII, one is non-ASCII like Japanese/Chinese/Korean),
-	// assume they're the same artist with different transliteration
 	expectedASCII := amazonIsASCIIString(expectedArtist)
 	foundASCII := amazonIsASCIIString(foundArtist)
 	if expectedASCII != foundASCII {
-		fmt.Printf("[Amazon] Artist names in different scripts, assuming match: '%s' vs '%s'\n", expectedArtist, foundArtist)
+		GoLog("[Amazon] Artist names in different scripts, assuming match: '%s' vs '%s'\n", expectedArtist, foundArtist)
 		return true
 	}
 
@@ -125,7 +120,6 @@ func (a *AmazonDownloader) waitForRateLimit() {
 
 	now := time.Now()
 
-	// Reset counter every minute
 	if now.Sub(a.apiCallResetTime) >= time.Minute {
 		a.apiCallCount = 0
 		a.apiCallResetTime = now
@@ -135,7 +129,7 @@ func (a *AmazonDownloader) waitForRateLimit() {
 	if a.apiCallCount >= 9 {
 		waitTime := time.Minute - now.Sub(a.apiCallResetTime)
 		if waitTime > 0 {
-			fmt.Printf("[Amazon] Rate limit reached, waiting %v...\n", waitTime.Round(time.Second))
+			GoLog("[Amazon] Rate limit reached, waiting %v...\n", waitTime.Round(time.Second))
 			time.Sleep(waitTime)
 			a.apiCallCount = 0
 			a.apiCallResetTime = time.Now()
@@ -148,12 +142,11 @@ func (a *AmazonDownloader) waitForRateLimit() {
 		minDelay := 7 * time.Second
 		if timeSinceLastCall < minDelay {
 			waitTime := minDelay - timeSinceLastCall
-			fmt.Printf("[Amazon] Rate limiting: waiting %v...\n", waitTime.Round(time.Second))
+			GoLog("[Amazon] Rate limiting: waiting %v...\n", waitTime.Round(time.Second))
 			time.Sleep(waitTime)
 		}
 	}
 
-	// Update tracking
 	a.lastAPICallTime = time.Now()
 	a.apiCallCount++
 }
@@ -173,14 +166,12 @@ func (a *AmazonDownloader) GetAvailableAPIs() []string {
 // downloadFromDoubleDoubleService downloads a track using DoubleDouble service (same as PC)
 // This uses submit → poll → download mechanism
 // Internal function - not exported to gomobile
-func (a *AmazonDownloader) downloadFromDoubleDoubleService(amazonURL, outputDir string) (string, string, string, error) {
+func (a *AmazonDownloader) downloadFromDoubleDoubleService(amazonURL, _ string) (string, string, string, error) {
 	var lastError error
 
 	for _, region := range a.regions {
-		fmt.Printf("[Amazon] Trying region: %s...\n", region)
+		GoLog("[Amazon] Trying region: %s...\n", region)
 
-		// Build base URL for DoubleDouble service
-		// Decode base64 service URL (same as PC)
 		serviceBase, _ := base64.StdEncoding.DecodeString("aHR0cHM6Ly8=")               // https://
 		serviceDomain, _ := base64.StdEncoding.DecodeString("LmRvdWJsZWRvdWJsZS50b3A=") // .doubledouble.top
 		baseURL := fmt.Sprintf("%s%s%s", string(serviceBase), region, string(serviceDomain))
@@ -216,7 +207,7 @@ func (a *AmazonDownloader) downloadFromDoubleDoubleService(amazonURL, outputDir
 				resp.Body.Close()
 				if retry < maxRetries-1 {
 					waitTime := 15 * time.Second
-					fmt.Printf("[Amazon] Rate limited (429), waiting %v before retry %d/%d...\n", waitTime, retry+2, maxRetries)
+					GoLog("[Amazon] Rate limited (429), waiting %v before retry %d/%d...\n", waitTime, retry+2, maxRetries)
 					time.Sleep(waitTime)
 					continue
 				}
@@ -255,7 +246,7 @@ func (a *AmazonDownloader) downloadFromDoubleDoubleService(amazonURL, outputDir
 		}
 
 		downloadID := submitResp.ID
-		fmt.Printf("[Amazon] Download ID: %s\n", downloadID)
+		GoLog("[Amazon] Download ID: %s\n", downloadID)
 
 		// Step 2: Poll for completion
 		statusURL := fmt.Sprintf("%s/dl/%s", baseURL, downloadID)
@@ -299,7 +290,6 @@ func (a *AmazonDownloader) downloadFromDoubleDoubleService(amazonURL, outputDir
 			if status.Status == "done" {
 				fmt.Println("\n[Amazon] Download ready!")
 
-				// Build download URL
 				fileURL := status.URL
 				if strings.HasPrefix(fileURL, "./") {
 					fileURL = fmt.Sprintf("%s/%s", baseURL, fileURL[2:])
@@ -310,7 +300,7 @@ func (a *AmazonDownloader) downloadFromDoubleDoubleService(amazonURL, outputDir
 				trackName := status.Current.Name
 				artist := status.Current.Artist
 
-				fmt.Printf("[Amazon] Downloading: %s - %s\n", artist, trackName)
+				GoLog("[Amazon] Downloading: %s - %s\n", artist, trackName)
 				return fileURL, trackName, artist, nil
 
 			} else if status.Status == "error" {
@@ -346,13 +336,21 @@ func (a *AmazonDownloader) downloadFromDoubleDoubleService(amazonURL, outputDir
 
 // DownloadFile downloads a file from URL with User-Agent and progress tracking
 func (a *AmazonDownloader) DownloadFile(downloadURL, outputPath, itemID string) error {
+	ctx := context.Background()
+
 	// Initialize item progress (required for all downloads)
 	if itemID != "" {
 		StartItemProgress(itemID)
 		defer CompleteItemProgress(itemID)
+		ctx = initDownloadCancel(itemID)
+		defer clearDownloadCancel(itemID)
 	}
 
-	req, err := http.NewRequest("GET", downloadURL, nil)
+	if isDownloadCancelled(itemID) {
+		return ErrDownloadCancelled
+	}
+
+	req, err := http.NewRequestWithContext(ctx, "GET", downloadURL, nil)
 	if err != nil {
 		return fmt.Errorf("failed to create request: %w", err)
 	}
@@ -361,6 +359,9 @@ func (a *AmazonDownloader) DownloadFile(downloadURL, outputPath, itemID string)
 
 	resp, err := a.client.Do(req)
 	if err != nil {
+		if isDownloadCancelled(itemID) {
+			return ErrDownloadCancelled
+		}
 		return err
 	}
 	defer resp.Body.Close()
@@ -370,7 +371,6 @@ func (a *AmazonDownloader) DownloadFile(downloadURL, outputPath, itemID string)
 	}
 
 	expectedSize := resp.ContentLength
-	// Set total bytes if available
 	if expectedSize > 0 && itemID != "" {
 		SetItemBytesTotal(itemID, expectedSize)
 	}
@@ -380,16 +380,13 @@ func (a *AmazonDownloader) DownloadFile(downloadURL, outputPath, itemID string)
 		return err
 	}
 
-	// Use buffered writer for better performance (256KB buffer)
 	bufWriter := bufio.NewWriterSize(out, 256*1024)
 
-	// Use item progress writer with buffered output
 	var written int64
 	if itemID != "" {
 		pw := NewItemProgressWriter(bufWriter, itemID)
 		written, err = io.Copy(pw, resp.Body)
 	} else {
-		// Fallback: direct copy without progress tracking
 		written, err = io.Copy(bufWriter, resp.Body)
 	}
 
@@ -397,9 +394,11 @@ func (a *AmazonDownloader) DownloadFile(downloadURL, outputPath, itemID string)
 	flushErr := bufWriter.Flush()
 	closeErr := out.Close()
 
-	// Check for any errors
 	if err != nil {
 		os.Remove(outputPath)
+		if isDownloadCancelled(itemID) {
+			return ErrDownloadCancelled
+		}
 		return fmt.Errorf("download interrupted: %w", err)
 	}
 	if flushErr != nil {
@@ -440,24 +439,19 @@ type AmazonDownloadResult struct {
 func downloadFromAmazon(req DownloadRequest) (AmazonDownloadResult, error) {
 	downloader := NewAmazonDownloader()
 
-	// Check for existing file first
 	if existingFile, exists := checkISRCExistsInternal(req.OutputDir, req.ISRC); exists {
 		return AmazonDownloadResult{FilePath: "EXISTS:" + existingFile}, nil
 	}
 
-	// Get Amazon URL from SongLink
 	songlink := NewSongLinkClient()
 	var availability *TrackAvailability
 	var err error
 
-	// Check if SpotifyID is actually a Deezer ID (format: "deezer:xxxxx")
 	if strings.HasPrefix(req.SpotifyID, "deezer:") {
-		// Extract Deezer ID and use Deezer-based lookup
 		deezerID := strings.TrimPrefix(req.SpotifyID, "deezer:")
-		fmt.Printf("[Amazon] Using Deezer ID for SongLink lookup: %s\n", deezerID)
+		GoLog("[Amazon] Using Deezer ID for SongLink lookup: %s\n", deezerID)
 		availability, err = songlink.CheckAvailabilityFromDeezer(deezerID)
 	} else if req.SpotifyID != "" {
-		// Use Spotify ID
 		availability, err = songlink.CheckTrackAvailability(req.SpotifyID, req.ISRC)
 	} else {
 		return AmazonDownloadResult{}, fmt.Errorf("no valid Spotify or Deezer ID provided for Amazon lookup")
@@ -471,7 +465,6 @@ func downloadFromAmazon(req DownloadRequest) (AmazonDownloadResult, error) {
 		return AmazonDownloadResult{}, fmt.Errorf("track not available on Amazon Music (SongLink returned no Amazon URL)")
 	}
 
-	// Create output directory if needed
 	if req.OutputDir != "." {
 		if err := os.MkdirAll(req.OutputDir, 0755); err != nil {
 			return AmazonDownloadResult{}, fmt.Errorf("failed to create output directory: %w", err)
@@ -486,14 +479,12 @@ func downloadFromAmazon(req DownloadRequest) (AmazonDownloadResult, error) {
 
 	// Verify artist matches
 	if artistName != "" && !amazonArtistsMatch(req.ArtistName, artistName) {
-		fmt.Printf("[Amazon] Artist mismatch: expected '%s', got '%s'. Rejecting.\n", req.ArtistName, artistName)
+		GoLog("[Amazon] Artist mismatch: expected '%s', got '%s'. Rejecting.\n", req.ArtistName, artistName)
 		return AmazonDownloadResult{}, fmt.Errorf("artist mismatch: expected '%s', got '%s'", req.ArtistName, artistName)
 	}
 
-	// Log match found
-	fmt.Printf("[Amazon] Match found: '%s' by '%s'\n", trackName, artistName)
+	GoLog("[Amazon] Match found: '%s' by '%s'\n", trackName, artistName)
 
-	// Build filename using Spotify metadata (more accurate)
 	filename := buildFilenameFromTemplate(req.FilenameFormat, map[string]interface{}{
 		"title":  req.TrackName,
 		"artist": req.ArtistName,
@@ -505,7 +496,6 @@ func downloadFromAmazon(req DownloadRequest) (AmazonDownloadResult, error) {
 	filename = sanitizeFilename(filename) + ".flac"
 	outputPath := filepath.Join(req.OutputDir, filename)
 
-	// Check if file already exists
 	if fileInfo, statErr := os.Stat(outputPath); statErr == nil && fileInfo.Size() > 0 {
 		return AmazonDownloadResult{FilePath: "EXISTS:" + outputPath}, nil
 	}
@@ -522,19 +512,21 @@ func downloadFromAmazon(req DownloadRequest) (AmazonDownloadResult, error) {
 			req.TrackName,
 			req.ArtistName,
 			req.EmbedLyrics,
+			int64(req.DurationMS),
 		)
 	}()
 
 	// Download audio file with item ID for progress tracking
 	if err := downloader.DownloadFile(downloadURL, outputPath, req.ItemID); err != nil {
+		if errors.Is(err, ErrDownloadCancelled) {
+			return AmazonDownloadResult{}, ErrDownloadCancelled
+		}
 		return AmazonDownloadResult{}, fmt.Errorf("download failed: %w", err)
 	}
 
 	// Wait for parallel operations to complete
 	<-parallelDone
 
-	// Set progress to 100% and status to finalizing (before embedding)
-	// This makes the UI show "Finalizing..." while embedding happens
 	if req.ItemID != "" {
 		SetItemProgress(req.ItemID, 1.0, 0, 0)
 		SetItemFinalizing(req.ItemID)
@@ -542,24 +534,21 @@ func downloadFromAmazon(req DownloadRequest) (AmazonDownloadResult, error) {
 
 	// Log track info from DoubleDouble (for debugging)
 	if trackName != "" && artistName != "" {
-		fmt.Printf("[Amazon] DoubleDouble returned: %s - %s\n", artistName, trackName)
+		GoLog("[Amazon] DoubleDouble returned: %s - %s\n", artistName, trackName)
 	}
 
-	// Read existing metadata from downloaded file BEFORE embedding
-	// Amazon/DoubleDouble files often have correct track/disc numbers that we should preserve
 	existingMeta, metaErr := ReadMetadata(outputPath)
 	actualTrackNum := req.TrackNumber
 	actualDiscNum := req.DiscNumber
 
 	if metaErr == nil && existingMeta != nil {
-		// Use file metadata if it has valid track/disc numbers and request doesn't have them
 		if existingMeta.TrackNumber > 0 && (req.TrackNumber == 0 || req.TrackNumber == 1) {
 			actualTrackNum = existingMeta.TrackNumber
-			fmt.Printf("[Amazon] Using track number from file: %d (request had: %d)\n", actualTrackNum, req.TrackNumber)
+			GoLog("[Amazon] Using track number from file: %d (request had: %d)\n", actualTrackNum, req.TrackNumber)
 		}
 		if existingMeta.DiscNumber > 0 && (req.DiscNumber == 0 || req.DiscNumber == 1) {
 			actualDiscNum = existingMeta.DiscNumber
-			fmt.Printf("[Amazon] Using disc number from file: %d (request had: %d)\n", actualDiscNum, req.DiscNumber)
+			GoLog("[Amazon] Using disc number from file: %d (request had: %d)\n", actualDiscNum, req.DiscNumber)
 		}
 	}
 
@@ -581,7 +570,7 @@ func downloadFromAmazon(req DownloadRequest) (AmazonDownloadResult, error) {
 	var coverData []byte
 	if parallelResult != nil && parallelResult.CoverData != nil {
 		coverData = parallelResult.CoverData
-		fmt.Printf("[Amazon] Using parallel-fetched cover (%d bytes)\n", len(coverData))
+		GoLog("[Amazon] Using parallel-fetched cover (%d bytes)\n", len(coverData))
 	}
 
 	if err := EmbedMetadataWithCoverData(outputPath, metadata, coverData); err != nil {
@@ -590,9 +579,9 @@ func downloadFromAmazon(req DownloadRequest) (AmazonDownloadResult, error) {
 
 	// Embed lyrics from parallel fetch
 	if req.EmbedLyrics && parallelResult != nil && parallelResult.LyricsLRC != "" {
-		fmt.Printf("[Amazon] Embedding parallel-fetched lyrics (%d lines)...\n", len(parallelResult.LyricsData.Lines))
+		GoLog("[Amazon] Embedding parallel-fetched lyrics (%d lines)...\n", len(parallelResult.LyricsData.Lines))
 		if embedErr := EmbedLyrics(outputPath, parallelResult.LyricsLRC); embedErr != nil {
-			fmt.Printf("[Amazon] Warning: failed to embed lyrics: %v\n", embedErr)
+			GoLog("[Amazon] Warning: failed to embed lyrics: %v\n", embedErr)
 		} else {
 			fmt.Println("[Amazon] Lyrics embedded successfully")
 		}
@@ -602,25 +591,20 @@ func downloadFromAmazon(req DownloadRequest) (AmazonDownloadResult, error) {
 
 	fmt.Println("[Amazon] ✓ Downloaded successfully from Amazon Music")
 
-	// Read actual quality from the downloaded FLAC file
-	// Amazon API doesn't provide quality info, but we can read it from the file itself
 	quality, err := GetAudioQuality(outputPath)
 	if err != nil {
-		fmt.Printf("[Amazon] Warning: couldn't read quality from file: %v\n", err)
+		GoLog("[Amazon] Warning: couldn't read quality from file: %v\n", err)
 	} else {
-		fmt.Printf("[Amazon] Actual quality: %d-bit/%dHz\n", quality.BitDepth, quality.SampleRate)
+		GoLog("[Amazon] Actual quality: %d-bit/%dHz\n", quality.BitDepth, quality.SampleRate)
 	}
 
-	// Read metadata from file AFTER embedding to get accurate values
-	// This ensures we return what's actually in the file
 	finalMeta, metaReadErr := ReadMetadata(outputPath)
 	if metaReadErr == nil && finalMeta != nil {
-		fmt.Printf("[Amazon] Final metadata from file - Track: %d, Disc: %d, Date: %s\n",
+		GoLog("[Amazon] Final metadata from file - Track: %d, Disc: %d, Date: %s\n",
 			finalMeta.TrackNumber, finalMeta.DiscNumber, finalMeta.Date)
 		actualTrackNum = finalMeta.TrackNumber
 		actualDiscNum = finalMeta.DiscNumber
 		if finalMeta.Date != "" {
-			// Use date from file if available
 			req.ReleaseDate = finalMeta.Date
 		}
 	}

go_backend/cancel.go

@@ -0,0 +1,78 @@
+package gobackend
+
+import (
+	"context"
+	"errors"
+	"sync"
+)
+
+// ErrDownloadCancelled is returned when a download is cancelled by the user.
+var ErrDownloadCancelled = errors.New("download cancelled")
+
+type cancelEntry struct {
+	cancel   context.CancelFunc
+	canceled bool
+}
+
+var (
+	cancelMu  sync.Mutex
+	cancelMap = make(map[string]*cancelEntry)
+)
+
+func initDownloadCancel(itemID string) context.Context {
+	if itemID == "" {
+		return context.Background()
+	}
+
+	cancelMu.Lock()
+	defer cancelMu.Unlock()
+
+	ctx, cancel := context.WithCancel(context.Background())
+	cancelMap[itemID] = &cancelEntry{
+		cancel:   cancel,
+		canceled: false,
+	}
+	return ctx
+}
+
+func cancelDownload(itemID string) {
+	if itemID == "" {
+		return
+	}
+
+	cancelMu.Lock()
+	entry, ok := cancelMap[itemID]
+	if ok {
+		entry.canceled = true
+		if entry.cancel != nil {
+			entry.cancel()
+		}
+	} else {
+		cancelMap[itemID] = &cancelEntry{canceled: true}
+	}
+	cancelMu.Unlock()
+
+	RemoveItemProgress(itemID)
+}
+
+func isDownloadCancelled(itemID string) bool {
+	if itemID == "" {
+		return false
+	}
+
+	cancelMu.Lock()
+	entry, ok := cancelMap[itemID]
+	canceled := ok && entry.canceled
+	cancelMu.Unlock()
+	return canceled
+}
+
+func clearDownloadCancel(itemID string) {
+	if itemID == "" {
+		return
+	}
+
+	cancelMu.Lock()
+	delete(cancelMap, itemID)
+	cancelMu.Unlock()
+}

go_backend/cover.go

@@ -4,15 +4,29 @@ import (
 	"fmt"
 	"io"
 	"net/http"
+	"regexp"
 	"strings"
 )
 
 // Spotify image size codes (same as PC version)
 const (
-	spotifySize640 = "ab67616d0000b273" // 640x640
+	spotifySize300 = "ab67616d00001e02" // 300x300 (small)
+	spotifySize640 = "ab67616d0000b273" // 640x640 (medium)
 	spotifySizeMax = "ab67616d000082c1" // Max resolution (~2000x2000)
 )
 
+// Deezer CDN supports these sizes: 56, 250, 500, 1000, 1400, 1800
+var deezerSizeRegex = regexp.MustCompile(`/(\d+)x(\d+)-\d+-\d+-\d+-\d+\.jpg$`)
+
+// convertSmallToMedium upgrades 300x300 cover URL to 640x640
+// Same logic as PC version for consistency
+func convertSmallToMedium(imageURL string) string {
+	if strings.Contains(imageURL, spotifySize300) {
+		return strings.Replace(imageURL, spotifySize300, spotifySize640, 1)
+	}
+	return imageURL
+}
+
 // downloadCoverToMemory downloads cover art and returns as bytes (no file creation)
 // This avoids file permission issues on Android
 func downloadCoverToMemory(coverURL string, maxQuality bool) ([]byte, error) {
@@ -20,20 +34,28 @@ func downloadCoverToMemory(coverURL string, maxQuality bool) ([]byte, error) {
 		return nil, fmt.Errorf("no cover URL provided")
 	}
 
-	fmt.Printf("[Cover] Downloading cover from: %s\n", coverURL)
+	GoLog("[Cover] Original URL: %s", coverURL)
+
+	downloadURL := convertSmallToMedium(coverURL)
+	if downloadURL != coverURL {
+		GoLog("[Cover] Upgraded 300x300 → 640x640")
+	}
 
-	// Upgrade to max quality if requested
-	downloadURL := coverURL
 	if maxQuality {
-		downloadURL = upgradeToMaxQuality(coverURL)
-		if downloadURL != coverURL {
-			fmt.Printf("[Cover] Upgraded to max quality URL: %s\n", downloadURL)
+		maxURL := upgradeToMaxQuality(downloadURL)
+		if maxURL != downloadURL {
+			downloadURL = maxURL
+			// Log already printed by upgradeToMaxQuality for Deezer
+			if strings.Contains(coverURL, "scdn.co") || strings.Contains(coverURL, "spotifycdn") {
+				GoLog("[Cover] Spotify: upgraded to max resolution (~2000x2000)")
+			}
 		}
 	}
 
+	GoLog("[Cover] Final URL: %s", downloadURL)
+
 	client := NewHTTPClientWithTimeout(DefaultTimeout)
 
-	// Create request with User-Agent (required by Spotify CDN)
 	req, err := http.NewRequest("GET", downloadURL, nil)
 	if err != nil {
 		return nil, fmt.Errorf("failed to create request: %w", err)
@@ -54,48 +76,64 @@ func downloadCoverToMemory(coverURL string, maxQuality bool) ([]byte, error) {
 		return nil, fmt.Errorf("failed to read cover data: %w", err)
 	}
 
-	fmt.Printf("[Cover] Downloaded %d bytes\n", len(data))
+	sizeKB := len(data) / 1024
+	var resolution string
+	if sizeKB > 200 {
+		resolution = "~2000x2000 (hi-res)"
+	} else if sizeKB > 50 {
+		resolution = "~640x640"
+	} else {
+		resolution = "~300x300"
+	}
+	GoLog("[Cover] Downloaded %d KB (%s)", sizeKB, resolution)
+
 	return data, nil
 }
 
-// upgradeToMaxQuality upgrades Spotify cover URL to maximum quality
-// Uses same logic as PC version - replaces 640x640 size code with max resolution
+// upgradeToMaxQuality upgrades cover URL to maximum quality
+// Supports both Spotify and Deezer CDNs
 func upgradeToMaxQuality(coverURL string) string {
-	// Spotify image URLs can be upgraded by changing the size parameter
-	// Format: https://i.scdn.co/image/ab67616d0000b273...
-	// ab67616d0000b273 = 640x640
-	// ab67616d000082c1 = Max resolution (~2000x2000)
-
+	// Spotify CDN upgrade
 	if strings.Contains(coverURL, spotifySize640) {
-		// Try max resolution first
-		maxURL := strings.Replace(coverURL, spotifySize640, spotifySizeMax, 1)
+		return strings.Replace(coverURL, spotifySize640, spotifySizeMax, 1)
+	}
 
-		// Verify max resolution URL is available
-		client := NewHTTPClientWithTimeout(DefaultTimeout)
-		req, err := http.NewRequest("HEAD", maxURL, nil)
-		if err == nil {
-			resp, err := DoRequestWithUserAgent(client, req)
-			if err == nil {
-				resp.Body.Close()
-				if resp.StatusCode == http.StatusOK {
-					return maxURL
-				}
-			}
-		}
+	// Deezer CDN upgrade
+	if strings.Contains(coverURL, "cdn-images.dzcdn.net") {
+		return upgradeDeezerCover(coverURL)
 	}
 
 	return coverURL
 }
 
+// upgradeDeezerCover upgrades Deezer cover URL to maximum quality (1800x1800)
+// Deezer CDN format: https://cdn-images.dzcdn.net/images/cover/{hash}/{size}x{size}-000000-80-0-0.jpg
+// Available sizes: 56, 250, 500, 1000, 1400, 1800
+func upgradeDeezerCover(coverURL string) string {
+	if !strings.Contains(coverURL, "cdn-images.dzcdn.net") {
+		return coverURL
+	}
+
+	// Replace any size pattern with 1800x1800
+	upgraded := deezerSizeRegex.ReplaceAllString(coverURL, "/1800x1800-000000-80-0-0.jpg")
+	if upgraded != coverURL {
+		GoLog("[Cover] Deezer: upgraded to 1800x1800")
+	}
+	return upgraded
+}
+
 // GetCoverFromSpotify gets cover URL from Spotify metadata
 func GetCoverFromSpotify(imageURL string, maxQuality bool) string {
 	if imageURL == "" {
 		return ""
 	}
 
+	// Always upgrade small to medium first
+	result := convertSmallToMedium(imageURL)
+
 	if maxQuality {
-		return upgradeToMaxQuality(imageURL)
+		result = upgradeToMaxQuality(result)
 	}
 
-	return imageURL
+	return result
 }

go_backend/deezer.go

@@ -19,11 +19,10 @@ const (
 	deezerAlbumURL    = deezerBaseURL + "/album/%s"
 	deezerArtistURL   = deezerBaseURL + "/artist/%s"
 	deezerPlaylistURL = deezerBaseURL + "/playlist/%s"
-	
+
 	deezerCacheTTL = 10 * time.Minute
-	
-	// Parallel ISRC fetching settings
-	deezerMaxParallelISRC = 10 // Max concurrent ISRC fetches
+
+	deezerMaxParallelISRC = 10
 )
 
 // DeezerClient handles Deezer API interactions (no auth required)
@@ -36,7 +35,6 @@ type DeezerClient struct {
 	cacheMu     sync.RWMutex
 }
 
-// Singleton instance
 var (
 	deezerClient     *DeezerClient
 	deezerClientOnce sync.Once
@@ -58,27 +56,27 @@ func GetDeezerClient() *DeezerClient {
 
 // Deezer API response types
 type deezerTrack struct {
-	ID             int64  `json:"id"`
-	Title          string `json:"title"`
-	Duration       int    `json:"duration"` // in seconds
-	TrackPosition  int    `json:"track_position"`
-	DiskNumber     int    `json:"disk_number"`
-	ISRC           string `json:"isrc"`
-	Link           string `json:"link"`
-	ReleaseDate    string `json:"release_date"` // Sometimes at track level
-	Artist         deezerArtist `json:"artist"`
-	Album          deezerAlbumSimple `json:"album"`
-	Contributors   []deezerArtist `json:"contributors"`
+	ID            int64             `json:"id"`
+	Title         string            `json:"title"`
+	Duration      int               `json:"duration"` // in seconds
+	TrackPosition int               `json:"track_position"`
+	DiskNumber    int               `json:"disk_number"`
+	ISRC          string            `json:"isrc"`
+	Link          string            `json:"link"`
+	ReleaseDate   string            `json:"release_date"` // Sometimes at track level
+	Artist        deezerArtist      `json:"artist"`
+	Album         deezerAlbumSimple `json:"album"`
+	Contributors  []deezerArtist    `json:"contributors"`
 }
 
 type deezerArtist struct {
-	ID        int64  `json:"id"`
-	Name      string `json:"name"`
-	Picture   string `json:"picture"`
+	ID            int64  `json:"id"`
+	Name          string `json:"name"`
+	Picture       string `json:"picture"`
 	PictureMedium string `json:"picture_medium"`
 	PictureBig    string `json:"picture_big"`
 	PictureXL     string `json:"picture_xl"`
-	NbFan     int    `json:"nb_fan"`
+	NbFan         int    `json:"nb_fan"`
 }
 
 type deezerAlbumSimple struct {
@@ -89,10 +87,9 @@ type deezerAlbumSimple struct {
 	CoverBig    string `json:"cover_big"`
 	CoverXL     string `json:"cover_xl"`
 	ReleaseDate string `json:"release_date"` // Sometimes at album level
+	RecordType  string `json:"record_type"`  // album, single, ep, compile
 }
-// ... (skip other structs as they are fine/unchanged) ...
 
-// ... (in convertTrack) ...
 func (c *DeezerClient) convertTrack(track deezerTrack) TrackMetadata {
 	artistName := track.Artist.Name
 	if len(track.Contributors) > 0 {
@@ -113,8 +110,7 @@ func (c *DeezerClient) convertTrack(track deezerTrack) TrackMetadata {
 	if albumImage == "" {
 		albumImage = track.Album.Cover
 	}
-	
-	// Try to find release date
+
 	releaseDate := track.ReleaseDate
 	if releaseDate == "" {
 		releaseDate = track.Album.ReleaseDate
@@ -137,17 +133,18 @@ func (c *DeezerClient) convertTrack(track deezerTrack) TrackMetadata {
 }
 
 type deezerAlbumFull struct {
-	ID          int64  `json:"id"`
-	Title       string `json:"title"`
-	Cover       string `json:"cover"`
-	CoverMedium string `json:"cover_medium"`
-	CoverBig    string `json:"cover_big"`
-	CoverXL     string `json:"cover_xl"`
-	ReleaseDate string `json:"release_date"`
-	NbTracks    int    `json:"nb_tracks"`
-	Artist      deezerArtist `json:"artist"`
+	ID           int64          `json:"id"`
+	Title        string         `json:"title"`
+	Cover        string         `json:"cover"`
+	CoverMedium  string         `json:"cover_medium"`
+	CoverBig     string         `json:"cover_big"`
+	CoverXL      string         `json:"cover_xl"`
+	ReleaseDate  string         `json:"release_date"`
+	NbTracks     int            `json:"nb_tracks"`
+	RecordType   string         `json:"record_type"` // album, single, ep, compile
+	Artist       deezerArtist   `json:"artist"`
 	Contributors []deezerArtist `json:"contributors"`
-	Tracks      struct {
+	Tracks       struct {
 		Data []deezerTrack `json:"data"`
 	} `json:"tracks"`
 }
@@ -164,17 +161,17 @@ type deezerArtistFull struct {
 }
 
 type deezerPlaylistFull struct {
-	ID          int64  `json:"id"`
-	Title       string `json:"title"`
-	Picture     string `json:"picture"`
+	ID            int64  `json:"id"`
+	Title         string `json:"title"`
+	Picture       string `json:"picture"`
 	PictureMedium string `json:"picture_medium"`
 	PictureBig    string `json:"picture_big"`
 	PictureXL     string `json:"picture_xl"`
-	NbTracks    int    `json:"nb_tracks"`
-	Creator     struct {
+	NbTracks      int    `json:"nb_tracks"`
+	Creator       struct {
 		Name string `json:"name"`
 	} `json:"creator"`
-	Tracks      struct {
+	Tracks struct {
 		Data []deezerTrack `json:"data"`
 	} `json:"tracks"`
 }
@@ -182,11 +179,14 @@ type deezerPlaylistFull struct {
 // SearchAll searches for tracks and artists on Deezer
 // NOTE: ISRC is NOT fetched during search for performance - use GetTrackISRC when needed for download
 func (c *DeezerClient) SearchAll(ctx context.Context, query string, trackLimit, artistLimit int) (*SearchAllResult, error) {
+	GoLog("[Deezer] SearchAll: query=%q, trackLimit=%d, artistLimit=%d\n", query, trackLimit, artistLimit)
+
 	cacheKey := fmt.Sprintf("deezer:all:%s:%d:%d", query, trackLimit, artistLimit)
-	
+
 	c.cacheMu.RLock()
 	if entry, ok := c.searchCache[cacheKey]; ok && !entry.isExpired() {
 		c.cacheMu.RUnlock()
+		GoLog("[Deezer] SearchAll: returning cached result\n")
 		return entry.data.(*SearchAllResult), nil
 	}
 	c.cacheMu.RUnlock()
@@ -198,13 +198,28 @@ func (c *DeezerClient) SearchAll(ctx context.Context, query string, trackLimit,
 
 	// Search tracks - NO ISRC fetch for performance
 	trackURL := fmt.Sprintf("%s/track?q=%s&limit=%d", deezerSearchURL, url.QueryEscape(query), trackLimit)
+	GoLog("[Deezer] Fetching tracks from: %s\n", trackURL)
+
 	var trackResp struct {
-		Data []deezerTrack `json:"data"`
+		Data  []deezerTrack `json:"data"`
+		Error *struct {
+			Type    string `json:"type"`
+			Message string `json:"message"`
+			Code    int    `json:"code"`
+		} `json:"error"`
 	}
 	if err := c.getJSON(ctx, trackURL, &trackResp); err != nil {
+		GoLog("[Deezer] Track search failed: %v\n", err)
 		return nil, fmt.Errorf("deezer track search failed: %w", err)
 	}
 
+	if trackResp.Error != nil {
+		GoLog("[Deezer] API error: type=%s, code=%d, message=%s\n", trackResp.Error.Type, trackResp.Error.Code, trackResp.Error.Message)
+		return nil, fmt.Errorf("deezer API error: %s (code %d)", trackResp.Error.Message, trackResp.Error.Code)
+	}
+
+	GoLog("[Deezer] Got %d tracks from API\n", len(trackResp.Data))
+
 	for _, track := range trackResp.Data {
 		// Convert directly without fetching ISRC - much faster
 		result.Tracks = append(result.Tracks, c.convertTrack(track))
@@ -212,21 +227,37 @@ func (c *DeezerClient) SearchAll(ctx context.Context, query string, trackLimit,
 
 	// Search artists
 	artistURL := fmt.Sprintf("%s/artist?q=%s&limit=%d", deezerSearchURL, url.QueryEscape(query), artistLimit)
+	GoLog("[Deezer] Fetching artists from: %s\n", artistURL)
+
 	var artistResp struct {
-		Data []deezerArtist `json:"data"`
+		Data  []deezerArtist `json:"data"`
+		Error *struct {
+			Type    string `json:"type"`
+			Message string `json:"message"`
+			Code    int    `json:"code"`
+		} `json:"error"`
 	}
 	if err := c.getJSON(ctx, artistURL, &artistResp); err == nil {
-		for _, artist := range artistResp.Data {
-			result.Artists = append(result.Artists, SearchArtistResult{
-				ID:         fmt.Sprintf("deezer:%d", artist.ID),
-				Name:       artist.Name,
-				Images:     c.getBestArtistImage(artist),
-				Followers:  artist.NbFan,
-				Popularity: 0,
-			})
+		if artistResp.Error != nil {
+			GoLog("[Deezer] Artist API error: type=%s, code=%d, message=%s\n", artistResp.Error.Type, artistResp.Error.Code, artistResp.Error.Message)
+		} else {
+			GoLog("[Deezer] Got %d artists from API\n", len(artistResp.Data))
+			for _, artist := range artistResp.Data {
+				result.Artists = append(result.Artists, SearchArtistResult{
+					ID:         fmt.Sprintf("deezer:%d", artist.ID),
+					Name:       artist.Name,
+					Images:     c.getBestArtistImage(artist),
+					Followers:  artist.NbFan,
+					Popularity: 0,
+				})
+			}
 		}
+	} else {
+		GoLog("[Deezer] Artist search failed: %v\n", err)
 	}
 
+	GoLog("[Deezer] SearchAll complete: %d tracks, %d artists\n", len(result.Tracks), len(result.Artists))
+
 	// Cache result
 	c.cacheMu.Lock()
 	c.searchCache[cacheKey] = &cacheEntry{
@@ -241,7 +272,7 @@ func (c *DeezerClient) SearchAll(ctx context.Context, query string, trackLimit,
 // GetTrack fetches a single track by Deezer ID
 func (c *DeezerClient) GetTrack(ctx context.Context, trackID string) (*TrackResponse, error) {
 	trackURL := fmt.Sprintf(deezerTrackURL, trackID)
-	
+
 	var track deezerTrack
 	if err := c.getJSON(ctx, trackURL, &track); err != nil {
 		return nil, err
@@ -263,7 +294,7 @@ func (c *DeezerClient) GetAlbum(ctx context.Context, albumID string) (*AlbumResp
 	c.cacheMu.RUnlock()
 
 	albumURL := fmt.Sprintf(deezerAlbumURL, albumID)
-	
+
 	var album deezerAlbumFull
 	if err := c.getJSON(ctx, albumURL, &album); err != nil {
 		return nil, err
@@ -291,6 +322,12 @@ func (c *DeezerClient) GetAlbum(ctx context.Context, albumID string) (*AlbumResp
 	isrcMap := c.fetchISRCsParallel(ctx, album.Tracks.Data)
 
 	tracks := make([]AlbumTrackMetadata, 0, len(album.Tracks.Data))
+	// Normalize record_type (Deezer uses "compile" instead of "compilation")
+	albumType := album.RecordType
+	if albumType == "compile" {
+		albumType = "compilation"
+	}
+
 	for _, track := range album.Tracks.Data {
 		trackIDStr := fmt.Sprintf("%d", track.ID)
 		isrc := isrcMap[trackIDStr]
@@ -310,6 +347,7 @@ func (c *DeezerClient) GetAlbum(ctx context.Context, albumID string) (*AlbumResp
 			ExternalURL: track.Link,
 			ISRC:        isrc,
 			AlbumID:     fmt.Sprintf("deezer:%d", album.ID),
+			AlbumType:   albumType,
 		})
 	}
 
@@ -375,7 +413,7 @@ func (c *DeezerClient) GetArtist(ctx context.Context, artistID string) (*ArtistR
 			if albumType == "compile" {
 				albumType = "compilation"
 			}
-			
+
 			coverURL := album.CoverXL
 			if coverURL == "" {
 				coverURL = album.CoverBig
@@ -418,7 +456,7 @@ func (c *DeezerClient) GetArtist(ctx context.Context, artistID string) (*ArtistR
 // ISRC is fetched in parallel for better performance
 func (c *DeezerClient) GetPlaylist(ctx context.Context, playlistID string) (*PlaylistResponsePayload, error) {
 	playlistURL := fmt.Sprintf(deezerPlaylistURL, playlistID)
-	
+
 	var playlist deezerPlaylistFull
 	if err := c.getJSON(ctx, playlistURL, &playlist); err != nil {
 		return nil, err
@@ -482,7 +520,7 @@ func (c *DeezerClient) SearchByISRC(ctx context.Context, isrc string) (*TrackMet
 	// Use direct ISRC endpoint (API 2.0)
 	// https://api.deezer.com/2.0/track/isrc:{ISRC}
 	directURL := fmt.Sprintf("%s/track/isrc:%s", deezerBaseURL, isrc)
-	
+
 	var track deezerTrack
 	if err := c.getJSON(ctx, directURL, &track); err != nil {
 		// Fallback to search if direct endpoint fails
@@ -500,7 +538,6 @@ func (c *DeezerClient) SearchByISRC(ctx context.Context, isrc string) (*TrackMet
 		return &result, nil
 	}
 
-	// Check if we got a valid response (ID > 0)
 	if track.ID == 0 {
 		return nil, fmt.Errorf("no track found for ISRC: %s", isrc)
 	}
@@ -522,8 +559,7 @@ func (c *DeezerClient) fetchFullTrack(ctx context.Context, trackID string) (*dee
 func (c *DeezerClient) fetchISRCsParallel(ctx context.Context, tracks []deezerTrack) map[string]string {
 	result := make(map[string]string)
 	var resultMu sync.Mutex
-	
-	// First, check cache for existing ISRCs
+
 	var tracksToFetch []deezerTrack
 	c.cacheMu.RLock()
 	for _, track := range tracks {
@@ -535,20 +571,20 @@ func (c *DeezerClient) fetchISRCsParallel(ctx context.Context, tracks []deezerTr
 		}
 	}
 	c.cacheMu.RUnlock()
-	
+
 	if len(tracksToFetch) == 0 {
 		return result
 	}
-	
+
 	// Use semaphore to limit concurrent requests
 	sem := make(chan struct{}, deezerMaxParallelISRC)
 	var wg sync.WaitGroup
-	
+
 	for _, track := range tracksToFetch {
 		wg.Add(1)
 		go func(t deezerTrack) {
 			defer wg.Done()
-			
+
 			// Acquire semaphore
 			select {
 			case sem <- struct{}{}:
@@ -556,24 +592,24 @@ func (c *DeezerClient) fetchISRCsParallel(ctx context.Context, tracks []deezerTr
 			case <-ctx.Done():
 				return
 			}
-			
+
 			trackIDStr := fmt.Sprintf("%d", t.ID)
 			fullTrack, err := c.fetchFullTrack(ctx, trackIDStr)
 			if err != nil || fullTrack == nil {
 				return
 			}
-			
+
 			// Store in result and cache
 			resultMu.Lock()
 			result[trackIDStr] = fullTrack.ISRC
 			resultMu.Unlock()
-			
+
 			c.cacheMu.Lock()
 			c.isrcCache[trackIDStr] = fullTrack.ISRC
 			c.cacheMu.Unlock()
 		}(track)
 	}
-	
+
 	wg.Wait()
 	return result
 }
@@ -581,30 +617,27 @@ func (c *DeezerClient) fetchISRCsParallel(ctx context.Context, tracks []deezerTr
 // GetTrackISRC fetches ISRC for a single track (with caching)
 // Use this when you need ISRC for download
 func (c *DeezerClient) GetTrackISRC(ctx context.Context, trackID string) (string, error) {
-	// Check cache first
 	c.cacheMu.RLock()
 	if isrc, ok := c.isrcCache[trackID]; ok {
 		c.cacheMu.RUnlock()
 		return isrc, nil
 	}
 	c.cacheMu.RUnlock()
-	
+
 	// Fetch from API
 	fullTrack, err := c.fetchFullTrack(ctx, trackID)
 	if err != nil {
 		return "", err
 	}
-	
+
 	// Cache the result
 	c.cacheMu.Lock()
 	c.isrcCache[trackID] = fullTrack.ISRC
 	c.cacheMu.Unlock()
-	
+
 	return fullTrack.ISRC, nil
 }
 
-
-
 func (c *DeezerClient) getBestArtistImage(artist deezerArtist) string {
 	if artist.PictureXL != "" {
 		return artist.PictureXL
@@ -687,7 +720,7 @@ func parseDeezerURL(input string) (string, string, error) {
 	}
 
 	parts := strings.Split(strings.Trim(parsed.Path, "/"), "/")
-	
+
 	// Skip language prefix if present (e.g., /en/, /fr/)
 	if len(parts) > 0 && len(parts[0]) == 2 {
 		parts = parts[1:]

go_backend/duplicate.go

@@ -18,30 +18,45 @@ type ISRCIndex struct {
 	mu        sync.RWMutex
 }
 
-// Global ISRC index cache (per output directory)
 var (
 	isrcIndexCache   = make(map[string]*ISRCIndex)
 	isrcIndexCacheMu sync.RWMutex
-	isrcIndexTTL     = 5 * time.Minute // Cache TTL - rebuild after 5 minutes
+	isrcBuildingMu   sync.Map // Per-directory build lock to prevent concurrent builds
+	isrcIndexTTL     = 5 * time.Minute
 )
 
 // GetISRCIndex returns or builds an ISRC index for the given directory
+// Uses per-directory mutex to prevent concurrent builds (race condition fix)
 func GetISRCIndex(outputDir string) *ISRCIndex {
+	// Fast path: check cache first
 	isrcIndexCacheMu.RLock()
 	idx, exists := isrcIndexCache[outputDir]
 	isrcIndexCacheMu.RUnlock()
 
-	// Return cached index if still valid
 	if exists && time.Since(idx.buildTime) < isrcIndexTTL {
 		return idx
 	}
 
-	// Build new index
+	// Slow path: need to build index
+	// Use per-directory mutex to prevent multiple goroutines from building simultaneously
+	buildLock, _ := isrcBuildingMu.LoadOrStore(outputDir, &sync.Mutex{})
+	mu := buildLock.(*sync.Mutex)
+	mu.Lock()
+	defer mu.Unlock()
+
+	// Double-check cache after acquiring lock (another goroutine may have built it)
+	isrcIndexCacheMu.RLock()
+	idx, exists = isrcIndexCache[outputDir]
+	isrcIndexCacheMu.RUnlock()
+
+	if exists && time.Since(idx.buildTime) < isrcIndexTTL {
+		return idx
+	}
+
 	return buildISRCIndex(outputDir)
 }
 
 // buildISRCIndex scans a directory and builds a map of ISRC -> file path
-// Same implementation as PC version for consistency
 func buildISRCIndex(outputDir string) *ISRCIndex {
 	idx := &ISRCIndex{
 		index:     make(map[string]string),
@@ -56,7 +71,6 @@ func buildISRCIndex(outputDir string) *ISRCIndex {
 	startTime := time.Now()
 	fileCount := 0
 
-	// Walk directory - only check .flac files
 	filepath.Walk(outputDir, func(path string, info os.FileInfo, err error) error {
 		if err != nil || info.IsDir() {
 			return nil
@@ -67,13 +81,11 @@ func buildISRCIndex(outputDir string) *ISRCIndex {
 			return nil
 		}
 
-		// Read ISRC from file
 		metadata, err := ReadMetadata(path)
 		if err != nil || metadata.ISRC == "" {
 			return nil
 		}
 
-		// Store in index (uppercase for case-insensitive matching)
 		idx.index[strings.ToUpper(metadata.ISRC)] = path
 		fileCount++
 		return nil
@@ -82,7 +94,6 @@ func buildISRCIndex(outputDir string) *ISRCIndex {
 	fmt.Printf("[ISRCIndex] Built index for %s: %d files in %v\n", 
 		outputDir, fileCount, time.Since(startTime).Round(time.Millisecond))
 
-	// Cache the index
 	isrcIndexCacheMu.Lock()
 	isrcIndexCache[outputDir] = idx
 	isrcIndexCacheMu.Unlock()
@@ -90,7 +101,6 @@ func buildISRCIndex(outputDir string) *ISRCIndex {
 	return idx
 }
 
-// lookup checks if an ISRC exists in the index (internal, returns bool)
 func (idx *ISRCIndex) lookup(isrc string) (string, bool) {
 	if isrc == "" {
 		return "", false
@@ -103,6 +113,18 @@ func (idx *ISRCIndex) lookup(isrc string) (string, bool) {
 	return path, exists
 }
 
+// remove deletes an ISRC entry from the index (internal use)
+func (idx *ISRCIndex) remove(isrc string) {
+	if isrc == "" {
+		return
+	}
+
+	idx.mu.Lock()
+	defer idx.mu.Unlock()
+
+	delete(idx.index, strings.ToUpper(isrc))
+}
+
 // Lookup checks if an ISRC exists in the index (gomobile compatible)
 // Returns filepath if found, empty string if not found
 func (idx *ISRCIndex) Lookup(isrc string) (string, error) {
@@ -138,7 +160,18 @@ func checkISRCExistsInternal(outputDir, isrc string) (string, bool) {
 
 	// Use index for fast lookup
 	idx := GetISRCIndex(outputDir)
-	return idx.lookup(isrc)
+	filePath, exists := idx.lookup(isrc)
+	if !exists {
+		return "", false
+	}
+
+	if !CheckFileExists(filePath) {
+		// Stale index entry; remove it and return not found.
+		idx.remove(isrc)
+		return "", false
+	}
+
+	return filePath, true
 }
 
 // CheckISRCExists is the exported version for gomobile (returns string, error)
@@ -170,7 +203,6 @@ type FileExistenceResult struct {
 // It builds an ISRC index from the output directory once, then checks all tracks against it
 // Same implementation as PC version for consistency
 func CheckFilesExistParallel(outputDir string, tracksJSON string) (string, error) {
-	// Parse input JSON
 	var tracks []struct {
 		ISRC       string `json:"isrc"`
 		TrackName  string `json:"track_name"`
@@ -182,10 +214,8 @@ func CheckFilesExistParallel(outputDir string, tracksJSON string) (string, error
 
 	results := make([]FileExistenceResult, len(tracks))
 
-	// Build ISRC index from output directory (scan once)
 	isrcIdx := GetISRCIndex(outputDir)
 
-	// Check each track against the index (parallel)
 	var wg sync.WaitGroup
 	for i, track := range tracks {
 		wg.Add(1)
@@ -216,7 +246,6 @@ func CheckFilesExistParallel(outputDir string, tracksJSON string) (string, error
 
 	wg.Wait()
 
-	// Return results as JSON
 	resultJSON, err := json.Marshal(results)
 	if err != nil {
 		return "", fmt.Errorf("failed to marshal results: %w", err)

go_backend/extension_manager.go

@@ -0,0 +1,961 @@
+// Package gobackend provides extension management functionality
+package gobackend
+
+import (
+	"archive/zip"
+	"encoding/json"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"sync"
+
+	"github.com/dop251/goja"
+)
+
+// compareVersions compares two semantic version strings
+// Returns: -1 if v1 < v2, 0 if v1 == v2, 1 if v1 > v2
+func compareVersions(v1, v2 string) int {
+	parts1 := strings.Split(strings.TrimPrefix(v1, "v"), ".")
+	parts2 := strings.Split(strings.TrimPrefix(v2, "v"), ".")
+
+	maxLen := len(parts1)
+	if len(parts2) > maxLen {
+		maxLen = len(parts2)
+	}
+
+	for i := 0; i < maxLen; i++ {
+		var n1, n2 int
+		if i < len(parts1) {
+			n1, _ = strconv.Atoi(parts1[i])
+		}
+		if i < len(parts2) {
+			n2, _ = strconv.Atoi(parts2[i])
+		}
+
+		if n1 < n2 {
+			return -1
+		}
+		if n1 > n2 {
+			return 1
+		}
+	}
+
+	return 0
+}
+
+// LoadedExtension represents an extension that has been loaded into memory
+type LoadedExtension struct {
+	ID        string             `json:"id"`
+	Manifest  *ExtensionManifest `json:"manifest"`
+	VM        *goja.Runtime      `json:"-"`
+	Enabled   bool               `json:"enabled"`
+	Error     string             `json:"error,omitempty"`
+	DataDir   string             `json:"data_dir"`
+	SourceDir string             `json:"source_dir"`
+	IconPath  string             `json:"icon_path"`
+}
+
+// ExtensionManager manages all loaded extensions
+type ExtensionManager struct {
+	mu            sync.RWMutex
+	extensions    map[string]*LoadedExtension
+	extensionsDir string // Base directory for extensions
+	dataDir       string // Base directory for extension data
+}
+
+var (
+	globalExtManager     *ExtensionManager
+	globalExtManagerOnce sync.Once
+)
+
+// GetExtensionManager returns the global extension manager instance
+func GetExtensionManager() *ExtensionManager {
+	globalExtManagerOnce.Do(func() {
+		globalExtManager = &ExtensionManager{
+			extensions: make(map[string]*LoadedExtension),
+		}
+	})
+	return globalExtManager
+}
+
+// SetDirectories sets the extensions and data directories
+func (m *ExtensionManager) SetDirectories(extensionsDir, dataDir string) error {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	m.extensionsDir = extensionsDir
+	m.dataDir = dataDir
+
+	if err := os.MkdirAll(extensionsDir, 0755); err != nil {
+		return fmt.Errorf("failed to create extensions directory: %w", err)
+	}
+	if err := os.MkdirAll(dataDir, 0755); err != nil {
+		return fmt.Errorf("failed to create data directory: %w", err)
+	}
+
+	return nil
+}
+
+// LoadExtensionFromFile loads an extension from a .spotiflac-ext file
+func (m *ExtensionManager) LoadExtensionFromFile(filePath string) (*LoadedExtension, error) {
+	// Validate file extension
+	if !strings.HasSuffix(strings.ToLower(filePath), ".spotiflac-ext") {
+		return nil, fmt.Errorf("Invalid file format. Please select a .spotiflac-ext file")
+	}
+
+	// Open the zip file
+	zipReader, err := zip.OpenReader(filePath)
+	if err != nil {
+		return nil, fmt.Errorf("Cannot open extension file. The file may be corrupted or not a valid extension package")
+	}
+	defer zipReader.Close()
+
+	var manifestData []byte
+	var hasIndexJS bool
+	for _, file := range zipReader.File {
+		name := filepath.Base(file.Name)
+		if name == "manifest.json" {
+			rc, err := file.Open()
+			if err != nil {
+				return nil, fmt.Errorf("failed to open manifest.json: %w", err)
+			}
+			manifestData, err = io.ReadAll(rc)
+			rc.Close()
+			if err != nil {
+				return nil, fmt.Errorf("failed to read manifest.json: %w", err)
+			}
+		}
+		if name == "index.js" {
+			hasIndexJS = true
+		}
+	}
+
+	if manifestData == nil {
+		return nil, fmt.Errorf("Invalid extension package: manifest.json not found")
+	}
+
+	if !hasIndexJS {
+		return nil, fmt.Errorf("Invalid extension package: index.js not found")
+	}
+
+	manifest, err := ParseManifest(manifestData)
+	if err != nil {
+		return nil, fmt.Errorf("Invalid extension manifest: %w", err)
+	}
+
+	m.mu.RLock()
+	existing, exists := m.extensions[manifest.Name]
+	var existingVersion string
+	var existingDisplayName string
+	if exists {
+		existingVersion = existing.Manifest.Version
+		existingDisplayName = existing.Manifest.DisplayName
+	}
+	m.mu.RUnlock()
+
+	if exists {
+		versionCompare := compareVersions(manifest.Version, existingVersion)
+		if versionCompare > 0 {
+			// This is an upgrade - call UpgradeExtension
+			return m.UpgradeExtension(filePath)
+		} else if versionCompare == 0 {
+			return nil, fmt.Errorf("Extension '%s' v%s is already installed", existingDisplayName, existingVersion)
+		} else {
+			return nil, fmt.Errorf("Cannot downgrade '%s' from v%s to v%s", existingDisplayName, existingVersion, manifest.Version)
+		}
+	}
+
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	if _, exists := m.extensions[manifest.Name]; exists {
+		return nil, fmt.Errorf("Extension '%s' was installed by another process", manifest.DisplayName)
+	}
+
+	extDir := filepath.Join(m.extensionsDir, manifest.Name)
+	if err := os.MkdirAll(extDir, 0755); err != nil {
+		return nil, fmt.Errorf("failed to create extension directory: %w", err)
+	}
+
+	// Extract all files (preserving directory structure)
+	for _, file := range zipReader.File {
+		if file.FileInfo().IsDir() {
+			continue
+		}
+
+		// Preserve relative path within the zip (support subdirectories)
+		// Clean the path to prevent path traversal attacks
+		relPath := filepath.Clean(file.Name)
+		if strings.HasPrefix(relPath, "..") || filepath.IsAbs(relPath) {
+			GoLog("[Extension] Skipping unsafe path in archive: %s\n", file.Name)
+			continue
+		}
+		destPath := filepath.Join(extDir, relPath)
+
+		destDir := filepath.Dir(destPath)
+		if err := os.MkdirAll(destDir, 0755); err != nil {
+			return nil, fmt.Errorf("failed to create directory %s: %w", destDir, err)
+		}
+
+		destFile, err := os.Create(destPath)
+		if err != nil {
+			return nil, fmt.Errorf("failed to create file %s: %w", destPath, err)
+		}
+
+		srcFile, err := file.Open()
+		if err != nil {
+			destFile.Close()
+			return nil, fmt.Errorf("failed to open file in archive: %w", err)
+		}
+
+		_, err = io.Copy(destFile, srcFile)
+		srcFile.Close()
+		destFile.Close()
+		if err != nil {
+			return nil, fmt.Errorf("failed to extract file: %w", err)
+		}
+	}
+
+	extDataDir := filepath.Join(m.dataDir, manifest.Name)
+	if err := os.MkdirAll(extDataDir, 0755); err != nil {
+		return nil, fmt.Errorf("failed to create extension data directory: %w", err)
+	}
+
+	ext := &LoadedExtension{
+		ID:        manifest.Name,
+		Manifest:  manifest,
+		Enabled:   false, // New extensions start disabled
+		DataDir:   extDataDir,
+		SourceDir: extDir,
+	}
+
+	// Initialize Goja VM
+	if err := m.initializeVM(ext); err != nil {
+		ext.Error = err.Error()
+		ext.Enabled = false
+		GoLog("[Extension] Failed to initialize VM for %s: %v\n", manifest.Name, err)
+	}
+
+	m.extensions[manifest.Name] = ext
+	GoLog("[Extension] Loaded extension: %s v%s\n", manifest.DisplayName, manifest.Version)
+
+	return ext, nil
+}
+
+// initializeVM creates and initializes the Goja VM for an extension
+func (m *ExtensionManager) initializeVM(ext *LoadedExtension) error {
+	vm := goja.New()
+	ext.VM = vm
+
+	indexPath := filepath.Join(ext.SourceDir, "index.js")
+	jsCode, err := os.ReadFile(indexPath)
+	if err != nil {
+		return fmt.Errorf("failed to read index.js: %w", err)
+	}
+
+	runtime := NewExtensionRuntime(ext)
+	runtime.RegisterAPIs(vm)
+	runtime.RegisterGoBackendAPIs(vm)
+
+	console := vm.NewObject()
+	console.Set("log", func(call goja.FunctionCall) goja.Value {
+		args := make([]interface{}, len(call.Arguments))
+		for i, arg := range call.Arguments {
+			args[i] = arg.Export()
+		}
+		GoLog("[Extension:%s] %v\n", ext.ID, args)
+		return goja.Undefined()
+	})
+	vm.Set("console", console)
+
+	var registeredExtension goja.Value
+	vm.Set("registerExtension", func(call goja.FunctionCall) goja.Value {
+		if len(call.Arguments) > 0 {
+			registeredExtension = call.Arguments[0]
+			vm.Set("extension", call.Arguments[0])
+		}
+		return goja.Undefined()
+	})
+
+	// Run the extension code
+	_, err = vm.RunString(string(jsCode))
+	if err != nil {
+		return fmt.Errorf("failed to execute extension code: %w", err)
+	}
+
+	// Verify extension was registered
+	if registeredExtension == nil || goja.IsUndefined(registeredExtension) {
+		return fmt.Errorf("extension did not call registerExtension()")
+	}
+
+	return nil
+}
+
+// UnloadExtension unloads an extension by ID
+func (m *ExtensionManager) UnloadExtension(extensionID string) error {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	ext, exists := m.extensions[extensionID]
+	if !exists {
+		return fmt.Errorf("Extension not found")
+	}
+
+	// Call cleanup if VM is initialized
+	if ext.VM != nil {
+		// Try to call cleanup function
+		cleanup, err := ext.VM.RunString("typeof extension !== 'undefined' && typeof extension.cleanup === 'function' ? extension.cleanup() : null")
+		if err != nil {
+			GoLog("[Extension] Error calling cleanup for %s: %v\n", extensionID, err)
+		} else if cleanup != nil && !goja.IsUndefined(cleanup) && !goja.IsNull(cleanup) {
+			GoLog("[Extension] Cleanup called for %s\n", extensionID)
+		}
+	}
+
+	// Remove from registry
+	delete(m.extensions, extensionID)
+	GoLog("[Extension] Unloaded extension: %s\n", extensionID)
+
+	return nil
+}
+
+// GetExtension returns a loaded extension by ID
+// Returns error if extension not found (gomobile compatible)
+func (m *ExtensionManager) GetExtension(extensionID string) (*LoadedExtension, error) {
+	m.mu.RLock()
+	defer m.mu.RUnlock()
+
+	ext, exists := m.extensions[extensionID]
+	if !exists {
+		return nil, fmt.Errorf("Extension not found")
+	}
+	return ext, nil
+}
+
+// GetAllExtensions returns all loaded extensions
+func (m *ExtensionManager) GetAllExtensions() []*LoadedExtension {
+	m.mu.RLock()
+	defer m.mu.RUnlock()
+
+	result := make([]*LoadedExtension, 0, len(m.extensions))
+	for _, ext := range m.extensions {
+		result = append(result, ext)
+	}
+	return result
+}
+
+// SetExtensionEnabled enables or disables an extension
+func (m *ExtensionManager) SetExtensionEnabled(extensionID string, enabled bool) error {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	ext, exists := m.extensions[extensionID]
+	if !exists {
+		return fmt.Errorf("Extension not found")
+	}
+
+	ext.Enabled = enabled
+	GoLog("[Extension] %s %s\n", extensionID, map[bool]string{true: "enabled", false: "disabled"}[enabled])
+
+	// Persist enabled state to settings store
+	store := GetExtensionSettingsStore()
+	if err := store.Set(extensionID, "_enabled", enabled); err != nil {
+		GoLog("[Extension] Failed to persist enabled state for %s: %v\n", extensionID, err)
+	}
+
+	return nil
+}
+
+// LoadExtensionsFromDirectory scans a directory and loads all valid extensions
+func (m *ExtensionManager) LoadExtensionsFromDirectory(dirPath string) ([]string, []error) {
+	var loaded []string
+	var errors []error
+
+	entries, err := os.ReadDir(dirPath)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return loaded, errors
+		}
+		return nil, []error{fmt.Errorf("failed to read extensions directory: %w", err)}
+	}
+
+	for _, entry := range entries {
+		if entry.IsDir() {
+			manifestPath := filepath.Join(dirPath, entry.Name(), "manifest.json")
+			if _, err := os.Stat(manifestPath); err == nil {
+				ext, err := m.loadExtensionFromDirectory(filepath.Join(dirPath, entry.Name()))
+				if err != nil {
+					GoLog("[Extension] Failed to load %s: %v\n", entry.Name(), err)
+					errors = append(errors, fmt.Errorf("%s: %w", entry.Name(), err))
+				} else {
+					loaded = append(loaded, ext.ID)
+				}
+			}
+		} else if strings.HasSuffix(strings.ToLower(entry.Name()), ".spotiflac-ext") {
+			ext, err := m.LoadExtensionFromFile(filepath.Join(dirPath, entry.Name()))
+			if err != nil {
+				GoLog("[Extension] Failed to load %s: %v\n", entry.Name(), err)
+				errors = append(errors, fmt.Errorf("%s: %w", entry.Name(), err))
+			} else {
+				loaded = append(loaded, ext.ID)
+			}
+		}
+	}
+
+	return loaded, errors
+}
+
+// loadExtensionFromDirectory loads an extension from an already extracted directory
+func (m *ExtensionManager) loadExtensionFromDirectory(dirPath string) (*LoadedExtension, error) {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	manifestPath := filepath.Join(dirPath, "manifest.json")
+	manifestData, err := os.ReadFile(manifestPath)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read manifest.json: %w", err)
+	}
+
+	// Parse and validate manifest
+	manifest, err := ParseManifest(manifestData)
+	if err != nil {
+		return nil, fmt.Errorf("Invalid extension manifest: %w", err)
+	}
+
+	indexPath := filepath.Join(dirPath, "index.js")
+	if _, err := os.Stat(indexPath); os.IsNotExist(err) {
+		return nil, fmt.Errorf("Extension is missing index.js file")
+	}
+
+	if existing, exists := m.extensions[manifest.Name]; exists {
+		GoLog("[Extension] Extension '%s' already loaded, skipping\n", manifest.DisplayName)
+		return existing, nil
+	}
+
+	extDataDir := filepath.Join(m.dataDir, manifest.Name)
+	if err := os.MkdirAll(extDataDir, 0755); err != nil {
+		return nil, fmt.Errorf("failed to create extension data directory: %w", err)
+	}
+
+	ext := &LoadedExtension{
+		ID:        manifest.Name,
+		Manifest:  manifest,
+		Enabled:   false, // Will be restored from settings store
+		DataDir:   extDataDir,
+		SourceDir: dirPath,
+	}
+
+	// Restore enabled state from settings store
+	store := GetExtensionSettingsStore()
+	if enabledVal, err := store.Get(manifest.Name, "_enabled"); err == nil {
+		if enabled, ok := enabledVal.(bool); ok {
+			ext.Enabled = enabled
+			GoLog("[Extension] Restored enabled state for %s: %v\n", manifest.Name, enabled)
+		}
+	}
+
+	// Initialize Goja VM
+	if err := m.initializeVM(ext); err != nil {
+		ext.Error = err.Error()
+		ext.Enabled = false
+		GoLog("[Extension] Failed to initialize VM for %s: %v\n", manifest.Name, err)
+	}
+
+	m.extensions[manifest.Name] = ext
+	GoLog("[Extension] Loaded extension: %s v%s\n", manifest.DisplayName, manifest.Version)
+
+	return ext, nil
+}
+
+// RemoveExtension completely removes an extension (unload + delete files)
+func (m *ExtensionManager) RemoveExtension(extensionID string) error {
+	ext, err := m.GetExtension(extensionID)
+	if err != nil {
+		return err
+	}
+
+	// Unload first
+	if err := m.UnloadExtension(extensionID); err != nil {
+		return err
+	}
+
+	// Remove source directory
+	if ext.SourceDir != "" {
+		if err := os.RemoveAll(ext.SourceDir); err != nil {
+			GoLog("[Extension] Warning: failed to remove source dir: %v\n", err)
+		}
+	}
+
+	// Optionally remove data directory (keep for now to preserve settings)
+	// if ext.DataDir != "" {
+	//     os.RemoveAll(ext.DataDir)
+	// }
+
+	return nil
+}
+
+// UpgradeExtension upgrades an existing extension from a new package file
+// Only allows upgrades (new version > current version), not downgrades
+func (m *ExtensionManager) UpgradeExtension(filePath string) (*LoadedExtension, error) {
+	// Validate file extension
+	if !strings.HasSuffix(strings.ToLower(filePath), ".spotiflac-ext") {
+		return nil, fmt.Errorf("Invalid file format. Please select a .spotiflac-ext file")
+	}
+
+	// Open the zip file
+	zipReader, err := zip.OpenReader(filePath)
+	if err != nil {
+		return nil, fmt.Errorf("Cannot open extension file. The file may be corrupted or not a valid extension package")
+	}
+	defer zipReader.Close()
+
+	var manifestData []byte
+	var hasIndexJS bool
+	for _, file := range zipReader.File {
+		name := filepath.Base(file.Name)
+		if name == "manifest.json" {
+			rc, err := file.Open()
+			if err != nil {
+				return nil, fmt.Errorf("failed to open manifest.json: %w", err)
+			}
+			manifestData, err = io.ReadAll(rc)
+			rc.Close()
+			if err != nil {
+				return nil, fmt.Errorf("failed to read manifest.json: %w", err)
+			}
+		}
+		if name == "index.js" {
+			hasIndexJS = true
+		}
+	}
+
+	if manifestData == nil {
+		return nil, fmt.Errorf("Invalid extension package: manifest.json not found")
+	}
+
+	if !hasIndexJS {
+		return nil, fmt.Errorf("Invalid extension package: index.js not found")
+	}
+
+	newManifest, err := ParseManifest(manifestData)
+	if err != nil {
+		return nil, fmt.Errorf("Invalid extension manifest: %w", err)
+	}
+
+	m.mu.RLock()
+	existing, exists := m.extensions[newManifest.Name]
+	m.mu.RUnlock()
+
+	if !exists {
+		return nil, fmt.Errorf("Extension '%s' is not installed. Use install instead of upgrade.", newManifest.DisplayName)
+	}
+
+	// Compare versions - only allow upgrade, not downgrade
+	versionCompare := compareVersions(newManifest.Version, existing.Manifest.Version)
+	if versionCompare < 0 {
+		return nil, fmt.Errorf("Cannot downgrade extension. Current version: %s, New version: %s", existing.Manifest.Version, newManifest.Version)
+	}
+	if versionCompare == 0 {
+		return nil, fmt.Errorf("Extension is already at version %s", existing.Manifest.Version)
+	}
+
+	GoLog("[Extension] Upgrading %s from v%s to v%s\n", newManifest.DisplayName, existing.Manifest.Version, newManifest.Version)
+
+	// Save data directory path and enabled state (we want to preserve them)
+	extDataDir := existing.DataDir
+	extDir := existing.SourceDir
+	wasEnabled := existing.Enabled
+
+	// Cleanup and unload existing extension
+	m.CleanupExtension(existing.ID)
+	m.UnloadExtension(existing.ID)
+
+	// Remove old source files but keep data directory
+	if extDir != "" {
+		if err := os.RemoveAll(extDir); err != nil {
+			GoLog("[Extension] Warning: failed to remove old source dir: %v\n", err)
+		}
+	}
+
+	if err := os.MkdirAll(extDir, 0755); err != nil {
+		return nil, fmt.Errorf("failed to create extension directory: %w", err)
+	}
+
+	for _, file := range zipReader.File {
+		if file.FileInfo().IsDir() {
+			continue
+		}
+
+		relPath := filepath.Clean(file.Name)
+		if strings.HasPrefix(relPath, "..") || filepath.IsAbs(relPath) {
+			GoLog("[Extension] Skipping unsafe path in archive: %s\n", file.Name)
+			continue
+		}
+		destPath := filepath.Join(extDir, relPath)
+
+		destDir := filepath.Dir(destPath)
+		if err := os.MkdirAll(destDir, 0755); err != nil {
+			return nil, fmt.Errorf("failed to create directory %s: %w", destDir, err)
+		}
+
+		destFile, err := os.Create(destPath)
+		if err != nil {
+			return nil, fmt.Errorf("failed to create file %s: %w", destPath, err)
+		}
+
+		srcFile, err := file.Open()
+		if err != nil {
+			destFile.Close()
+			return nil, fmt.Errorf("failed to open file in archive: %w", err)
+		}
+
+		_, err = io.Copy(destFile, srcFile)
+		srcFile.Close()
+		destFile.Close()
+		if err != nil {
+			return nil, fmt.Errorf("failed to extract file: %w", err)
+		}
+	}
+
+	ext := &LoadedExtension{
+		ID:        newManifest.Name,
+		Manifest:  newManifest,
+		Enabled:   wasEnabled, // Preserve enabled state from before upgrade
+		DataDir:   extDataDir,
+		SourceDir: extDir,
+	}
+
+	// Initialize Goja VM
+	if err := m.initializeVM(ext); err != nil {
+		ext.Error = err.Error()
+		ext.Enabled = false
+		GoLog("[Extension] Failed to initialize VM for %s: %v\n", newManifest.Name, err)
+	}
+
+	m.mu.Lock()
+	m.extensions[newManifest.Name] = ext
+	m.mu.Unlock()
+
+	GoLog("[Extension] Upgraded extension: %s to v%s\n", newManifest.DisplayName, newManifest.Version)
+
+	return ext, nil
+}
+
+// ExtensionUpgradeInfo holds information about extension upgrade check
+type ExtensionUpgradeInfo struct {
+	ExtensionID    string `json:"extension_id"`
+	CurrentVersion string `json:"current_version"`
+	NewVersion     string `json:"new_version"`
+	CanUpgrade     bool   `json:"can_upgrade"`
+	IsInstalled    bool   `json:"is_installed"`
+}
+
+// checkExtensionUpgradeInternal checks if a package file is an upgrade for an existing extension
+// Internal function that returns struct
+func (m *ExtensionManager) checkExtensionUpgradeInternal(filePath string) (*ExtensionUpgradeInfo, error) {
+	// Validate file extension
+	if !strings.HasSuffix(strings.ToLower(filePath), ".spotiflac-ext") {
+		return nil, fmt.Errorf("Invalid file format")
+	}
+
+	// Open the zip file
+	zipReader, err := zip.OpenReader(filePath)
+	if err != nil {
+		return nil, fmt.Errorf("Cannot open extension file")
+	}
+	defer zipReader.Close()
+
+	var manifestData []byte
+	for _, file := range zipReader.File {
+		name := filepath.Base(file.Name)
+		if name == "manifest.json" {
+			rc, err := file.Open()
+			if err != nil {
+				return nil, fmt.Errorf("failed to open manifest.json")
+			}
+			manifestData, err = io.ReadAll(rc)
+			rc.Close()
+			if err != nil {
+				return nil, fmt.Errorf("failed to read manifest.json")
+			}
+			break
+		}
+	}
+
+	if manifestData == nil {
+		return nil, fmt.Errorf("manifest.json not found")
+	}
+
+	newManifest, err := ParseManifest(manifestData)
+	if err != nil {
+		return nil, fmt.Errorf("Invalid manifest: %w", err)
+	}
+
+	m.mu.RLock()
+	existing, exists := m.extensions[newManifest.Name]
+	m.mu.RUnlock()
+
+	info := &ExtensionUpgradeInfo{
+		ExtensionID: newManifest.Name,
+		NewVersion:  newManifest.Version,
+		IsInstalled: exists,
+	}
+
+	if !exists {
+		// Not installed - this is a new install, not upgrade
+		info.CurrentVersion = ""
+		info.CanUpgrade = false
+	} else {
+		info.CurrentVersion = existing.Manifest.Version
+		info.CanUpgrade = compareVersions(newManifest.Version, existing.Manifest.Version) > 0
+	}
+
+	return info, nil
+}
+
+// CheckExtensionUpgradeJSON checks if a package file is an upgrade and returns JSON
+func (m *ExtensionManager) CheckExtensionUpgradeJSON(filePath string) (string, error) {
+	info, err := m.checkExtensionUpgradeInternal(filePath)
+	if err != nil {
+		return "", err
+	}
+
+	jsonBytes, err := json.Marshal(info)
+	if err != nil {
+		return "", err
+	}
+
+	return string(jsonBytes), nil
+}
+
+// GetInstalledExtensionsJSON returns all extensions as JSON for Flutter
+func (m *ExtensionManager) GetInstalledExtensionsJSON() (string, error) {
+	extensions := m.GetAllExtensions()
+
+	type ExtensionInfo struct {
+		ID                     string                `json:"id"`
+		Name                   string                `json:"name"`
+		DisplayName            string                `json:"display_name"`
+		Version                string                `json:"version"`
+		Author                 string                `json:"author"`
+		Description            string                `json:"description"`
+		Homepage               string                `json:"homepage,omitempty"`
+		IconPath               string                `json:"icon_path,omitempty"`
+		Types                  []ExtensionType       `json:"types"`
+		Enabled                bool                  `json:"enabled"`
+		Status                 string                `json:"status"`
+		Error                  string                `json:"error_message,omitempty"`
+		Settings               []ExtensionSetting    `json:"settings,omitempty"`
+		QualityOptions         []QualityOption       `json:"quality_options,omitempty"`
+		Permissions            []string              `json:"permissions"`
+		HasMetadataProvider    bool                  `json:"has_metadata_provider"`
+		HasDownloadProvider    bool                  `json:"has_download_provider"`
+		SkipMetadataEnrichment bool                  `json:"skip_metadata_enrichment"`
+		SearchBehavior         *SearchBehaviorConfig `json:"search_behavior,omitempty"`
+		TrackMatching          *TrackMatchingConfig  `json:"track_matching,omitempty"`
+		PostProcessing         *PostProcessingConfig `json:"post_processing,omitempty"`
+	}
+
+	infos := make([]ExtensionInfo, len(extensions))
+	for i, ext := range extensions {
+		permissions := []string{}
+		for _, domain := range ext.Manifest.Permissions.Network {
+			permissions = append(permissions, "network:"+domain)
+		}
+		if ext.Manifest.Permissions.Storage {
+			permissions = append(permissions, "storage:enabled")
+		}
+
+		// Determine status
+		status := "loaded"
+		if ext.Error != "" {
+			status = "error"
+		} else if !ext.Enabled {
+			status = "disabled"
+		}
+
+		iconPath := ""
+		if ext.Manifest.Icon != "" && ext.SourceDir != "" {
+			possibleIcon := filepath.Join(ext.SourceDir, ext.Manifest.Icon)
+			if _, err := os.Stat(possibleIcon); err == nil {
+				iconPath = possibleIcon
+			}
+		}
+		if iconPath == "" && ext.SourceDir != "" {
+			possibleIcon := filepath.Join(ext.SourceDir, "icon.png")
+			if _, err := os.Stat(possibleIcon); err == nil {
+				iconPath = possibleIcon
+			}
+		}
+
+		infos[i] = ExtensionInfo{
+			ID:                     ext.ID,
+			Name:                   ext.Manifest.Name,
+			DisplayName:            ext.Manifest.DisplayName,
+			Version:                ext.Manifest.Version,
+			Author:                 ext.Manifest.Author,
+			Description:            ext.Manifest.Description,
+			Homepage:               ext.Manifest.Homepage,
+			IconPath:               iconPath,
+			Types:                  ext.Manifest.Types,
+			Enabled:                ext.Enabled,
+			Status:                 status,
+			Error:                  ext.Error,
+			Settings:               ext.Manifest.Settings,
+			QualityOptions:         ext.Manifest.QualityOptions,
+			Permissions:            permissions,
+			HasMetadataProvider:    ext.Manifest.IsMetadataProvider(),
+			HasDownloadProvider:    ext.Manifest.IsDownloadProvider(),
+			SkipMetadataEnrichment: ext.Manifest.SkipMetadataEnrichment,
+			SearchBehavior:         ext.Manifest.SearchBehavior,
+			TrackMatching:          ext.Manifest.TrackMatching,
+			PostProcessing:         ext.Manifest.PostProcessing,
+		}
+	}
+
+	jsonBytes, err := json.Marshal(infos)
+	if err != nil {
+		return "", err
+	}
+
+	return string(jsonBytes), nil
+}
+
+// ==================== Extension Lifecycle ====================
+
+// InitializeExtension calls the extension's initialize method with settings
+func (m *ExtensionManager) InitializeExtension(extensionID string, settings map[string]interface{}) error {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	ext, exists := m.extensions[extensionID]
+	if !exists {
+		return fmt.Errorf("Extension not found")
+	}
+
+	if ext.VM == nil {
+		return fmt.Errorf("Extension failed to load. Please reinstall the extension")
+	}
+
+	settingsJSON, err := json.Marshal(settings)
+	if err != nil {
+		return fmt.Errorf("Failed to save settings")
+	}
+
+	script := fmt.Sprintf(`
+		(function() {
+			var settings = %s;
+			if (typeof extension !== 'undefined' && typeof extension.initialize === 'function') {
+				try {
+					extension.initialize(settings);
+					return { success: true };
+				} catch (e) {
+					return { success: false, error: e.toString() };
+				}
+			}
+			return { success: true, message: 'no initialize function' };
+		})()
+	`, string(settingsJSON))
+
+	result, err := ext.VM.RunString(script)
+	if err != nil {
+		ext.Error = fmt.Sprintf("initialize failed: %v", err)
+		ext.Enabled = false
+		GoLog("[Extension] Initialize error for %s: %v\n", extensionID, err)
+		return err
+	}
+
+	if result != nil && !goja.IsUndefined(result) {
+		exported := result.Export()
+		if resultMap, ok := exported.(map[string]interface{}); ok {
+			if success, ok := resultMap["success"].(bool); ok && !success {
+				errMsg := "unknown error"
+				if e, ok := resultMap["error"].(string); ok {
+					errMsg = e
+				}
+				ext.Error = errMsg
+				ext.Enabled = false
+				GoLog("[Extension] Initialize failed for %s: %s\n", extensionID, errMsg)
+				return fmt.Errorf("initialize failed: %s", errMsg)
+			}
+		}
+	}
+
+	GoLog("[Extension] Initialized %s\n", extensionID)
+	return nil
+}
+
+// CleanupExtension calls the extension's cleanup method
+func (m *ExtensionManager) CleanupExtension(extensionID string) error {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	ext, exists := m.extensions[extensionID]
+	if !exists {
+		return fmt.Errorf("Extension not found")
+	}
+
+	if ext.VM == nil {
+		return nil // No VM, nothing to cleanup
+	}
+
+	// Call cleanup function
+	script := `
+		(function() {
+			if (typeof extension !== 'undefined' && typeof extension.cleanup === 'function') {
+				try {
+					extension.cleanup();
+					return { success: true };
+				} catch (e) {
+					return { success: false, error: e.toString() };
+				}
+			}
+			return { success: true, message: 'no cleanup function' };
+		})()
+	`
+
+	result, err := ext.VM.RunString(script)
+	if err != nil {
+		GoLog("[Extension] Cleanup error for %s: %v\n", extensionID, err)
+		return err
+	}
+
+	if result != nil && !goja.IsUndefined(result) {
+		exported := result.Export()
+		if resultMap, ok := exported.(map[string]interface{}); ok {
+			if success, ok := resultMap["success"].(bool); ok && !success {
+				errMsg := "unknown error"
+				if e, ok := resultMap["error"].(string); ok {
+					errMsg = e
+				}
+				GoLog("[Extension] Cleanup failed for %s: %s\n", extensionID, errMsg)
+				return fmt.Errorf("cleanup failed: %s", errMsg)
+			}
+		}
+	}
+
+	GoLog("[Extension] Cleaned up %s\n", extensionID)
+	return nil
+}
+
+// UnloadAllExtensions unloads all extensions gracefully
+func (m *ExtensionManager) UnloadAllExtensions() {
+	m.mu.Lock()
+	extensionIDs := make([]string, 0, len(m.extensions))
+	for id := range m.extensions {
+		extensionIDs = append(extensionIDs, id)
+	}
+	m.mu.Unlock()
+
+	for _, id := range extensionIDs {
+		// Call cleanup first
+		m.CleanupExtension(id)
+		// Then unload
+		m.UnloadExtension(id)
+	}
+
+	GoLog("[Extension] All extensions unloaded\n")
+}

go_backend/extension_manifest.go

@@ -0,0 +1,315 @@
+// Package gobackend provides extension manifest parsing and validation
+package gobackend
+
+import (
+	"encoding/json"
+	"fmt"
+	"strings"
+)
+
+// ExtensionType represents the type of extension
+type ExtensionType string
+
+const (
+	ExtensionTypeMetadataProvider ExtensionType = "metadata_provider"
+	ExtensionTypeDownloadProvider ExtensionType = "download_provider"
+)
+
+// SettingType represents the type of a setting field
+type SettingType string
+
+const (
+	SettingTypeString SettingType = "string"
+	SettingTypeNumber SettingType = "number"
+	SettingTypeBool   SettingType = "boolean"
+	SettingTypeSelect SettingType = "select"
+)
+
+// ExtensionPermissions defines what resources an extension can access
+type ExtensionPermissions struct {
+	Network []string `json:"network"` // List of allowed domains
+	Storage bool     `json:"storage"` // Whether extension can use storage API
+	File    bool     `json:"file"`    // Whether extension can use file API
+}
+
+// ExtensionSetting defines a configurable setting for an extension
+type ExtensionSetting struct {
+	Key         string      `json:"key"`
+	Type        SettingType `json:"type"`
+	Label       string      `json:"label"`
+	Description string      `json:"description,omitempty"`
+	Required    bool        `json:"required,omitempty"`
+	Secret      bool        `json:"secret,omitempty"`
+	Default     interface{} `json:"default,omitempty"`
+	Options     []string    `json:"options,omitempty"` // For select type
+}
+
+// QualityOption represents a quality option for download providers
+type QualityOption struct {
+	ID          string                   `json:"id"`                 // Unique identifier (e.g., "mp3_320", "opus_128")
+	Label       string                   `json:"label"`              // Display name (e.g., "MP3 320kbps")
+	Description string                   `json:"description"`        // Optional description (e.g., "Best quality MP3")
+	Settings    []QualitySpecificSetting `json:"settings,omitempty"` // Quality-specific settings
+}
+
+// QualitySpecificSetting represents a setting that's specific to a quality option
+type QualitySpecificSetting struct {
+	Key         string      `json:"key"`
+	Type        SettingType `json:"type"`
+	Label       string      `json:"label"`
+	Description string      `json:"description,omitempty"`
+	Required    bool        `json:"required,omitempty"`
+	Secret      bool        `json:"secret,omitempty"`
+	Default     interface{} `json:"default,omitempty"`
+	Options     []string    `json:"options,omitempty"` // For select type
+}
+
+// SearchBehaviorConfig defines custom search behavior for an extension
+type SearchBehaviorConfig struct {
+	Enabled         bool   `json:"enabled"`                   // Whether extension provides custom search
+	Placeholder     string `json:"placeholder,omitempty"`     // Placeholder text for search box
+	Primary         bool   `json:"primary,omitempty"`         // If true, show as primary search tab
+	Icon            string `json:"icon,omitempty"`            // Icon for search tab
+	ThumbnailRatio  string `json:"thumbnailRatio,omitempty"`  // Thumbnail aspect ratio: "square" (1:1), "wide" (16:9), "portrait" (2:3)
+	ThumbnailWidth  int    `json:"thumbnailWidth,omitempty"`  // Custom thumbnail width in pixels
+	ThumbnailHeight int    `json:"thumbnailHeight,omitempty"` // Custom thumbnail height in pixels
+}
+
+// URLHandlerConfig defines custom URL handling for an extension
+type URLHandlerConfig struct {
+	Enabled  bool     `json:"enabled"`            // Whether extension handles URLs
+	Patterns []string `json:"patterns,omitempty"` // URL patterns to match (e.g., "music.youtube.com", "soundcloud.com")
+}
+
+// TrackMatchingConfig defines custom track matching behavior
+type TrackMatchingConfig struct {
+	CustomMatching    bool   `json:"customMatching"`              // Whether extension handles matching
+	Strategy          string `json:"strategy,omitempty"`          // "isrc", "name", "duration", "custom"
+	DurationTolerance int    `json:"durationTolerance,omitempty"` // Tolerance in seconds for duration matching
+}
+
+// PostProcessingHook defines a post-processing hook
+type PostProcessingHook struct {
+	ID               string   `json:"id"`                         // Unique identifier
+	Name             string   `json:"name"`                       // Display name
+	Description      string   `json:"description,omitempty"`      // Description
+	DefaultEnabled   bool     `json:"defaultEnabled,omitempty"`   // Whether enabled by default
+	SupportedFormats []string `json:"supportedFormats,omitempty"` // Supported file formats (e.g., ["flac", "mp3"])
+}
+
+// PostProcessingConfig defines post-processing capabilities
+type PostProcessingConfig struct {
+	Enabled bool                 `json:"enabled"`         // Whether extension provides post-processing
+	Hooks   []PostProcessingHook `json:"hooks,omitempty"` // Available hooks
+}
+
+// ExtensionManifest represents the manifest.json of an extension
+type ExtensionManifest struct {
+	Name                   string                `json:"name"`
+	DisplayName            string                `json:"displayName"`
+	Version                string                `json:"version"`
+	Author                 string                `json:"author"`
+	Description            string                `json:"description"`
+	Homepage               string                `json:"homepage,omitempty"`
+	Icon                   string                `json:"icon,omitempty"` // Icon filename (e.g., "icon.png")
+	Types                  []ExtensionType       `json:"type"`
+	Permissions            ExtensionPermissions  `json:"permissions"`
+	Settings               []ExtensionSetting    `json:"settings,omitempty"`
+	QualityOptions         []QualityOption       `json:"qualityOptions,omitempty"` // Custom quality options for download providers
+	MinAppVersion          string                `json:"minAppVersion,omitempty"`
+	SkipMetadataEnrichment bool                  `json:"skipMetadataEnrichment,omitempty"` // If true, don't enrich metadata from Deezer/Spotify
+	SkipBuiltInFallback    bool                  `json:"skipBuiltInFallback,omitempty"`    // If true, don't fallback to built-in providers (tidal/qobuz/amazon)
+	SearchBehavior         *SearchBehaviorConfig `json:"searchBehavior,omitempty"`         // Custom search behavior
+	URLHandler             *URLHandlerConfig     `json:"urlHandler,omitempty"`             // Custom URL handling
+	TrackMatching          *TrackMatchingConfig  `json:"trackMatching,omitempty"`          // Custom track matching
+	PostProcessing         *PostProcessingConfig `json:"postProcessing,omitempty"`         // Post-processing hooks
+}
+
+// ManifestValidationError represents a validation error in the manifest
+type ManifestValidationError struct {
+	Field   string
+	Message string
+}
+
+func (e *ManifestValidationError) Error() string {
+	return fmt.Sprintf("manifest validation error: %s - %s", e.Field, e.Message)
+}
+
+// ParseManifest parses and validates a manifest from JSON bytes
+func ParseManifest(data []byte) (*ExtensionManifest, error) {
+	var manifest ExtensionManifest
+	if err := json.Unmarshal(data, &manifest); err != nil {
+		return nil, fmt.Errorf("failed to parse manifest JSON: %w", err)
+	}
+
+	if err := manifest.Validate(); err != nil {
+		return nil, err
+	}
+
+	return &manifest, nil
+}
+
+// Validate checks if the manifest has all required fields and valid values
+func (m *ExtensionManifest) Validate() error {
+	// Check required fields
+	if strings.TrimSpace(m.Name) == "" {
+		return &ManifestValidationError{Field: "name", Message: "name is required"}
+	}
+
+	if strings.TrimSpace(m.Version) == "" {
+		return &ManifestValidationError{Field: "version", Message: "version is required"}
+	}
+
+	if strings.TrimSpace(m.Author) == "" {
+		return &ManifestValidationError{Field: "author", Message: "author is required"}
+	}
+
+	if strings.TrimSpace(m.Description) == "" {
+		return &ManifestValidationError{Field: "description", Message: "description is required"}
+	}
+
+	if len(m.Types) == 0 {
+		return &ManifestValidationError{Field: "type", Message: "at least one type is required"}
+	}
+
+	// Validate extension types
+	for _, t := range m.Types {
+		if t != ExtensionTypeMetadataProvider && t != ExtensionTypeDownloadProvider {
+			return &ManifestValidationError{
+				Field:   "type",
+				Message: fmt.Sprintf("invalid extension type: %s (must be 'metadata_provider' or 'download_provider')", t),
+			}
+		}
+	}
+
+	// Validate settings if present
+	for i, setting := range m.Settings {
+		if strings.TrimSpace(setting.Key) == "" {
+			return &ManifestValidationError{
+				Field:   fmt.Sprintf("settings[%d].key", i),
+				Message: "setting key is required",
+			}
+		}
+
+		if setting.Type == "" {
+			return &ManifestValidationError{
+				Field:   fmt.Sprintf("settings[%d].type", i),
+				Message: "setting type is required",
+			}
+		}
+
+		// Validate setting type
+		validTypes := map[SettingType]bool{
+			SettingTypeString: true,
+			SettingTypeNumber: true,
+			SettingTypeBool:   true,
+			SettingTypeSelect: true,
+		}
+		if !validTypes[setting.Type] {
+			return &ManifestValidationError{
+				Field:   fmt.Sprintf("settings[%d].type", i),
+				Message: fmt.Sprintf("invalid setting type: %s", setting.Type),
+			}
+		}
+
+		// Select type requires options
+		if setting.Type == SettingTypeSelect && len(setting.Options) == 0 {
+			return &ManifestValidationError{
+				Field:   fmt.Sprintf("settings[%d].options", i),
+				Message: "select type requires options",
+			}
+		}
+	}
+
+	return nil
+}
+
+// HasType checks if the extension has a specific type
+func (m *ExtensionManifest) HasType(t ExtensionType) bool {
+	for _, et := range m.Types {
+		if et == t {
+			return true
+		}
+	}
+	return false
+}
+
+// IsMetadataProvider returns true if extension provides metadata
+func (m *ExtensionManifest) IsMetadataProvider() bool {
+	return m.HasType(ExtensionTypeMetadataProvider)
+}
+
+// IsDownloadProvider returns true if extension provides downloads
+func (m *ExtensionManifest) IsDownloadProvider() bool {
+	return m.HasType(ExtensionTypeDownloadProvider)
+}
+
+// IsDomainAllowed checks if a domain is in the allowed network permissions
+func (m *ExtensionManifest) IsDomainAllowed(domain string) bool {
+	domain = strings.ToLower(strings.TrimSpace(domain))
+	for _, allowed := range m.Permissions.Network {
+		allowed = strings.ToLower(strings.TrimSpace(allowed))
+		if allowed == domain {
+			return true
+		}
+		// Support wildcard subdomains (e.g., *.example.com)
+		if strings.HasPrefix(allowed, "*.") {
+			suffix := allowed[1:] // Remove the *
+			if strings.HasSuffix(domain, suffix) {
+				return true
+			}
+		}
+	}
+	return false
+}
+
+// HasCustomSearch returns true if extension provides custom search
+func (m *ExtensionManifest) HasCustomSearch() bool {
+	return m.SearchBehavior != nil && m.SearchBehavior.Enabled
+}
+
+// HasCustomMatching returns true if extension provides custom track matching
+func (m *ExtensionManifest) HasCustomMatching() bool {
+	return m.TrackMatching != nil && m.TrackMatching.CustomMatching
+}
+
+// HasPostProcessing returns true if extension provides post-processing
+func (m *ExtensionManifest) HasPostProcessing() bool {
+	return m.PostProcessing != nil && m.PostProcessing.Enabled
+}
+
+// HasURLHandler returns true if extension handles custom URLs
+func (m *ExtensionManifest) HasURLHandler() bool {
+	return m.URLHandler != nil && m.URLHandler.Enabled && len(m.URLHandler.Patterns) > 0
+}
+
+// MatchesURL checks if a URL matches any of the extension's URL patterns
+func (m *ExtensionManifest) MatchesURL(urlStr string) bool {
+	if !m.HasURLHandler() {
+		return false
+	}
+
+	// Parse URL to get host
+	urlStr = strings.ToLower(strings.TrimSpace(urlStr))
+	for _, pattern := range m.URLHandler.Patterns {
+		pattern = strings.ToLower(strings.TrimSpace(pattern))
+		// Check if URL contains the pattern (host match)
+		if strings.Contains(urlStr, pattern) {
+			return true
+		}
+	}
+	return false
+}
+
+// GetPostProcessingHooks returns all post-processing hooks
+func (m *ExtensionManifest) GetPostProcessingHooks() []PostProcessingHook {
+	if m.PostProcessing == nil {
+		return nil
+	}
+	return m.PostProcessing.Hooks
+}
+
+// ToJSON serializes the manifest to JSON
+func (m *ExtensionManifest) ToJSON() ([]byte, error) {
+	return json.Marshal(m)
+}

go_backend/extension_runtime.go

@@ -0,0 +1,335 @@
+// Package gobackend provides extension runtime with sandboxed execution
+package gobackend
+
+import (
+	"net/http"
+	"net/url"
+	"sync"
+	"time"
+
+	"github.com/dop251/goja"
+)
+
+const DefaultJSTimeout = 30 * time.Second
+
+var (
+	extensionAuthState   = make(map[string]*ExtensionAuthState)
+	extensionAuthStateMu sync.RWMutex
+)
+
+// ExtensionAuthState holds auth state for an extension
+type ExtensionAuthState struct {
+	PendingAuthURL  string
+	AuthCode        string
+	AccessToken     string
+	RefreshToken    string
+	ExpiresAt       time.Time
+	IsAuthenticated bool
+	// PKCE support
+	PKCEVerifier  string
+	PKCEChallenge string
+}
+
+// PendingAuthRequest holds a pending OAuth request that needs Flutter to open URL
+type PendingAuthRequest struct {
+	ExtensionID string
+	AuthURL     string
+	CallbackURL string
+}
+
+var (
+	pendingAuthRequests   = make(map[string]*PendingAuthRequest)
+	pendingAuthRequestsMu sync.RWMutex
+)
+
+// GetPendingAuthRequest returns pending auth request for an extension (called from Flutter)
+func GetPendingAuthRequest(extensionID string) *PendingAuthRequest {
+	pendingAuthRequestsMu.RLock()
+	defer pendingAuthRequestsMu.RUnlock()
+	return pendingAuthRequests[extensionID]
+}
+
+func ClearPendingAuthRequest(extensionID string) {
+	pendingAuthRequestsMu.Lock()
+	defer pendingAuthRequestsMu.Unlock()
+	delete(pendingAuthRequests, extensionID)
+}
+
+// SetExtensionAuthCode sets auth code for an extension (called from Flutter after OAuth callback)
+func SetExtensionAuthCode(extensionID string, authCode string) {
+	extensionAuthStateMu.Lock()
+	defer extensionAuthStateMu.Unlock()
+
+	state, exists := extensionAuthState[extensionID]
+	if !exists {
+		state = &ExtensionAuthState{}
+		extensionAuthState[extensionID] = state
+	}
+	state.AuthCode = authCode
+}
+
+// SetExtensionTokens sets access/refresh tokens for an extension
+func SetExtensionTokens(extensionID string, accessToken, refreshToken string, expiresAt time.Time) {
+	extensionAuthStateMu.Lock()
+	defer extensionAuthStateMu.Unlock()
+
+	state, exists := extensionAuthState[extensionID]
+	if !exists {
+		state = &ExtensionAuthState{}
+		extensionAuthState[extensionID] = state
+	}
+	state.AccessToken = accessToken
+	state.RefreshToken = refreshToken
+	state.ExpiresAt = expiresAt
+	state.IsAuthenticated = accessToken != ""
+}
+
+// ExtensionRuntime provides sandboxed APIs for extensions
+type ExtensionRuntime struct {
+	extensionID string
+	manifest    *ExtensionManifest
+	settings    map[string]interface{}
+	httpClient  *http.Client
+	cookieJar   http.CookieJar
+	dataDir     string
+	vm          *goja.Runtime
+}
+
+// NewExtensionRuntime creates a new runtime for an extension
+func NewExtensionRuntime(ext *LoadedExtension) *ExtensionRuntime {
+	jar, _ := newSimpleCookieJar()
+
+	runtime := &ExtensionRuntime{
+		extensionID: ext.ID,
+		manifest:    ext.Manifest,
+		settings:    make(map[string]interface{}),
+		cookieJar:   jar,
+		dataDir:     ext.DataDir,
+		vm:          ext.VM,
+	}
+
+	// Create HTTP client with redirect validation to prevent SSRF via open redirect
+	client := &http.Client{
+		Timeout: 30 * time.Second,
+		Jar:     jar,
+		CheckRedirect: func(req *http.Request, via []*http.Request) error {
+			// Validate redirect target domain against allowed domains
+			domain := req.URL.Hostname()
+			if !ext.Manifest.IsDomainAllowed(domain) {
+				GoLog("[Extension:%s] Redirect blocked: domain '%s' not in allowed list\n", ext.ID, domain)
+				return &RedirectBlockedError{Domain: domain}
+			}
+			// Also block redirects to private/local networks (SSRF protection)
+			if isPrivateIP(domain) {
+				GoLog("[Extension:%s] Redirect blocked: private IP '%s'\n", ext.ID, domain)
+				return &RedirectBlockedError{Domain: domain, IsPrivate: true}
+			}
+			// Default redirect limit (10)
+			if len(via) >= 10 {
+				return http.ErrUseLastResponse
+			}
+			return nil
+		},
+	}
+	runtime.httpClient = client
+
+	return runtime
+}
+
+// RedirectBlockedError is returned when a redirect is blocked due to domain validation
+type RedirectBlockedError struct {
+	Domain    string
+	IsPrivate bool
+}
+
+func (e *RedirectBlockedError) Error() string {
+	if e.IsPrivate {
+		return "redirect blocked: private/local network access denied"
+	}
+	return "redirect blocked: domain '" + e.Domain + "' not in allowed list"
+}
+
+// isPrivateIP checks if a hostname resolves to a private/local IP address
+func isPrivateIP(host string) bool {
+	// Block common private network patterns
+	// This is a simple check - for production, consider DNS resolution
+	privatePatterns := []string{
+		"localhost",
+		"127.",
+		"10.",
+		"172.16.", "172.17.", "172.18.", "172.19.",
+		"172.20.", "172.21.", "172.22.", "172.23.",
+		"172.24.", "172.25.", "172.26.", "172.27.",
+		"172.28.", "172.29.", "172.30.", "172.31.",
+		"192.168.",
+		"169.254.", // Link-local
+		"::1",      // IPv6 localhost
+		"fc00:",    // IPv6 private
+		"fe80:",    // IPv6 link-local
+	}
+
+	hostLower := host
+	for _, pattern := range privatePatterns {
+		if hostLower == pattern || len(hostLower) > len(pattern) && hostLower[:len(pattern)] == pattern {
+			return true
+		}
+	}
+
+	// Also block .local domains
+	if len(host) > 6 && host[len(host)-6:] == ".local" {
+		return true
+	}
+
+	return false
+}
+
+// simpleCookieJar is a simple in-memory cookie jar
+type simpleCookieJar struct {
+	cookies map[string][]*http.Cookie
+	mu      sync.RWMutex
+}
+
+func newSimpleCookieJar() (*simpleCookieJar, error) {
+	return &simpleCookieJar{
+		cookies: make(map[string][]*http.Cookie),
+	}, nil
+}
+
+func (j *simpleCookieJar) SetCookies(u *url.URL, cookies []*http.Cookie) {
+	j.mu.Lock()
+	defer j.mu.Unlock()
+	key := u.Host
+	j.cookies[key] = append(j.cookies[key], cookies...)
+}
+
+func (j *simpleCookieJar) Cookies(u *url.URL) []*http.Cookie {
+	j.mu.RLock()
+	defer j.mu.RUnlock()
+	return j.cookies[u.Host]
+}
+
+// SetSettings updates the runtime settings
+func (r *ExtensionRuntime) SetSettings(settings map[string]interface{}) {
+	r.settings = settings
+}
+
+// RegisterAPIs registers all sandboxed APIs to the Goja VM
+func (r *ExtensionRuntime) RegisterAPIs(vm *goja.Runtime) {
+	r.vm = vm
+
+	// HTTP client (sandboxed to allowed domains)
+	httpObj := vm.NewObject()
+	httpObj.Set("get", r.httpGet)
+	httpObj.Set("post", r.httpPost)
+	httpObj.Set("put", r.httpPut)
+	httpObj.Set("delete", r.httpDelete)
+	httpObj.Set("patch", r.httpPatch)
+	httpObj.Set("request", r.httpRequest) // Generic HTTP request (GET, POST, PUT, DELETE, etc.)
+	httpObj.Set("clearCookies", r.httpClearCookies)
+	vm.Set("http", httpObj)
+
+	// Storage API
+	storageObj := vm.NewObject()
+	storageObj.Set("get", r.storageGet)
+	storageObj.Set("set", r.storageSet)
+	storageObj.Set("remove", r.storageRemove)
+	vm.Set("storage", storageObj)
+
+	// Secure Credentials API (encrypted storage for sensitive data)
+	credentialsObj := vm.NewObject()
+	credentialsObj.Set("store", r.credentialsStore)
+	credentialsObj.Set("get", r.credentialsGet)
+	credentialsObj.Set("remove", r.credentialsRemove)
+	credentialsObj.Set("has", r.credentialsHas)
+	vm.Set("credentials", credentialsObj)
+
+	// Auth API (for OAuth and other auth flows)
+	authObj := vm.NewObject()
+	authObj.Set("openAuthUrl", r.authOpenUrl)
+	authObj.Set("getAuthCode", r.authGetCode)
+	authObj.Set("setAuthCode", r.authSetCode)
+	authObj.Set("clearAuth", r.authClear)
+	authObj.Set("isAuthenticated", r.authIsAuthenticated)
+	authObj.Set("getTokens", r.authGetTokens)
+	// PKCE support
+	authObj.Set("generatePKCE", r.authGeneratePKCE)
+	authObj.Set("getPKCE", r.authGetPKCE)
+	authObj.Set("startOAuthWithPKCE", r.authStartOAuthWithPKCE)
+	authObj.Set("exchangeCodeWithPKCE", r.authExchangeCodeWithPKCE)
+	vm.Set("auth", authObj)
+
+	// File operations (sandboxed)
+	fileObj := vm.NewObject()
+	fileObj.Set("download", r.fileDownload)
+	fileObj.Set("exists", r.fileExists)
+	fileObj.Set("delete", r.fileDelete)
+	fileObj.Set("read", r.fileRead)
+	fileObj.Set("write", r.fileWrite)
+	fileObj.Set("copy", r.fileCopy)
+	fileObj.Set("move", r.fileMove)
+	fileObj.Set("getSize", r.fileGetSize)
+	vm.Set("file", fileObj)
+
+	// FFmpeg API (for post-processing)
+	ffmpegObj := vm.NewObject()
+	ffmpegObj.Set("execute", r.ffmpegExecute)
+	ffmpegObj.Set("getInfo", r.ffmpegGetInfo)
+	ffmpegObj.Set("convert", r.ffmpegConvert)
+	vm.Set("ffmpeg", ffmpegObj)
+
+	// Track matching API
+	matchingObj := vm.NewObject()
+	matchingObj.Set("compareStrings", r.matchingCompareStrings)
+	matchingObj.Set("compareDuration", r.matchingCompareDuration)
+	matchingObj.Set("normalizeString", r.matchingNormalizeString)
+	vm.Set("matching", matchingObj)
+
+	// Utilities
+	utilsObj := vm.NewObject()
+	utilsObj.Set("base64Encode", r.base64Encode)
+	utilsObj.Set("base64Decode", r.base64Decode)
+	utilsObj.Set("md5", r.md5Hash)
+	utilsObj.Set("sha256", r.sha256Hash)
+	utilsObj.Set("hmacSHA256", r.hmacSHA256)
+	utilsObj.Set("hmacSHA256Base64", r.hmacSHA256Base64)
+	utilsObj.Set("hmacSHA1", r.hmacSHA1)
+	utilsObj.Set("parseJSON", r.parseJSON)
+	utilsObj.Set("stringifyJSON", r.stringifyJSON)
+	// Crypto utilities for developers
+	utilsObj.Set("encrypt", r.cryptoEncrypt)
+	utilsObj.Set("decrypt", r.cryptoDecrypt)
+	utilsObj.Set("generateKey", r.cryptoGenerateKey)
+	vm.Set("utils", utilsObj)
+
+	// Log object (already set in extension_manager.go, but we can enhance it)
+	logObj := vm.NewObject()
+	logObj.Set("debug", r.logDebug)
+	logObj.Set("info", r.logInfo)
+	logObj.Set("warn", r.logWarn)
+	logObj.Set("error", r.logError)
+	vm.Set("log", logObj)
+
+	// Go backend functions
+	gobackendObj := vm.NewObject()
+	gobackendObj.Set("sanitizeFilename", r.sanitizeFilenameWrapper)
+	vm.Set("gobackend", gobackendObj)
+
+	// ==================== Browser-like Polyfills ====================
+	// These make porting browser/Node.js libraries easier
+
+	// Global fetch() - Promise-style HTTP API (browser-compatible)
+	vm.Set("fetch", r.fetchPolyfill)
+
+	// Global atob/btoa - Base64 encoding (browser-compatible)
+	vm.Set("atob", r.atobPolyfill)
+	vm.Set("btoa", r.btoaPolyfill)
+
+	// TextEncoder/TextDecoder constructors
+	r.registerTextEncoderDecoder(vm)
+
+	// URL class for URL parsing
+	r.registerURLClass(vm)
+
+	// JSON global (browser-compatible)
+	r.registerJSONGlobal(vm)
+}

go_backend/extension_runtime_auth.go

@@ -0,0 +1,547 @@
+// Package gobackend provides Auth API and PKCE support for extension runtime
+package gobackend
+
+import (
+	"crypto/rand"
+	"crypto/sha256"
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"strings"
+	"time"
+
+	"github.com/dop251/goja"
+)
+
+// ==================== Auth API (OAuth Support) ====================
+
+// authOpenUrl requests Flutter to open an OAuth URL
+func (r *ExtensionRuntime) authOpenUrl(call goja.FunctionCall) goja.Value {
+	if len(call.Arguments) < 1 {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   "auth URL is required",
+		})
+	}
+
+	authURL := call.Arguments[0].String()
+	callbackURL := ""
+	if len(call.Arguments) > 1 && !goja.IsUndefined(call.Arguments[1]) {
+		callbackURL = call.Arguments[1].String()
+	}
+
+	// Store pending auth request for Flutter to pick up
+	pendingAuthRequestsMu.Lock()
+	pendingAuthRequests[r.extensionID] = &PendingAuthRequest{
+		ExtensionID: r.extensionID,
+		AuthURL:     authURL,
+		CallbackURL: callbackURL,
+	}
+	pendingAuthRequestsMu.Unlock()
+
+	// Update auth state
+	extensionAuthStateMu.Lock()
+	state, exists := extensionAuthState[r.extensionID]
+	if !exists {
+		state = &ExtensionAuthState{}
+		extensionAuthState[r.extensionID] = state
+	}
+	state.PendingAuthURL = authURL
+	state.AuthCode = "" // Clear any previous auth code
+	extensionAuthStateMu.Unlock()
+
+	GoLog("[Extension:%s] Auth URL requested: %s\n", r.extensionID, authURL)
+
+	return r.vm.ToValue(map[string]interface{}{
+		"success": true,
+		"message": "Auth URL will be opened by the app",
+	})
+}
+
+// authGetCode gets the auth code (set by Flutter after OAuth callback)
+func (r *ExtensionRuntime) authGetCode(call goja.FunctionCall) goja.Value {
+	extensionAuthStateMu.RLock()
+	defer extensionAuthStateMu.RUnlock()
+
+	state, exists := extensionAuthState[r.extensionID]
+	if !exists || state.AuthCode == "" {
+		return goja.Undefined()
+	}
+
+	return r.vm.ToValue(state.AuthCode)
+}
+
+// authSetCode sets auth code and tokens (can be called by extension after token exchange)
+func (r *ExtensionRuntime) authSetCode(call goja.FunctionCall) goja.Value {
+	if len(call.Arguments) < 1 {
+		return r.vm.ToValue(false)
+	}
+
+	// Can accept either just auth code or an object with tokens
+	arg := call.Arguments[0].Export()
+
+	extensionAuthStateMu.Lock()
+	defer extensionAuthStateMu.Unlock()
+
+	state, exists := extensionAuthState[r.extensionID]
+	if !exists {
+		state = &ExtensionAuthState{}
+		extensionAuthState[r.extensionID] = state
+	}
+
+	switch v := arg.(type) {
+	case string:
+		state.AuthCode = v
+	case map[string]interface{}:
+		if code, ok := v["code"].(string); ok {
+			state.AuthCode = code
+		}
+		if accessToken, ok := v["access_token"].(string); ok {
+			state.AccessToken = accessToken
+			state.IsAuthenticated = true
+		}
+		if refreshToken, ok := v["refresh_token"].(string); ok {
+			state.RefreshToken = refreshToken
+		}
+		if expiresIn, ok := v["expires_in"].(float64); ok {
+			state.ExpiresAt = time.Now().Add(time.Duration(expiresIn) * time.Second)
+		}
+	}
+
+	return r.vm.ToValue(true)
+}
+
+// authClear clears all auth state for the extension
+func (r *ExtensionRuntime) authClear(call goja.FunctionCall) goja.Value {
+	extensionAuthStateMu.Lock()
+	delete(extensionAuthState, r.extensionID)
+	extensionAuthStateMu.Unlock()
+
+	pendingAuthRequestsMu.Lock()
+	delete(pendingAuthRequests, r.extensionID)
+	pendingAuthRequestsMu.Unlock()
+
+	GoLog("[Extension:%s] Auth state cleared\n", r.extensionID)
+	return r.vm.ToValue(true)
+}
+
+// authIsAuthenticated checks if extension has valid auth
+func (r *ExtensionRuntime) authIsAuthenticated(call goja.FunctionCall) goja.Value {
+	extensionAuthStateMu.RLock()
+	defer extensionAuthStateMu.RUnlock()
+
+	state, exists := extensionAuthState[r.extensionID]
+	if !exists {
+		return r.vm.ToValue(false)
+	}
+
+	// Check if token is expired
+	if state.IsAuthenticated && !state.ExpiresAt.IsZero() && time.Now().After(state.ExpiresAt) {
+		return r.vm.ToValue(false)
+	}
+
+	return r.vm.ToValue(state.IsAuthenticated)
+}
+
+// authGetTokens returns current tokens (for extension to use in API calls)
+func (r *ExtensionRuntime) authGetTokens(call goja.FunctionCall) goja.Value {
+	extensionAuthStateMu.RLock()
+	defer extensionAuthStateMu.RUnlock()
+
+	state, exists := extensionAuthState[r.extensionID]
+	if !exists {
+		return r.vm.ToValue(map[string]interface{}{})
+	}
+
+	result := map[string]interface{}{
+		"access_token":     state.AccessToken,
+		"refresh_token":    state.RefreshToken,
+		"is_authenticated": state.IsAuthenticated,
+	}
+
+	if !state.ExpiresAt.IsZero() {
+		result["expires_at"] = state.ExpiresAt.Unix()
+		result["is_expired"] = time.Now().After(state.ExpiresAt)
+	}
+
+	return r.vm.ToValue(result)
+}
+
+// ==================== PKCE Support ====================
+
+// generatePKCEVerifier generates a cryptographically random code verifier
+// Length should be between 43-128 characters (RFC 7636)
+func generatePKCEVerifier(length int) (string, error) {
+	if length < 43 {
+		length = 43
+	}
+	if length > 128 {
+		length = 128
+	}
+
+	// Generate random bytes
+	bytes := make([]byte, length)
+	if _, err := rand.Read(bytes); err != nil {
+		return "", err
+	}
+
+	// Use base64url encoding without padding (RFC 7636 compliant)
+	verifier := base64.RawURLEncoding.EncodeToString(bytes)
+
+	// Trim to exact length
+	if len(verifier) > length {
+		verifier = verifier[:length]
+	}
+
+	return verifier, nil
+}
+
+// generatePKCEChallenge generates a code challenge from verifier using S256 method
+func generatePKCEChallenge(verifier string) string {
+	hash := sha256.Sum256([]byte(verifier))
+	// Base64url encode without padding (RFC 7636)
+	return base64.RawURLEncoding.EncodeToString(hash[:])
+}
+
+// authGeneratePKCE generates a PKCE code verifier and challenge pair
+// Returns: { verifier: string, challenge: string, method: "S256" }
+func (r *ExtensionRuntime) authGeneratePKCE(call goja.FunctionCall) goja.Value {
+	// Default length is 64 characters
+	length := 64
+	if len(call.Arguments) > 0 && !goja.IsUndefined(call.Arguments[0]) {
+		if l, ok := call.Arguments[0].Export().(float64); ok && l >= 43 && l <= 128 {
+			length = int(l)
+		}
+	}
+
+	verifier, err := generatePKCEVerifier(length)
+	if err != nil {
+		GoLog("[Extension:%s] PKCE generation error: %v\n", r.extensionID, err)
+		return r.vm.ToValue(map[string]interface{}{
+			"error": err.Error(),
+		})
+	}
+
+	challenge := generatePKCEChallenge(verifier)
+
+	// Store in auth state for later use
+	extensionAuthStateMu.Lock()
+	state, exists := extensionAuthState[r.extensionID]
+	if !exists {
+		state = &ExtensionAuthState{}
+		extensionAuthState[r.extensionID] = state
+	}
+	state.PKCEVerifier = verifier
+	state.PKCEChallenge = challenge
+	extensionAuthStateMu.Unlock()
+
+	GoLog("[Extension:%s] PKCE generated (verifier length: %d)\n", r.extensionID, len(verifier))
+
+	return r.vm.ToValue(map[string]interface{}{
+		"verifier":  verifier,
+		"challenge": challenge,
+		"method":    "S256",
+	})
+}
+
+// authGetPKCE returns the current PKCE verifier and challenge (if generated)
+func (r *ExtensionRuntime) authGetPKCE(call goja.FunctionCall) goja.Value {
+	extensionAuthStateMu.RLock()
+	defer extensionAuthStateMu.RUnlock()
+
+	state, exists := extensionAuthState[r.extensionID]
+	if !exists || state.PKCEVerifier == "" {
+		return r.vm.ToValue(map[string]interface{}{})
+	}
+
+	return r.vm.ToValue(map[string]interface{}{
+		"verifier":  state.PKCEVerifier,
+		"challenge": state.PKCEChallenge,
+		"method":    "S256",
+	})
+}
+
+// authStartOAuthWithPKCE is a high-level helper that generates PKCE and opens OAuth URL
+// config: { authUrl, clientId, redirectUri, scope, extraParams }
+// Returns: { success, authUrl, pkce: { verifier, challenge } }
+func (r *ExtensionRuntime) authStartOAuthWithPKCE(call goja.FunctionCall) goja.Value {
+	if len(call.Arguments) < 1 {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   "config object is required",
+		})
+	}
+
+	configObj := call.Arguments[0].Export()
+	config, ok := configObj.(map[string]interface{})
+	if !ok {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   "config must be an object",
+		})
+	}
+
+	// Required fields
+	authURL, _ := config["authUrl"].(string)
+	clientID, _ := config["clientId"].(string)
+	redirectURI, _ := config["redirectUri"].(string)
+
+	if authURL == "" || clientID == "" || redirectURI == "" {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   "authUrl, clientId, and redirectUri are required",
+		})
+	}
+
+	// Optional fields
+	scope, _ := config["scope"].(string)
+	extraParams, _ := config["extraParams"].(map[string]interface{})
+
+	// Generate PKCE
+	verifier, err := generatePKCEVerifier(64)
+	if err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   fmt.Sprintf("failed to generate PKCE: %v", err),
+		})
+	}
+	challenge := generatePKCEChallenge(verifier)
+
+	// Store PKCE in auth state
+	extensionAuthStateMu.Lock()
+	state, exists := extensionAuthState[r.extensionID]
+	if !exists {
+		state = &ExtensionAuthState{}
+		extensionAuthState[r.extensionID] = state
+	}
+	state.PKCEVerifier = verifier
+	state.PKCEChallenge = challenge
+	state.AuthCode = "" // Clear any previous auth code
+	extensionAuthStateMu.Unlock()
+
+	// Build OAuth URL with PKCE parameters
+	parsedURL, err := url.Parse(authURL)
+	if err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   fmt.Sprintf("invalid authUrl: %v", err),
+		})
+	}
+
+	query := parsedURL.Query()
+	query.Set("client_id", clientID)
+	query.Set("redirect_uri", redirectURI)
+	query.Set("response_type", "code")
+	query.Set("code_challenge", challenge)
+	query.Set("code_challenge_method", "S256")
+
+	if scope != "" {
+		query.Set("scope", scope)
+	}
+
+	// Add extra params
+	for k, v := range extraParams {
+		query.Set(k, fmt.Sprintf("%v", v))
+	}
+
+	parsedURL.RawQuery = query.Encode()
+	fullAuthURL := parsedURL.String()
+
+	// Store pending auth request for Flutter
+	pendingAuthRequestsMu.Lock()
+	pendingAuthRequests[r.extensionID] = &PendingAuthRequest{
+		ExtensionID: r.extensionID,
+		AuthURL:     fullAuthURL,
+		CallbackURL: redirectURI,
+	}
+	pendingAuthRequestsMu.Unlock()
+
+	GoLog("[Extension:%s] PKCE OAuth started: %s\n", r.extensionID, fullAuthURL)
+
+	return r.vm.ToValue(map[string]interface{}{
+		"success": true,
+		"authUrl": fullAuthURL,
+		"pkce": map[string]interface{}{
+			"verifier":  verifier,
+			"challenge": challenge,
+			"method":    "S256",
+		},
+	})
+}
+
+// authExchangeCodeWithPKCE exchanges auth code for tokens using PKCE
+// config: { tokenUrl, clientId, redirectUri, code, extraParams }
+// Uses the stored PKCE verifier automatically
+func (r *ExtensionRuntime) authExchangeCodeWithPKCE(call goja.FunctionCall) goja.Value {
+	if len(call.Arguments) < 1 {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   "config object is required",
+		})
+	}
+
+	configObj := call.Arguments[0].Export()
+	config, ok := configObj.(map[string]interface{})
+	if !ok {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   "config must be an object",
+		})
+	}
+
+	// Required fields
+	tokenURL, _ := config["tokenUrl"].(string)
+	clientID, _ := config["clientId"].(string)
+	redirectURI, _ := config["redirectUri"].(string)
+	code, _ := config["code"].(string)
+
+	if tokenURL == "" || clientID == "" || code == "" {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   "tokenUrl, clientId, and code are required",
+		})
+	}
+
+	// Get stored PKCE verifier
+	extensionAuthStateMu.RLock()
+	state, exists := extensionAuthState[r.extensionID]
+	var verifier string
+	if exists {
+		verifier = state.PKCEVerifier
+	}
+	extensionAuthStateMu.RUnlock()
+
+	if verifier == "" {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   "no PKCE verifier found - call generatePKCE or startOAuthWithPKCE first",
+		})
+	}
+
+	// Validate domain
+	if err := r.validateDomain(tokenURL); err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   err.Error(),
+		})
+	}
+
+	// Build token request body
+	formData := url.Values{}
+	formData.Set("grant_type", "authorization_code")
+	formData.Set("client_id", clientID)
+	formData.Set("code", code)
+	formData.Set("code_verifier", verifier)
+	if redirectURI != "" {
+		formData.Set("redirect_uri", redirectURI)
+	}
+
+	// Add extra params
+	if extraParams, ok := config["extraParams"].(map[string]interface{}); ok {
+		for k, v := range extraParams {
+			formData.Set(k, fmt.Sprintf("%v", v))
+		}
+	}
+
+	// Make token request
+	req, err := http.NewRequest("POST", tokenURL, strings.NewReader(formData.Encode()))
+	if err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   err.Error(),
+		})
+	}
+
+	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+	req.Header.Set("User-Agent", "SpotiFLAC-Extension/1.0")
+
+	resp, err := r.httpClient.Do(req)
+	if err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   err.Error(),
+		})
+	}
+	defer resp.Body.Close()
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   err.Error(),
+		})
+	}
+
+	// Parse response
+	var tokenResp map[string]interface{}
+	if err := json.Unmarshal(body, &tokenResp); err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   fmt.Sprintf("failed to parse token response: %v", err),
+			"body":    string(body),
+		})
+	}
+
+	// Check for error in response
+	if errMsg, ok := tokenResp["error"].(string); ok {
+		errDesc, _ := tokenResp["error_description"].(string)
+		return r.vm.ToValue(map[string]interface{}{
+			"success":           false,
+			"error":             errMsg,
+			"error_description": errDesc,
+		})
+	}
+
+	// Extract tokens
+	accessToken, _ := tokenResp["access_token"].(string)
+	refreshToken, _ := tokenResp["refresh_token"].(string)
+	expiresIn, _ := tokenResp["expires_in"].(float64)
+
+	if accessToken == "" {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   "no access_token in response",
+			"body":    string(body),
+		})
+	}
+
+	// Store tokens in auth state
+	extensionAuthStateMu.Lock()
+	state, exists = extensionAuthState[r.extensionID]
+	if !exists {
+		state = &ExtensionAuthState{}
+		extensionAuthState[r.extensionID] = state
+	}
+	state.AccessToken = accessToken
+	state.RefreshToken = refreshToken
+	state.IsAuthenticated = true
+	if expiresIn > 0 {
+		state.ExpiresAt = time.Now().Add(time.Duration(expiresIn) * time.Second)
+	}
+	// Clear PKCE after successful exchange
+	state.PKCEVerifier = ""
+	state.PKCEChallenge = ""
+	extensionAuthStateMu.Unlock()
+
+	GoLog("[Extension:%s] PKCE token exchange successful\n", r.extensionID)
+
+	// Return full token response
+	result := map[string]interface{}{
+		"success":       true,
+		"access_token":  accessToken,
+		"refresh_token": refreshToken,
+		"token_type":    tokenResp["token_type"],
+	}
+	if expiresIn > 0 {
+		result["expires_in"] = expiresIn
+	}
+	// Include any additional fields from response
+	if scope, ok := tokenResp["scope"].(string); ok {
+		result["scope"] = scope
+	}
+
+	return r.vm.ToValue(result)
+}

go_backend/extension_runtime_ffmpeg.go

@@ -0,0 +1,204 @@
+// Package gobackend provides FFmpeg API for extension runtime
+package gobackend
+
+import (
+	"fmt"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/dop251/goja"
+)
+
+// ==================== FFmpeg API (Post-Processing) ====================
+
+// FFmpegCommand holds a pending FFmpeg command for Flutter to execute
+type FFmpegCommand struct {
+	ExtensionID string
+	Command     string
+	InputPath   string
+	OutputPath  string
+	Completed   bool
+	Success     bool
+	Error       string
+	Output      string
+}
+
+// Global FFmpeg command queue
+var (
+	ffmpegCommands   = make(map[string]*FFmpegCommand)
+	ffmpegCommandsMu sync.RWMutex
+	ffmpegCommandID  int64
+)
+
+// GetPendingFFmpegCommand returns a pending FFmpeg command (called from Flutter)
+func GetPendingFFmpegCommand(commandID string) *FFmpegCommand {
+	ffmpegCommandsMu.RLock()
+	defer ffmpegCommandsMu.RUnlock()
+	return ffmpegCommands[commandID]
+}
+
+// SetFFmpegCommandResult sets the result of an FFmpeg command (called from Flutter)
+func SetFFmpegCommandResult(commandID string, success bool, output, errorMsg string) {
+	ffmpegCommandsMu.Lock()
+	defer ffmpegCommandsMu.Unlock()
+	if cmd, exists := ffmpegCommands[commandID]; exists {
+		cmd.Completed = true
+		cmd.Success = success
+		cmd.Output = output
+		cmd.Error = errorMsg
+	}
+}
+
+// ClearFFmpegCommand removes a completed FFmpeg command
+func ClearFFmpegCommand(commandID string) {
+	ffmpegCommandsMu.Lock()
+	defer ffmpegCommandsMu.Unlock()
+	delete(ffmpegCommands, commandID)
+}
+
+// ffmpegExecute queues an FFmpeg command for execution by Flutter
+func (r *ExtensionRuntime) ffmpegExecute(call goja.FunctionCall) goja.Value {
+	if len(call.Arguments) < 1 {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   "command is required",
+		})
+	}
+
+	command := call.Arguments[0].String()
+
+	// Generate unique command ID
+	ffmpegCommandsMu.Lock()
+	ffmpegCommandID++
+	cmdID := fmt.Sprintf("%s_%d", r.extensionID, ffmpegCommandID)
+	ffmpegCommands[cmdID] = &FFmpegCommand{
+		ExtensionID: r.extensionID,
+		Command:     command,
+		Completed:   false,
+	}
+	ffmpegCommandsMu.Unlock()
+
+	GoLog("[Extension:%s] FFmpeg command queued: %s\n", r.extensionID, cmdID)
+
+	// Wait for completion (with timeout)
+	timeout := 5 * time.Minute
+	start := time.Now()
+	for {
+		ffmpegCommandsMu.RLock()
+		cmd := ffmpegCommands[cmdID]
+		completed := cmd != nil && cmd.Completed
+		ffmpegCommandsMu.RUnlock()
+
+		if completed {
+			ffmpegCommandsMu.RLock()
+			result := map[string]interface{}{
+				"success": cmd.Success,
+				"output":  cmd.Output,
+			}
+			if cmd.Error != "" {
+				result["error"] = cmd.Error
+			}
+			ffmpegCommandsMu.RUnlock()
+
+			// Cleanup
+			ClearFFmpegCommand(cmdID)
+			return r.vm.ToValue(result)
+		}
+
+		if time.Since(start) > timeout {
+			ClearFFmpegCommand(cmdID)
+			return r.vm.ToValue(map[string]interface{}{
+				"success": false,
+				"error":   "FFmpeg command timed out",
+			})
+		}
+
+		time.Sleep(100 * time.Millisecond)
+	}
+}
+
+// ffmpegGetInfo gets audio file information using FFprobe
+func (r *ExtensionRuntime) ffmpegGetInfo(call goja.FunctionCall) goja.Value {
+	if len(call.Arguments) < 1 {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   "file path is required",
+		})
+	}
+
+	filePath := call.Arguments[0].String()
+
+	// Use Go's built-in audio quality function
+	quality, err := GetAudioQuality(filePath)
+	if err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   err.Error(),
+		})
+	}
+
+	return r.vm.ToValue(map[string]interface{}{
+		"success":       true,
+		"bit_depth":     quality.BitDepth,
+		"sample_rate":   quality.SampleRate,
+		"total_samples": quality.TotalSamples,
+		"duration":      float64(quality.TotalSamples) / float64(quality.SampleRate),
+	})
+}
+
+// ffmpegConvert is a helper for common conversion operations
+func (r *ExtensionRuntime) ffmpegConvert(call goja.FunctionCall) goja.Value {
+	if len(call.Arguments) < 2 {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   "input and output paths are required",
+		})
+	}
+
+	inputPath := call.Arguments[0].String()
+	outputPath := call.Arguments[1].String()
+
+	// Get options if provided
+	options := map[string]interface{}{}
+	if len(call.Arguments) > 2 && !goja.IsUndefined(call.Arguments[2]) && !goja.IsNull(call.Arguments[2]) {
+		if opts, ok := call.Arguments[2].Export().(map[string]interface{}); ok {
+			options = opts
+		}
+	}
+
+	// Build FFmpeg command
+	var cmdParts []string
+	cmdParts = append(cmdParts, "-i", fmt.Sprintf("%q", inputPath))
+
+	// Audio codec
+	if codec, ok := options["codec"].(string); ok {
+		cmdParts = append(cmdParts, "-c:a", codec)
+	}
+
+	// Bitrate
+	if bitrate, ok := options["bitrate"].(string); ok {
+		cmdParts = append(cmdParts, "-b:a", bitrate)
+	}
+
+	// Sample rate
+	if sampleRate, ok := options["sample_rate"].(float64); ok {
+		cmdParts = append(cmdParts, "-ar", fmt.Sprintf("%d", int(sampleRate)))
+	}
+
+	// Channels
+	if channels, ok := options["channels"].(float64); ok {
+		cmdParts = append(cmdParts, "-ac", fmt.Sprintf("%d", int(channels)))
+	}
+
+	// Overwrite output
+	cmdParts = append(cmdParts, "-y", fmt.Sprintf("%q", outputPath))
+
+	command := strings.Join(cmdParts, " ")
+
+	// Execute via ffmpegExecute
+	execCall := goja.FunctionCall{
+		Arguments: []goja.Value{r.vm.ToValue(command)},
+	}
+	return r.ffmpegExecute(execCall)
+}

go_backend/extension_runtime_file.go

@@ -0,0 +1,523 @@
+// Package gobackend provides File API for extension runtime
+package gobackend
+
+import (
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"path/filepath"
+	"strings"
+	"sync"
+
+	"github.com/dop251/goja"
+)
+
+// ==================== File API (Sandboxed) ====================
+
+// List of allowed directories for file operations (set by Go backend for download operations)
+var (
+	allowedDownloadDirs   []string
+	allowedDownloadDirsMu sync.RWMutex
+)
+
+// SetAllowedDownloadDirs sets the list of directories where extensions can write files
+// This should be called by the Go backend when setting up download paths
+func SetAllowedDownloadDirs(dirs []string) {
+	allowedDownloadDirsMu.Lock()
+	defer allowedDownloadDirsMu.Unlock()
+	allowedDownloadDirs = dirs
+	GoLog("[Extension] Allowed download directories set: %v\n", dirs)
+}
+
+// AddAllowedDownloadDir adds a directory to the allowed list
+func AddAllowedDownloadDir(dir string) {
+	allowedDownloadDirsMu.Lock()
+	defer allowedDownloadDirsMu.Unlock()
+	absDir, err := filepath.Abs(dir)
+	if err == nil {
+		allowedDownloadDirs = append(allowedDownloadDirs, absDir)
+	}
+}
+
+// isPathInAllowedDirs checks if an absolute path is within any allowed directory
+func isPathInAllowedDirs(absPath string) bool {
+	allowedDownloadDirsMu.RLock()
+	defer allowedDownloadDirsMu.RUnlock()
+
+	for _, allowedDir := range allowedDownloadDirs {
+		if strings.HasPrefix(absPath, allowedDir) {
+			return true
+		}
+	}
+	return false
+}
+
+// validatePath checks if the path is within the extension's sandbox
+// Security: Absolute paths are BLOCKED unless they're in allowed download directories
+// Extensions should use relative paths for their own data storage
+func (r *ExtensionRuntime) validatePath(path string) (string, error) {
+	// Check if extension has file permission
+	if !r.manifest.Permissions.File {
+		return "", fmt.Errorf("file access denied: extension does not have 'file' permission")
+	}
+
+	// Clean and resolve the path
+	cleanPath := filepath.Clean(path)
+
+	// SECURITY: Block absolute paths by default
+	// Only allow if path is in explicitly allowed download directories
+	if filepath.IsAbs(cleanPath) {
+		absPath, err := filepath.Abs(cleanPath)
+		if err != nil {
+			return "", fmt.Errorf("invalid path: %w", err)
+		}
+
+		// Check if path is in allowed download directories
+		if isPathInAllowedDirs(absPath) {
+			return absPath, nil
+		}
+
+		// Block all other absolute paths
+		return "", fmt.Errorf("file access denied: absolute paths are not allowed. Use relative paths within extension sandbox")
+	}
+
+	// For relative paths, join with data directory (extension's sandbox)
+	fullPath := filepath.Join(r.dataDir, cleanPath)
+
+	// Resolve to absolute path
+	absPath, err := filepath.Abs(fullPath)
+	if err != nil {
+		return "", fmt.Errorf("invalid path: %w", err)
+	}
+
+	// Ensure path is within data directory (prevent path traversal)
+	absDataDir, _ := filepath.Abs(r.dataDir)
+	if !strings.HasPrefix(absPath, absDataDir) {
+		return "", fmt.Errorf("file access denied: path '%s' is outside sandbox", path)
+	}
+
+	return absPath, nil
+}
+
+// fileDownload downloads a file from URL to the specified path
+// Supports progress callback via options.onProgress
+func (r *ExtensionRuntime) fileDownload(call goja.FunctionCall) goja.Value {
+	if len(call.Arguments) < 2 {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   "URL and output path are required",
+		})
+	}
+
+	urlStr := call.Arguments[0].String()
+	outputPath := call.Arguments[1].String()
+
+	// Validate domain
+	if err := r.validateDomain(urlStr); err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   err.Error(),
+		})
+	}
+
+	// Validate output path (allows absolute paths for download queue)
+	fullPath, err := r.validatePath(outputPath)
+	if err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   err.Error(),
+		})
+	}
+
+	// Get options if provided
+	var onProgress goja.Callable
+	var headers map[string]string
+	if len(call.Arguments) > 2 && !goja.IsUndefined(call.Arguments[2]) && !goja.IsNull(call.Arguments[2]) {
+		optionsObj := call.Arguments[2].Export()
+		if opts, ok := optionsObj.(map[string]interface{}); ok {
+			// Extract headers
+			if h, ok := opts["headers"].(map[string]interface{}); ok {
+				headers = make(map[string]string)
+				for k, v := range h {
+					headers[k] = fmt.Sprintf("%v", v)
+				}
+			}
+			// Extract onProgress callback
+			if progressVal, ok := opts["onProgress"]; ok {
+				if callable, ok := goja.AssertFunction(r.vm.ToValue(progressVal)); ok {
+					onProgress = callable
+				}
+			}
+		}
+	}
+
+	// Create directory if needed
+	dir := filepath.Dir(fullPath)
+	if err := os.MkdirAll(dir, 0755); err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   fmt.Sprintf("failed to create directory: %v", err),
+		})
+	}
+
+	// Create HTTP request
+	req, err := http.NewRequest("GET", urlStr, nil)
+	if err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   err.Error(),
+		})
+	}
+
+	// Set headers
+	for k, v := range headers {
+		req.Header.Set(k, v)
+	}
+	if req.Header.Get("User-Agent") == "" {
+		req.Header.Set("User-Agent", "SpotiFLAC-Extension/1.0")
+	}
+
+	// Download file
+	resp, err := r.httpClient.Do(req)
+	if err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   err.Error(),
+		})
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != 200 {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   fmt.Sprintf("HTTP error: %d", resp.StatusCode),
+		})
+	}
+
+	// Create output file
+	out, err := os.Create(fullPath)
+	if err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   fmt.Sprintf("failed to create file: %v", err),
+		})
+	}
+	defer out.Close()
+
+	// Get content length for progress
+	contentLength := resp.ContentLength
+
+	// Copy content with progress reporting
+	var written int64
+	buf := make([]byte, 32*1024) // 32KB buffer
+	for {
+		nr, er := resp.Body.Read(buf)
+		if nr > 0 {
+			nw, ew := out.Write(buf[0:nr])
+			if nw < 0 || nr < nw {
+				nw = 0
+				if ew == nil {
+					ew = fmt.Errorf("invalid write result")
+				}
+			}
+			written += int64(nw)
+			if ew != nil {
+				return r.vm.ToValue(map[string]interface{}{
+					"success": false,
+					"error":   fmt.Sprintf("failed to write file: %v", ew),
+				})
+			}
+			if nr != nw {
+				return r.vm.ToValue(map[string]interface{}{
+					"success": false,
+					"error":   "short write",
+				})
+			}
+
+			// Report progress
+			if onProgress != nil && contentLength > 0 {
+				_, _ = onProgress(goja.Undefined(), r.vm.ToValue(written), r.vm.ToValue(contentLength))
+			}
+		}
+		if er != nil {
+			if er != io.EOF {
+				return r.vm.ToValue(map[string]interface{}{
+					"success": false,
+					"error":   fmt.Sprintf("failed to read response: %v", er),
+				})
+			}
+			break
+		}
+	}
+
+	GoLog("[Extension:%s] Downloaded %d bytes to %s\n", r.extensionID, written, fullPath)
+
+	return r.vm.ToValue(map[string]interface{}{
+		"success": true,
+		"path":    fullPath,
+		"size":    written,
+	})
+}
+
+// fileExists checks if a file exists in the sandbox
+func (r *ExtensionRuntime) fileExists(call goja.FunctionCall) goja.Value {
+	if len(call.Arguments) < 1 {
+		return r.vm.ToValue(false)
+	}
+
+	path := call.Arguments[0].String()
+	fullPath, err := r.validatePath(path)
+	if err != nil {
+		return r.vm.ToValue(false)
+	}
+
+	_, err = os.Stat(fullPath)
+	return r.vm.ToValue(err == nil)
+}
+
+// fileDelete deletes a file in the sandbox
+func (r *ExtensionRuntime) fileDelete(call goja.FunctionCall) goja.Value {
+	if len(call.Arguments) < 1 {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   "path is required",
+		})
+	}
+
+	path := call.Arguments[0].String()
+	fullPath, err := r.validatePath(path)
+	if err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   err.Error(),
+		})
+	}
+
+	if err := os.Remove(fullPath); err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   err.Error(),
+		})
+	}
+
+	return r.vm.ToValue(map[string]interface{}{
+		"success": true,
+	})
+}
+
+// fileRead reads a file from the sandbox
+func (r *ExtensionRuntime) fileRead(call goja.FunctionCall) goja.Value {
+	if len(call.Arguments) < 1 {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   "path is required",
+		})
+	}
+
+	path := call.Arguments[0].String()
+	fullPath, err := r.validatePath(path)
+	if err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   err.Error(),
+		})
+	}
+
+	data, err := os.ReadFile(fullPath)
+	if err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   err.Error(),
+		})
+	}
+
+	return r.vm.ToValue(map[string]interface{}{
+		"success": true,
+		"data":    string(data),
+	})
+}
+
+// fileWrite writes data to a file in the sandbox
+func (r *ExtensionRuntime) fileWrite(call goja.FunctionCall) goja.Value {
+	if len(call.Arguments) < 2 {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   "path and data are required",
+		})
+	}
+
+	path := call.Arguments[0].String()
+	data := call.Arguments[1].String()
+
+	fullPath, err := r.validatePath(path)
+	if err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   err.Error(),
+		})
+	}
+
+	// Create directory if needed
+	dir := filepath.Dir(fullPath)
+	if err := os.MkdirAll(dir, 0755); err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   fmt.Sprintf("failed to create directory: %v", err),
+		})
+	}
+
+	if err := os.WriteFile(fullPath, []byte(data), 0644); err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   err.Error(),
+		})
+	}
+
+	return r.vm.ToValue(map[string]interface{}{
+		"success": true,
+		"path":    fullPath,
+	})
+}
+
+// fileCopy copies a file within the sandbox
+func (r *ExtensionRuntime) fileCopy(call goja.FunctionCall) goja.Value {
+	if len(call.Arguments) < 2 {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   "source and destination paths are required",
+		})
+	}
+
+	srcPath := call.Arguments[0].String()
+	dstPath := call.Arguments[1].String()
+
+	fullSrc, err := r.validatePath(srcPath)
+	if err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   err.Error(),
+		})
+	}
+
+	fullDst, err := r.validatePath(dstPath)
+	if err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   err.Error(),
+		})
+	}
+
+	// Read source file
+	data, err := os.ReadFile(fullSrc)
+	if err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   fmt.Sprintf("failed to read source: %v", err),
+		})
+	}
+
+	// Create destination directory if needed
+	dir := filepath.Dir(fullDst)
+	if err := os.MkdirAll(dir, 0755); err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   fmt.Sprintf("failed to create directory: %v", err),
+		})
+	}
+
+	// Write to destination
+	if err := os.WriteFile(fullDst, data, 0644); err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   fmt.Sprintf("failed to write destination: %v", err),
+		})
+	}
+
+	return r.vm.ToValue(map[string]interface{}{
+		"success": true,
+		"path":    fullDst,
+	})
+}
+
+// fileMove moves/renames a file within the sandbox
+func (r *ExtensionRuntime) fileMove(call goja.FunctionCall) goja.Value {
+	if len(call.Arguments) < 2 {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   "source and destination paths are required",
+		})
+	}
+
+	srcPath := call.Arguments[0].String()
+	dstPath := call.Arguments[1].String()
+
+	fullSrc, err := r.validatePath(srcPath)
+	if err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   err.Error(),
+		})
+	}
+
+	fullDst, err := r.validatePath(dstPath)
+	if err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   err.Error(),
+		})
+	}
+
+	// Create destination directory if needed
+	dir := filepath.Dir(fullDst)
+	if err := os.MkdirAll(dir, 0755); err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   fmt.Sprintf("failed to create directory: %v", err),
+		})
+	}
+
+	if err := os.Rename(fullSrc, fullDst); err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   fmt.Sprintf("failed to move file: %v", err),
+		})
+	}
+
+	return r.vm.ToValue(map[string]interface{}{
+		"success": true,
+		"path":    fullDst,
+	})
+}
+
+// fileGetSize returns the size of a file in bytes
+func (r *ExtensionRuntime) fileGetSize(call goja.FunctionCall) goja.Value {
+	if len(call.Arguments) < 1 {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   "path is required",
+		})
+	}
+
+	path := call.Arguments[0].String()
+	fullPath, err := r.validatePath(path)
+	if err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   err.Error(),
+		})
+	}
+
+	info, err := os.Stat(fullPath)
+	if err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   err.Error(),
+		})
+	}
+
+	return r.vm.ToValue(map[string]interface{}{
+		"success": true,
+		"size":    info.Size(),
+	})
+}

go_backend/extension_runtime_http.go

@@ -0,0 +1,505 @@
+// Package gobackend provides HTTP API for extension runtime
+package gobackend
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"strings"
+
+	"github.com/dop251/goja"
+)
+
+// ==================== HTTP API (Sandboxed) ====================
+
+// HTTPResponse represents the response from an HTTP request
+type HTTPResponse struct {
+	StatusCode int               `json:"statusCode"`
+	Body       string            `json:"body"`
+	Headers    map[string]string `json:"headers"`
+}
+
+// validateDomain checks if the domain is allowed by the extension's permissions
+func (r *ExtensionRuntime) validateDomain(urlStr string) error {
+	parsed, err := url.Parse(urlStr)
+	if err != nil {
+		return fmt.Errorf("invalid URL: %w", err)
+	}
+
+	domain := parsed.Hostname()
+
+	// Block private/local network access (SSRF protection)
+	if isPrivateIP(domain) {
+		return fmt.Errorf("network access denied: private/local network '%s' not allowed", domain)
+	}
+
+	if !r.manifest.IsDomainAllowed(domain) {
+		return fmt.Errorf("network access denied: domain '%s' not in allowed list", domain)
+	}
+
+	return nil
+}
+
+// httpGet performs a GET request (sandboxed)
+func (r *ExtensionRuntime) httpGet(call goja.FunctionCall) goja.Value {
+	if len(call.Arguments) < 1 {
+		return r.vm.ToValue(map[string]interface{}{
+			"error": "URL is required",
+		})
+	}
+
+	urlStr := call.Arguments[0].String()
+
+	// Validate domain
+	if err := r.validateDomain(urlStr); err != nil {
+		GoLog("[Extension:%s] HTTP blocked: %v\n", r.extensionID, err)
+		return r.vm.ToValue(map[string]interface{}{
+			"error": err.Error(),
+		})
+	}
+
+	// Get headers if provided
+	headers := make(map[string]string)
+	if len(call.Arguments) > 1 && !goja.IsUndefined(call.Arguments[1]) && !goja.IsNull(call.Arguments[1]) {
+		headersObj := call.Arguments[1].Export()
+		if h, ok := headersObj.(map[string]interface{}); ok {
+			for k, v := range h {
+				headers[k] = fmt.Sprintf("%v", v)
+			}
+		}
+	}
+
+	// Create request
+	req, err := http.NewRequest("GET", urlStr, nil)
+	if err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"error": err.Error(),
+		})
+	}
+
+	// Set headers - user headers first
+	for k, v := range headers {
+		req.Header.Set(k, v)
+	}
+	// Only set default User-Agent if not provided by extension
+	if req.Header.Get("User-Agent") == "" {
+		req.Header.Set("User-Agent", "Spotiflac-Extension/1.0")
+	}
+
+	// Execute request
+	resp, err := r.httpClient.Do(req)
+	if err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"error": err.Error(),
+		})
+	}
+	defer resp.Body.Close()
+
+	// Read body
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"error": err.Error(),
+		})
+	}
+
+	// Extract response headers - return all values as arrays for multi-value headers (cookies, etc.)
+	respHeaders := make(map[string]interface{})
+	for k, v := range resp.Header {
+		if len(v) == 1 {
+			respHeaders[k] = v[0]
+		} else {
+			respHeaders[k] = v // Return as array if multiple values
+		}
+	}
+
+	return r.vm.ToValue(map[string]interface{}{
+		"statusCode": resp.StatusCode,
+		"status":     resp.StatusCode, // Alias for convenience
+		"ok":         resp.StatusCode >= 200 && resp.StatusCode < 300,
+		"body":       string(body),
+		"headers":    respHeaders,
+	})
+}
+
+// httpPost performs a POST request (sandboxed)
+func (r *ExtensionRuntime) httpPost(call goja.FunctionCall) goja.Value {
+	if len(call.Arguments) < 1 {
+		return r.vm.ToValue(map[string]interface{}{
+			"error": "URL is required",
+		})
+	}
+
+	urlStr := call.Arguments[0].String()
+
+	// Validate domain
+	if err := r.validateDomain(urlStr); err != nil {
+		GoLog("[Extension:%s] HTTP blocked: %v\n", r.extensionID, err)
+		return r.vm.ToValue(map[string]interface{}{
+			"error": err.Error(),
+		})
+	}
+
+	// Get body if provided - support both string and object
+	var bodyStr string
+	if len(call.Arguments) > 1 && !goja.IsUndefined(call.Arguments[1]) && !goja.IsNull(call.Arguments[1]) {
+		bodyArg := call.Arguments[1].Export()
+		switch v := bodyArg.(type) {
+		case string:
+			bodyStr = v
+		case map[string]interface{}, []interface{}:
+			// Auto-stringify objects and arrays to JSON
+			jsonBytes, err := json.Marshal(v)
+			if err != nil {
+				return r.vm.ToValue(map[string]interface{}{
+					"error": fmt.Sprintf("failed to stringify body: %v", err),
+				})
+			}
+			bodyStr = string(jsonBytes)
+		default:
+			// Fallback to string conversion
+			bodyStr = call.Arguments[1].String()
+		}
+	}
+
+	// Get headers if provided
+	headers := make(map[string]string)
+	if len(call.Arguments) > 2 && !goja.IsUndefined(call.Arguments[2]) && !goja.IsNull(call.Arguments[2]) {
+		headersObj := call.Arguments[2].Export()
+		if h, ok := headersObj.(map[string]interface{}); ok {
+			for k, v := range h {
+				headers[k] = fmt.Sprintf("%v", v)
+			}
+		}
+	}
+
+	// Create request
+	req, err := http.NewRequest("POST", urlStr, strings.NewReader(bodyStr))
+	if err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"error": err.Error(),
+		})
+	}
+
+	// Set headers - user headers first
+	for k, v := range headers {
+		req.Header.Set(k, v)
+	}
+	// Only set defaults if not provided by extension
+	if req.Header.Get("User-Agent") == "" {
+		req.Header.Set("User-Agent", "Spotiflac-Extension/1.0")
+	}
+	if req.Header.Get("Content-Type") == "" {
+		req.Header.Set("Content-Type", "application/json")
+	}
+
+	// Execute request
+	resp, err := r.httpClient.Do(req)
+	if err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"error": err.Error(),
+		})
+	}
+	defer resp.Body.Close()
+
+	// Read body
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"error": err.Error(),
+		})
+	}
+
+	// Extract response headers - return all values as arrays for multi-value headers
+	respHeaders := make(map[string]interface{})
+	for k, v := range resp.Header {
+		if len(v) == 1 {
+			respHeaders[k] = v[0]
+		} else {
+			respHeaders[k] = v // Return as array if multiple values
+		}
+	}
+
+	return r.vm.ToValue(map[string]interface{}{
+		"statusCode": resp.StatusCode,
+		"status":     resp.StatusCode, // Alias for convenience
+		"ok":         resp.StatusCode >= 200 && resp.StatusCode < 300,
+		"body":       string(body),
+		"headers":    respHeaders,
+	})
+}
+
+// httpRequest performs a generic HTTP request (GET, POST, PUT, DELETE, etc.)
+// Usage: http.request(url, options) where options = { method, body, headers }
+func (r *ExtensionRuntime) httpRequest(call goja.FunctionCall) goja.Value {
+	if len(call.Arguments) < 1 {
+		return r.vm.ToValue(map[string]interface{}{
+			"error": "URL is required",
+		})
+	}
+
+	urlStr := call.Arguments[0].String()
+
+	// Validate domain
+	if err := r.validateDomain(urlStr); err != nil {
+		GoLog("[Extension:%s] HTTP blocked: %v\n", r.extensionID, err)
+		return r.vm.ToValue(map[string]interface{}{
+			"error": err.Error(),
+		})
+	}
+
+	// Default options
+	method := "GET"
+	var bodyStr string
+	headers := make(map[string]string)
+
+	// Parse options if provided
+	if len(call.Arguments) > 1 && !goja.IsUndefined(call.Arguments[1]) && !goja.IsNull(call.Arguments[1]) {
+		optionsObj := call.Arguments[1].Export()
+		if opts, ok := optionsObj.(map[string]interface{}); ok {
+			// Get method
+			if m, ok := opts["method"].(string); ok {
+				method = strings.ToUpper(m)
+			}
+
+			// Get body - support both string and object
+			if bodyArg, ok := opts["body"]; ok && bodyArg != nil {
+				switch v := bodyArg.(type) {
+				case string:
+					bodyStr = v
+				case map[string]interface{}, []interface{}:
+					// Auto-stringify objects and arrays to JSON
+					jsonBytes, err := json.Marshal(v)
+					if err != nil {
+						return r.vm.ToValue(map[string]interface{}{
+							"error": fmt.Sprintf("failed to stringify body: %v", err),
+						})
+					}
+					bodyStr = string(jsonBytes)
+				default:
+					bodyStr = fmt.Sprintf("%v", v)
+				}
+			}
+
+			// Get headers
+			if h, ok := opts["headers"].(map[string]interface{}); ok {
+				for k, v := range h {
+					headers[k] = fmt.Sprintf("%v", v)
+				}
+			}
+		}
+	}
+
+	// Create request
+	var reqBody io.Reader
+	if bodyStr != "" {
+		reqBody = strings.NewReader(bodyStr)
+	}
+
+	req, err := http.NewRequest(method, urlStr, reqBody)
+	if err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"error": err.Error(),
+		})
+	}
+
+	// Set headers - user headers first
+	for k, v := range headers {
+		req.Header.Set(k, v)
+	}
+	// Only set defaults if not provided by extension
+	if req.Header.Get("User-Agent") == "" {
+		req.Header.Set("User-Agent", "Spotiflac-Extension/1.0")
+	}
+	if bodyStr != "" && req.Header.Get("Content-Type") == "" {
+		req.Header.Set("Content-Type", "application/json")
+	}
+
+	// Execute request
+	resp, err := r.httpClient.Do(req)
+	if err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"error": err.Error(),
+		})
+	}
+	defer resp.Body.Close()
+
+	// Read body
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"error": err.Error(),
+		})
+	}
+
+	// Extract response headers - return all values as arrays for multi-value headers
+	respHeaders := make(map[string]interface{})
+	for k, v := range resp.Header {
+		if len(v) == 1 {
+			respHeaders[k] = v[0]
+		} else {
+			respHeaders[k] = v // Return as array if multiple values
+		}
+	}
+
+	// Return response with helper properties
+	return r.vm.ToValue(map[string]interface{}{
+		"statusCode": resp.StatusCode,
+		"status":     resp.StatusCode, // Alias for convenience
+		"ok":         resp.StatusCode >= 200 && resp.StatusCode < 300,
+		"body":       string(body),
+		"headers":    respHeaders,
+	})
+}
+
+// httpPut performs a PUT request (shortcut for http.request with method: "PUT")
+func (r *ExtensionRuntime) httpPut(call goja.FunctionCall) goja.Value {
+	return r.httpMethodShortcut("PUT", call)
+}
+
+// httpDelete performs a DELETE request (shortcut for http.request with method: "DELETE")
+func (r *ExtensionRuntime) httpDelete(call goja.FunctionCall) goja.Value {
+	return r.httpMethodShortcut("DELETE", call)
+}
+
+// httpPatch performs a PATCH request (shortcut for http.request with method: "PATCH")
+func (r *ExtensionRuntime) httpPatch(call goja.FunctionCall) goja.Value {
+	return r.httpMethodShortcut("PATCH", call)
+}
+
+// httpMethodShortcut is a helper for PUT/DELETE/PATCH shortcuts
+// Signature: http.put(url, body, headers) / http.delete(url, headers) / http.patch(url, body, headers)
+func (r *ExtensionRuntime) httpMethodShortcut(method string, call goja.FunctionCall) goja.Value {
+	if len(call.Arguments) < 1 {
+		return r.vm.ToValue(map[string]interface{}{
+			"error": "URL is required",
+		})
+	}
+
+	urlStr := call.Arguments[0].String()
+
+	// Validate domain
+	if err := r.validateDomain(urlStr); err != nil {
+		GoLog("[Extension:%s] HTTP blocked: %v\n", r.extensionID, err)
+		return r.vm.ToValue(map[string]interface{}{
+			"error": err.Error(),
+		})
+	}
+
+	var bodyStr string
+	headers := make(map[string]string)
+
+	// For DELETE, second arg is headers; for PUT/PATCH, second arg is body
+	if method == "DELETE" {
+		// http.delete(url, headers)
+		if len(call.Arguments) > 1 && !goja.IsUndefined(call.Arguments[1]) && !goja.IsNull(call.Arguments[1]) {
+			headersObj := call.Arguments[1].Export()
+			if h, ok := headersObj.(map[string]interface{}); ok {
+				for k, v := range h {
+					headers[k] = fmt.Sprintf("%v", v)
+				}
+			}
+		}
+	} else {
+		// http.put(url, body, headers) / http.patch(url, body, headers)
+		if len(call.Arguments) > 1 && !goja.IsUndefined(call.Arguments[1]) && !goja.IsNull(call.Arguments[1]) {
+			bodyArg := call.Arguments[1].Export()
+			switch v := bodyArg.(type) {
+			case string:
+				bodyStr = v
+			case map[string]interface{}, []interface{}:
+				jsonBytes, err := json.Marshal(v)
+				if err != nil {
+					return r.vm.ToValue(map[string]interface{}{
+						"error": fmt.Sprintf("failed to stringify body: %v", err),
+					})
+				}
+				bodyStr = string(jsonBytes)
+			default:
+				bodyStr = call.Arguments[1].String()
+			}
+		}
+
+		if len(call.Arguments) > 2 && !goja.IsUndefined(call.Arguments[2]) && !goja.IsNull(call.Arguments[2]) {
+			headersObj := call.Arguments[2].Export()
+			if h, ok := headersObj.(map[string]interface{}); ok {
+				for k, v := range h {
+					headers[k] = fmt.Sprintf("%v", v)
+				}
+			}
+		}
+	}
+
+	// Create request
+	var reqBody io.Reader
+	if bodyStr != "" {
+		reqBody = strings.NewReader(bodyStr)
+	}
+
+	req, err := http.NewRequest(method, urlStr, reqBody)
+	if err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"error": err.Error(),
+		})
+	}
+
+	// Set headers - user headers first
+	for k, v := range headers {
+		req.Header.Set(k, v)
+	}
+	if req.Header.Get("User-Agent") == "" {
+		req.Header.Set("User-Agent", "Spotiflac-Extension/1.0")
+	}
+	if bodyStr != "" && req.Header.Get("Content-Type") == "" {
+		req.Header.Set("Content-Type", "application/json")
+	}
+
+	// Execute request
+	resp, err := r.httpClient.Do(req)
+	if err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"error": err.Error(),
+		})
+	}
+	defer resp.Body.Close()
+
+	// Read body
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"error": err.Error(),
+		})
+	}
+
+	// Extract response headers
+	respHeaders := make(map[string]interface{})
+	for k, v := range resp.Header {
+		if len(v) == 1 {
+			respHeaders[k] = v[0]
+		} else {
+			respHeaders[k] = v
+		}
+	}
+
+	return r.vm.ToValue(map[string]interface{}{
+		"statusCode": resp.StatusCode,
+		"status":     resp.StatusCode,
+		"ok":         resp.StatusCode >= 200 && resp.StatusCode < 300,
+		"body":       string(body),
+		"headers":    respHeaders,
+	})
+}
+
+// httpClearCookies clears all cookies for this extension
+func (r *ExtensionRuntime) httpClearCookies(call goja.FunctionCall) goja.Value {
+	if jar, ok := r.cookieJar.(*simpleCookieJar); ok {
+		jar.mu.Lock()
+		jar.cookies = make(map[string][]*http.Cookie)
+		jar.mu.Unlock()
+		GoLog("[Extension:%s] Cookies cleared\n", r.extensionID)
+		return r.vm.ToValue(true)
+	}
+	return r.vm.ToValue(false)
+}

go_backend/extension_runtime_matching.go

@@ -0,0 +1,151 @@
+// Package gobackend provides Track Matching API for extension runtime
+package gobackend
+
+import (
+	"strings"
+
+	"github.com/dop251/goja"
+)
+
+// ==================== Track Matching API ====================
+
+// matchingCompareStrings compares two strings with fuzzy matching
+func (r *ExtensionRuntime) matchingCompareStrings(call goja.FunctionCall) goja.Value {
+	if len(call.Arguments) < 2 {
+		return r.vm.ToValue(0.0)
+	}
+
+	str1 := strings.ToLower(strings.TrimSpace(call.Arguments[0].String()))
+	str2 := strings.ToLower(strings.TrimSpace(call.Arguments[1].String()))
+
+	if str1 == str2 {
+		return r.vm.ToValue(1.0)
+	}
+
+	// Calculate Levenshtein distance-based similarity
+	similarity := calculateStringSimilarity(str1, str2)
+	return r.vm.ToValue(similarity)
+}
+
+// matchingCompareDuration compares two durations with tolerance
+func (r *ExtensionRuntime) matchingCompareDuration(call goja.FunctionCall) goja.Value {
+	if len(call.Arguments) < 2 {
+		return r.vm.ToValue(false)
+	}
+
+	dur1 := int(call.Arguments[0].ToInteger())
+	dur2 := int(call.Arguments[1].ToInteger())
+
+	// Default tolerance: 3 seconds
+	tolerance := 3000 // milliseconds
+	if len(call.Arguments) > 2 && !goja.IsUndefined(call.Arguments[2]) {
+		tolerance = int(call.Arguments[2].ToInteger())
+	}
+
+	diff := dur1 - dur2
+	if diff < 0 {
+		diff = -diff
+	}
+
+	return r.vm.ToValue(diff <= tolerance)
+}
+
+// matchingNormalizeString normalizes a string for comparison
+func (r *ExtensionRuntime) matchingNormalizeString(call goja.FunctionCall) goja.Value {
+	if len(call.Arguments) < 1 {
+		return r.vm.ToValue("")
+	}
+
+	str := call.Arguments[0].String()
+	normalized := normalizeStringForMatching(str)
+	return r.vm.ToValue(normalized)
+}
+
+// calculateStringSimilarity calculates similarity between two strings (0-1)
+func calculateStringSimilarity(s1, s2 string) float64 {
+	if len(s1) == 0 && len(s2) == 0 {
+		return 1.0
+	}
+	if len(s1) == 0 || len(s2) == 0 {
+		return 0.0
+	}
+
+	// Use Levenshtein distance
+	distance := levenshteinDistance(s1, s2)
+	maxLen := len(s1)
+	if len(s2) > maxLen {
+		maxLen = len(s2)
+	}
+
+	return 1.0 - float64(distance)/float64(maxLen)
+}
+
+// levenshteinDistance calculates the Levenshtein distance between two strings
+func levenshteinDistance(s1, s2 string) int {
+	if len(s1) == 0 {
+		return len(s2)
+	}
+	if len(s2) == 0 {
+		return len(s1)
+	}
+
+	// Create matrix
+	matrix := make([][]int, len(s1)+1)
+	for i := range matrix {
+		matrix[i] = make([]int, len(s2)+1)
+		matrix[i][0] = i
+	}
+	for j := range matrix[0] {
+		matrix[0][j] = j
+	}
+
+	// Fill matrix
+	for i := 1; i <= len(s1); i++ {
+		for j := 1; j <= len(s2); j++ {
+			cost := 1
+			if s1[i-1] == s2[j-1] {
+				cost = 0
+			}
+			matrix[i][j] = min(
+				matrix[i-1][j]+1,      // deletion
+				matrix[i][j-1]+1,      // insertion
+				matrix[i-1][j-1]+cost, // substitution
+			)
+		}
+	}
+
+	return matrix[len(s1)][len(s2)]
+}
+
+// normalizeStringForMatching normalizes a string for comparison
+func normalizeStringForMatching(s string) string {
+	// Convert to lowercase
+	s = strings.ToLower(s)
+
+	// Remove common suffixes/prefixes
+	suffixes := []string{
+		" (remastered)", " (remaster)", " - remastered", " - remaster",
+		" (deluxe)", " (deluxe edition)", " - deluxe", " - deluxe edition",
+		" (explicit)", " (clean)", " [explicit]", " [clean]",
+		" (album version)", " (single version)", " (radio edit)",
+		" (feat.", " (ft.", " feat.", " ft.",
+	}
+	for _, suffix := range suffixes {
+		if idx := strings.Index(s, suffix); idx != -1 {
+			s = s[:idx]
+		}
+	}
+
+	// Remove special characters
+	var result strings.Builder
+	for _, r := range s {
+		if (r >= 'a' && r <= 'z') || (r >= '0' && r <= '9') || r == ' ' {
+			result.WriteRune(r)
+		}
+	}
+
+	// Collapse multiple spaces
+	s = strings.Join(strings.Fields(result.String()), " ")
+
+	return strings.TrimSpace(s)
+}

go_backend/extension_runtime_polyfills.go

@@ -0,0 +1,488 @@
+// Package gobackend provides Browser-like Polyfills for extension runtime
+package gobackend
+
+import (
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"strings"
+
+	"github.com/dop251/goja"
+)
+
+// ==================== Browser-like Polyfills ====================
+// These polyfills make porting browser/Node.js libraries easier
+// without compromising sandbox security
+
+// fetchPolyfill implements browser-compatible fetch() API
+// Returns a Promise-like object with json(), text() methods
+func (r *ExtensionRuntime) fetchPolyfill(call goja.FunctionCall) goja.Value {
+	if len(call.Arguments) < 1 {
+		return r.createFetchError("URL is required")
+	}
+
+	urlStr := call.Arguments[0].String()
+
+	// Validate domain
+	if err := r.validateDomain(urlStr); err != nil {
+		GoLog("[Extension:%s] fetch blocked: %v\n", r.extensionID, err)
+		return r.createFetchError(err.Error())
+	}
+
+	// Parse options
+	method := "GET"
+	var bodyStr string
+	headers := make(map[string]string)
+
+	if len(call.Arguments) > 1 && !goja.IsUndefined(call.Arguments[1]) && !goja.IsNull(call.Arguments[1]) {
+		optionsObj := call.Arguments[1].Export()
+		if opts, ok := optionsObj.(map[string]interface{}); ok {
+			// Method
+			if m, ok := opts["method"].(string); ok {
+				method = strings.ToUpper(m)
+			}
+
+			// Body - support string, object (auto-stringify), or nil
+			if bodyArg, ok := opts["body"]; ok && bodyArg != nil {
+				switch v := bodyArg.(type) {
+				case string:
+					bodyStr = v
+				case map[string]interface{}, []interface{}:
+					jsonBytes, err := json.Marshal(v)
+					if err != nil {
+						return r.createFetchError(fmt.Sprintf("failed to stringify body: %v", err))
+					}
+					bodyStr = string(jsonBytes)
+				default:
+					bodyStr = fmt.Sprintf("%v", v)
+				}
+			}
+
+			// Headers
+			if h, ok := opts["headers"]; ok && h != nil {
+				switch hv := h.(type) {
+				case map[string]interface{}:
+					for k, v := range hv {
+						headers[k] = fmt.Sprintf("%v", v)
+					}
+				}
+			}
+		}
+	}
+
+	// Create HTTP request
+	var reqBody io.Reader
+	if bodyStr != "" {
+		reqBody = strings.NewReader(bodyStr)
+	}
+
+	req, err := http.NewRequest(method, urlStr, reqBody)
+	if err != nil {
+		return r.createFetchError(err.Error())
+	}
+
+	// Set headers - user headers first
+	for k, v := range headers {
+		req.Header.Set(k, v)
+	}
+	// Set defaults if not provided
+	if req.Header.Get("User-Agent") == "" {
+		req.Header.Set("User-Agent", "SpotiFLAC-Extension/1.0")
+	}
+	if bodyStr != "" && req.Header.Get("Content-Type") == "" {
+		req.Header.Set("Content-Type", "application/json")
+	}
+
+	// Execute request
+	resp, err := r.httpClient.Do(req)
+	if err != nil {
+		return r.createFetchError(err.Error())
+	}
+	defer resp.Body.Close()
+
+	// Read body
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return r.createFetchError(err.Error())
+	}
+
+	// Extract response headers
+	respHeaders := make(map[string]interface{})
+	for k, v := range resp.Header {
+		if len(v) == 1 {
+			respHeaders[k] = v[0]
+		} else {
+			respHeaders[k] = v
+		}
+	}
+
+	// Create Response object (browser-compatible)
+	responseObj := r.vm.NewObject()
+	responseObj.Set("ok", resp.StatusCode >= 200 && resp.StatusCode < 300)
+	responseObj.Set("status", resp.StatusCode)
+	responseObj.Set("statusText", http.StatusText(resp.StatusCode))
+	responseObj.Set("headers", respHeaders)
+	responseObj.Set("url", urlStr)
+
+	// Store body for methods
+	bodyString := string(body)
+
+	// text() method - returns body as string
+	responseObj.Set("text", func(call goja.FunctionCall) goja.Value {
+		return r.vm.ToValue(bodyString)
+	})
+
+	// json() method - parses body as JSON
+	responseObj.Set("json", func(call goja.FunctionCall) goja.Value {
+		var result interface{}
+		if err := json.Unmarshal(body, &result); err != nil {
+			GoLog("[Extension:%s] fetch json() parse error: %v\n", r.extensionID, err)
+			return goja.Undefined()
+		}
+		return r.vm.ToValue(result)
+	})
+
+	// arrayBuffer() method - returns body as array (simplified)
+	responseObj.Set("arrayBuffer", func(call goja.FunctionCall) goja.Value {
+		// Return as array of bytes
+		byteArray := make([]interface{}, len(body))
+		for i, b := range body {
+			byteArray[i] = int(b)
+		}
+		return r.vm.ToValue(byteArray)
+	})
+
+	return responseObj
+}
+
+// createFetchError creates a fetch error response
+func (r *ExtensionRuntime) createFetchError(message string) goja.Value {
+	errorObj := r.vm.NewObject()
+	errorObj.Set("ok", false)
+	errorObj.Set("status", 0)
+	errorObj.Set("statusText", "Network Error")
+	errorObj.Set("error", message)
+	errorObj.Set("text", func(call goja.FunctionCall) goja.Value {
+		return r.vm.ToValue("")
+	})
+	errorObj.Set("json", func(call goja.FunctionCall) goja.Value {
+		return goja.Undefined()
+	})
+	return errorObj
+}
+
+// atobPolyfill implements browser atob() - decode base64 to string
+func (r *ExtensionRuntime) atobPolyfill(call goja.FunctionCall) goja.Value {
+	if len(call.Arguments) < 1 {
+		return r.vm.ToValue("")
+	}
+	input := call.Arguments[0].String()
+	decoded, err := base64.StdEncoding.DecodeString(input)
+	if err != nil {
+		// Try URL-safe base64
+		decoded, err = base64.URLEncoding.DecodeString(input)
+		if err != nil {
+			GoLog("[Extension:%s] atob decode error: %v\n", r.extensionID, err)
+			return r.vm.ToValue("")
+		}
+	}
+	return r.vm.ToValue(string(decoded))
+}
+
+// btoaPolyfill implements browser btoa() - encode string to base64
+func (r *ExtensionRuntime) btoaPolyfill(call goja.FunctionCall) goja.Value {
+	if len(call.Arguments) < 1 {
+		return r.vm.ToValue("")
+	}
+	input := call.Arguments[0].String()
+	return r.vm.ToValue(base64.StdEncoding.EncodeToString([]byte(input)))
+}
+
+// registerTextEncoderDecoder registers TextEncoder and TextDecoder classes
+func (r *ExtensionRuntime) registerTextEncoderDecoder(vm *goja.Runtime) {
+	// TextEncoder constructor
+	vm.Set("TextEncoder", func(call goja.ConstructorCall) *goja.Object {
+		encoder := call.This
+		encoder.Set("encoding", "utf-8")
+
+		// encode() method - string to Uint8Array
+		encoder.Set("encode", func(call goja.FunctionCall) goja.Value {
+			if len(call.Arguments) < 1 {
+				return vm.ToValue([]byte{})
+			}
+			input := call.Arguments[0].String()
+			bytes := []byte(input)
+
+			// Return as array (Uint8Array-like)
+			result := make([]interface{}, len(bytes))
+			for i, b := range bytes {
+				result[i] = int(b)
+			}
+			return vm.ToValue(result)
+		})
+
+		// encodeInto() method
+		encoder.Set("encodeInto", func(call goja.FunctionCall) goja.Value {
+			// Simplified implementation
+			if len(call.Arguments) < 2 {
+				return vm.ToValue(map[string]interface{}{"read": 0, "written": 0})
+			}
+			input := call.Arguments[0].String()
+			return vm.ToValue(map[string]interface{}{
+				"read":    len(input),
+				"written": len([]byte(input)),
+			})
+		})
+
+		return nil
+	})
+
+	// TextDecoder constructor
+	vm.Set("TextDecoder", func(call goja.ConstructorCall) *goja.Object {
+		decoder := call.This
+
+		// Get encoding from arguments (default: utf-8)
+		encoding := "utf-8"
+		if len(call.Arguments) > 0 && !goja.IsUndefined(call.Arguments[0]) {
+			encoding = call.Arguments[0].String()
+		}
+		decoder.Set("encoding", encoding)
+		decoder.Set("fatal", false)
+		decoder.Set("ignoreBOM", false)
+
+		// decode() method - Uint8Array to string
+		decoder.Set("decode", func(call goja.FunctionCall) goja.Value {
+			if len(call.Arguments) < 1 {
+				return vm.ToValue("")
+			}
+
+			// Handle different input types
+			input := call.Arguments[0].Export()
+			var bytes []byte
+
+			switch v := input.(type) {
+			case []byte:
+				bytes = v
+			case []interface{}:
+				bytes = make([]byte, len(v))
+				for i, val := range v {
+					switch n := val.(type) {
+					case int64:
+						bytes[i] = byte(n)
+					case float64:
+						bytes[i] = byte(n)
+					case int:
+						bytes[i] = byte(n)
+					}
+				}
+			case string:
+				// Already a string, just return it
+				return vm.ToValue(v)
+			default:
+				return vm.ToValue("")
+			}
+
+			return vm.ToValue(string(bytes))
+		})
+
+		return nil
+	})
+}
+
+// registerURLClass registers the URL class for URL parsing
+func (r *ExtensionRuntime) registerURLClass(vm *goja.Runtime) {
+	vm.Set("URL", func(call goja.ConstructorCall) *goja.Object {
+		urlObj := call.This
+
+		if len(call.Arguments) < 1 {
+			urlObj.Set("href", "")
+			return nil
+		}
+
+		urlStr := call.Arguments[0].String()
+
+		// Handle relative URLs with base
+		if len(call.Arguments) > 1 && !goja.IsUndefined(call.Arguments[1]) {
+			baseStr := call.Arguments[1].String()
+			baseURL, err := url.Parse(baseStr)
+			if err == nil {
+				relURL, err := url.Parse(urlStr)
+				if err == nil {
+					urlStr = baseURL.ResolveReference(relURL).String()
+				}
+			}
+		}
+
+		parsed, err := url.Parse(urlStr)
+		if err != nil {
+			urlObj.Set("href", urlStr)
+			return nil
+		}
+
+		// Set URL properties
+		urlObj.Set("href", parsed.String())
+		urlObj.Set("protocol", parsed.Scheme+":")
+		urlObj.Set("host", parsed.Host)
+		urlObj.Set("hostname", parsed.Hostname())
+		urlObj.Set("port", parsed.Port())
+		urlObj.Set("pathname", parsed.Path)
+		urlObj.Set("search", "")
+		if parsed.RawQuery != "" {
+			urlObj.Set("search", "?"+parsed.RawQuery)
+		}
+		urlObj.Set("hash", "")
+		if parsed.Fragment != "" {
+			urlObj.Set("hash", "#"+parsed.Fragment)
+		}
+		urlObj.Set("origin", parsed.Scheme+"://"+parsed.Host)
+		urlObj.Set("username", parsed.User.Username())
+		password, _ := parsed.User.Password()
+		urlObj.Set("password", password)
+
+		// searchParams object
+		searchParams := vm.NewObject()
+		queryValues := parsed.Query()
+
+		searchParams.Set("get", func(call goja.FunctionCall) goja.Value {
+			if len(call.Arguments) < 1 {
+				return goja.Null()
+			}
+			key := call.Arguments[0].String()
+			if val := queryValues.Get(key); val != "" {
+				return vm.ToValue(val)
+			}
+			return goja.Null()
+		})
+
+		searchParams.Set("getAll", func(call goja.FunctionCall) goja.Value {
+			if len(call.Arguments) < 1 {
+				return vm.ToValue([]string{})
+			}
+			key := call.Arguments[0].String()
+			return vm.ToValue(queryValues[key])
+		})
+
+		searchParams.Set("has", func(call goja.FunctionCall) goja.Value {
+			if len(call.Arguments) < 1 {
+				return vm.ToValue(false)
+			}
+			key := call.Arguments[0].String()
+			return vm.ToValue(queryValues.Has(key))
+		})
+
+		searchParams.Set("toString", func(call goja.FunctionCall) goja.Value {
+			return vm.ToValue(queryValues.Encode())
+		})
+
+		urlObj.Set("searchParams", searchParams)
+
+		// toString method
+		urlObj.Set("toString", func(call goja.FunctionCall) goja.Value {
+			return vm.ToValue(parsed.String())
+		})
+
+		// toJSON method
+		urlObj.Set("toJSON", func(call goja.FunctionCall) goja.Value {
+			return vm.ToValue(parsed.String())
+		})
+
+		return nil
+	})
+
+	// URLSearchParams constructor
+	vm.Set("URLSearchParams", func(call goja.ConstructorCall) *goja.Object {
+		paramsObj := call.This
+		values := url.Values{}
+
+		// Parse initial value if provided
+		if len(call.Arguments) > 0 && !goja.IsUndefined(call.Arguments[0]) {
+			init := call.Arguments[0].Export()
+			switch v := init.(type) {
+			case string:
+				// Parse query string
+				parsed, _ := url.ParseQuery(strings.TrimPrefix(v, "?"))
+				values = parsed
+			case map[string]interface{}:
+				for k, val := range v {
+					values.Set(k, fmt.Sprintf("%v", val))
+				}
+			}
+		}
+
+		paramsObj.Set("append", func(call goja.FunctionCall) goja.Value {
+			if len(call.Arguments) >= 2 {
+				values.Add(call.Arguments[0].String(), call.Arguments[1].String())
+			}
+			return goja.Undefined()
+		})
+
+		paramsObj.Set("delete", func(call goja.FunctionCall) goja.Value {
+			if len(call.Arguments) >= 1 {
+				values.Del(call.Arguments[0].String())
+			}
+			return goja.Undefined()
+		})
+
+		paramsObj.Set("get", func(call goja.FunctionCall) goja.Value {
+			if len(call.Arguments) < 1 {
+				return goja.Null()
+			}
+			if val := values.Get(call.Arguments[0].String()); val != "" {
+				return vm.ToValue(val)
+			}
+			return goja.Null()
+		})
+
+		paramsObj.Set("getAll", func(call goja.FunctionCall) goja.Value {
+			if len(call.Arguments) < 1 {
+				return vm.ToValue([]string{})
+			}
+			return vm.ToValue(values[call.Arguments[0].String()])
+		})
+
+		paramsObj.Set("has", func(call goja.FunctionCall) goja.Value {
+			if len(call.Arguments) < 1 {
+				return vm.ToValue(false)
+			}
+			return vm.ToValue(values.Has(call.Arguments[0].String()))
+		})
+
+		paramsObj.Set("set", func(call goja.FunctionCall) goja.Value {
+			if len(call.Arguments) >= 2 {
+				values.Set(call.Arguments[0].String(), call.Arguments[1].String())
+			}
+			return goja.Undefined()
+		})
+
+		paramsObj.Set("toString", func(call goja.FunctionCall) goja.Value {
+			return vm.ToValue(values.Encode())
+		})
+
+		return nil
+	})
+}
+
+// registerJSONGlobal ensures JSON global is properly set up
+func (r *ExtensionRuntime) registerJSONGlobal(vm *goja.Runtime) {
+	// JSON is already built-in to Goja, but we can enhance it
+	// This ensures JSON.parse and JSON.stringify work as expected
+
+	// The built-in JSON object should already work, but let's verify
+	// and add any missing functionality if needed
+	jsonScript := `
+		if (typeof JSON === 'undefined') {
+			var JSON = {
+				parse: function(text) {
+					return utils.parseJSON(text);
+				},
+				stringify: function(value, replacer, space) {
+					return utils.stringifyJSON(value);
+				}
+			};
+		}
+	`
+	_, _ = vm.RunString(jsonScript)
+}

go_backend/extension_runtime_storage.go

@@ -0,0 +1,381 @@
+// Package gobackend provides Storage and Credentials API for extension runtime
+package gobackend
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/rand"
+	"crypto/sha256"
+	"encoding/json"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+
+	"github.com/dop251/goja"
+)
+
+// ==================== Storage API ====================
+
+// getStoragePath returns the path to the extension's storage file
+func (r *ExtensionRuntime) getStoragePath() string {
+	return filepath.Join(r.dataDir, "storage.json")
+}
+
+// loadStorage loads the storage data from disk
+func (r *ExtensionRuntime) loadStorage() (map[string]interface{}, error) {
+	storagePath := r.getStoragePath()
+	data, err := os.ReadFile(storagePath)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return make(map[string]interface{}), nil
+		}
+		return nil, err
+	}
+
+	var storage map[string]interface{}
+	if err := json.Unmarshal(data, &storage); err != nil {
+		return nil, err
+	}
+
+	return storage, nil
+}
+
+// saveStorage saves the storage data to disk
+func (r *ExtensionRuntime) saveStorage(storage map[string]interface{}) error {
+	storagePath := r.getStoragePath()
+	data, err := json.MarshalIndent(storage, "", "  ")
+	if err != nil {
+		return err
+	}
+
+	return os.WriteFile(storagePath, data, 0644)
+}
+
+// storageGet retrieves a value from storage
+func (r *ExtensionRuntime) storageGet(call goja.FunctionCall) goja.Value {
+	if len(call.Arguments) < 1 {
+		return goja.Undefined()
+	}
+
+	key := call.Arguments[0].String()
+
+	storage, err := r.loadStorage()
+	if err != nil {
+		GoLog("[Extension:%s] Storage load error: %v\n", r.extensionID, err)
+		return goja.Undefined()
+	}
+
+	value, exists := storage[key]
+	if !exists {
+		// Return default value if provided
+		if len(call.Arguments) > 1 {
+			return call.Arguments[1]
+		}
+		return goja.Undefined()
+	}
+
+	return r.vm.ToValue(value)
+}
+
+// storageSet stores a value in storage
+func (r *ExtensionRuntime) storageSet(call goja.FunctionCall) goja.Value {
+	if len(call.Arguments) < 2 {
+		return r.vm.ToValue(false)
+	}
+
+	key := call.Arguments[0].String()
+	value := call.Arguments[1].Export()
+
+	storage, err := r.loadStorage()
+	if err != nil {
+		GoLog("[Extension:%s] Storage load error: %v\n", r.extensionID, err)
+		return r.vm.ToValue(false)
+	}
+
+	storage[key] = value
+
+	if err := r.saveStorage(storage); err != nil {
+		GoLog("[Extension:%s] Storage save error: %v\n", r.extensionID, err)
+		return r.vm.ToValue(false)
+	}
+
+	return r.vm.ToValue(true)
+}
+
+// storageRemove removes a value from storage
+func (r *ExtensionRuntime) storageRemove(call goja.FunctionCall) goja.Value {
+	if len(call.Arguments) < 1 {
+		return r.vm.ToValue(false)
+	}
+
+	key := call.Arguments[0].String()
+
+	storage, err := r.loadStorage()
+	if err != nil {
+		GoLog("[Extension:%s] Storage load error: %v\n", r.extensionID, err)
+		return r.vm.ToValue(false)
+	}
+
+	delete(storage, key)
+
+	if err := r.saveStorage(storage); err != nil {
+		GoLog("[Extension:%s] Storage save error: %v\n", r.extensionID, err)
+		return r.vm.ToValue(false)
+	}
+
+	return r.vm.ToValue(true)
+}
+
+// ==================== Credentials API (Encrypted Storage) ====================
+
+// getCredentialsPath returns the path to the extension's encrypted credentials file
+func (r *ExtensionRuntime) getCredentialsPath() string {
+	return filepath.Join(r.dataDir, ".credentials.enc")
+}
+
+// getSaltPath returns the path to the extension's encryption salt file
+func (r *ExtensionRuntime) getSaltPath() string {
+	return filepath.Join(r.dataDir, ".cred_salt")
+}
+
+// getOrCreateSalt gets existing salt or creates a new random one
+func (r *ExtensionRuntime) getOrCreateSalt() ([]byte, error) {
+	saltPath := r.getSaltPath()
+
+	// Try to read existing salt
+	salt, err := os.ReadFile(saltPath)
+	if err == nil && len(salt) == 32 {
+		return salt, nil
+	}
+
+	// Generate new random salt (32 bytes)
+	salt = make([]byte, 32)
+	if _, err := io.ReadFull(rand.Reader, salt); err != nil {
+		return nil, fmt.Errorf("failed to generate salt: %w", err)
+	}
+
+	// Save salt to file
+	if err := os.WriteFile(saltPath, salt, 0600); err != nil {
+		return nil, fmt.Errorf("failed to save salt: %w", err)
+	}
+
+	return salt, nil
+}
+
+// getEncryptionKey derives an encryption key from extension ID + random salt
+func (r *ExtensionRuntime) getEncryptionKey() ([]byte, error) {
+	// Get or create per-installation random salt
+	salt, err := r.getOrCreateSalt()
+	if err != nil {
+		return nil, err
+	}
+
+	// Combine extension ID + random salt for key derivation
+	// This makes each installation unique, preventing mass decryption attacks
+	combined := append([]byte(r.extensionID), salt...)
+	hash := sha256.Sum256(combined)
+	return hash[:], nil
+}
+
+// loadCredentials loads and decrypts credentials from disk
+func (r *ExtensionRuntime) loadCredentials() (map[string]interface{}, error) {
+	credPath := r.getCredentialsPath()
+	data, err := os.ReadFile(credPath)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return make(map[string]interface{}), nil
+		}
+		return nil, err
+	}
+
+	// Decrypt the data
+	key, err := r.getEncryptionKey()
+	if err != nil {
+		return nil, fmt.Errorf("failed to get encryption key: %w", err)
+	}
+	decrypted, err := decryptAES(data, key)
+	if err != nil {
+		return nil, fmt.Errorf("failed to decrypt credentials: %w", err)
+	}
+
+	var creds map[string]interface{}
+	if err := json.Unmarshal(decrypted, &creds); err != nil {
+		return nil, err
+	}
+
+	return creds, nil
+}
+
+// saveCredentials encrypts and saves credentials to disk
+func (r *ExtensionRuntime) saveCredentials(creds map[string]interface{}) error {
+	data, err := json.Marshal(creds)
+	if err != nil {
+		return err
+	}
+
+	// Encrypt the data
+	key, err := r.getEncryptionKey()
+	if err != nil {
+		return fmt.Errorf("failed to get encryption key: %w", err)
+	}
+	encrypted, err := encryptAES(data, key)
+	if err != nil {
+		return fmt.Errorf("failed to encrypt credentials: %w", err)
+	}
+
+	credPath := r.getCredentialsPath()
+	return os.WriteFile(credPath, encrypted, 0600) // Restrictive permissions
+}
+
+// credentialsStore stores an encrypted credential
+func (r *ExtensionRuntime) credentialsStore(call goja.FunctionCall) goja.Value {
+	if len(call.Arguments) < 2 {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   "key and value are required",
+		})
+	}
+
+	key := call.Arguments[0].String()
+	value := call.Arguments[1].Export()
+
+	creds, err := r.loadCredentials()
+	if err != nil {
+		GoLog("[Extension:%s] Credentials load error: %v\n", r.extensionID, err)
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   err.Error(),
+		})
+	}
+
+	creds[key] = value
+
+	if err := r.saveCredentials(creds); err != nil {
+		GoLog("[Extension:%s] Credentials save error: %v\n", r.extensionID, err)
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   err.Error(),
+		})
+	}
+
+	return r.vm.ToValue(map[string]interface{}{
+		"success": true,
+	})
+}
+
+// credentialsGet retrieves a decrypted credential
+func (r *ExtensionRuntime) credentialsGet(call goja.FunctionCall) goja.Value {
+	if len(call.Arguments) < 1 {
+		return goja.Undefined()
+	}
+
+	key := call.Arguments[0].String()
+
+	creds, err := r.loadCredentials()
+	if err != nil {
+		GoLog("[Extension:%s] Credentials load error: %v\n", r.extensionID, err)
+		return goja.Undefined()
+	}
+
+	value, exists := creds[key]
+	if !exists {
+		// Return default value if provided
+		if len(call.Arguments) > 1 {
+			return call.Arguments[1]
+		}
+		return goja.Undefined()
+	}
+
+	return r.vm.ToValue(value)
+}
+
+// credentialsRemove removes a credential
+func (r *ExtensionRuntime) credentialsRemove(call goja.FunctionCall) goja.Value {
+	if len(call.Arguments) < 1 {
+		return r.vm.ToValue(false)
+	}
+
+	key := call.Arguments[0].String()
+
+	creds, err := r.loadCredentials()
+	if err != nil {
+		GoLog("[Extension:%s] Credentials load error: %v\n", r.extensionID, err)
+		return r.vm.ToValue(false)
+	}
+
+	delete(creds, key)
+
+	if err := r.saveCredentials(creds); err != nil {
+		GoLog("[Extension:%s] Credentials save error: %v\n", r.extensionID, err)
+		return r.vm.ToValue(false)
+	}
+
+	return r.vm.ToValue(true)
+}
+
+// credentialsHas checks if a credential exists
+func (r *ExtensionRuntime) credentialsHas(call goja.FunctionCall) goja.Value {
+	if len(call.Arguments) < 1 {
+		return r.vm.ToValue(false)
+	}
+
+	key := call.Arguments[0].String()
+
+	creds, err := r.loadCredentials()
+	if err != nil {
+		return r.vm.ToValue(false)
+	}
+
+	_, exists := creds[key]
+	return r.vm.ToValue(exists)
+}
+
+// ==================== Crypto Utilities ====================
+
+// encryptAES encrypts data using AES-GCM
+func encryptAES(plaintext []byte, key []byte) ([]byte, error) {
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		return nil, err
+	}
+
+	gcm, err := cipher.NewGCM(block)
+	if err != nil {
+		return nil, err
+	}
+
+	nonce := make([]byte, gcm.NonceSize())
+	if _, err := io.ReadFull(rand.Reader, nonce); err != nil {
+		return nil, err
+	}
+
+	ciphertext := gcm.Seal(nonce, nonce, plaintext, nil)
+	return ciphertext, nil
+}
+
+// decryptAES decrypts data using AES-GCM
+func decryptAES(ciphertext []byte, key []byte) ([]byte, error) {
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		return nil, err
+	}
+
+	gcm, err := cipher.NewGCM(block)
+	if err != nil {
+		return nil, err
+	}
+
+	nonceSize := gcm.NonceSize()
+	if len(ciphertext) < nonceSize {
+		return nil, fmt.Errorf("ciphertext too short")
+	}
+
+	nonce, ciphertext := ciphertext[:nonceSize], ciphertext[nonceSize:]
+	plaintext, err := gcm.Open(nil, nonce, ciphertext, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	return plaintext, nil
+}

go_backend/extension_runtime_utils.go

@@ -0,0 +1,372 @@
+// Package gobackend provides Utility functions for extension runtime
+package gobackend
+
+import (
+	"crypto/hmac"
+	"crypto/md5"
+	"crypto/rand"
+	"crypto/sha1"
+	"crypto/sha256"
+	"encoding/base64"
+	"encoding/hex"
+	"encoding/json"
+	"fmt"
+	"strings"
+
+	"github.com/dop251/goja"
+)
+
+// ==================== Utility Functions ====================
+
+// base64Encode encodes a string to base64
+func (r *ExtensionRuntime) base64Encode(call goja.FunctionCall) goja.Value {
+	if len(call.Arguments) < 1 {
+		return r.vm.ToValue("")
+	}
+	input := call.Arguments[0].String()
+	return r.vm.ToValue(base64.StdEncoding.EncodeToString([]byte(input)))
+}
+
+// base64Decode decodes a base64 string
+func (r *ExtensionRuntime) base64Decode(call goja.FunctionCall) goja.Value {
+	if len(call.Arguments) < 1 {
+		return r.vm.ToValue("")
+	}
+	input := call.Arguments[0].String()
+	decoded, err := base64.StdEncoding.DecodeString(input)
+	if err != nil {
+		return r.vm.ToValue("")
+	}
+	return r.vm.ToValue(string(decoded))
+}
+
+// md5Hash computes MD5 hash of a string
+func (r *ExtensionRuntime) md5Hash(call goja.FunctionCall) goja.Value {
+	if len(call.Arguments) < 1 {
+		return r.vm.ToValue("")
+	}
+	input := call.Arguments[0].String()
+	hash := md5.Sum([]byte(input))
+	return r.vm.ToValue(hex.EncodeToString(hash[:]))
+}
+
+// sha256Hash computes SHA256 hash of a string
+func (r *ExtensionRuntime) sha256Hash(call goja.FunctionCall) goja.Value {
+	if len(call.Arguments) < 1 {
+		return r.vm.ToValue("")
+	}
+	input := call.Arguments[0].String()
+	hash := sha256.Sum256([]byte(input))
+	return r.vm.ToValue(hex.EncodeToString(hash[:]))
+}
+
+// hmacSHA256 computes HMAC-SHA256 of a message with a key
+func (r *ExtensionRuntime) hmacSHA256(call goja.FunctionCall) goja.Value {
+	if len(call.Arguments) < 2 {
+		return r.vm.ToValue("")
+	}
+	message := call.Arguments[0].String()
+	key := call.Arguments[1].String()
+
+	mac := hmac.New(sha256.New, []byte(key))
+	mac.Write([]byte(message))
+	return r.vm.ToValue(hex.EncodeToString(mac.Sum(nil)))
+}
+
+// hmacSHA256Base64 computes HMAC-SHA256 and returns base64 encoded result
+func (r *ExtensionRuntime) hmacSHA256Base64(call goja.FunctionCall) goja.Value {
+	if len(call.Arguments) < 2 {
+		return r.vm.ToValue("")
+	}
+	message := call.Arguments[0].String()
+	key := call.Arguments[1].String()
+
+	mac := hmac.New(sha256.New, []byte(key))
+	mac.Write([]byte(message))
+	return r.vm.ToValue(base64.StdEncoding.EncodeToString(mac.Sum(nil)))
+}
+
+// hmacSHA1 computes HMAC-SHA1 of a message with a key (for TOTP)
+// Arguments: message (string or array of bytes), key (string or array of bytes)
+// Returns: array of bytes (for TOTP dynamic truncation)
+func (r *ExtensionRuntime) hmacSHA1(call goja.FunctionCall) goja.Value {
+	if len(call.Arguments) < 2 {
+		return r.vm.ToValue([]byte{})
+	}
+
+	// Get key - can be string or array of bytes
+	var keyBytes []byte
+	keyArg := call.Arguments[0].Export()
+	switch k := keyArg.(type) {
+	case string:
+		keyBytes = []byte(k)
+	case []interface{}:
+		keyBytes = make([]byte, len(k))
+		for i, v := range k {
+			if num, ok := v.(int64); ok {
+				keyBytes[i] = byte(num)
+			} else if num, ok := v.(float64); ok {
+				keyBytes[i] = byte(int(num))
+			}
+		}
+	default:
+		return r.vm.ToValue([]byte{})
+	}
+
+	// Get message - can be string or array of bytes
+	var msgBytes []byte
+	msgArg := call.Arguments[1].Export()
+	switch m := msgArg.(type) {
+	case string:
+		msgBytes = []byte(m)
+	case []interface{}:
+		msgBytes = make([]byte, len(m))
+		for i, v := range m {
+			if num, ok := v.(int64); ok {
+				msgBytes[i] = byte(num)
+			} else if num, ok := v.(float64); ok {
+				msgBytes[i] = byte(int(num))
+			}
+		}
+	default:
+		return r.vm.ToValue([]byte{})
+	}
+
+	mac := hmac.New(sha1.New, keyBytes)
+	mac.Write(msgBytes)
+	result := mac.Sum(nil)
+
+	// Convert to array of numbers for JavaScript
+	jsArray := make([]interface{}, len(result))
+	for i, b := range result {
+		jsArray[i] = int(b)
+	}
+	return r.vm.ToValue(jsArray)
+}
+
+// parseJSON parses a JSON string
+func (r *ExtensionRuntime) parseJSON(call goja.FunctionCall) goja.Value {
+	if len(call.Arguments) < 1 {
+		return goja.Undefined()
+	}
+	input := call.Arguments[0].String()
+
+	var result interface{}
+	if err := json.Unmarshal([]byte(input), &result); err != nil {
+		GoLog("[Extension:%s] JSON parse error: %v\n", r.extensionID, err)
+		return goja.Undefined()
+	}
+
+	return r.vm.ToValue(result)
+}
+
+// stringifyJSON converts a value to JSON string
+func (r *ExtensionRuntime) stringifyJSON(call goja.FunctionCall) goja.Value {
+	if len(call.Arguments) < 1 {
+		return r.vm.ToValue("")
+	}
+	input := call.Arguments[0].Export()
+
+	data, err := json.Marshal(input)
+	if err != nil {
+		GoLog("[Extension:%s] JSON stringify error: %v\n", r.extensionID, err)
+		return r.vm.ToValue("")
+	}
+
+	return r.vm.ToValue(string(data))
+}
+
+// ==================== Crypto Utilities for Extensions ====================
+
+// cryptoEncrypt encrypts a string using AES-GCM (for extension use)
+func (r *ExtensionRuntime) cryptoEncrypt(call goja.FunctionCall) goja.Value {
+	if len(call.Arguments) < 2 {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   "plaintext and key are required",
+		})
+	}
+
+	plaintext := call.Arguments[0].String()
+	keyStr := call.Arguments[1].String()
+
+	// Derive 32-byte key from provided key string
+	keyHash := sha256.Sum256([]byte(keyStr))
+
+	encrypted, err := encryptAES([]byte(plaintext), keyHash[:])
+	if err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   err.Error(),
+		})
+	}
+
+	return r.vm.ToValue(map[string]interface{}{
+		"success": true,
+		"data":    base64.StdEncoding.EncodeToString(encrypted),
+	})
+}
+
+// cryptoDecrypt decrypts a string using AES-GCM (for extension use)
+func (r *ExtensionRuntime) cryptoDecrypt(call goja.FunctionCall) goja.Value {
+	if len(call.Arguments) < 2 {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   "ciphertext and key are required",
+		})
+	}
+
+	ciphertextB64 := call.Arguments[0].String()
+	keyStr := call.Arguments[1].String()
+
+	ciphertext, err := base64.StdEncoding.DecodeString(ciphertextB64)
+	if err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   "invalid base64 ciphertext",
+		})
+	}
+
+	// Derive 32-byte key from provided key string
+	keyHash := sha256.Sum256([]byte(keyStr))
+
+	decrypted, err := decryptAES(ciphertext, keyHash[:])
+	if err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   err.Error(),
+		})
+	}
+
+	return r.vm.ToValue(map[string]interface{}{
+		"success": true,
+		"data":    string(decrypted),
+	})
+}
+
+// cryptoGenerateKey generates a random encryption key
+func (r *ExtensionRuntime) cryptoGenerateKey(call goja.FunctionCall) goja.Value {
+	length := 32 // Default 256-bit key
+	if len(call.Arguments) > 0 && !goja.IsUndefined(call.Arguments[0]) {
+		if l, ok := call.Arguments[0].Export().(float64); ok {
+			length = int(l)
+		}
+	}
+
+	key := make([]byte, length)
+	if _, err := rand.Read(key); err != nil {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   err.Error(),
+		})
+	}
+
+	return r.vm.ToValue(map[string]interface{}{
+		"success": true,
+		"key":     base64.StdEncoding.EncodeToString(key),
+		"hex":     hex.EncodeToString(key),
+	})
+}
+
+// ==================== Logging Functions ====================
+
+func (r *ExtensionRuntime) logDebug(call goja.FunctionCall) goja.Value {
+	msg := r.formatLogArgs(call.Arguments)
+	GoLog("[Extension:%s:DEBUG] %s\n", r.extensionID, msg)
+	return goja.Undefined()
+}
+
+func (r *ExtensionRuntime) logInfo(call goja.FunctionCall) goja.Value {
+	msg := r.formatLogArgs(call.Arguments)
+	GoLog("[Extension:%s:INFO] %s\n", r.extensionID, msg)
+	return goja.Undefined()
+}
+
+func (r *ExtensionRuntime) logWarn(call goja.FunctionCall) goja.Value {
+	msg := r.formatLogArgs(call.Arguments)
+	GoLog("[Extension:%s:WARN] %s\n", r.extensionID, msg)
+	return goja.Undefined()
+}
+
+func (r *ExtensionRuntime) logError(call goja.FunctionCall) goja.Value {
+	msg := r.formatLogArgs(call.Arguments)
+	GoLog("[Extension:%s:ERROR] %s\n", r.extensionID, msg)
+	return goja.Undefined()
+}
+
+func (r *ExtensionRuntime) formatLogArgs(args []goja.Value) string {
+	parts := make([]string, len(args))
+	for i, arg := range args {
+		parts[i] = fmt.Sprintf("%v", arg.Export())
+	}
+	return strings.Join(parts, " ")
+}
+
+// ==================== Go Backend Wrappers ====================
+
+func (r *ExtensionRuntime) sanitizeFilenameWrapper(call goja.FunctionCall) goja.Value {
+	if len(call.Arguments) < 1 {
+		return r.vm.ToValue("")
+	}
+	input := call.Arguments[0].String()
+	return r.vm.ToValue(sanitizeFilename(input))
+}
+
+// RegisterGoBackendAPIs adds more Go backend functions to the VM
+func (r *ExtensionRuntime) RegisterGoBackendAPIs(vm *goja.Runtime) {
+	gobackendObj := vm.Get("gobackend")
+	if gobackendObj == nil || goja.IsUndefined(gobackendObj) {
+		gobackendObj = vm.NewObject()
+		vm.Set("gobackend", gobackendObj)
+	}
+
+	obj := gobackendObj.(*goja.Object)
+
+	// Expose sanitizeFilename
+	obj.Set("sanitizeFilename", func(call goja.FunctionCall) goja.Value {
+		if len(call.Arguments) < 1 {
+			return vm.ToValue("")
+		}
+		return vm.ToValue(sanitizeFilename(call.Arguments[0].String()))
+	})
+
+	// Expose getAudioQuality
+	obj.Set("getAudioQuality", func(call goja.FunctionCall) goja.Value {
+		if len(call.Arguments) < 1 {
+			return vm.ToValue(map[string]interface{}{
+				"error": "file path is required",
+			})
+		}
+
+		filePath := call.Arguments[0].String()
+		quality, err := GetAudioQuality(filePath)
+		if err != nil {
+			return vm.ToValue(map[string]interface{}{
+				"error": err.Error(),
+			})
+		}
+
+		return vm.ToValue(map[string]interface{}{
+			"bitDepth":     quality.BitDepth,
+			"sampleRate":   quality.SampleRate,
+			"totalSamples": quality.TotalSamples,
+		})
+	})
+
+	// Expose buildFilename
+	obj.Set("buildFilename", func(call goja.FunctionCall) goja.Value {
+		if len(call.Arguments) < 2 {
+			return vm.ToValue("")
+		}
+
+		template := call.Arguments[0].String()
+		metadataObj := call.Arguments[1].Export()
+
+		metadata, ok := metadataObj.(map[string]interface{})
+		if !ok {
+			return vm.ToValue("")
+		}
+
+		return vm.ToValue(buildFilenameFromTemplate(template, metadata))
+	})
+}

go_backend/extension_settings.go

@@ -0,0 +1,221 @@
+// Package gobackend provides extension settings storage
+package gobackend
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+	"path/filepath"
+	"sync"
+)
+
+// ExtensionSettingsStore manages settings for all extensions
+type ExtensionSettingsStore struct {
+	mu       sync.RWMutex
+	dataDir  string
+	settings map[string]map[string]interface{} // extensionID -> settings
+}
+
+// Global settings store
+var (
+	globalSettingsStore     *ExtensionSettingsStore
+	globalSettingsStoreOnce sync.Once
+)
+
+// GetExtensionSettingsStore returns the global settings store
+func GetExtensionSettingsStore() *ExtensionSettingsStore {
+	globalSettingsStoreOnce.Do(func() {
+		globalSettingsStore = &ExtensionSettingsStore{
+			settings: make(map[string]map[string]interface{}),
+		}
+	})
+	return globalSettingsStore
+}
+
+// SetDataDir sets the data directory for settings storage
+func (s *ExtensionSettingsStore) SetDataDir(dataDir string) error {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	s.dataDir = dataDir
+	if err := os.MkdirAll(dataDir, 0755); err != nil {
+		return fmt.Errorf("failed to create settings directory: %w", err)
+	}
+
+	// Load all existing settings
+	return s.loadAllSettings()
+}
+
+// getSettingsPath returns the path to an extension's settings file
+func (s *ExtensionSettingsStore) getSettingsPath(extensionID string) string {
+	return filepath.Join(s.dataDir, extensionID, "settings.json")
+}
+
+// loadAllSettings loads settings for all extensions from disk
+func (s *ExtensionSettingsStore) loadAllSettings() error {
+	entries, err := os.ReadDir(s.dataDir)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return nil
+		}
+		return err
+	}
+
+	for _, entry := range entries {
+		if entry.IsDir() {
+			extensionID := entry.Name()
+			settings, err := s.loadSettings(extensionID)
+			if err != nil {
+				GoLog("[ExtensionSettings] Failed to load settings for %s: %v\n", extensionID, err)
+				continue
+			}
+			s.settings[extensionID] = settings
+		}
+	}
+
+	return nil
+}
+
+// loadSettings loads settings for a specific extension
+func (s *ExtensionSettingsStore) loadSettings(extensionID string) (map[string]interface{}, error) {
+	settingsPath := s.getSettingsPath(extensionID)
+	data, err := os.ReadFile(settingsPath)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return make(map[string]interface{}), nil
+		}
+		return nil, err
+	}
+
+	var settings map[string]interface{}
+	if err := json.Unmarshal(data, &settings); err != nil {
+		return nil, err
+	}
+
+	return settings, nil
+}
+
+// saveSettings saves settings for a specific extension
+func (s *ExtensionSettingsStore) saveSettings(extensionID string, settings map[string]interface{}) error {
+	settingsPath := s.getSettingsPath(extensionID)
+
+	// Create directory if needed
+	dir := filepath.Dir(settingsPath)
+	if err := os.MkdirAll(dir, 0755); err != nil {
+		return err
+	}
+
+	data, err := json.MarshalIndent(settings, "", "  ")
+	if err != nil {
+		return err
+	}
+
+	return os.WriteFile(settingsPath, data, 0644)
+}
+
+// Get retrieves a setting value for an extension
+// Returns error if extension or key not found (gomobile compatible)
+func (s *ExtensionSettingsStore) Get(extensionID, key string) (interface{}, error) {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+
+	extSettings, exists := s.settings[extensionID]
+	if !exists {
+		return nil, fmt.Errorf("extension '%s' settings not found", extensionID)
+	}
+
+	value, exists := extSettings[key]
+	if !exists {
+		return nil, fmt.Errorf("setting '%s' not found for extension '%s'", key, extensionID)
+	}
+	return value, nil
+}
+
+// GetAll retrieves all settings for an extension
+func (s *ExtensionSettingsStore) GetAll(extensionID string) map[string]interface{} {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+
+	extSettings, exists := s.settings[extensionID]
+	if !exists {
+		return make(map[string]interface{})
+	}
+
+	// Return a copy
+	result := make(map[string]interface{})
+	for k, v := range extSettings {
+		result[k] = v
+	}
+	return result
+}
+
+// Set stores a setting value for an extension
+func (s *ExtensionSettingsStore) Set(extensionID, key string, value interface{}) error {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	if _, exists := s.settings[extensionID]; !exists {
+		s.settings[extensionID] = make(map[string]interface{})
+	}
+
+	s.settings[extensionID][key] = value
+
+	// Persist to disk
+	return s.saveSettings(extensionID, s.settings[extensionID])
+}
+
+// SetAll stores all settings for an extension
+func (s *ExtensionSettingsStore) SetAll(extensionID string, settings map[string]interface{}) error {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	s.settings[extensionID] = settings
+
+	// Persist to disk
+	return s.saveSettings(extensionID, settings)
+}
+
+// Remove removes a setting for an extension
+func (s *ExtensionSettingsStore) Remove(extensionID, key string) error {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	extSettings, exists := s.settings[extensionID]
+	if !exists {
+		return nil
+	}
+
+	delete(extSettings, key)
+
+	// Persist to disk
+	return s.saveSettings(extensionID, extSettings)
+}
+
+// RemoveAll removes all settings for an extension
+func (s *ExtensionSettingsStore) RemoveAll(extensionID string) error {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	delete(s.settings, extensionID)
+
+	// Remove settings file
+	settingsPath := s.getSettingsPath(extensionID)
+	if err := os.Remove(settingsPath); err != nil && !os.IsNotExist(err) {
+		return err
+	}
+
+	return nil
+}
+
+// GetAllExtensionSettings returns settings for all extensions as JSON
+func (s *ExtensionSettingsStore) GetAllExtensionSettingsJSON() (string, error) {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+
+	data, err := json.Marshal(s.settings)
+	if err != nil {
+		return "", err
+	}
+
+	return string(data), nil
+}

go_backend/extension_store.go

@@ -0,0 +1,453 @@
+package gobackend
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"path/filepath"
+	"sync"
+	"time"
+)
+
+// Extension categories
+const (
+	CategoryMetadata    = "metadata"
+	CategoryDownload    = "download"
+	CategoryUtility     = "utility"
+	CategoryLyrics      = "lyrics"
+	CategoryIntegration = "integration"
+)
+
+// StoreExtension represents an extension in the store
+type StoreExtension struct {
+	ID            string   `json:"id"`
+	Name          string   `json:"name"`
+	DisplayName   string   `json:"display_name,omitempty"`
+	Version       string   `json:"version"`
+	Author        string   `json:"author"`
+	Description   string   `json:"description"`
+	DownloadURL   string   `json:"download_url,omitempty"`
+	IconURL       string   `json:"icon_url,omitempty"`
+	Category      string   `json:"category"`
+	Tags          []string `json:"tags,omitempty"`
+	Downloads     int      `json:"downloads"`
+	UpdatedAt     string   `json:"updated_at"`
+	MinAppVersion string   `json:"min_app_version,omitempty"`
+	// Alternative camelCase fields (for flexibility)
+	DisplayNameAlt   string `json:"displayName,omitempty"`
+	DownloadURLAlt   string `json:"downloadUrl,omitempty"`
+	IconURLAlt       string `json:"iconUrl,omitempty"`
+	MinAppVersionAlt string `json:"minAppVersion,omitempty"`
+}
+
+// getDisplayName returns display name, falling back to name (private to avoid gomobile conflict)
+func (e *StoreExtension) getDisplayName() string {
+	if e.DisplayName != "" {
+		return e.DisplayName
+	}
+	if e.DisplayNameAlt != "" {
+		return e.DisplayNameAlt
+	}
+	return e.Name
+}
+
+// getDownloadURL returns download URL from either field (private to avoid gomobile conflict)
+func (e *StoreExtension) getDownloadURL() string {
+	if e.DownloadURL != "" {
+		return e.DownloadURL
+	}
+	return e.DownloadURLAlt
+}
+
+// getIconURL returns icon URL from either field (private to avoid gomobile conflict)
+func (e *StoreExtension) getIconURL() string {
+	if e.IconURL != "" {
+		return e.IconURL
+	}
+	return e.IconURLAlt
+}
+
+// getMinAppVersion returns min app version from either field (private to avoid gomobile conflict)
+func (e *StoreExtension) getMinAppVersion() string {
+	if e.MinAppVersion != "" {
+		return e.MinAppVersion
+	}
+	return e.MinAppVersionAlt
+}
+
+// StoreRegistry represents the extension registry
+type StoreRegistry struct {
+	Version    int              `json:"version"`
+	UpdatedAt  string           `json:"updated_at"`
+	Extensions []StoreExtension `json:"extensions"`
+}
+
+// StoreExtensionResponse is the normalized response sent to Flutter
+type StoreExtensionResponse struct {
+	ID               string   `json:"id"`
+	Name             string   `json:"name"`
+	DisplayName      string   `json:"display_name"`
+	Version          string   `json:"version"`
+	Author           string   `json:"author"`
+	Description      string   `json:"description"`
+	DownloadURL      string   `json:"download_url"`
+	IconURL          string   `json:"icon_url,omitempty"`
+	Category         string   `json:"category"`
+	Tags             []string `json:"tags,omitempty"`
+	Downloads        int      `json:"downloads"`
+	UpdatedAt        string   `json:"updated_at"`
+	MinAppVersion    string   `json:"min_app_version,omitempty"`
+	IsInstalled      bool     `json:"is_installed"`
+	InstalledVersion string   `json:"installed_version,omitempty"`
+	HasUpdate        bool     `json:"has_update"`
+}
+
+// ToResponse converts StoreExtension to normalized response
+func (e *StoreExtension) ToResponse() StoreExtensionResponse {
+	return StoreExtensionResponse{
+		ID:            e.ID,
+		Name:          e.Name,
+		DisplayName:   e.getDisplayName(),
+		Version:       e.Version,
+		Author:        e.Author,
+		Description:   e.Description,
+		DownloadURL:   e.getDownloadURL(),
+		IconURL:       e.getIconURL(),
+		Category:      e.Category,
+		Tags:          e.Tags,
+		Downloads:     e.Downloads,
+		UpdatedAt:     e.UpdatedAt,
+		MinAppVersion: e.getMinAppVersion(),
+	}
+}
+
+// ExtensionStore manages the extension store
+type ExtensionStore struct {
+	registryURL string
+	cacheDir    string
+	cache       *StoreRegistry
+	cacheMu     sync.RWMutex
+	cacheTime   time.Time
+	cacheTTL    time.Duration
+}
+
+var (
+	extensionStore   *ExtensionStore
+	extensionStoreMu sync.Mutex
+)
+
+const (
+	defaultRegistryURL = "https://raw.githubusercontent.com/zarzet/SpotiFLAC-Extension/main/registry.json"
+	cacheTTL           = 30 * time.Minute
+	cacheFileName      = "store_cache.json"
+)
+
+// InitExtensionStore initializes the extension store
+func InitExtensionStore(cacheDir string) *ExtensionStore {
+	extensionStoreMu.Lock()
+	defer extensionStoreMu.Unlock()
+
+	if extensionStore == nil {
+		extensionStore = &ExtensionStore{
+			registryURL: defaultRegistryURL,
+			cacheDir:    cacheDir,
+			cacheTTL:    cacheTTL,
+		}
+		// Try to load from disk cache
+		extensionStore.loadDiskCache()
+	}
+	return extensionStore
+}
+
+// GetExtensionStore returns the singleton store instance
+func GetExtensionStore() *ExtensionStore {
+	extensionStoreMu.Lock()
+	defer extensionStoreMu.Unlock()
+	return extensionStore
+}
+
+// loadDiskCache loads cached registry from disk
+func (s *ExtensionStore) loadDiskCache() {
+	if s.cacheDir == "" {
+		return
+	}
+
+	cachePath := filepath.Join(s.cacheDir, cacheFileName)
+	data, err := os.ReadFile(cachePath)
+	if err != nil {
+		return
+	}
+
+	var cacheData struct {
+		Registry  StoreRegistry `json:"registry"`
+		CacheTime int64         `json:"cache_time"`
+	}
+
+	if err := json.Unmarshal(data, &cacheData); err != nil {
+		return
+	}
+
+	s.cache = &cacheData.Registry
+	s.cacheTime = time.Unix(cacheData.CacheTime, 0)
+	LogDebug("ExtensionStore", "Loaded %d extensions from disk cache", len(s.cache.Extensions))
+}
+
+// saveDiskCache saves registry to disk cache
+func (s *ExtensionStore) saveDiskCache() {
+	if s.cacheDir == "" || s.cache == nil {
+		return
+	}
+
+	cacheData := struct {
+		Registry  StoreRegistry `json:"registry"`
+		CacheTime int64         `json:"cache_time"`
+	}{
+		Registry:  *s.cache,
+		CacheTime: s.cacheTime.Unix(),
+	}
+
+	data, err := json.Marshal(cacheData)
+	if err != nil {
+		return
+	}
+
+	cachePath := filepath.Join(s.cacheDir, cacheFileName)
+	os.WriteFile(cachePath, data, 0644)
+}
+
+// FetchRegistry fetches the extension registry from GitHub
+func (s *ExtensionStore) FetchRegistry(forceRefresh bool) (*StoreRegistry, error) {
+	s.cacheMu.Lock()
+	defer s.cacheMu.Unlock()
+
+	// Return cached if valid and not forcing refresh
+	if !forceRefresh && s.cache != nil && time.Since(s.cacheTime) < s.cacheTTL {
+		LogDebug("ExtensionStore", "Using cached registry (%d extensions)", len(s.cache.Extensions))
+		return s.cache, nil
+	}
+
+	LogInfo("ExtensionStore", "Fetching registry from %s", s.registryURL)
+
+	client := &http.Client{Timeout: 30 * time.Second}
+	resp, err := client.Get(s.registryURL)
+	if err != nil {
+		// Return cached data if available on network error
+		if s.cache != nil {
+			LogWarn("ExtensionStore", "Network error, using cached registry: %v", err)
+			return s.cache, nil
+		}
+		return nil, fmt.Errorf("failed to fetch registry: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		if s.cache != nil {
+			LogWarn("ExtensionStore", "HTTP %d, using cached registry", resp.StatusCode)
+			return s.cache, nil
+		}
+		return nil, fmt.Errorf("registry returned HTTP %d", resp.StatusCode)
+	}
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read registry: %w", err)
+	}
+
+	var registry StoreRegistry
+	if err := json.Unmarshal(body, &registry); err != nil {
+		return nil, fmt.Errorf("failed to parse registry: %w", err)
+	}
+
+	s.cache = &registry
+	s.cacheTime = time.Now()
+	s.saveDiskCache()
+
+	LogInfo("ExtensionStore", "Fetched %d extensions from registry", len(registry.Extensions))
+	return &registry, nil
+}
+
+// GetExtensionsWithStatus returns extensions with installation status
+func (s *ExtensionStore) GetExtensionsWithStatus() ([]StoreExtensionResponse, error) {
+	registry, err := s.FetchRegistry(false)
+	if err != nil {
+		return nil, err
+	}
+
+	manager := GetExtensionManager()
+	installed := make(map[string]string) // id -> version
+
+	if manager != nil {
+		for _, ext := range manager.GetAllExtensions() {
+			installed[ext.ID] = ext.Manifest.Version
+		}
+	}
+
+	result := make([]StoreExtensionResponse, len(registry.Extensions))
+	for i, ext := range registry.Extensions {
+		resp := ext.ToResponse()
+
+		if installedVersion, ok := installed[ext.ID]; ok {
+			resp.IsInstalled = true
+			resp.InstalledVersion = installedVersion
+			resp.HasUpdate = compareVersions(ext.Version, installedVersion) > 0
+		}
+
+		result[i] = resp
+	}
+
+	return result, nil
+}
+
+// DownloadExtension downloads an extension package to the specified path
+func (s *ExtensionStore) DownloadExtension(extensionID string, destPath string) error {
+	registry, err := s.FetchRegistry(false)
+	if err != nil {
+		return err
+	}
+
+	var ext *StoreExtension
+	for _, e := range registry.Extensions {
+		if e.ID == extensionID {
+			ext = &e
+			break
+		}
+	}
+
+	if ext == nil {
+		return fmt.Errorf("extension %s not found in store", extensionID)
+	}
+
+	LogInfo("ExtensionStore", "Downloading %s from %s", ext.getDisplayName(), ext.getDownloadURL())
+
+	client := &http.Client{Timeout: 5 * time.Minute}
+	resp, err := client.Get(ext.getDownloadURL())
+	if err != nil {
+		return fmt.Errorf("failed to download: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return fmt.Errorf("download returned HTTP %d", resp.StatusCode)
+	}
+
+	// Create destination file
+	out, err := os.Create(destPath)
+	if err != nil {
+		return fmt.Errorf("failed to create file: %w", err)
+	}
+	defer out.Close()
+
+	_, err = io.Copy(out, resp.Body)
+	if err != nil {
+		os.Remove(destPath)
+		return fmt.Errorf("failed to write file: %w", err)
+	}
+
+	LogInfo("ExtensionStore", "Downloaded %s to %s", ext.getDisplayName(), destPath)
+	return nil
+}
+
+// GetCategories returns all available categories
+func (s *ExtensionStore) GetCategories() []string {
+	return []string{
+		CategoryMetadata,
+		CategoryDownload,
+		CategoryUtility,
+		CategoryLyrics,
+		CategoryIntegration,
+	}
+}
+
+// SearchExtensions searches extensions by query
+func (s *ExtensionStore) SearchExtensions(query string, category string) ([]StoreExtensionResponse, error) {
+	extensions, err := s.GetExtensionsWithStatus()
+	if err != nil {
+		return nil, err
+	}
+
+	if query == "" && category == "" {
+		return extensions, nil
+	}
+
+	var result []StoreExtensionResponse
+	queryLower := toLower(query)
+
+	for _, ext := range extensions {
+		// Filter by category
+		if category != "" && ext.Category != category {
+			continue
+		}
+
+		// Filter by query
+		if query != "" {
+			if !containsIgnoreCase(ext.Name, queryLower) &&
+				!containsIgnoreCase(ext.DisplayName, queryLower) &&
+				!containsIgnoreCase(ext.Description, queryLower) &&
+				!containsIgnoreCase(ext.Author, queryLower) {
+				// Check tags
+				found := false
+				for _, tag := range ext.Tags {
+					if containsIgnoreCase(tag, queryLower) {
+						found = true
+						break
+					}
+				}
+				if !found {
+					continue
+				}
+			}
+		}
+
+		result = append(result, ext)
+	}
+
+	return result, nil
+}
+
+// ClearCache clears the in-memory and disk cache
+func (s *ExtensionStore) ClearCache() {
+	s.cacheMu.Lock()
+	defer s.cacheMu.Unlock()
+
+	s.cache = nil
+	s.cacheTime = time.Time{}
+
+	if s.cacheDir != "" {
+		cachePath := filepath.Join(s.cacheDir, cacheFileName)
+		os.Remove(cachePath)
+	}
+
+	LogInfo("ExtensionStore", "Cache cleared")
+}
+
+// Helper: case-insensitive contains
+func containsIgnoreCase(s, substr string) bool {
+	return containsStr(toLower(s), substr)
+}
+
+func toLower(s string) string {
+	result := make([]byte, len(s))
+	for i := 0; i < len(s); i++ {
+		c := s[i]
+		if c >= 'A' && c <= 'Z' {
+			c += 'a' - 'A'
+		}
+		result[i] = c
+	}
+	return string(result)
+}
+
+func containsStr(s, substr string) bool {
+	return len(substr) == 0 || (len(s) >= len(substr) && findSubstring(s, substr) >= 0)
+}
+
+func findSubstring(s, substr string) int {
+	for i := 0; i <= len(s)-len(substr); i++ {
+		if s[i:i+len(substr)] == substr {
+			return i
+		}
+	}
+	return -1
+}

go_backend/extension_test.go

@@ -0,0 +1,329 @@
+package gobackend
+
+import (
+	"path/filepath"
+	"testing"
+
+	"github.com/dop251/goja"
+)
+
+func TestParseManifest_Valid(t *testing.T) {
+	validManifest := `{
+		"name": "test-provider",
+		"displayName": "Test Provider",
+		"version": "1.0.0",
+		"author": "Test Author",
+		"description": "A test extension",
+		"type": ["metadata_provider"],
+		"permissions": {
+			"network": ["api.test.com"],
+			"storage": true
+		}
+	}`
+
+	manifest, err := ParseManifest([]byte(validManifest))
+	if err != nil {
+		t.Fatalf("Expected valid manifest to parse, got error: %v", err)
+	}
+
+	if manifest.Name != "test-provider" {
+		t.Errorf("Expected name 'test-provider', got '%s'", manifest.Name)
+	}
+
+	if manifest.Version != "1.0.0" {
+		t.Errorf("Expected version '1.0.0', got '%s'", manifest.Version)
+	}
+
+	if !manifest.IsMetadataProvider() {
+		t.Error("Expected IsMetadataProvider() to return true")
+	}
+
+	if manifest.IsDownloadProvider() {
+		t.Error("Expected IsDownloadProvider() to return false")
+	}
+}
+
+func TestParseManifest_MissingName(t *testing.T) {
+	invalidManifest := `{
+		"version": "1.0.0",
+		"author": "Test Author",
+		"description": "A test extension",
+		"type": ["metadata_provider"]
+	}`
+
+	_, err := ParseManifest([]byte(invalidManifest))
+	if err == nil {
+		t.Fatal("Expected error for missing name")
+	}
+}
+
+func TestParseManifest_MissingType(t *testing.T) {
+	invalidManifest := `{
+		"name": "test-provider",
+		"version": "1.0.0",
+		"author": "Test Author",
+		"description": "A test extension"
+	}`
+
+	_, err := ParseManifest([]byte(invalidManifest))
+	if err == nil {
+		t.Fatal("Expected error for missing type")
+	}
+}
+
+func TestIsDomainAllowed(t *testing.T) {
+	manifest := &ExtensionManifest{
+		Permissions: ExtensionPermissions{
+			Network: []string{"api.test.com", "*.example.com"},
+		},
+	}
+
+	tests := []struct {
+		domain   string
+		expected bool
+	}{
+		{"api.test.com", true},
+		{"api.example.com", true},
+		{"sub.example.com", true},
+		{"notallowed.com", false},
+		{"test.com", false},
+	}
+
+	for _, tt := range tests {
+		result := manifest.IsDomainAllowed(tt.domain)
+		if result != tt.expected {
+			t.Errorf("IsDomainAllowed(%s) = %v, expected %v", tt.domain, result, tt.expected)
+		}
+	}
+}
+
+func TestExtensionRuntime_NetworkSandbox(t *testing.T) {
+	// Create a mock extension with limited network permissions
+	ext := &LoadedExtension{
+		ID: "test-ext",
+		Manifest: &ExtensionManifest{
+			Name: "test-ext",
+			Permissions: ExtensionPermissions{
+				Network: []string{"api.allowed.com", "*.wildcard.com"},
+			},
+		},
+		DataDir: t.TempDir(),
+	}
+
+	runtime := NewExtensionRuntime(ext)
+
+	// Test allowed domains
+	if err := runtime.validateDomain("https://api.allowed.com/path"); err != nil {
+		t.Errorf("Expected api.allowed.com to be allowed, got error: %v", err)
+	}
+
+	if err := runtime.validateDomain("https://sub.wildcard.com/path"); err != nil {
+		t.Errorf("Expected sub.wildcard.com to be allowed (wildcard), got error: %v", err)
+	}
+
+	// Test blocked domains
+	if err := runtime.validateDomain("https://blocked.com/path"); err == nil {
+		t.Error("Expected blocked.com to be denied")
+	}
+
+	if err := runtime.validateDomain("https://notallowed.com/path"); err == nil {
+		t.Error("Expected notallowed.com to be denied")
+	}
+}
+
+func TestExtensionRuntime_FileSandbox(t *testing.T) {
+	tempDir := t.TempDir()
+
+	ext := &LoadedExtension{
+		ID: "test-ext",
+		Manifest: &ExtensionManifest{
+			Name: "test-ext",
+			Permissions: ExtensionPermissions{
+				File: true, // Enable file permission for test
+			},
+		},
+		DataDir: tempDir,
+	}
+
+	runtime := NewExtensionRuntime(ext)
+
+	// Test valid path within sandbox
+	validPath, err := runtime.validatePath("test.txt")
+	if err != nil {
+		t.Errorf("Expected relative path to be valid, got error: %v", err)
+	}
+	if validPath == "" {
+		t.Error("Expected non-empty path")
+	}
+
+	// Test path traversal attack
+	_, err = runtime.validatePath("../../../etc/passwd")
+	if err == nil {
+		t.Error("Expected path traversal to be blocked")
+	}
+
+	// Test nested path within sandbox (should be allowed)
+	nestedPath, err := runtime.validatePath("subdir/file.txt")
+	if err != nil {
+		t.Errorf("Expected nested path to be valid, got error: %v", err)
+	}
+	if nestedPath == "" {
+		t.Error("Expected non-empty nested path")
+	}
+
+	// Test absolute path should be blocked (security fix)
+	// Use platform-appropriate absolute path
+	var absPath string
+	if filepath.IsAbs("C:\\Windows\\System32") {
+		absPath = "C:\\Windows\\System32\\test.txt" // Windows
+	} else {
+		absPath = "/etc/passwd" // Unix
+	}
+	_, err = runtime.validatePath(absPath)
+	if err == nil {
+		t.Error("Expected absolute path to be blocked")
+	}
+
+	// Test that extension without file permission is blocked
+	extNoFile := &LoadedExtension{
+		ID: "test-ext-no-file",
+		Manifest: &ExtensionManifest{
+			Name: "test-ext-no-file",
+			Permissions: ExtensionPermissions{
+				File: false, // No file permission
+			},
+		},
+		DataDir: tempDir,
+	}
+	runtimeNoFile := NewExtensionRuntime(extNoFile)
+	_, err = runtimeNoFile.validatePath("test.txt")
+	if err == nil {
+		t.Error("Expected file access to be denied without file permission")
+	}
+}
+
+func TestExtensionRuntime_UtilityFunctions(t *testing.T) {
+	ext := &LoadedExtension{
+		ID: "test-ext",
+		Manifest: &ExtensionManifest{
+			Name: "test-ext",
+		},
+		DataDir: t.TempDir(),
+	}
+
+	runtime := NewExtensionRuntime(ext)
+	vm := goja.New()
+	runtime.RegisterAPIs(vm)
+
+	// Test base64 encode/decode
+	result, err := vm.RunString(`utils.base64Encode("hello")`)
+	if err != nil {
+		t.Fatalf("base64Encode failed: %v", err)
+	}
+	if result.String() != "aGVsbG8=" {
+		t.Errorf("Expected 'aGVsbG8=', got '%s'", result.String())
+	}
+
+	result, err = vm.RunString(`utils.base64Decode("aGVsbG8=")`)
+	if err != nil {
+		t.Fatalf("base64Decode failed: %v", err)
+	}
+	if result.String() != "hello" {
+		t.Errorf("Expected 'hello', got '%s'", result.String())
+	}
+
+	// Test MD5
+	result, err = vm.RunString(`utils.md5("hello")`)
+	if err != nil {
+		t.Fatalf("md5 failed: %v", err)
+	}
+	if result.String() != "5d41402abc4b2a76b9719d911017c592" {
+		t.Errorf("Expected '5d41402abc4b2a76b9719d911017c592', got '%s'", result.String())
+	}
+
+	// Test JSON parse/stringify
+	result, err = vm.RunString(`utils.stringifyJSON({name: "test", value: 123})`)
+	if err != nil {
+		t.Fatalf("stringifyJSON failed: %v", err)
+	}
+	// JSON output may vary in order, just check it's valid
+	if result.String() == "" {
+		t.Error("Expected non-empty JSON string")
+	}
+}
+
+func TestExtensionRuntime_SSRFProtection(t *testing.T) {
+	// Create extension with limited network permissions
+	ext := &LoadedExtension{
+		ID: "test-ext",
+		Manifest: &ExtensionManifest{
+			Name: "test-ext",
+			Permissions: ExtensionPermissions{
+				Network: []string{"api.example.com"},
+			},
+		},
+		DataDir: t.TempDir(),
+	}
+
+	runtime := NewExtensionRuntime(ext)
+
+	// Test that private IPs are blocked (SSRF protection)
+	privateIPs := []string{
+		"http://localhost/admin",
+		"http://127.0.0.1/admin",
+		"http://192.168.1.1/admin",
+		"http://10.0.0.1/admin",
+		"http://172.16.0.1/admin",
+		"http://169.254.169.254/latest/meta-data/", // AWS metadata
+		"http://router.local/admin",
+	}
+
+	for _, url := range privateIPs {
+		err := runtime.validateDomain(url)
+		if err == nil {
+			t.Errorf("Expected private IP/host '%s' to be blocked", url)
+		}
+	}
+
+	// Test that allowed public domain still works
+	if err := runtime.validateDomain("https://api.example.com/path"); err != nil {
+		t.Errorf("Expected api.example.com to be allowed, got error: %v", err)
+	}
+}
+
+func TestIsPrivateIP(t *testing.T) {
+	tests := []struct {
+		host     string
+		expected bool
+	}{
+		// Private IPs should be blocked
+		{"localhost", true},
+		{"127.0.0.1", true},
+		{"127.0.0.2", true},
+		{"10.0.0.1", true},
+		{"10.255.255.255", true},
+		{"172.16.0.1", true},
+		{"172.31.255.255", true},
+		{"192.168.0.1", true},
+		{"192.168.255.255", true},
+		{"169.254.169.254", true}, // AWS metadata
+		{"router.local", true},
+		{"mydevice.local", true},
+
+		// Public IPs should be allowed
+		{"8.8.8.8", false},
+		{"1.1.1.1", false},
+		{"api.example.com", false},
+		{"google.com", false},
+		{"172.15.0.1", false},  // Just outside 172.16-31 range
+		{"172.32.0.1", false},  // Just outside 172.16-31 range
+		{"192.167.0.1", false}, // Not 192.168.x.x
+	}
+
+	for _, tt := range tests {
+		result := isPrivateIP(tt.host)
+		if result != tt.expected {
+			t.Errorf("isPrivateIP(%s) = %v, expected %v", tt.host, result, tt.expected)
+		}
+	}
+}

go_backend/extension_timeout.go

@@ -0,0 +1,118 @@
+// Package gobackend provides timeout execution for extension JS code
+package gobackend
+
+import (
+	"context"
+	"fmt"
+	"sync"
+	"time"
+
+	"github.com/dop251/goja"
+)
+
+// JSExecutionError represents an error during JS execution
+type JSExecutionError struct {
+	Message   string
+	IsTimeout bool
+}
+
+func (e *JSExecutionError) Error() string {
+	return e.Message
+}
+
+// RunWithTimeout executes JavaScript code with a timeout
+// Returns the result value and any error (including timeout)
+func RunWithTimeout(vm *goja.Runtime, script string, timeout time.Duration) (goja.Value, error) {
+	if timeout <= 0 {
+		timeout = DefaultJSTimeout
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), timeout)
+	defer cancel()
+
+	// Channel to receive result
+	type result struct {
+		value goja.Value
+		err   error
+	}
+	resultCh := make(chan result, 1)
+
+	// Track if we've interrupted
+	var interrupted bool
+	var interruptMu sync.Mutex
+
+	// Run script in goroutine
+	go func() {
+		defer func() {
+			if r := recover(); r != nil {
+				// Check if this was our interrupt
+				interruptMu.Lock()
+				wasInterrupted := interrupted
+				interruptMu.Unlock()
+
+				if wasInterrupted {
+					resultCh <- result{nil, &JSExecutionError{
+						Message:   "execution timeout exceeded",
+						IsTimeout: true,
+					}}
+				} else {
+					resultCh <- result{nil, fmt.Errorf("panic during execution: %v", r)}
+				}
+			}
+		}()
+
+		val, err := vm.RunString(script)
+		resultCh <- result{val, err}
+	}()
+
+	// Wait for result or timeout
+	select {
+	case res := <-resultCh:
+		return res.value, res.err
+	case <-ctx.Done():
+		// Timeout - interrupt the VM
+		interruptMu.Lock()
+		interrupted = true
+		interruptMu.Unlock()
+
+		vm.Interrupt("execution timeout")
+
+		// Wait a bit for the goroutine to finish
+		select {
+		case res := <-resultCh:
+			// If we got a result after interrupt, it might be the timeout error
+			if res.err != nil {
+				return nil, res.err
+			}
+			return nil, &JSExecutionError{
+				Message:   "execution timeout exceeded",
+				IsTimeout: true,
+			}
+		case <-time.After(1 * time.Second):
+			// Force return timeout error
+			return nil, &JSExecutionError{
+				Message:   "execution timeout exceeded (force)",
+				IsTimeout: true,
+			}
+		}
+	}
+}
+
+// RunWithTimeoutAndRecover runs JS with timeout and clears interrupt state after
+// This should be used when you want to continue using the VM after a timeout
+func RunWithTimeoutAndRecover(vm *goja.Runtime, script string, timeout time.Duration) (goja.Value, error) {
+	result, err := RunWithTimeout(vm, script, timeout)
+
+	// Clear any interrupt state so VM can be reused
+	vm.ClearInterrupt()
+
+	return result, err
+}
+
+// IsTimeoutError checks if an error is a timeout error
+func IsTimeoutError(err error) bool {
+	if jsErr, ok := err.(*JSExecutionError); ok {
+		return jsErr.IsTimeout
+	}
+	return false
+}

go_backend/filename.go

@@ -11,23 +11,18 @@ var invalidChars = regexp.MustCompile(`[<>:"/\\|?*\x00-\x1f]`)
 
 // sanitizeFilename removes invalid characters from filename
 func sanitizeFilename(filename string) string {
-	// Replace invalid characters with underscore
 	sanitized := invalidChars.ReplaceAllString(filename, "_")
 	
-	// Remove leading/trailing spaces and dots
 	sanitized = strings.TrimSpace(sanitized)
 	sanitized = strings.Trim(sanitized, ".")
 	
-	// Collapse multiple underscores
 	multiUnderscore := regexp.MustCompile(`_+`)
 	sanitized = multiUnderscore.ReplaceAllString(sanitized, "_")
 	
-	// Limit length (Android has 255 byte limit for filenames)
 	if len(sanitized) > 200 {
 		sanitized = sanitized[:200]
 	}
 	
-	// Ensure not empty
 	if sanitized == "" {
 		sanitized = "untitled"
 	}
@@ -43,7 +38,6 @@ func buildFilenameFromTemplate(template string, metadata map[string]interface{})
 	
 	result := template
 	
-	// Replace placeholders
 	placeholders := map[string]string{
 		"{title}":  getString(metadata, "title"),
 		"{artist}": getString(metadata, "artist"),
@@ -63,7 +57,6 @@ func buildFilenameFromTemplate(template string, metadata map[string]interface{})
 func getString(m map[string]interface{}, key string) string {
 	if v, ok := m[key]; ok {
 		if s, ok := v.(string); ok {
-			// Trim leading/trailing whitespace to prevent filename issues
 			return strings.TrimSpace(s)
 		}
 	}

go_backend/go.mod

@@ -5,14 +5,19 @@ go 1.24.0
 toolchain go1.24.5
 
 require (
+	github.com/dop251/goja v0.0.0-20260106131823-651366fbe6e3
 	github.com/go-flac/flacpicture v0.3.0
 	github.com/go-flac/flacvorbis v0.2.0
 	github.com/go-flac/go-flac v1.0.0
 )
 
 require (
+	github.com/dlclark/regexp2 v1.11.4 // indirect
+	github.com/go-sourcemap/sourcemap v2.1.3+incompatible // indirect
+	github.com/google/pprof v0.0.0-20230207041349-798e818bf904 // indirect
 	golang.org/x/mobile v0.0.0-20251209145715-2553ed8ce294 // indirect
 	golang.org/x/mod v0.31.0 // indirect
 	golang.org/x/sync v0.19.0 // indirect
+	golang.org/x/text v0.3.8 // indirect
 	golang.org/x/tools v0.40.0 // indirect
 )

go_backend/go.sum

@@ -1,14 +1,28 @@
+github.com/Masterminds/semver/v3 v3.2.1 h1:RN9w6+7QoMeJVGyfmbcgs28Br8cvmnucEXnY0rYXWg0=
+github.com/Masterminds/semver/v3 v3.2.1/go.mod h1:qvl/7zhW3nngYb5+80sSMF+FG2BjYrf8m9wsX0PNOMQ=
+github.com/dlclark/regexp2 v1.11.4 h1:rPYF9/LECdNymJufQKmri9gV604RvvABwgOA8un7yAo=
+github.com/dlclark/regexp2 v1.11.4/go.mod h1:DHkYz0B9wPfa6wondMfaivmHpzrQ3v9q8cnmRbL6yW8=
+github.com/dop251/goja v0.0.0-20260106131823-651366fbe6e3 h1:bVp3yUzvSAJzu9GqID+Z96P+eu5TKnIMJSV4QaZMauM=
+github.com/dop251/goja v0.0.0-20260106131823-651366fbe6e3/go.mod h1:MxLav0peU43GgvwVgNbLAj1s/bSGboKkhuULvq/7hx4=
 github.com/go-flac/flacpicture v0.3.0 h1:LkmTxzFLIynwfhHiZsX0s8xcr3/u33MzvV89u+zOT8I=
 github.com/go-flac/flacpicture v0.3.0/go.mod h1:DPbrzVYQ3fJcvSgLFp9HXIrEQEdfdk/+m0nQCzwodZI=
 github.com/go-flac/flacvorbis v0.2.0 h1:KH0xjpkNTXFER4cszH4zeJxYcrHbUobz/RticWGOESs=
 github.com/go-flac/flacvorbis v0.2.0/go.mod h1:uIysHOtuU7OLGoCRG92bvnkg7QEqHx19qKRV6K1pBrI=
 github.com/go-flac/go-flac v1.0.0 h1:6qI9XOVLcO50xpzm3nXvO31BgDgHhnr/p/rER/K/doY=
 github.com/go-flac/go-flac v1.0.0/go.mod h1:WnZhcpmq4u1UdZMNn9LYSoASpWOCMOoxXxcWEHSzkW8=
+github.com/go-sourcemap/sourcemap v2.1.3+incompatible h1:W1iEw64niKVGogNgBN3ePyLFfuisuzeidWPMPWmECqU=
+github.com/go-sourcemap/sourcemap v2.1.3+incompatible/go.mod h1:F8jJfvm2KbVjc5NqelyYJmf/v5J0dwNLS2mL4sNA1Jg=
+github.com/google/pprof v0.0.0-20230207041349-798e818bf904 h1:4/hN5RUoecvl+RmJRE2YxKWtnnQls6rQjjW5oV7qg2U=
+github.com/google/pprof v0.0.0-20230207041349-798e818bf904/go.mod h1:uglQLonpP8qtYCYyzA+8c/9qtqgA3qsXGYqCPKARAFg=
 golang.org/x/mobile v0.0.0-20251209145715-2553ed8ce294 h1:Cr6kbEvA6nqvdHynE4CtVKlqpZB9dS1Jva/6IsHA19g=
 golang.org/x/mobile v0.0.0-20251209145715-2553ed8ce294/go.mod h1:RdZ+3sb4CVgpCFnzv+I4haEpwqFfsfzlLHs3L7ok+e0=
 golang.org/x/mod v0.31.0 h1:HaW9xtz0+kOcWKwli0ZXy79Ix+UW/vOfmWI5QVd2tgI=
 golang.org/x/mod v0.31.0/go.mod h1:43JraMp9cGx1Rx3AqioxrbrhNsLl2l/iNAvuBkrezpg=
 golang.org/x/sync v0.19.0 h1:vV+1eWNmZ5geRlYjzm2adRgW2/mcpevXNg50YZtPCE4=
 golang.org/x/sync v0.19.0/go.mod h1:9KTHXmSnoGruLpwFjVSX0lNNA75CykiMECbovNTZqGI=
+golang.org/x/text v0.3.8 h1:nAL+RVCQ9uMn3vJZbV+MRnydTJFPf8qqY42YiA6MrqY=
+golang.org/x/text v0.3.8/go.mod h1:E6s5w1FMmriuDzIBO73fBruAKo1PCIq6d2Q6DHfQ8WQ=
 golang.org/x/tools v0.40.0 h1:yLkxfA+Qnul4cs9QA3KnlFu0lVmd8JJfoq+E41uSutA=
 golang.org/x/tools v0.40.0/go.mod h1:Ik/tzLRlbscWpqqMRjyWYDisX8bG13FrdXp3o4Sr9lc=
+gopkg.in/yaml.v2 v2.4.0 h1:D8xgwECY7CYvx+Y2n4sBz93Jn9JRvxdiyyo8CTfuKaY=
+gopkg.in/yaml.v2 v2.4.0/go.mod h1:RDklbk79AGWmwhnvt/jBztapEOGDOx6ZbXqjP6csGnQ=

go_backend/httputil.go

@@ -1,12 +1,17 @@
 package gobackend
 
 import (
+	"crypto/tls"
+	"errors"
 	"fmt"
 	"io"
 	"math/rand"
 	"net"
 	"net/http"
+	"net/url"
 	"strconv"
+	"strings"
+	"syscall"
 	"time"
 )
 
@@ -15,14 +20,12 @@ import (
 // getRandomUserAgent generates a random Windows Chrome User-Agent string
 // Uses same format as PC version (referensi/backend/spotify_metadata.go) for better API compatibility
 func getRandomUserAgent() string {
-	// Windows 10/11 Chrome format - same as PC version for maximum compatibility
-	// Some APIs may block mobile User-Agents, so we use desktop format
-	winMajor := rand.Intn(2) + 10  // Windows 10 or 11
-	
-	chromeVersion := rand.Intn(25) + 100 // Chrome 100-124
-	chromeBuild := rand.Intn(1500) + 3000 // Build 3000-4500
-	chromePatch := rand.Intn(65) + 60 // Patch 60-125
-	
+	winMajor := rand.Intn(2) + 10
+
+	chromeVersion := rand.Intn(25) + 100
+	chromeBuild := rand.Intn(1500) + 3000
+	chromePatch := rand.Intn(65) + 60
+
 	return fmt.Sprintf(
 		"Mozilla/5.0 (Windows NT %d.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/%d.0.%d.%d Safari/537.36",
 		winMajor,
@@ -34,50 +37,48 @@ func getRandomUserAgent() string {
 
 // getRandomMacUserAgent generates a random Mac Chrome User-Agent string
 // Alternative format matching referensi/backend/spotify_metadata.go exactly
-func getRandomMacUserAgent() string {
-	macMajor := rand.Intn(4) + 11  // macOS 11-14
-	macMinor := rand.Intn(5) + 4   // Minor 4-8
-	webkitMajor := rand.Intn(7) + 530
-	webkitMinor := rand.Intn(7) + 30
-	chromeMajor := rand.Intn(25) + 80
-	chromeBuild := rand.Intn(1500) + 3000
-	chromePatch := rand.Intn(65) + 60
-	safariMajor := rand.Intn(7) + 530
-	safariMinor := rand.Intn(6) + 30
-
-	return fmt.Sprintf(
-		"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_%d_%d) AppleWebKit/%d.%d (KHTML, like Gecko) Chrome/%d.0.%d.%d Safari/%d.%d",
-		macMajor,
-		macMinor,
-		webkitMajor,
-		webkitMinor,
-		chromeMajor,
-		chromeBuild,
-		chromePatch,
-		safariMajor,
-		safariMinor,
-	)
-}
+// func getRandomMacUserAgent() string {
+// 	macMajor := rand.Intn(4) + 11 // macOS 11-14
+// 	macMinor := rand.Intn(5) + 4  // Minor 4-8
+// 	webkitMajor := rand.Intn(7) + 530
+// 	webkitMinor := rand.Intn(7) + 30
+// 	chromeMajor := rand.Intn(25) + 80
+// 	chromeBuild := rand.Intn(1500) + 3000
+// 	chromePatch := rand.Intn(65) + 60
+// 	safariMajor := rand.Intn(7) + 530
+// 	safariMinor := rand.Intn(6) + 30
+//
+// 	return fmt.Sprintf(
+// 		"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_%d_%d) AppleWebKit/%d.%d (KHTML, like Gecko) Chrome/%d.0.%d.%d Safari/%d.%d",
+// 		macMajor,
+// 		macMinor,
+// 		webkitMajor,
+// 		webkitMinor,
+// 		chromeMajor,
+// 		chromeBuild,
+// 		chromePatch,
+// 		safariMajor,
+// 		safariMinor,
+// 	)
+// }
 
 // getRandomDesktopUserAgent randomly picks between Windows and Mac User-Agent
-func getRandomDesktopUserAgent() string {
-	if rand.Intn(2) == 0 {
-		return getRandomUserAgent() // Windows
-	}
-	return getRandomMacUserAgent() // Mac
-}
+// func getRandomDesktopUserAgent() string {
+// 	if rand.Intn(2) == 0 {
+// 		return getRandomUserAgent() // Windows
+// 	}
+// 	return getRandomMacUserAgent() // Mac
+// }
 
-// Default timeout values
 const (
-	DefaultTimeout     = 60 * time.Second  // Default HTTP timeout
-	DownloadTimeout    = 120 * time.Second // Timeout for file downloads
-	SongLinkTimeout    = 30 * time.Second  // Timeout for SongLink API
-	DefaultMaxRetries  = 3                 // Default retry count
-	DefaultRetryDelay  = 1 * time.Second   // Initial retry delay
+	DefaultTimeout    = 60 * time.Second
+	DownloadTimeout   = 120 * time.Second
+	SongLinkTimeout   = 30 * time.Second
+	DefaultMaxRetries = 3
+	DefaultRetryDelay = 1 * time.Second
 )
 
 // Shared transport with connection pooling to prevent TCP exhaustion
-// Optimized for large file downloads (FLAC ~30-50MB)
 var sharedTransport = &http.Transport{
 	DialContext: (&net.Dialer{
 		Timeout:   30 * time.Second,
@@ -89,27 +90,24 @@ var sharedTransport = &http.Transport{
 	IdleConnTimeout:       90 * time.Second,
 	TLSHandshakeTimeout:   10 * time.Second,
 	ExpectContinueTimeout: 1 * time.Second,
-	DisableKeepAlives:     false, // Enable keep-alives for connection reuse
+	DisableKeepAlives:     false,
 	ForceAttemptHTTP2:     true,
-	WriteBufferSize:       64 * 1024,  // 64KB write buffer
-	ReadBufferSize:        64 * 1024,  // 64KB read buffer
-	DisableCompression:    true,       // FLAC is already compressed
+	WriteBufferSize:       64 * 1024,
+	ReadBufferSize:        64 * 1024,
+	DisableCompression:    true,
 }
 
-// Shared HTTP client for general requests (reuses connections)
 var sharedClient = &http.Client{
 	Transport: sharedTransport,
 	Timeout:   DefaultTimeout,
 }
 
-// Shared HTTP client for downloads (longer timeout, reuses connections)
 var downloadClient = &http.Client{
 	Transport: sharedTransport,
 	Timeout:   DownloadTimeout,
 }
 
 // NewHTTPClientWithTimeout creates an HTTP client with specified timeout
-// Uses shared transport for connection reuse
 func NewHTTPClientWithTimeout(timeout time.Duration) *http.Client {
 	return &http.Client{
 		Transport: sharedTransport,
@@ -117,26 +115,28 @@ func NewHTTPClientWithTimeout(timeout time.Duration) *http.Client {
 	}
 }
 
-// GetSharedClient returns the shared HTTP client for general requests
 func GetSharedClient() *http.Client {
 	return sharedClient
 }
 
-// GetDownloadClient returns the shared HTTP client for downloads
 func GetDownloadClient() *http.Client {
 	return downloadClient
 }
 
 // CloseIdleConnections closes idle connections in the shared transport
-// Call this periodically during large batch downloads to prevent connection buildup
 func CloseIdleConnections() {
 	sharedTransport.CloseIdleConnections()
 }
 
 // DoRequestWithUserAgent executes an HTTP request with a random User-Agent header
+// Also checks for ISP blocking on errors
 func DoRequestWithUserAgent(client *http.Client, req *http.Request) (*http.Response, error) {
 	req.Header.Set("User-Agent", getRandomUserAgent())
-	return client.Do(req)
+	resp, err := client.Do(req)
+	if err != nil {
+		CheckAndLogISPBlocking(err, req.URL.String(), "HTTP")
+	}
+	return resp, err
 }
 
 // RetryConfig holds configuration for retry logic
@@ -159,9 +159,11 @@ func DefaultRetryConfig() RetryConfig {
 
 // DoRequestWithRetry executes an HTTP request with retry logic and exponential backoff
 // Handles 429 (Too Many Requests) responses with Retry-After header
+// Also detects and logs ISP blocking
 func DoRequestWithRetry(client *http.Client, req *http.Request, config RetryConfig) (*http.Response, error) {
 	var lastErr error
 	delay := config.InitialDelay
+	requestURL := req.URL.String()
 
 	for attempt := 0; attempt <= config.MaxRetries; attempt++ {
 		// Clone request for retry (body needs to be re-readable)
@@ -171,7 +173,16 @@ func DoRequestWithRetry(client *http.Client, req *http.Request, config RetryConf
 		resp, err := client.Do(reqCopy)
 		if err != nil {
 			lastErr = err
+
+			// Check for ISP blocking on network errors
+			if CheckAndLogISPBlocking(err, requestURL, "HTTP") {
+				// Don't retry if ISP blocking is detected - it won't help
+				return nil, WrapErrorWithISPCheck(err, requestURL, "HTTP")
+			}
+
 			if attempt < config.MaxRetries {
+				GoLog("[HTTP] Request failed (attempt %d/%d): %v, retrying in %v...\n",
+					attempt+1, config.MaxRetries+1, err, delay)
 				time.Sleep(delay)
 				delay = calculateNextDelay(delay, config)
 			}
@@ -192,17 +203,43 @@ func DoRequestWithRetry(client *http.Client, req *http.Request, config RetryConf
 			}
 			lastErr = fmt.Errorf("rate limited (429)")
 			if attempt < config.MaxRetries {
+				GoLog("[HTTP] Rate limited, waiting %v before retry...\n", delay)
 				time.Sleep(delay)
 				delay = calculateNextDelay(delay, config)
 			}
 			continue
 		}
 
+		// Check for ISP blocking via HTTP status codes
+		// Some ISPs return 403 or 451 when blocking content
+		if resp.StatusCode == 403 || resp.StatusCode == 451 {
+			body, _ := io.ReadAll(resp.Body)
+			resp.Body.Close()
+			bodyStr := strings.ToLower(string(body))
+
+			// Check if response looks like ISP blocking page
+			ispBlockingIndicators := []string{
+				"blocked", "forbidden", "access denied", "not available in your",
+				"restricted", "censored", "unavailable for legal", "blocked by",
+			}
+
+			for _, indicator := range ispBlockingIndicators {
+				if strings.Contains(bodyStr, indicator) {
+					LogError("HTTP", "ISP BLOCKING DETECTED via HTTP %d response", resp.StatusCode)
+					LogError("HTTP", "Domain: %s", req.URL.Host)
+					LogError("HTTP", "Response contains: %s", indicator)
+					LogError("HTTP", "Suggestion: Try using a VPN or changing your DNS to 1.1.1.1 or 8.8.8.8")
+					return nil, fmt.Errorf("ISP blocking detected for %s (HTTP %d) - try using VPN or change DNS", req.URL.Host, resp.StatusCode)
+				}
+			}
+		}
+
 		// Server errors (5xx) - retry
 		if resp.StatusCode >= 500 {
 			resp.Body.Close()
 			lastErr = fmt.Errorf("server error: HTTP %d", resp.StatusCode)
 			if attempt < config.MaxRetries {
+				GoLog("[HTTP] Server error %d, retrying in %v...\n", resp.StatusCode, delay)
 				time.Sleep(delay)
 				delay = calculateNextDelay(delay, config)
 			}
@@ -219,10 +256,7 @@ func DoRequestWithRetry(client *http.Client, req *http.Request, config RetryConf
 // calculateNextDelay calculates the next delay with exponential backoff
 func calculateNextDelay(currentDelay time.Duration, config RetryConfig) time.Duration {
 	nextDelay := time.Duration(float64(currentDelay) * config.BackoffFactor)
-	if nextDelay > config.MaxDelay {
-		nextDelay = config.MaxDelay
-	}
-	return nextDelay
+	return min(nextDelay, config.MaxDelay)
 }
 
 // getRetryAfterDuration parses Retry-After header and returns duration
@@ -296,3 +330,172 @@ func BuildErrorMessage(apiURL string, statusCode int, responsePreview string) st
 	}
 	return msg
 }
+
+// ISPBlockingError represents an error caused by ISP blocking
+type ISPBlockingError struct {
+	Domain      string
+	Reason      string
+	OriginalErr error
+}
+
+func (e *ISPBlockingError) Error() string {
+	return fmt.Sprintf("ISP blocking detected for %s: %s", e.Domain, e.Reason)
+}
+
+// IsISPBlocking checks if an error is likely caused by ISP blocking
+// Returns the ISPBlockingError if detected, nil otherwise
+func IsISPBlocking(err error, requestURL string) *ISPBlockingError {
+	if err == nil {
+		return nil
+	}
+
+	// Extract domain from URL
+	domain := extractDomain(requestURL)
+	errStr := strings.ToLower(err.Error())
+
+	// Check for DNS resolution failure (common ISP blocking method)
+	var dnsErr *net.DNSError
+	if errors.As(err, &dnsErr) {
+		if dnsErr.IsNotFound || dnsErr.IsTemporary {
+			return &ISPBlockingError{
+				Domain:      domain,
+				Reason:      "DNS resolution failed - domain may be blocked by ISP",
+				OriginalErr: err,
+			}
+		}
+	}
+
+	// Check for connection refused (ISP firewall blocking)
+	var opErr *net.OpError
+	if errors.As(err, &opErr) {
+		if opErr.Op == "dial" {
+			// Check for specific syscall errors
+			var syscallErr syscall.Errno
+			if errors.As(opErr.Err, &syscallErr) {
+				switch syscallErr {
+				case syscall.ECONNREFUSED:
+					return &ISPBlockingError{
+						Domain:      domain,
+						Reason:      "Connection refused - port may be blocked by ISP/firewall",
+						OriginalErr: err,
+					}
+				case syscall.ECONNRESET:
+					return &ISPBlockingError{
+						Domain:      domain,
+						Reason:      "Connection reset - ISP may be intercepting traffic",
+						OriginalErr: err,
+					}
+				case syscall.ETIMEDOUT:
+					return &ISPBlockingError{
+						Domain:      domain,
+						Reason:      "Connection timed out - ISP may be blocking access",
+						OriginalErr: err,
+					}
+				case syscall.ENETUNREACH:
+					return &ISPBlockingError{
+						Domain:      domain,
+						Reason:      "Network unreachable - ISP may be blocking route",
+						OriginalErr: err,
+					}
+				case syscall.EHOSTUNREACH:
+					return &ISPBlockingError{
+						Domain:      domain,
+						Reason:      "Host unreachable - ISP may be blocking destination",
+						OriginalErr: err,
+					}
+				}
+			}
+		}
+	}
+
+	// Check for TLS handshake failure (ISP MITM or blocking HTTPS)
+	var tlsErr *tls.RecordHeaderError
+	if errors.As(err, &tlsErr) {
+		return &ISPBlockingError{
+			Domain:      domain,
+			Reason:      "TLS handshake failed - ISP may be intercepting HTTPS traffic",
+			OriginalErr: err,
+		}
+	}
+
+	// Check error message patterns for common ISP blocking indicators
+	blockingPatterns := []struct {
+		pattern string
+		reason  string
+	}{
+		{"connection reset by peer", "Connection reset - ISP may be intercepting traffic"},
+		{"connection refused", "Connection refused - port may be blocked"},
+		{"no such host", "DNS lookup failed - domain may be blocked by ISP"},
+		{"i/o timeout", "Connection timed out - ISP may be blocking access"},
+		{"network is unreachable", "Network unreachable - ISP may be blocking route"},
+		{"tls: ", "TLS error - ISP may be intercepting HTTPS traffic"},
+		{"certificate", "Certificate error - ISP may be using MITM proxy"},
+		{"eof", "Connection closed unexpectedly - ISP may be blocking"},
+		{"context deadline exceeded", "Request timed out - ISP may be throttling"},
+	}
+
+	for _, bp := range blockingPatterns {
+		if strings.Contains(errStr, bp.pattern) {
+			return &ISPBlockingError{
+				Domain:      domain,
+				Reason:      bp.reason,
+				OriginalErr: err,
+			}
+		}
+	}
+
+	return nil
+}
+
+// CheckAndLogISPBlocking checks for ISP blocking and logs if detected
+// Returns true if ISP blocking was detected
+func CheckAndLogISPBlocking(err error, requestURL string, tag string) bool {
+	ispErr := IsISPBlocking(err, requestURL)
+	if ispErr != nil {
+		LogError(tag, "ISP BLOCKING DETECTED: %s", ispErr.Error())
+		LogError(tag, "Domain: %s", ispErr.Domain)
+		LogError(tag, "Reason: %s", ispErr.Reason)
+		LogError(tag, "Original error: %v", ispErr.OriginalErr)
+		LogError(tag, "Suggestion: Try using a VPN or changing your DNS to 1.1.1.1 or 8.8.8.8")
+		return true
+	}
+	return false
+}
+
+// extractDomain extracts the domain from a URL string
+func extractDomain(rawURL string) string {
+	if rawURL == "" {
+		return "unknown"
+	}
+
+	parsed, err := url.Parse(rawURL)
+	if err != nil {
+		// Try to extract domain manually
+		rawURL = strings.TrimPrefix(rawURL, "https://")
+		rawURL = strings.TrimPrefix(rawURL, "http://")
+		if idx := strings.Index(rawURL, "/"); idx > 0 {
+			return rawURL[:idx]
+		}
+		return rawURL
+	}
+
+	if parsed.Host != "" {
+		return parsed.Host
+	}
+	return "unknown"
+}
+
+// WrapErrorWithISPCheck wraps an error with ISP blocking detection
+// If ISP blocking is detected, returns a more descriptive error
+func WrapErrorWithISPCheck(err error, requestURL string, tag string) error {
+	if err == nil {
+		return nil
+	}
+
+	if CheckAndLogISPBlocking(err, requestURL, tag) {
+		domain := extractDomain(requestURL)
+		return fmt.Errorf("ISP blocking detected for %s - try using VPN or change DNS to 1.1.1.1/8.8.8.8: %w", domain, err)
+	}
+
+	return err
+}

go_backend/logbuffer.go

@@ -0,0 +1,199 @@
+package gobackend
+
+import (
+	"encoding/json"
+	"fmt"
+	"strings"
+	"sync"
+	"time"
+)
+
+// LogEntry represents a single log entry
+type LogEntry struct {
+	Timestamp string `json:"timestamp"`
+	Level     string `json:"level"`
+	Tag       string `json:"tag"`
+	Message   string `json:"message"`
+}
+
+// LogBuffer stores logs in a circular buffer for retrieval by Flutter
+type LogBuffer struct {
+	entries        []LogEntry
+	maxSize        int
+	mu             sync.RWMutex
+	loggingEnabled bool
+}
+
+var (
+	globalLogBuffer *LogBuffer
+	logBufferOnce   sync.Once
+)
+
+// GetLogBuffer returns the singleton log buffer instance
+func GetLogBuffer() *LogBuffer {
+	logBufferOnce.Do(func() {
+		globalLogBuffer = &LogBuffer{
+			entries:        make([]LogEntry, 0, 1000),
+			maxSize:        1000,
+			loggingEnabled: false, // Default: disabled for performance (user can enable in settings)
+		}
+	})
+	return globalLogBuffer
+}
+
+// SetLoggingEnabled enables or disables logging
+func (lb *LogBuffer) SetLoggingEnabled(enabled bool) {
+	lb.mu.Lock()
+	defer lb.mu.Unlock()
+	lb.loggingEnabled = enabled
+}
+
+// IsLoggingEnabled returns whether logging is enabled
+func (lb *LogBuffer) IsLoggingEnabled() bool {
+	lb.mu.RLock()
+	defer lb.mu.RUnlock()
+	return lb.loggingEnabled
+}
+
+// Add adds a log entry to the buffer
+func (lb *LogBuffer) Add(level, tag, message string) {
+	lb.mu.Lock()
+	defer lb.mu.Unlock()
+
+	if !lb.loggingEnabled && level != "ERROR" && level != "FATAL" {
+		return
+	}
+
+	entry := LogEntry{
+		Timestamp: time.Now().Format("15:04:05.000"),
+		Level:     level,
+		Tag:       tag,
+		Message:   message,
+	}
+
+	if len(lb.entries) >= lb.maxSize {
+		lb.entries = lb.entries[1:]
+	}
+	lb.entries = append(lb.entries, entry)
+
+	fmt.Printf("[%s] %s\n", tag, message)
+}
+
+// GetAll returns all log entries as JSON
+func (lb *LogBuffer) GetAll() string {
+	lb.mu.RLock()
+	defer lb.mu.RUnlock()
+
+	jsonBytes, _ := json.Marshal(lb.entries)
+	return string(jsonBytes)
+}
+
+func (lb *LogBuffer) getSince(index int) ([]LogEntry, int) {
+	lb.mu.RLock()
+	defer lb.mu.RUnlock()
+
+	if index < 0 {
+		index = 0
+	}
+	if index >= len(lb.entries) {
+		return []LogEntry{}, len(lb.entries)
+	}
+
+	entries := lb.entries[index:]
+	return entries, len(lb.entries)
+}
+
+// Clear clears all log entries
+func (lb *LogBuffer) Clear() {
+	lb.mu.Lock()
+	defer lb.mu.Unlock()
+	lb.entries = lb.entries[:0]
+}
+
+// Count returns the number of log entries
+func (lb *LogBuffer) Count() int {
+	lb.mu.RLock()
+	defer lb.mu.RUnlock()
+	return len(lb.entries)
+}
+
+// Helper functions for logging with different levels
+func LogDebug(tag, format string, args ...interface{}) {
+	GetLogBuffer().Add("DEBUG", tag, fmt.Sprintf(format, args...))
+}
+
+func LogInfo(tag, format string, args ...interface{}) {
+	GetLogBuffer().Add("INFO", tag, fmt.Sprintf(format, args...))
+}
+
+func LogWarn(tag, format string, args ...interface{}) {
+	GetLogBuffer().Add("WARN", tag, fmt.Sprintf(format, args...))
+}
+
+func LogError(tag, format string, args ...interface{}) {
+	GetLogBuffer().Add("ERROR", tag, fmt.Sprintf(format, args...))
+}
+
+// GoLog is a drop-in replacement for fmt.Printf that also logs to buffer
+// It parses the tag from the format string if it starts with [Tag]
+func GoLog(format string, args ...interface{}) {
+	message := fmt.Sprintf(format, args...)
+	message = strings.TrimSuffix(message, "\n")
+
+	// Extract tag from message if present (e.g., "[Tidal] message")
+	tag := "Go"
+	level := "INFO"
+
+	if strings.HasPrefix(message, "[") {
+		endBracket := strings.Index(message, "]")
+		if endBracket > 1 {
+			tag = message[1:endBracket]
+			message = strings.TrimSpace(message[endBracket+1:])
+		}
+	}
+
+	// Determine level from message content
+	msgLower := strings.ToLower(message)
+	if strings.Contains(msgLower, "error") || strings.Contains(msgLower, "failed") || strings.HasPrefix(message, "✗") {
+		level = "ERROR"
+	} else if strings.Contains(msgLower, "warning") || strings.Contains(msgLower, "warn") {
+		level = "WARN"
+	} else if strings.HasPrefix(message, "✓") || strings.Contains(msgLower, "success") || strings.Contains(msgLower, "match found") {
+		level = "INFO"
+	} else if strings.Contains(msgLower, "searching") || strings.Contains(msgLower, "trying") || strings.Contains(msgLower, "found") {
+		level = "DEBUG"
+	}
+
+	GetLogBuffer().Add(level, tag, message)
+}
+
+// Exported functions for Flutter
+
+// GetLogs returns all logs as JSON array
+func GetLogs() string {
+	return GetLogBuffer().GetAll()
+}
+
+// GetLogsSince returns logs since the given index
+// Returns JSON: {"logs": [...], "next_index": N}
+func GetLogsSince(index int) string {
+	entries, nextIndex := GetLogBuffer().getSince(index)
+	logsJson, _ := json.Marshal(entries)
+	result := fmt.Sprintf(`{"logs":%s,"next_index":%d}`, string(logsJson), nextIndex)
+	return result
+}
+
+// ClearLogs clears all logs
+func ClearLogs() {
+	GetLogBuffer().Clear()
+}
+
+// GetLogCount returns the number of log entries
+func GetLogCount() int {
+	return GetLogBuffer().Count()
+}
+
+// SetLoggingEnabled enables or disables logging from Flutter
+func SetLoggingEnabled(enabled bool) {
+	GetLogBuffer().SetLoggingEnabled(enabled)
+}

go_backend/lyrics.go

@@ -3,14 +3,100 @@ package gobackend
 import (
 	"encoding/json"
 	"fmt"
+	"math"
 	"net/http"
 	"net/url"
 	"regexp"
 	"strconv"
 	"strings"
+	"sync"
 	"time"
 )
 
+// ========================================
+// Lyrics Cache with TTL
+// ========================================
+
+const (
+	lyricsCacheTTL       = 24 * time.Hour // Cache lyrics for 24 hours
+	durationToleranceSec = 10.0           // Duration matching tolerance in seconds
+)
+
+type lyricsCacheEntry struct {
+	response  *LyricsResponse
+	expiresAt time.Time
+}
+
+type lyricsCache struct {
+	mu    sync.RWMutex
+	cache map[string]*lyricsCacheEntry
+}
+
+var globalLyricsCache = &lyricsCache{
+	cache: make(map[string]*lyricsCacheEntry),
+}
+
+func (c *lyricsCache) generateKey(artist, track string, durationSec float64) string {
+	// Normalize key: lowercase, trim spaces
+	normalizedArtist := strings.ToLower(strings.TrimSpace(artist))
+	normalizedTrack := strings.ToLower(strings.TrimSpace(track))
+	// Round duration to nearest 10 seconds for cache key
+	roundedDuration := math.Round(durationSec/10) * 10
+	return fmt.Sprintf("%s|%s|%.0f", normalizedArtist, normalizedTrack, roundedDuration)
+}
+
+func (c *lyricsCache) Get(artist, track string, durationSec float64) (*LyricsResponse, bool) {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+
+	key := c.generateKey(artist, track, durationSec)
+	entry, exists := c.cache[key]
+	if !exists {
+		return nil, false
+	}
+
+	// Check if expired
+	if time.Now().After(entry.expiresAt) {
+		return nil, false
+	}
+
+	return entry.response, true
+}
+
+func (c *lyricsCache) Set(artist, track string, durationSec float64, response *LyricsResponse) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	key := c.generateKey(artist, track, durationSec)
+	c.cache[key] = &lyricsCacheEntry{
+		response:  response,
+		expiresAt: time.Now().Add(lyricsCacheTTL),
+	}
+}
+
+// CleanExpired removes expired entries from cache
+func (c *lyricsCache) CleanExpired() int {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	now := time.Now()
+	cleaned := 0
+	for key, entry := range c.cache {
+		if now.After(entry.expiresAt) {
+			delete(c.cache, key)
+			cleaned++
+		}
+	}
+	return cleaned
+}
+
+// Size returns current cache size
+func (c *lyricsCache) Size() int {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+	return len(c.cache)
+}
+
 type LRCLibResponse struct {
 	ID           int     `json:"id"`
 	Name         string  `json:"name"`
@@ -86,7 +172,9 @@ func (c *LyricsClient) FetchLyricsWithMetadata(artist, track string) (*LyricsRes
 	return c.parseLRCLibResponse(&lrcResp), nil
 }
 
-func (c *LyricsClient) FetchLyricsFromLRCLibSearch(query string) (*LyricsResponse, error) {
+// FetchLyricsFromLRCLibSearch searches lyrics with optional duration matching
+// durationSec: track duration in seconds, use 0 to skip duration matching
+func (c *LyricsClient) FetchLyricsFromLRCLibSearch(query string, durationSec float64) (*LyricsResponse, error) {
 	baseURL := "https://lrclib.net/api/search"
 	params := url.Values{}
 	params.Set("q", query)
@@ -118,6 +206,13 @@ func (c *LyricsClient) FetchLyricsFromLRCLibSearch(query string) (*LyricsRespons
 		return nil, fmt.Errorf("no lyrics found")
 	}
 
+	// Filter and score results based on duration matching and synced lyrics
+	bestMatch := c.findBestMatch(results, durationSec)
+	if bestMatch != nil {
+		return c.parseLRCLibResponse(bestMatch), nil
+	}
+
+	// Fallback: return first result with synced lyrics
 	for _, result := range results {
 		if result.SyncedLyrics != "" {
 			return c.parseLRCLibResponse(&result), nil
@@ -127,38 +222,89 @@ func (c *LyricsClient) FetchLyricsFromLRCLibSearch(query string) (*LyricsRespons
 	return c.parseLRCLibResponse(&results[0]), nil
 }
 
-func (c *LyricsClient) FetchLyricsAllSources(spotifyID, trackName, artistName string) (*LyricsResponse, error) {
-	// Strategy 1: Direct match with artist and track name
-	lyrics, err := c.FetchLyricsWithMetadata(artistName, trackName)
+// findBestMatch finds the best matching lyrics based on duration and sync status
+func (c *LyricsClient) findBestMatch(results []LRCLibResponse, targetDurationSec float64) *LRCLibResponse {
+	var bestSynced *LRCLibResponse
+	var bestPlain *LRCLibResponse
+
+	for i := range results {
+		result := &results[i]
+
+		// Check duration match if target duration is provided
+		durationMatches := targetDurationSec == 0 || c.durationMatches(result.Duration, targetDurationSec)
+
+		if durationMatches {
+			// Prefer synced lyrics over plain
+			if result.SyncedLyrics != "" && bestSynced == nil {
+				bestSynced = result
+			} else if result.PlainLyrics != "" && bestPlain == nil {
+				bestPlain = result
+			}
+		}
+	}
+
+	// Return synced first, then plain
+	if bestSynced != nil {
+		return bestSynced
+	}
+	return bestPlain
+}
+
+// durationMatches checks if two durations are within tolerance
+func (c *LyricsClient) durationMatches(lrcDuration, targetDuration float64) bool {
+	diff := math.Abs(lrcDuration - targetDuration)
+	return diff <= durationToleranceSec
+}
+
+// FetchLyricsAllSources fetches lyrics from multiple sources with caching and duration matching
+// durationSec: track duration in seconds for matching, use 0 to skip duration matching
+func (c *LyricsClient) FetchLyricsAllSources(spotifyID, trackName, artistName string, durationSec float64) (*LyricsResponse, error) {
+	// Check cache first
+	if cached, found := globalLyricsCache.Get(artistName, trackName, durationSec); found {
+		fmt.Printf("[Lyrics] Cache hit for: %s - %s\n", artistName, trackName)
+		cachedCopy := *cached
+		cachedCopy.Source = cached.Source + " (cached)"
+		return &cachedCopy, nil
+	}
+
+	var lyrics *LyricsResponse
+	var err error
+
+	// Try exact match first
+	lyrics, err = c.FetchLyricsWithMetadata(artistName, trackName)
 	if err == nil && lyrics != nil && len(lyrics.Lines) > 0 {
 		lyrics.Source = "LRCLIB"
+		globalLyricsCache.Set(artistName, trackName, durationSec, lyrics)
 		return lyrics, nil
 	}
 
-	// Strategy 2: Try with simplified track name
+	// Try with simplified track name
 	simplifiedTrack := simplifyTrackName(trackName)
 	if simplifiedTrack != trackName {
 		lyrics, err = c.FetchLyricsWithMetadata(artistName, simplifiedTrack)
 		if err == nil && lyrics != nil && len(lyrics.Lines) > 0 {
 			lyrics.Source = "LRCLIB (simplified)"
+			globalLyricsCache.Set(artistName, trackName, durationSec, lyrics)
 			return lyrics, nil
 		}
 	}
 
-	// Strategy 3: Search with full query
+	// Search with duration matching
 	query := artistName + " " + trackName
-	lyrics, err = c.FetchLyricsFromLRCLibSearch(query)
+	lyrics, err = c.FetchLyricsFromLRCLibSearch(query, durationSec)
 	if err == nil && lyrics != nil && len(lyrics.Lines) > 0 {
 		lyrics.Source = "LRCLIB Search"
+		globalLyricsCache.Set(artistName, trackName, durationSec, lyrics)
 		return lyrics, nil
 	}
 
-	// Strategy 4: Search with simplified query
+	// Search with simplified name and duration matching
 	if simplifiedTrack != trackName {
 		query = artistName + " " + simplifiedTrack
-		lyrics, err = c.FetchLyricsFromLRCLibSearch(query)
+		lyrics, err = c.FetchLyricsFromLRCLibSearch(query, durationSec)
 		if err == nil && lyrics != nil && len(lyrics.Lines) > 0 {
 			lyrics.Source = "LRCLIB Search (simplified)"
+			globalLyricsCache.Set(artistName, trackName, durationSec, lyrics)
 			return lyrics, nil
 		}
 	}
@@ -250,29 +396,30 @@ func msToLRCTimestamp(ms int64) string {
 
 // convertToLRC converts lyrics to LRC format string (without metadata headers)
 // Use convertToLRCWithMetadata for full LRC with headers
-func convertToLRC(lyrics *LyricsResponse) string {
-	if lyrics == nil || len(lyrics.Lines) == 0 {
-		return ""
-	}
-
-	var builder strings.Builder
-
-	if lyrics.SyncType == "LINE_SYNCED" {
-		for _, line := range lyrics.Lines {
-			timestamp := msToLRCTimestamp(line.StartTimeMs)
-			builder.WriteString(timestamp)
-			builder.WriteString(line.Words)
-			builder.WriteString("\n")
-		}
-	} else {
-		for _, line := range lyrics.Lines {
-			builder.WriteString(line.Words)
-			builder.WriteString("\n")
-		}
-	}
-
-	return builder.String()
-}
+// Kept for potential future use
+// func convertToLRC(lyrics *LyricsResponse) string {
+// 	if lyrics == nil || len(lyrics.Lines) == 0 {
+// 		return ""
+// 	}
+//
+// 	var builder strings.Builder
+//
+// 	if lyrics.SyncType == "LINE_SYNCED" {
+// 		for _, line := range lyrics.Lines {
+// 			timestamp := msToLRCTimestamp(line.StartTimeMs)
+// 			builder.WriteString(timestamp)
+// 			builder.WriteString(line.Words)
+// 			builder.WriteString("\n")
+// 		}
+// 	} else {
+// 		for _, line := range lyrics.Lines {
+// 			builder.WriteString(line.Words)
+// 			builder.WriteString("\n")
+// 		}
+// 	}
+//
+// 	return builder.String()
+// }
 
 // convertToLRCWithMetadata converts lyrics to LRC format with metadata headers
 // Includes [ti:], [ar:], [by:] headers

go_backend/metadata.go

@@ -33,7 +33,6 @@ func EmbedMetadata(filePath string, metadata Metadata, coverPath string) error {
 		return fmt.Errorf("failed to parse FLAC file: %w", err)
 	}
 
-	// Find or create vorbis comment block
 	var cmtIdx int = -1
 	var cmt *flacvorbis.MetaDataBlockVorbisComment
 
@@ -52,13 +51,12 @@ func EmbedMetadata(filePath string, metadata Metadata, coverPath string) error {
 		cmt = flacvorbis.New()
 	}
 
-	// Set metadata fields
 	setComment(cmt, "TITLE", metadata.Title)
 	setComment(cmt, "ARTIST", metadata.Artist)
 	setComment(cmt, "ALBUM", metadata.Album)
 	setComment(cmt, "ALBUMARTIST", metadata.AlbumArtist)
 	setComment(cmt, "DATE", metadata.Date)
-	
+
 	if metadata.TrackNumber > 0 {
 		if metadata.TotalTracks > 0 {
 			setComment(cmt, "TRACKNUMBER", fmt.Sprintf("%d/%d", metadata.TrackNumber, metadata.TotalTracks))
@@ -66,15 +64,15 @@ func EmbedMetadata(filePath string, metadata Metadata, coverPath string) error {
 			setComment(cmt, "TRACKNUMBER", strconv.Itoa(metadata.TrackNumber))
 		}
 	}
-	
+
 	if metadata.DiscNumber > 0 {
 		setComment(cmt, "DISCNUMBER", strconv.Itoa(metadata.DiscNumber))
 	}
-	
+
 	if metadata.ISRC != "" {
 		setComment(cmt, "ISRC", metadata.ISRC)
 	}
-	
+
 	if metadata.Description != "" {
 		setComment(cmt, "DESCRIPTION", metadata.Description)
 	}
@@ -84,7 +82,6 @@ func EmbedMetadata(filePath string, metadata Metadata, coverPath string) error {
 		setComment(cmt, "UNSYNCEDLYRICS", metadata.Lyrics)
 	}
 
-	// Update or add vorbis comment block
 	cmtBlock := cmt.Marshal()
 	if cmtIdx >= 0 {
 		f.Meta[cmtIdx] = &cmtBlock
@@ -92,20 +89,18 @@ func EmbedMetadata(filePath string, metadata Metadata, coverPath string) error {
 		f.Meta = append(f.Meta, &cmtBlock)
 	}
 
-	// Add cover art if provided
 	if coverPath != "" {
 		if fileExists(coverPath) {
 			coverData, err := os.ReadFile(coverPath)
 			if err != nil {
 				fmt.Printf("[Metadata] Warning: Failed to read cover file %s: %v\n", coverPath, err)
 			} else {
-				// Remove existing picture blocks first (like PC version)
 				for i := len(f.Meta) - 1; i >= 0; i-- {
 					if f.Meta[i].Type == flac.Picture {
 						f.Meta = append(f.Meta[:i], f.Meta[i+1:]...)
 					}
 				}
-				
+
 				picture, err := flacpicture.NewFromImageData(
 					flacpicture.PictureTypeFrontCover,
 					"Front Cover",
@@ -125,7 +120,6 @@ func EmbedMetadata(filePath string, metadata Metadata, coverPath string) error {
 		}
 	}
 
-	// Save file
 	return f.Save(filePath)
 }
 
@@ -137,7 +131,6 @@ func EmbedMetadataWithCoverData(filePath string, metadata Metadata, coverData []
 		return fmt.Errorf("failed to parse FLAC file: %w", err)
 	}
 
-	// Find or create vorbis comment block
 	var cmtIdx int = -1
 	var cmt *flacvorbis.MetaDataBlockVorbisComment
 
@@ -156,13 +149,12 @@ func EmbedMetadataWithCoverData(filePath string, metadata Metadata, coverData []
 		cmt = flacvorbis.New()
 	}
 
-	// Set metadata fields
 	setComment(cmt, "TITLE", metadata.Title)
 	setComment(cmt, "ARTIST", metadata.Artist)
 	setComment(cmt, "ALBUM", metadata.Album)
 	setComment(cmt, "ALBUMARTIST", metadata.AlbumArtist)
 	setComment(cmt, "DATE", metadata.Date)
-	
+
 	if metadata.TrackNumber > 0 {
 		if metadata.TotalTracks > 0 {
 			setComment(cmt, "TRACKNUMBER", fmt.Sprintf("%d/%d", metadata.TrackNumber, metadata.TotalTracks))
@@ -170,15 +162,15 @@ func EmbedMetadataWithCoverData(filePath string, metadata Metadata, coverData []
 			setComment(cmt, "TRACKNUMBER", strconv.Itoa(metadata.TrackNumber))
 		}
 	}
-	
+
 	if metadata.DiscNumber > 0 {
 		setComment(cmt, "DISCNUMBER", strconv.Itoa(metadata.DiscNumber))
 	}
-	
+
 	if metadata.ISRC != "" {
 		setComment(cmt, "ISRC", metadata.ISRC)
 	}
-	
+
 	if metadata.Description != "" {
 		setComment(cmt, "DESCRIPTION", metadata.Description)
 	}
@@ -188,7 +180,6 @@ func EmbedMetadataWithCoverData(filePath string, metadata Metadata, coverData []
 		setComment(cmt, "UNSYNCEDLYRICS", metadata.Lyrics)
 	}
 
-	// Update or add vorbis comment block
 	cmtBlock := cmt.Marshal()
 	if cmtIdx >= 0 {
 		f.Meta[cmtIdx] = &cmtBlock
@@ -196,15 +187,13 @@ func EmbedMetadataWithCoverData(filePath string, metadata Metadata, coverData []
 		f.Meta = append(f.Meta, &cmtBlock)
 	}
 
-	// Add cover art if provided
 	if len(coverData) > 0 {
-		// Remove existing picture blocks first
 		for i := len(f.Meta) - 1; i >= 0; i-- {
 			if f.Meta[i].Type == flac.Picture {
 				f.Meta = append(f.Meta[:i], f.Meta[i+1:]...)
 			}
 		}
-		
+
 		picture, err := flacpicture.NewFromImageData(
 			flacpicture.PictureTypeFrontCover,
 			"Front Cover",
@@ -220,7 +209,6 @@ func EmbedMetadataWithCoverData(filePath string, metadata Metadata, coverData []
 		}
 	}
 
-	// Save file
 	return f.Save(filePath)
 }
 
@@ -257,7 +245,6 @@ func ReadMetadata(filePath string) (*Metadata, error) {
 			if trackNum != "" {
 				fmt.Sscanf(trackNum, "%d", &metadata.TrackNumber)
 			}
-			// Also try lowercase variant (some encoders use lowercase)
 			if metadata.TrackNumber == 0 {
 				trackNum = getComment(cmt, "TRACK")
 				if trackNum != "" {
@@ -269,15 +256,13 @@ func ReadMetadata(filePath string) (*Metadata, error) {
 			if discNum != "" {
 				fmt.Sscanf(discNum, "%d", &metadata.DiscNumber)
 			}
-			// Also try DISC variant
 			if metadata.DiscNumber == 0 {
 				discNum = getComment(cmt, "DISC")
 				if discNum != "" {
 					fmt.Sscanf(discNum, "%d", &metadata.DiscNumber)
 				}
 			}
-			
-			// Try DATE variants
+
 			if metadata.Date == "" {
 				metadata.Date = getComment(cmt, "YEAR")
 			}
@@ -293,7 +278,6 @@ func setComment(cmt *flacvorbis.MetaDataBlockVorbisComment, key, value string) {
 	if value == "" {
 		return
 	}
-	// Remove existing (case-insensitive comparison for Vorbis comments)
 	keyUpper := strings.ToUpper(key)
 	for i := len(cmt.Comments) - 1; i >= 0; i-- {
 		comment := cmt.Comments[i]
@@ -305,7 +289,6 @@ func setComment(cmt *flacvorbis.MetaDataBlockVorbisComment, key, value string) {
 			}
 		}
 	}
-	// Add new
 	cmt.Comments = append(cmt.Comments, key+"="+value)
 }
 
@@ -313,7 +296,6 @@ func getComment(cmt *flacvorbis.MetaDataBlockVorbisComment, key string) string {
 	keyUpper := strings.ToUpper(key) + "="
 	for _, comment := range cmt.Comments {
 		if len(comment) > len(key) {
-			// Case-insensitive comparison for Vorbis comments
 			commentUpper := strings.ToUpper(comment[:len(key)+1])
 			if commentUpper == keyUpper {
 				return comment[len(key)+1:]
@@ -323,7 +305,6 @@ func getComment(cmt *flacvorbis.MetaDataBlockVorbisComment, key string) string {
 	return ""
 }
 
-// fileExists checks if a file exists
 func fileExists(path string) bool {
 	_, err := os.Stat(path)
 	return err == nil
@@ -380,14 +361,12 @@ func ExtractLyrics(filePath string) (string, error) {
 			if err != nil {
 				continue
 			}
-			
-			// Try LYRICS tag first
+
 			lyrics, err := cmt.Get("LYRICS")
 			if err == nil && len(lyrics) > 0 && lyrics[0] != "" {
 				return lyrics[0], nil
 			}
-			
-			// Fallback to UNSYNCEDLYRICS
+
 			lyrics, err = cmt.Get("UNSYNCEDLYRICS")
 			if err == nil && len(lyrics) > 0 && lyrics[0] != "" {
 				return lyrics[0], nil
@@ -400,8 +379,9 @@ func ExtractLyrics(filePath string) (string, error) {
 
 // AudioQuality represents audio quality info from a FLAC file
 type AudioQuality struct {
-	BitDepth   int `json:"bit_depth"`
-	SampleRate int `json:"sample_rate"`
+	BitDepth     int   `json:"bit_depth"`
+	SampleRate   int   `json:"sample_rate"`
+	TotalSamples int64 `json:"total_samples"`
 }
 
 // GetAudioQuality reads bit depth and sample rate from a FLAC file's StreamInfo block
@@ -414,16 +394,12 @@ func GetAudioQuality(filePath string) (AudioQuality, error) {
 	}
 	defer file.Close()
 
-	// Read first 4 bytes to detect file type
 	marker := make([]byte, 4)
 	if _, err := file.Read(marker); err != nil {
 		return AudioQuality{}, fmt.Errorf("failed to read marker: %w", err)
 	}
-	
-	// Check if it's a FLAC file
+
 	if string(marker) == "fLaC" {
-		// Continue reading FLAC metadata
-		// Read metadata block header (4 bytes)
 		header := make([]byte, 4)
 		if _, err := file.Read(header); err != nil {
 			return AudioQuality{}, fmt.Errorf("failed to read header: %w", err)
@@ -434,82 +410,74 @@ func GetAudioQuality(filePath string) (AudioQuality, error) {
 			return AudioQuality{}, fmt.Errorf("first block is not STREAMINFO")
 		}
 
-		// Read STREAMINFO block (34 bytes minimum)
 		streamInfo := make([]byte, 34)
 		if _, err := file.Read(streamInfo); err != nil {
 			return AudioQuality{}, fmt.Errorf("failed to read STREAMINFO: %w", err)
 		}
 
-		// Parse sample rate (20 bits starting at byte 10)
 		sampleRate := (int(streamInfo[10]) << 12) | (int(streamInfo[11]) << 4) | (int(streamInfo[12]) >> 4)
 
-		// Parse bits per sample (5 bits)
 		bitsPerSample := ((int(streamInfo[12]) & 0x01) << 4) | (int(streamInfo[13]) >> 4) + 1
 
+		totalSamples := int64(streamInfo[13]&0x0F)<<32 |
+			int64(streamInfo[14])<<24 |
+			int64(streamInfo[15])<<16 |
+			int64(streamInfo[16])<<8 |
+			int64(streamInfo[17])
+
 		return AudioQuality{
-			BitDepth:   bitsPerSample,
-			SampleRate: sampleRate,
+			BitDepth:     bitsPerSample,
+			SampleRate:   sampleRate,
+			TotalSamples: totalSamples,
 		}, nil
 	}
-	
-	// Check if it's an M4A/MP4 file (starts with size + "ftyp")
-	// First 4 bytes are size, next 4 should be "ftyp"
-	file.Seek(0, 0) // Reset to beginning
+
+	file.Seek(0, 0)
 	header8 := make([]byte, 8)
 	if _, err := file.Read(header8); err != nil {
 		return AudioQuality{}, fmt.Errorf("failed to read header: %w", err)
 	}
-	
+
 	if string(header8[4:8]) == "ftyp" {
-		// It's an M4A/MP4 file, use M4A quality reader
-		file.Close() // Close before calling GetM4AQuality which opens the file again
+		file.Close()
 		return GetM4AQuality(filePath)
 	}
-	
+
 	return AudioQuality{}, fmt.Errorf("unsupported file format (not FLAC or M4A)")
 }
 
-
 // ========================================
 // M4A (MP4/AAC) Metadata Embedding
 // ========================================
 
 // EmbedM4AMetadata embeds metadata into an M4A file using iTunes-style atoms
-// This is a simplified implementation that writes metadata to the file
 func EmbedM4AMetadata(filePath string, metadata Metadata, coverData []byte) error {
-	// Read the entire file
 	data, err := os.ReadFile(filePath)
 	if err != nil {
 		return fmt.Errorf("failed to read M4A file: %w", err)
 	}
 
-	// Find moov atom position
 	moovPos := findAtom(data, "moov", 0)
 	if moovPos < 0 {
 		return fmt.Errorf("moov atom not found in M4A file")
 	}
 
-	// Find udta atom inside moov, or create one
-	moovSize := int(data[moovPos]<<24 | data[moovPos+1]<<16 | data[moovPos+2]<<8 | data[moovPos+3])
+	moovSize := int(uint32(data[moovPos])<<24 | uint32(data[moovPos+1])<<16 | uint32(data[moovPos+2])<<8 | uint32(data[moovPos+3]))
 	udtaPos := findAtom(data, "udta", moovPos+8)
-	
-	// Build new metadata atoms
+
 	metaAtom := buildMetaAtom(metadata, coverData)
-	
+
 	var newData []byte
 	if udtaPos >= 0 && udtaPos < moovPos+moovSize {
-		// udta exists, find meta inside it or replace
-		udtaSize := int(data[udtaPos]<<24 | data[udtaPos+1]<<16 | data[udtaPos+2]<<8 | data[udtaPos+3])
+		udtaSize := int(uint32(data[udtaPos])<<24 | uint32(data[udtaPos+1])<<16 | uint32(data[udtaPos+2])<<8 | uint32(data[udtaPos+3]))
 		metaPos := findAtom(data, "meta", udtaPos+8)
-		
+
 		if metaPos >= 0 && metaPos < udtaPos+udtaSize {
-			// Replace existing meta atom
-			metaSize := int(data[metaPos]<<24 | data[metaPos+1]<<16 | data[metaPos+2]<<8 | data[metaPos+3])
+			metaSize := int(uint32(data[metaPos])<<24 | uint32(data[metaPos+1])<<16 | uint32(data[metaPos+2])<<8 | uint32(data[metaPos+3]))
 			newData = append(newData, data[:metaPos]...)
 			newData = append(newData, metaAtom...)
 			newData = append(newData, data[metaPos+metaSize:]...)
 		} else {
-			// Add meta atom to udta
 			newUdtaContent := append(data[udtaPos+8:udtaPos+udtaSize], metaAtom...)
 			newUdtaSize := 8 + len(newUdtaContent)
 			newUdta := make([]byte, 4)
@@ -519,13 +487,12 @@ func EmbedM4AMetadata(filePath string, metadata Metadata, coverData []byte) erro
 			newUdta[3] = byte(newUdtaSize)
 			newUdta = append(newUdta, []byte("udta")...)
 			newUdta = append(newUdta, newUdtaContent...)
-			
+
 			newData = append(newData, data[:udtaPos]...)
 			newData = append(newData, newUdta...)
 			newData = append(newData, data[udtaPos+udtaSize:]...)
 		}
 	} else {
-		// Create new udta with meta
 		udtaContent := metaAtom
 		udtaSize := 8 + len(udtaContent)
 		newUdta := make([]byte, 4)
@@ -535,22 +502,19 @@ func EmbedM4AMetadata(filePath string, metadata Metadata, coverData []byte) erro
 		newUdta[3] = byte(udtaSize)
 		newUdta = append(newUdta, []byte("udta")...)
 		newUdta = append(newUdta, udtaContent...)
-		
-		// Insert udta at end of moov
+
 		insertPos := moovPos + moovSize
 		newData = append(newData, data[:insertPos]...)
 		newData = append(newData, newUdta...)
 		newData = append(newData, data[insertPos:]...)
 	}
-	
-	// Update moov size
+
 	newMoovSize := moovSize + len(newData) - len(data)
 	newData[moovPos] = byte(newMoovSize >> 24)
 	newData[moovPos+1] = byte(newMoovSize >> 16)
 	newData[moovPos+2] = byte(newMoovSize >> 8)
 	newData[moovPos+3] = byte(newMoovSize)
 
-	// Write back to file
 	if err := os.WriteFile(filePath, newData, 0644); err != nil {
 		return fmt.Errorf("failed to write M4A file: %w", err)
 	}
@@ -562,7 +526,7 @@ func EmbedM4AMetadata(filePath string, metadata Metadata, coverData []byte) erro
 // findAtom finds an atom by name starting from offset
 func findAtom(data []byte, name string, offset int) int {
 	for i := offset; i < len(data)-8; {
-		size := int(data[i]<<24 | data[i+1]<<16 | data[i+2]<<8 | data[i+3])
+		size := int(uint32(data[i])<<24 | uint32(data[i+1])<<16 | uint32(data[i+2])<<8 | uint32(data[i+3]))
 		if size < 8 {
 			break
 		}
@@ -577,55 +541,44 @@ func findAtom(data []byte, name string, offset int) int {
 
 // buildMetaAtom builds a complete meta atom with ilst containing metadata
 func buildMetaAtom(metadata Metadata, coverData []byte) []byte {
-	// Build ilst content
 	var ilst []byte
-	
-	// ©nam - Title
+
 	if metadata.Title != "" {
 		ilst = append(ilst, buildTextAtom("©nam", metadata.Title)...)
 	}
-	
-	// ©ART - Artist
+
 	if metadata.Artist != "" {
 		ilst = append(ilst, buildTextAtom("©ART", metadata.Artist)...)
 	}
-	
-	// ©alb - Album
+
 	if metadata.Album != "" {
 		ilst = append(ilst, buildTextAtom("©alb", metadata.Album)...)
 	}
-	
-	// aART - Album Artist
+
 	if metadata.AlbumArtist != "" {
 		ilst = append(ilst, buildTextAtom("aART", metadata.AlbumArtist)...)
 	}
-	
-	// ©day - Year/Date
+
 	if metadata.Date != "" {
 		ilst = append(ilst, buildTextAtom("©day", metadata.Date)...)
 	}
-	
-	// trkn - Track Number
+
 	if metadata.TrackNumber > 0 {
 		ilst = append(ilst, buildTrackNumberAtom(metadata.TrackNumber, metadata.TotalTracks)...)
 	}
-	
-	// disk - Disc Number
+
 	if metadata.DiscNumber > 0 {
 		ilst = append(ilst, buildDiscNumberAtom(metadata.DiscNumber, 0)...)
 	}
-	
-	// ©lyr - Lyrics
+
 	if metadata.Lyrics != "" {
 		ilst = append(ilst, buildTextAtom("©lyr", metadata.Lyrics)...)
 	}
-	
-	// covr - Cover Art
+
 	if len(coverData) > 0 {
 		ilst = append(ilst, buildCoverAtom(coverData)...)
 	}
-	
-	// Build ilst atom
+
 	ilstSize := 8 + len(ilst)
 	ilstAtom := make([]byte, 4)
 	ilstAtom[0] = byte(ilstSize >> 24)
@@ -634,8 +587,7 @@ func buildMetaAtom(metadata Metadata, coverData []byte) []byte {
 	ilstAtom[3] = byte(ilstSize)
 	ilstAtom = append(ilstAtom, []byte("ilst")...)
 	ilstAtom = append(ilstAtom, ilst...)
-	
-	// Build hdlr atom (required for meta)
+
 	hdlr := []byte{
 		0, 0, 0, 33, // size = 33
 		'h', 'd', 'l', 'r',
@@ -647,11 +599,10 @@ func buildMetaAtom(metadata Metadata, coverData []byte) []byte {
 		0, 0, 0, 0, // component flags mask
 		0, // null terminator
 	}
-	
-	// Build meta atom
+
 	metaContent := append([]byte{0, 0, 0, 0}, hdlr...) // version + flags + hdlr
 	metaContent = append(metaContent, ilstAtom...)
-	
+
 	metaSize := 8 + len(metaContent)
 	metaAtom := make([]byte, 4)
 	metaAtom[0] = byte(metaSize >> 24)
@@ -660,15 +611,14 @@ func buildMetaAtom(metadata Metadata, coverData []byte) []byte {
 	metaAtom[3] = byte(metaSize)
 	metaAtom = append(metaAtom, []byte("meta")...)
 	metaAtom = append(metaAtom, metaContent...)
-	
+
 	return metaAtom
 }
 
 // buildTextAtom builds a text metadata atom (©nam, ©ART, etc.)
 func buildTextAtom(name, value string) []byte {
 	valueBytes := []byte(value)
-	
-	// data atom
+
 	dataSize := 16 + len(valueBytes)
 	dataAtom := make([]byte, 4)
 	dataAtom[0] = byte(dataSize >> 24)
@@ -679,8 +629,7 @@ func buildTextAtom(name, value string) []byte {
 	dataAtom = append(dataAtom, 0, 0, 0, 1) // type = UTF-8
 	dataAtom = append(dataAtom, 0, 0, 0, 0) // locale
 	dataAtom = append(dataAtom, valueBytes...)
-	
-	// container atom
+
 	atomSize := 8 + len(dataAtom)
 	atom := make([]byte, 4)
 	atom[0] = byte(atomSize >> 24)
@@ -689,13 +638,12 @@ func buildTextAtom(name, value string) []byte {
 	atom[3] = byte(atomSize)
 	atom = append(atom, []byte(name)...)
 	atom = append(atom, dataAtom...)
-	
+
 	return atom
 }
 
 // buildTrackNumberAtom builds trkn atom
 func buildTrackNumberAtom(track, total int) []byte {
-	// data atom with track number
 	dataAtom := []byte{
 		0, 0, 0, 24, // size
 		'd', 'a', 't', 'a',
@@ -706,8 +654,7 @@ func buildTrackNumberAtom(track, total int) []byte {
 		byte(total >> 8), byte(total), // total tracks
 		0, 0, // padding
 	}
-	
-	// trkn atom
+
 	atomSize := 8 + len(dataAtom)
 	atom := make([]byte, 4)
 	atom[0] = byte(atomSize >> 24)
@@ -716,13 +663,12 @@ func buildTrackNumberAtom(track, total int) []byte {
 	atom[3] = byte(atomSize)
 	atom = append(atom, []byte("trkn")...)
 	atom = append(atom, dataAtom...)
-	
+
 	return atom
 }
 
 // buildDiscNumberAtom builds disk atom
 func buildDiscNumberAtom(disc, total int) []byte {
-	// data atom with disc number
 	dataAtom := []byte{
 		0, 0, 0, 22, // size
 		'd', 'a', 't', 'a',
@@ -732,8 +678,7 @@ func buildDiscNumberAtom(disc, total int) []byte {
 		byte(disc >> 8), byte(disc), // disc number
 		byte(total >> 8), byte(total), // total discs
 	}
-	
-	// disk atom
+
 	atomSize := 8 + len(dataAtom)
 	atom := make([]byte, 4)
 	atom[0] = byte(atomSize >> 24)
@@ -742,19 +687,17 @@ func buildDiscNumberAtom(disc, total int) []byte {
 	atom[3] = byte(atomSize)
 	atom = append(atom, []byte("disk")...)
 	atom = append(atom, dataAtom...)
-	
+
 	return atom
 }
 
 // buildCoverAtom builds covr atom with image data
 func buildCoverAtom(coverData []byte) []byte {
-	// Detect image type (JPEG = 13, PNG = 14)
 	imageType := byte(13) // default JPEG
 	if len(coverData) > 8 && coverData[0] == 0x89 && coverData[1] == 'P' && coverData[2] == 'N' && coverData[3] == 'G' {
 		imageType = 14 // PNG
 	}
-	
-	// data atom
+
 	dataSize := 16 + len(coverData)
 	dataAtom := make([]byte, 4)
 	dataAtom[0] = byte(dataSize >> 24)
@@ -765,8 +708,7 @@ func buildCoverAtom(coverData []byte) []byte {
 	dataAtom = append(dataAtom, 0, 0, 0, imageType) // type = JPEG or PNG
 	dataAtom = append(dataAtom, 0, 0, 0, 0)         // locale
 	dataAtom = append(dataAtom, coverData...)
-	
-	// covr atom
+
 	atomSize := 8 + len(dataAtom)
 	atom := make([]byte, 4)
 	atom[0] = byte(atomSize >> 24)
@@ -775,7 +717,7 @@ func buildCoverAtom(coverData []byte) []byte {
 	atom[3] = byte(atomSize)
 	atom = append(atom, []byte("covr")...)
 	atom = append(atom, dataAtom...)
-	
+
 	return atom
 }
 
@@ -786,24 +728,18 @@ func GetM4AQuality(filePath string) (AudioQuality, error) {
 		return AudioQuality{}, fmt.Errorf("failed to read M4A file: %w", err)
 	}
 
-	// Find moov -> trak -> mdia -> minf -> stbl -> stsd
 	moovPos := findAtom(data, "moov", 0)
 	if moovPos < 0 {
 		return AudioQuality{}, fmt.Errorf("moov atom not found")
 	}
 
-	// Search for mp4a or alac atom which contains audio info
-	// This is a simplified search - real implementation would traverse the atom tree
 	for i := moovPos; i < len(data)-20; i++ {
 		if string(data[i:i+4]) == "mp4a" || string(data[i:i+4]) == "alac" {
-			// Sample rate is at offset 22-23 from atom start (16-bit big-endian)
 			if i+24 < len(data) {
 				sampleRate := int(data[i+22])<<8 | int(data[i+23])
-				// For AAC, bit depth is typically 16
 				bitDepth := 16
 				if string(data[i:i+4]) == "alac" {
-					// ALAC can have higher bit depth, check esds or alac specific data
-					bitDepth = 24 // Assume 24-bit for ALAC
+					bitDepth = 24
 				}
 				return AudioQuality{BitDepth: bitDepth, SampleRate: sampleRate}, nil
 			}

go_backend/parallel.go

@@ -35,7 +35,7 @@ func GetTrackIDCache() *TrackIDCache {
 	trackIDCacheOnce.Do(func() {
 		globalTrackIDCache = &TrackIDCache{
 			cache: make(map[string]*TrackIDCacheEntry),
-			ttl:   30 * time.Minute, // Cache for 30 minutes
+			ttl:   30 * time.Minute,
 		}
 	})
 	return globalTrackIDCache
@@ -124,6 +124,7 @@ type ParallelDownloadResult struct {
 
 // FetchCoverAndLyricsParallel downloads cover and fetches lyrics in parallel
 // This runs while the main audio download is happening
+// durationMs: track duration in milliseconds for lyrics matching
 func FetchCoverAndLyricsParallel(
 	coverURL string,
 	maxQualityCover bool,
@@ -131,11 +132,11 @@ func FetchCoverAndLyricsParallel(
 	trackName string,
 	artistName string,
 	embedLyrics bool,
+	durationMs int64,
 ) *ParallelDownloadResult {
 	result := &ParallelDownloadResult{}
 	var wg sync.WaitGroup
 
-	// Download cover in parallel
 	if coverURL != "" {
 		wg.Add(1)
 		go func() {
@@ -159,13 +160,13 @@ func FetchCoverAndLyricsParallel(
 			defer wg.Done()
 			fmt.Println("[Parallel] Starting lyrics fetch...")
 			client := NewLyricsClient()
-			lyrics, err := client.FetchLyricsAllSources(spotifyID, trackName, artistName)
+			durationSec := float64(durationMs) / 1000.0
+			lyrics, err := client.FetchLyricsAllSources(spotifyID, trackName, artistName, durationSec)
 			if err != nil {
 				result.LyricsErr = err
 				fmt.Printf("[Parallel] Lyrics fetch failed: %v\n", err)
 			} else if lyrics != nil && len(lyrics.Lines) > 0 {
 				result.LyricsData = lyrics
-				// Use LRC with metadata headers (like PC version)
 				result.LyricsLRC = convertToLRCWithMetadata(lyrics, trackName, artistName)
 				fmt.Printf("[Parallel] Lyrics fetched: %d lines\n", len(lyrics.Lines))
 			} else {
@@ -202,12 +203,10 @@ func PreWarmTrackCache(requests []PreWarmCacheRequest) {
 	fmt.Printf("[Cache] Pre-warming cache for %d tracks...\n", len(requests))
 	cache := GetTrackIDCache()
 
-	// Limit concurrent pre-warm requests
-	semaphore := make(chan struct{}, 3) // Max 3 concurrent
+	semaphore := make(chan struct{}, 3)
 	var wg sync.WaitGroup
 
 	for _, req := range requests {
-		// Skip if already cached
 		if cached := cache.Get(req.ISRC); cached != nil {
 			continue
 		}
@@ -233,7 +232,7 @@ func PreWarmTrackCache(requests []PreWarmCacheRequest) {
 	fmt.Printf("[Cache] Pre-warm complete. Cache size: %d\n", cache.Size())
 }
 
-func preWarmTidalCache(isrc, trackName, artistName string) {
+func preWarmTidalCache(isrc, _, _ string) {
 	downloader := NewTidalDownloader()
 	track, err := downloader.SearchTrackByISRC(isrc)
 	if err == nil && track != nil {
@@ -252,11 +251,9 @@ func preWarmQobuzCache(isrc string) {
 }
 
 func preWarmAmazonCache(isrc, spotifyID string) {
-	// Amazon uses SongLink to get URL, so we pre-warm by checking availability
 	client := NewSongLinkClient()
 	availability, err := client.CheckTrackAvailability(spotifyID, isrc)
 	if err == nil && availability != nil && availability.Amazon {
-		// Store Amazon URL in cache (using ISRC as key)
 		GetTrackIDCache().SetAmazon(isrc, availability.AmazonURL)
 		fmt.Printf("[Cache] Cached Amazon URL for ISRC %s\n", isrc)
 	}
@@ -270,10 +267,8 @@ func preWarmAmazonCache(isrc, spotifyID string) {
 // tracksJSON is a JSON array of {isrc, track_name, artist_name, service}
 func PreWarmCache(tracksJSON string) error {
 	var requests []PreWarmCacheRequest
-	// Parse JSON (simplified - in production use proper JSON parsing)
-	// For now, this is called from exports.go with proper parsing
-	
-	go PreWarmTrackCache(requests) // Run in background
+
+	go PreWarmTrackCache(requests)
 	return nil
 }
 

go_backend/progress.go

@@ -23,7 +23,7 @@ type ItemProgress struct {
 	ItemID        string  `json:"item_id"`
 	BytesTotal    int64   `json:"bytes_total"`
 	BytesReceived int64   `json:"bytes_received"`
-	Progress      float64 `json:"progress"` // 0.0 to 1.0
+	Progress      float64 `json:"progress"`   // 0.0 to 1.0
 	SpeedMBps     float64 `json:"speed_mbps"` // Download speed in MB/s
 	IsDownloading bool    `json:"is_downloading"`
 	Status        string  `json:"status"` // "downloading", "finalizing", "completed"
@@ -44,16 +44,14 @@ var (
 )
 
 // getProgress returns current download progress from multi-progress system
-// Returns first active item's progress for backward compatibility
 func getProgress() DownloadProgress {
 	multiMu.RLock()
 	defer multiMu.RUnlock()
 
-	// Find first active item
 	for _, item := range multiProgress.Items {
 		return DownloadProgress{
 			CurrentFile:   item.ItemID,
-			Progress:      item.Progress * 100, // Convert to percentage
+			Progress:      item.Progress * 100,
 			BytesTotal:    item.BytesTotal,
 			BytesReceived: item.BytesReceived,
 			IsDownloading: item.IsDownloading,
@@ -204,11 +202,12 @@ func setDownloadDir(path string) error {
 }
 
 // getDownloadDir returns the default download directory
-func getDownloadDir() string {
-	downloadDirMu.RLock()
-	defer downloadDirMu.RUnlock()
-	return downloadDir
-}
+// Kept for potential future use
+// func getDownloadDir() string {
+// 	downloadDirMu.RLock()
+// 	defer downloadDirMu.RUnlock()
+// 	return downloadDir
+// }
 
 // ItemProgressWriter wraps io.Writer to track download progress for a specific item
 type ItemProgressWriter struct {
@@ -239,16 +238,16 @@ func NewItemProgressWriter(w interface{ Write([]byte) (int, error) }, itemID str
 
 // Write implements io.Writer with threshold-based progress updates and speed tracking
 func (pw *ItemProgressWriter) Write(p []byte) (int, error) {
+	if pw.itemID != "" && isDownloadCancelled(pw.itemID) {
+		return 0, ErrDownloadCancelled
+	}
 	n, err := pw.writer.Write(p)
 	if err != nil {
 		return n, err
 	}
 	pw.current += int64(n)
 
-	// Update progress when we've received at least 64KB since last update
-	// Also update on first write to show download has started
 	if pw.lastReported == 0 || pw.current-pw.lastReported >= progressUpdateThreshold {
-		// Calculate speed (MB/s) based on bytes received since last update
 		now := time.Now()
 		elapsed := now.Sub(pw.lastTime).Seconds()
 		var speedMBps float64
@@ -256,7 +255,7 @@ func (pw *ItemProgressWriter) Write(p []byte) (int, error) {
 			bytesInInterval := pw.current - pw.lastBytes
 			speedMBps = float64(bytesInInterval) / (1024 * 1024) / elapsed
 		}
-		
+
 		SetItemBytesReceivedWithSpeed(pw.itemID, pw.current, speedMBps)
 		pw.lastReported = pw.current
 		pw.lastTime = now

go_backend/qobuz.go

@@ -2,8 +2,10 @@ package gobackend
 
 import (
 	"bufio"
+	"context"
 	"encoding/base64"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io"
 	"net/http"
@@ -12,6 +14,7 @@ import (
 	"path/filepath"
 	"strings"
 	"sync"
+	"time"
 )
 
 // QobuzDownloader handles Qobuz downloads
@@ -22,7 +25,6 @@ type QobuzDownloader struct {
 }
 
 var (
-	// Global Qobuz downloader instance for connection reuse
 	globalQobuzDownloader *QobuzDownloader
 	qobuzDownloaderOnce   sync.Once
 )
@@ -63,48 +65,281 @@ func qobuzArtistsMatch(expectedArtist, foundArtist string) bool {
 		return true
 	}
 
-	// Check first artist (before comma or feat)
-	expectedFirst := strings.Split(normExpected, ",")[0]
-	expectedFirst = strings.Split(expectedFirst, " feat")[0]
-	expectedFirst = strings.Split(expectedFirst, " ft.")[0]
-	expectedFirst = strings.TrimSpace(expectedFirst)
+	expectedArtists := qobuzSplitArtists(normExpected)
+	foundArtists := qobuzSplitArtists(normFound)
 
-	foundFirst := strings.Split(normFound, ",")[0]
-	foundFirst = strings.Split(foundFirst, " feat")[0]
-	foundFirst = strings.Split(foundFirst, " ft.")[0]
-	foundFirst = strings.TrimSpace(foundFirst)
-
-	if expectedFirst == foundFirst {
-		return true
+	for _, exp := range expectedArtists {
+		for _, fnd := range foundArtists {
+			if exp == fnd {
+				return true
+			}
+			if strings.Contains(exp, fnd) || strings.Contains(fnd, exp) {
+				return true
+			}
+			if qobuzSameWordsUnordered(exp, fnd) {
+				GoLog("[Qobuz] Artist names have same words in different order: '%s' vs '%s'\n", exp, fnd)
+				return true
+			}
+		}
 	}
 
-	// Check if first artist is contained in the other
-	if strings.Contains(expectedFirst, foundFirst) || strings.Contains(foundFirst, expectedFirst) {
-		return true
-	}
-
-	// If scripts are different (one is ASCII, one is non-ASCII like Japanese/Chinese/Korean),
-	// assume they're the same artist with different transliteration
-	expectedASCII := qobuzIsASCIIString(expectedArtist)
-	foundASCII := qobuzIsASCIIString(foundArtist)
-	if expectedASCII != foundASCII {
-		fmt.Printf("[Qobuz] Artist names in different scripts, assuming match: '%s' vs '%s'\n", expectedArtist, foundArtist)
+	expectedLatin := qobuzIsLatinScript(expectedArtist)
+	foundLatin := qobuzIsLatinScript(foundArtist)
+	if expectedLatin != foundLatin {
+		GoLog("[Qobuz] Artist names in different scripts, assuming match: '%s' vs '%s'\n", expectedArtist, foundArtist)
 		return true
 	}
 
 	return false
 }
 
-// qobuzIsASCIIString checks if a string contains only ASCII characters
-func qobuzIsASCIIString(s string) bool {
-	for _, r := range s {
-		if r > 127 {
+// qobuzSplitArtists splits artist string by common separators
+func qobuzSplitArtists(artists string) []string {
+	// Replace common separators with a standard one
+	normalized := artists
+	normalized = strings.ReplaceAll(normalized, " feat. ", "|")
+	normalized = strings.ReplaceAll(normalized, " feat ", "|")
+	normalized = strings.ReplaceAll(normalized, " ft. ", "|")
+	normalized = strings.ReplaceAll(normalized, " ft ", "|")
+	normalized = strings.ReplaceAll(normalized, " & ", "|")
+	normalized = strings.ReplaceAll(normalized, " and ", "|")
+	normalized = strings.ReplaceAll(normalized, ", ", "|")
+	normalized = strings.ReplaceAll(normalized, " x ", "|")
+
+	parts := strings.Split(normalized, "|")
+	result := make([]string, 0, len(parts))
+	for _, p := range parts {
+		trimmed := strings.TrimSpace(p)
+		if trimmed != "" {
+			result = append(result, trimmed)
+		}
+	}
+	return result
+}
+
+// qobuzSameWordsUnordered checks if two strings have the same words regardless of order
+// Useful for Japanese names: "Sawano Hiroyuki" vs "Hiroyuki Sawano"
+func qobuzSameWordsUnordered(a, b string) bool {
+	wordsA := strings.Fields(a)
+	wordsB := strings.Fields(b)
+
+	// Must have same number of words
+	if len(wordsA) != len(wordsB) || len(wordsA) == 0 {
+		return false
+	}
+
+	// Sort and compare
+	sortedA := make([]string, len(wordsA))
+	sortedB := make([]string, len(wordsB))
+	copy(sortedA, wordsA)
+	copy(sortedB, wordsB)
+
+	// Simple bubble sort (usually just 2-3 words)
+	for i := 0; i < len(sortedA)-1; i++ {
+		for j := i + 1; j < len(sortedA); j++ {
+			if sortedA[i] > sortedA[j] {
+				sortedA[i], sortedA[j] = sortedA[j], sortedA[i]
+			}
+			if sortedB[i] > sortedB[j] {
+				sortedB[i], sortedB[j] = sortedB[j], sortedB[i]
+			}
+		}
+	}
+
+	for i := range sortedA {
+		if sortedA[i] != sortedB[i] {
 			return false
 		}
 	}
 	return true
 }
 
+// qobuzTitlesMatch checks if track titles are similar enough
+func qobuzTitlesMatch(expectedTitle, foundTitle string) bool {
+	normExpected := strings.ToLower(strings.TrimSpace(expectedTitle))
+	normFound := strings.ToLower(strings.TrimSpace(foundTitle))
+
+	// Exact match
+	if normExpected == normFound {
+		return true
+	}
+
+	// Check if one contains the other
+	if strings.Contains(normExpected, normFound) || strings.Contains(normFound, normExpected) {
+		return true
+	}
+
+	// Clean BOTH titles and compare (removes suffixes like remaster, remix, etc)
+	cleanExpected := qobuzCleanTitle(normExpected)
+	cleanFound := qobuzCleanTitle(normFound)
+
+	if cleanExpected == cleanFound {
+		return true
+	}
+
+	// Check if cleaned versions contain each other
+	if cleanExpected != "" && cleanFound != "" {
+		if strings.Contains(cleanExpected, cleanFound) || strings.Contains(cleanFound, cleanExpected) {
+			return true
+		}
+	}
+
+	// Extract core title (before any parentheses/brackets)
+	coreExpected := qobuzExtractCoreTitle(normExpected)
+	coreFound := qobuzExtractCoreTitle(normFound)
+
+	if coreExpected != "" && coreFound != "" && coreExpected == coreFound {
+		return true
+	}
+
+	// If scripts are TRULY different (Latin vs CJK/Arabic/Cyrillic), assume match (transliteration)
+	// Don't treat Latin Extended (Polish, French, etc.) as different script
+	expectedLatin := qobuzIsLatinScript(expectedTitle)
+	foundLatin := qobuzIsLatinScript(foundTitle)
+	if expectedLatin != foundLatin {
+		GoLog("[Qobuz] Titles in different scripts, assuming match: '%s' vs '%s'\n", expectedTitle, foundTitle)
+		return true
+	}
+
+	return false
+}
+
+// qobuzExtractCoreTitle extracts the main title before any parentheses or brackets
+func qobuzExtractCoreTitle(title string) string {
+	// Find first occurrence of ( or [
+	parenIdx := strings.Index(title, "(")
+	bracketIdx := strings.Index(title, "[")
+	dashIdx := strings.Index(title, " - ")
+
+	cutIdx := len(title)
+	if parenIdx > 0 && parenIdx < cutIdx {
+		cutIdx = parenIdx
+	}
+	if bracketIdx > 0 && bracketIdx < cutIdx {
+		cutIdx = bracketIdx
+	}
+	if dashIdx > 0 && dashIdx < cutIdx {
+		cutIdx = dashIdx
+	}
+
+	return strings.TrimSpace(title[:cutIdx])
+}
+
+// qobuzCleanTitle removes common suffixes from track titles for comparison
+func qobuzCleanTitle(title string) string {
+	cleaned := title
+
+	// Remove content in parentheses/brackets that are version indicators
+	// This helps match "Song (Remastered)" with "Song" or "Song (2024 Remaster)"
+	versionPatterns := []string{
+		"remaster", "remastered", "deluxe", "bonus", "single",
+		"album version", "radio edit", "original mix", "extended",
+		"club mix", "remix", "live", "acoustic", "demo",
+	}
+
+	// Remove parenthetical content if it contains version indicators
+	for {
+		startParen := strings.LastIndex(cleaned, "(")
+		endParen := strings.LastIndex(cleaned, ")")
+		if startParen >= 0 && endParen > startParen {
+			content := strings.ToLower(cleaned[startParen+1 : endParen])
+			isVersionIndicator := false
+			for _, pattern := range versionPatterns {
+				if strings.Contains(content, pattern) {
+					isVersionIndicator = true
+					break
+				}
+			}
+			if isVersionIndicator {
+				cleaned = strings.TrimSpace(cleaned[:startParen]) + cleaned[endParen+1:]
+				continue
+			}
+		}
+		break
+	}
+
+	// Same for brackets
+	for {
+		startBracket := strings.LastIndex(cleaned, "[")
+		endBracket := strings.LastIndex(cleaned, "]")
+		if startBracket >= 0 && endBracket > startBracket {
+			content := strings.ToLower(cleaned[startBracket+1 : endBracket])
+			isVersionIndicator := false
+			for _, pattern := range versionPatterns {
+				if strings.Contains(content, pattern) {
+					isVersionIndicator = true
+					break
+				}
+			}
+			if isVersionIndicator {
+				cleaned = strings.TrimSpace(cleaned[:startBracket]) + cleaned[endBracket+1:]
+				continue
+			}
+		}
+		break
+	}
+
+	// Remove trailing " - version" patterns
+	dashPatterns := []string{
+		" - remaster", " - remastered", " - single version", " - radio edit",
+		" - live", " - acoustic", " - demo", " - remix",
+	}
+	for _, pattern := range dashPatterns {
+		if strings.HasSuffix(strings.ToLower(cleaned), pattern) {
+			cleaned = cleaned[:len(cleaned)-len(pattern)]
+		}
+	}
+
+	// Remove multiple spaces
+	for strings.Contains(cleaned, "  ") {
+		cleaned = strings.ReplaceAll(cleaned, "  ", " ")
+	}
+
+	return strings.TrimSpace(cleaned)
+}
+
+// qobuzIsLatinScript checks if a string is primarily Latin script
+// Returns true for ASCII and Latin Extended characters (European languages)
+// Returns false for CJK, Arabic, Cyrillic, etc.
+func qobuzIsLatinScript(s string) bool {
+	for _, r := range s {
+		// Skip common punctuation and numbers
+		if r < 128 {
+			continue
+		}
+		// Latin Extended-A: U+0100 to U+017F (Polish, Czech, etc.)
+		// Latin Extended-B: U+0180 to U+024F
+		// Latin Extended Additional: U+1E00 to U+1EFF
+		// Latin Extended-C/D/E: various ranges
+		if (r >= 0x0100 && r <= 0x024F) || // Latin Extended A & B
+			(r >= 0x1E00 && r <= 0x1EFF) || // Latin Extended Additional
+			(r >= 0x00C0 && r <= 0x00FF) { // Latin-1 Supplement (accented chars)
+			continue
+		}
+		// CJK ranges - definitely different script
+		if (r >= 0x4E00 && r <= 0x9FFF) || // CJK Unified Ideographs
+			(r >= 0x3040 && r <= 0x309F) || // Hiragana
+			(r >= 0x30A0 && r <= 0x30FF) || // Katakana
+			(r >= 0xAC00 && r <= 0xD7AF) || // Hangul (Korean)
+			(r >= 0x0600 && r <= 0x06FF) || // Arabic
+			(r >= 0x0400 && r <= 0x04FF) { // Cyrillic
+			return false
+		}
+	}
+	return true
+}
+
+// qobuzIsASCIIString checks if a string contains only ASCII characters
+// Kept for potential future use
+// func qobuzIsASCIIString(s string) bool {
+// 	for _, r := range s {
+// 		if r > 127 {
+// 			return false
+// 		}
+// 	}
+// 	return true
+// }
+
 // containsQueryQobuz checks if a query already exists in the list
 func containsQueryQobuz(queries []string, query string) bool {
 	for _, q := range queries {
@@ -126,6 +361,35 @@ func NewQobuzDownloader() *QobuzDownloader {
 	return globalQobuzDownloader
 }
 
+// GetTrackByID fetches track info directly by Qobuz track ID
+func (q *QobuzDownloader) GetTrackByID(trackID int64) (*QobuzTrack, error) {
+	// Qobuz API: /track/get?track_id=XXX
+	apiBase, _ := base64.StdEncoding.DecodeString("aHR0cHM6Ly93d3cucW9idXouY29tL2FwaS5qc29uLzAuMi90cmFjay9nZXQ/dHJhY2tfaWQ9")
+	trackURL := fmt.Sprintf("%s%d&app_id=%s", string(apiBase), trackID, q.appID)
+
+	req, err := http.NewRequest("GET", trackURL, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	resp, err := DoRequestWithUserAgent(q.client, req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != 200 {
+		return nil, fmt.Errorf("get track failed: HTTP %d", resp.StatusCode)
+	}
+
+	var track QobuzTrack
+	if err := json.NewDecoder(resp.Body).Decode(&track); err != nil {
+		return nil, err
+	}
+
+	return &track, nil
+}
+
 // GetAvailableAPIs returns list of available Qobuz APIs
 // Uses same APIs as PC version for compatibility
 func (q *QobuzDownloader) GetAvailableAPIs() []string {
@@ -194,8 +458,8 @@ func (q *QobuzDownloader) SearchTrackByISRC(isrc string) (*QobuzTrack, error) {
 // SearchTrackByISRCWithTitle searches for a track by ISRC with duration verification
 // expectedDurationSec is the expected duration in seconds (0 to skip verification)
 func (q *QobuzDownloader) SearchTrackByISRCWithDuration(isrc string, expectedDurationSec int) (*QobuzTrack, error) {
-	fmt.Printf("[Qobuz] Searching by ISRC: %s\n", isrc)
-	
+	GoLog("[Qobuz] Searching by ISRC: %s\n", isrc)
+
 	apiBase, _ := base64.StdEncoding.DecodeString("aHR0cHM6Ly93d3cucW9idXouY29tL2FwaS5qc29uLzAuMi90cmFjay9zZWFyY2g/cXVlcnk9")
 	searchURL := fmt.Sprintf("%s%s&limit=50&app_id=%s", string(apiBase), url.QueryEscape(isrc), q.appID)
 
@@ -223,7 +487,7 @@ func (q *QobuzDownloader) SearchTrackByISRCWithDuration(isrc string, expectedDur
 		return nil, err
 	}
 
-	fmt.Printf("[Qobuz] ISRC search returned %d results\n", len(result.Tracks.Items))
+	GoLog("[Qobuz] ISRC search returned %d results\n", len(result.Tracks.Items))
 
 	// Find ISRC matches
 	var isrcMatches []*QobuzTrack
@@ -233,7 +497,7 @@ func (q *QobuzDownloader) SearchTrackByISRCWithDuration(isrc string, expectedDur
 		}
 	}
 
-	fmt.Printf("[Qobuz] Found %d exact ISRC matches\n", len(isrcMatches))
+	GoLog("[Qobuz] Found %d exact ISRC matches\n", len(isrcMatches))
 
 	if len(isrcMatches) > 0 {
 		// Verify duration if provided
@@ -251,20 +515,20 @@ func (q *QobuzDownloader) SearchTrackByISRCWithDuration(isrc string, expectedDur
 			}
 
 			if len(durationVerifiedMatches) > 0 {
-				fmt.Printf("[Qobuz] ISRC match with duration verification: '%s' (expected %ds, found %ds)\n",
+				GoLog("[Qobuz] ISRC match with duration verification: '%s' (expected %ds, found %ds)\n",
 					durationVerifiedMatches[0].Title, expectedDurationSec, durationVerifiedMatches[0].Duration)
 				return durationVerifiedMatches[0], nil
 			}
 
 			// ISRC matches but duration doesn't
-			fmt.Printf("[Qobuz] WARNING: ISRC %s found but duration mismatch. Expected=%ds, Found=%ds. Rejecting.\n",
+			GoLog("[Qobuz] WARNING: ISRC %s found but duration mismatch. Expected=%ds, Found=%ds. Rejecting.\n",
 				isrc, expectedDurationSec, isrcMatches[0].Duration)
 			return nil, fmt.Errorf("ISRC found but duration mismatch: expected %ds, found %ds (likely different version)",
 				expectedDurationSec, isrcMatches[0].Duration)
 		}
 
 		// No duration to verify, return first match
-		fmt.Printf("[Qobuz] ISRC match (no duration verification): '%s'\n", isrcMatches[0].Title)
+		GoLog("[Qobuz] ISRC match (no duration verification): '%s'\n", isrcMatches[0].Title)
 		return isrcMatches[0], nil
 	}
 
@@ -287,6 +551,7 @@ func (q *QobuzDownloader) SearchTrackByMetadata(trackName, artistName string) (*
 
 // SearchTrackByMetadataWithDuration searches for a track with duration verification
 // Now includes romaji conversion for Japanese text (same as Tidal)
+// Also includes title verification to prevent wrong song downloads
 func (q *QobuzDownloader) SearchTrackByMetadataWithDuration(trackName, artistName string, expectedDurationSec int) (*QobuzTrack, error) {
 	apiBase, _ := base64.StdEncoding.DecodeString("aHR0cHM6Ly93d3cucW9idXouY29tL2FwaS5qc29uLzAuMi90cmFjay9zZWFyY2g/cXVlcnk9")
 
@@ -318,7 +583,7 @@ func (q *QobuzDownloader) SearchTrackByMetadataWithDuration(trackName, artistNam
 			romajiQuery := cleanRomajiArtist + " " + cleanRomajiTrack
 			if !containsQueryQobuz(queries, romajiQuery) {
 				queries = append(queries, romajiQuery)
-				fmt.Printf("[Qobuz] Japanese detected, adding romaji query: %s\n", romajiQuery)
+				GoLog("[Qobuz] Japanese detected, adding romaji query: %s\n", romajiQuery)
 			}
 		}
 
@@ -348,7 +613,7 @@ func (q *QobuzDownloader) SearchTrackByMetadataWithDuration(trackName, artistNam
 		}
 		searchedQueries[cleanQuery] = true
 
-		fmt.Printf("[Qobuz] Searching for: %s\n", cleanQuery)
+		GoLog("[Qobuz] Searching for: %s\n", cleanQuery)
 
 		searchURL := fmt.Sprintf("%s%s&limit=50&app_id=%s", string(apiBase), url.QueryEscape(cleanQuery), q.appID)
 
@@ -359,7 +624,7 @@ func (q *QobuzDownloader) SearchTrackByMetadataWithDuration(trackName, artistNam
 
 		resp, err := DoRequestWithUserAgent(q.client, req)
 		if err != nil {
-			fmt.Printf("[Qobuz] Search error for '%s': %v\n", cleanQuery, err)
+			GoLog("[Qobuz] Search error for '%s': %v\n", cleanQuery, err)
 			continue
 		}
 
@@ -380,7 +645,7 @@ func (q *QobuzDownloader) SearchTrackByMetadataWithDuration(trackName, artistNam
 		resp.Body.Close()
 
 		if len(result.Tracks.Items) > 0 {
-			fmt.Printf("[Qobuz] Found %d results for '%s'\n", len(result.Tracks.Items), cleanQuery)
+			GoLog("[Qobuz] Found %d results for '%s'\n", len(result.Tracks.Items), cleanQuery)
 			allTracks = append(allTracks, result.Tracks.Items...)
 		}
 	}
@@ -389,11 +654,30 @@ func (q *QobuzDownloader) SearchTrackByMetadataWithDuration(trackName, artistNam
 		return nil, fmt.Errorf("no tracks found for: %s - %s", artistName, trackName)
 	}
 
+	// Filter by title match first (NEW - like Tidal)
+	var titleMatches []*QobuzTrack
+	for i := range allTracks {
+		track := &allTracks[i]
+		if qobuzTitlesMatch(trackName, track.Title) {
+			titleMatches = append(titleMatches, track)
+		}
+	}
+
+	GoLog("[Qobuz] Title matches: %d out of %d results\n", len(titleMatches), len(allTracks))
+
+	// If no title matches, log warning but continue with all tracks
+	tracksToCheck := titleMatches
+	if len(titleMatches) == 0 {
+		GoLog("[Qobuz] WARNING: No title matches for '%s', checking all %d results\n", trackName, len(allTracks))
+		for i := range allTracks {
+			tracksToCheck = append(tracksToCheck, &allTracks[i])
+		}
+	}
+
 	// If duration verification is requested
 	if expectedDurationSec > 0 {
 		var durationMatches []*QobuzTrack
-		for i := range allTracks {
-			track := &allTracks[i]
+		for _, track := range tracksToCheck {
 			durationDiff := track.Duration - expectedDurationSec
 			if durationDiff < 0 {
 				durationDiff = -durationDiff
@@ -407,105 +691,163 @@ func (q *QobuzDownloader) SearchTrackByMetadataWithDuration(trackName, artistNam
 			// Return best quality among duration matches
 			for _, track := range durationMatches {
 				if track.MaximumBitDepth >= 24 {
+					GoLog("[Qobuz] ✓ Match found: '%s' by '%s' (title+duration verified, hi-res)\n",
+						track.Title, track.Performer.Name)
 					return track, nil
 				}
 			}
+			GoLog("[Qobuz] ✓ Match found: '%s' by '%s' (title+duration verified)\n",
+				durationMatches[0].Title, durationMatches[0].Performer.Name)
 			return durationMatches[0], nil
 		}
 
 		// No duration match found
-		return nil, fmt.Errorf("no tracks found with matching duration (expected %ds)", expectedDurationSec)
+		return nil, fmt.Errorf("no tracks found with matching title and duration (expected '%s', %ds)", trackName, expectedDurationSec)
 	}
 
-	// No duration verification, return best quality
-	for i := range allTracks {
-		track := &allTracks[i]
+	// No duration verification, return best quality from title matches
+	for _, track := range tracksToCheck {
 		if track.MaximumBitDepth >= 24 {
+			GoLog("[Qobuz] ✓ Match found: '%s' by '%s' (title verified, hi-res)\n",
+				track.Title, track.Performer.Name)
 			return track, nil
 		}
 	}
-	return &allTracks[0], nil
+
+	if len(tracksToCheck) > 0 {
+		GoLog("[Qobuz] ✓ Match found: '%s' by '%s' (title verified)\n",
+			tracksToCheck[0].Title, tracksToCheck[0].Performer.Name)
+		return tracksToCheck[0], nil
+	}
+
+	return nil, fmt.Errorf("no matching track found for: %s - %s", artistName, trackName)
 }
 
-// getQobuzDownloadURLSequential requests download URL from APIs sequentially
-// Uses same URL format as PC version: /api/stream?trackId={id}&quality={quality}
-func getQobuzDownloadURLSequential(apis []string, trackID int64, quality string) (string, string, error) {
+// qobuzAPIResult holds the result from a parallel API request
+type qobuzAPIResult struct {
+	apiURL      string
+	downloadURL string
+	err         error
+	duration    time.Duration
+}
+
+// getQobuzDownloadURLParallel requests download URL from all APIs in parallel
+// "Siapa cepat dia dapat" - first successful response wins
+func getQobuzDownloadURLParallel(apis []string, trackID int64, quality string) (string, string, error) {
 	if len(apis) == 0 {
 		return "", "", fmt.Errorf("no APIs available")
 	}
 
-	client := NewHTTPClientWithTimeout(DefaultTimeout)
-	retryConfig := DefaultRetryConfig()
-	var errors []string
+	GoLog("[Qobuz] Requesting download URL from %d APIs in parallel...\n", len(apis))
 
+	resultChan := make(chan qobuzAPIResult, len(apis))
+	startTime := time.Now()
+
+	// Start all requests in parallel
 	for _, apiURL := range apis {
-		// All APIs now use same format: https://domain/api/stream?trackId={id}&quality={quality}
-		// The apiURL already includes the path, just append trackID and quality
-		reqURL := fmt.Sprintf("%s%d&quality=%s", apiURL, trackID, quality)
+		go func(api string) {
+			reqStart := time.Now()
 
-		fmt.Printf("[Qobuz] Trying: %s\n", reqURL)
+			client := &http.Client{
+				Timeout: 15 * time.Second,
+			}
 
-		req, err := http.NewRequest("GET", reqURL, nil)
-		if err != nil {
-			errors = append(errors, BuildErrorMessage(apiURL, 0, err.Error()))
-			continue
-		}
+			reqURL := fmt.Sprintf("%s%d&quality=%s", api, trackID, quality)
 
-		resp, err := DoRequestWithRetry(client, req, retryConfig)
-		if err != nil {
-			errors = append(errors, BuildErrorMessage(apiURL, 0, err.Error()))
-			continue
-		}
+			req, err := http.NewRequest("GET", reqURL, nil)
+			if err != nil {
+				resultChan <- qobuzAPIResult{apiURL: api, err: err, duration: time.Since(reqStart)}
+				return
+			}
 
-		body, err := ReadResponseBody(resp)
-		resp.Body.Close()
-		if err != nil {
-			errors = append(errors, BuildErrorMessage(apiURL, resp.StatusCode, err.Error()))
-			continue
-		}
+			resp, err := client.Do(req)
+			if err != nil {
+				resultChan <- qobuzAPIResult{apiURL: api, err: err, duration: time.Since(reqStart)}
+				return
+			}
+			defer resp.Body.Close()
 
-		// Check if response is HTML (error page)
-		if len(body) > 0 && body[0] == '<' {
-			errors = append(errors, BuildErrorMessage(apiURL, resp.StatusCode, "received HTML instead of JSON"))
-			continue
-		}
+			if resp.StatusCode != 200 {
+				resultChan <- qobuzAPIResult{apiURL: api, err: fmt.Errorf("HTTP %d", resp.StatusCode), duration: time.Since(reqStart)}
+				return
+			}
 
-		// Check for error in JSON response
-		var errorResp struct {
-			Error string `json:"error"`
-		}
-		if json.Unmarshal(body, &errorResp) == nil && errorResp.Error != "" {
-			errors = append(errors, BuildErrorMessage(apiURL, resp.StatusCode, errorResp.Error))
-			continue
-		}
+			body, err := io.ReadAll(resp.Body)
+			if err != nil {
+				resultChan <- qobuzAPIResult{apiURL: api, err: err, duration: time.Since(reqStart)}
+				return
+			}
 
-		var result struct {
-			URL string `json:"url"`
-		}
-		if err := json.Unmarshal(body, &result); err != nil {
-			errors = append(errors, BuildErrorMessage(apiURL, resp.StatusCode, "invalid JSON: "+err.Error()))
-			continue
-		}
+			// Check if response is HTML (error page)
+			if len(body) > 0 && body[0] == '<' {
+				resultChan <- qobuzAPIResult{apiURL: api, err: fmt.Errorf("received HTML instead of JSON"), duration: time.Since(reqStart)}
+				return
+			}
 
-		if result.URL != "" {
-			fmt.Printf("[Qobuz] Got download URL from: %s\n", apiURL)
-			return apiURL, result.URL, nil
-		}
+			// Check for error in JSON response
+			var errorResp struct {
+				Error string `json:"error"`
+			}
+			if json.Unmarshal(body, &errorResp) == nil && errorResp.Error != "" {
+				resultChan <- qobuzAPIResult{apiURL: api, err: fmt.Errorf("%s", errorResp.Error), duration: time.Since(reqStart)}
+				return
+			}
 
-		errors = append(errors, BuildErrorMessage(apiURL, resp.StatusCode, "no download URL in response"))
+			var result struct {
+				URL string `json:"url"`
+			}
+			if err := json.Unmarshal(body, &result); err != nil {
+				resultChan <- qobuzAPIResult{apiURL: api, err: fmt.Errorf("invalid JSON: %v", err), duration: time.Since(reqStart)}
+				return
+			}
+
+			if result.URL != "" {
+				resultChan <- qobuzAPIResult{apiURL: api, downloadURL: result.URL, err: nil, duration: time.Since(reqStart)}
+				return
+			}
+
+			resultChan <- qobuzAPIResult{apiURL: api, err: fmt.Errorf("no download URL in response"), duration: time.Since(reqStart)}
+		}(apiURL)
 	}
 
+	// Collect results - return first success
+	var errors []string
+
+	for i := 0; i < len(apis); i++ {
+		result := <-resultChan
+		if result.err == nil {
+			GoLog("[Qobuz] [Parallel] ✓ Got response from %s in %v\n", result.apiURL, result.duration)
+
+			// Drain remaining results to avoid goroutine leaks
+			go func(remaining int) {
+				for j := 0; j < remaining; j++ {
+					<-resultChan
+				}
+			}(len(apis) - i - 1)
+
+			GoLog("[Qobuz] [Parallel] Total time: %v (first success)\n", time.Since(startTime))
+			return result.apiURL, result.downloadURL, nil
+		}
+		errMsg := result.err.Error()
+		if len(errMsg) > 50 {
+			errMsg = errMsg[:50] + "..."
+		}
+		errors = append(errors, fmt.Sprintf("%s: %s", result.apiURL, errMsg))
+	}
+
+	GoLog("[Qobuz] [Parallel] All %d APIs failed in %v\n", len(apis), time.Since(startTime))
 	return "", "", fmt.Errorf("all %d Qobuz APIs failed. Errors: %v", len(apis), errors)
 }
 
-// GetDownloadURL gets download URL for a track - tries APIs sequentially
+// GetDownloadURL gets download URL for a track - tries ALL APIs in parallel
+// "Siapa cepat dia dapat" - first successful response wins
 func (q *QobuzDownloader) GetDownloadURL(trackID int64, quality string) (string, error) {
 	apis := q.GetAvailableAPIs()
 	if len(apis) == 0 {
 		return "", fmt.Errorf("no Qobuz API available")
 	}
 
-	_, downloadURL, err := getQobuzDownloadURLSequential(apis, trackID, quality)
+	_, downloadURL, err := getQobuzDownloadURLParallel(apis, trackID, quality)
 	if err != nil {
 		return "", err
 	}
@@ -515,19 +857,30 @@ func (q *QobuzDownloader) GetDownloadURL(trackID int64, quality string) (string,
 
 // DownloadFile downloads a file from URL with User-Agent and progress tracking
 func (q *QobuzDownloader) DownloadFile(downloadURL, outputPath, itemID string) error {
+	ctx := context.Background()
+
 	// Initialize item progress (required for all downloads)
 	if itemID != "" {
 		StartItemProgress(itemID)
 		defer CompleteItemProgress(itemID)
+		ctx = initDownloadCancel(itemID)
+		defer clearDownloadCancel(itemID)
 	}
 
-	req, err := http.NewRequest("GET", downloadURL, nil)
+	if isDownloadCancelled(itemID) {
+		return ErrDownloadCancelled
+	}
+
+	req, err := http.NewRequestWithContext(ctx, "GET", downloadURL, nil)
 	if err != nil {
 		return fmt.Errorf("failed to create request: %w", err)
 	}
 
 	resp, err := DoRequestWithUserAgent(q.client, req)
 	if err != nil {
+		if isDownloadCancelled(itemID) {
+			return ErrDownloadCancelled
+		}
 		return err
 	}
 	defer resp.Body.Close()
@@ -537,7 +890,6 @@ func (q *QobuzDownloader) DownloadFile(downloadURL, outputPath, itemID string) e
 	}
 
 	expectedSize := resp.ContentLength
-	// Set total bytes if available
 	if expectedSize > 0 && itemID != "" {
 		SetItemBytesTotal(itemID, expectedSize)
 	}
@@ -547,16 +899,13 @@ func (q *QobuzDownloader) DownloadFile(downloadURL, outputPath, itemID string) e
 		return err
 	}
 
-	// Use buffered writer for better performance (256KB buffer)
 	bufWriter := bufio.NewWriterSize(out, 256*1024)
 
-	// Use item progress writer with buffered output
 	var written int64
 	if itemID != "" {
 		progressWriter := NewItemProgressWriter(bufWriter, itemID)
 		written, err = io.Copy(progressWriter, resp.Body)
 	} else {
-		// Fallback: direct copy without progress tracking
 		written, err = io.Copy(bufWriter, resp.Body)
 	}
 
@@ -564,9 +913,11 @@ func (q *QobuzDownloader) DownloadFile(downloadURL, outputPath, itemID string) e
 	flushErr := bufWriter.Flush()
 	closeErr := out.Close()
 
-	// Check for any errors
 	if err != nil {
 		os.Remove(outputPath)
+		if isDownloadCancelled(itemID) {
+			return ErrDownloadCancelled
+		}
 		return fmt.Errorf("download interrupted: %w", err)
 	}
 	if flushErr != nil {
@@ -605,25 +956,37 @@ type QobuzDownloadResult struct {
 func downloadFromQobuz(req DownloadRequest) (QobuzDownloadResult, error) {
 	downloader := NewQobuzDownloader()
 
-	// Check for existing file first
 	if existingFile, exists := checkISRCExistsInternal(req.OutputDir, req.ISRC); exists {
 		return QobuzDownloadResult{FilePath: "EXISTS:" + existingFile}, nil
 	}
 
-	// Convert expected duration from ms to seconds
 	expectedDurationSec := req.DurationMS / 1000
 
 	var track *QobuzTrack
 	var err error
 
+	if req.QobuzID != "" {
+		GoLog("[Qobuz] Using Qobuz ID from Odesli enrichment: %s\n", req.QobuzID)
+		var trackID int64
+		if _, parseErr := fmt.Sscanf(req.QobuzID, "%d", &trackID); parseErr == nil && trackID > 0 {
+			track, err = downloader.GetTrackByID(trackID)
+			if err != nil {
+				GoLog("[Qobuz] Failed to get track by Odesli ID %d: %v\n", trackID, err)
+				track = nil
+			} else if track != nil {
+				GoLog("[Qobuz] Successfully found track via Odesli ID: '%s' by '%s'\n", track.Title, track.Performer.Name)
+			}
+		}
+	}
+
 	// OPTIMIZATION: Check cache first for track ID
-	if req.ISRC != "" {
+	if track == nil && req.ISRC != "" {
 		if cached := GetTrackIDCache().Get(req.ISRC); cached != nil && cached.QobuzTrackID > 0 {
-			fmt.Printf("[Qobuz] Cache hit! Using cached track ID: %d\n", cached.QobuzTrackID)
+			GoLog("[Qobuz] Cache hit! Using cached track ID: %d\n", cached.QobuzTrackID)
 			// For Qobuz we need to search again to get full track info, but we can use the ID
 			track, err = downloader.SearchTrackByISRC(req.ISRC)
 			if err != nil {
-				fmt.Printf("[Qobuz] Cache hit but search failed: %v\n", err)
+				GoLog("[Qobuz] Cache hit but search failed: %v\n", err)
 				track = nil
 			}
 		}
@@ -631,22 +994,28 @@ func downloadFromQobuz(req DownloadRequest) (QobuzDownloadResult, error) {
 
 	// Strategy 1: Search by ISRC with duration verification
 	if track == nil && req.ISRC != "" {
-		fmt.Printf("[Qobuz] Trying ISRC search: %s\n", req.ISRC)
+		GoLog("[Qobuz] Trying ISRC search: %s\n", req.ISRC)
 		track, err = downloader.SearchTrackByISRCWithDuration(req.ISRC, expectedDurationSec)
-		// Verify artist
-		if track != nil && !qobuzArtistsMatch(req.ArtistName, track.Performer.Name) {
-			fmt.Printf("[Qobuz] Artist mismatch from ISRC search: expected '%s', got '%s'. Rejecting.\n",
-				req.ArtistName, track.Performer.Name)
-			track = nil
+		// Verify artist AND title
+		if track != nil {
+			if !qobuzArtistsMatch(req.ArtistName, track.Performer.Name) {
+				GoLog("[Qobuz] Artist mismatch from ISRC search: expected '%s', got '%s'. Rejecting.\n",
+					req.ArtistName, track.Performer.Name)
+				track = nil
+			} else if !qobuzTitlesMatch(req.TrackName, track.Title) {
+				GoLog("[Qobuz] Title mismatch from ISRC search: expected '%s', got '%s'. Rejecting.\n",
+					req.TrackName, track.Title)
+				track = nil
+			}
 		}
 	}
 
-	// Strategy 2: Search by metadata with duration verification
+	// Strategy 2: Search by metadata with duration verification (includes title verification)
 	if track == nil {
 		track, err = downloader.SearchTrackByMetadataWithDuration(req.TrackName, req.ArtistName, expectedDurationSec)
-		// Verify artist
+		// Verify artist (title already verified in SearchTrackByMetadataWithDuration)
 		if track != nil && !qobuzArtistsMatch(req.ArtistName, track.Performer.Name) {
-			fmt.Printf("[Qobuz] Artist mismatch from metadata search: expected '%s', got '%s'. Rejecting.\n",
+			GoLog("[Qobuz] Artist mismatch from metadata search: expected '%s', got '%s'. Rejecting.\n",
 				req.ArtistName, track.Performer.Name)
 			track = nil
 		}
@@ -661,12 +1030,11 @@ func downloadFromQobuz(req DownloadRequest) (QobuzDownloadResult, error) {
 	}
 
 	// Log match found and cache the track ID
-	fmt.Printf("[Qobuz] Match found: '%s' by '%s' (duration: %ds)\n", track.Title, track.Performer.Name, track.Duration)
+	GoLog("[Qobuz] Match found: '%s' by '%s' (duration: %ds)\n", track.Title, track.Performer.Name, track.Duration)
 	if req.ISRC != "" {
 		GetTrackIDCache().SetQobuz(req.ISRC, track.ID)
 	}
 
-	// Build filename
 	filename := buildFilenameFromTemplate(req.FilenameFormat, map[string]interface{}{
 		"title":  req.TrackName,
 		"artist": req.ArtistName,
@@ -678,7 +1046,6 @@ func downloadFromQobuz(req DownloadRequest) (QobuzDownloadResult, error) {
 	filename = sanitizeFilename(filename) + ".flac"
 	outputPath := filepath.Join(req.OutputDir, filename)
 
-	// Check if file already exists
 	if fileInfo, statErr := os.Stat(outputPath); statErr == nil && fileInfo.Size() > 0 {
 		return QobuzDownloadResult{FilePath: "EXISTS:" + outputPath}, nil
 	}
@@ -695,14 +1062,12 @@ func downloadFromQobuz(req DownloadRequest) (QobuzDownloadResult, error) {
 	case "HI_RES_LOSSLESS":
 		qobuzQuality = "27" // 24-bit 192kHz
 	}
-	fmt.Printf("[Qobuz] Using quality: %s (mapped from %s)\n", qobuzQuality, req.Quality)
+	GoLog("[Qobuz] Using quality: %s (mapped from %s)\n", qobuzQuality, req.Quality)
 
-	// Get actual quality from track metadata
 	actualBitDepth := track.MaximumBitDepth
 	actualSampleRate := int(track.MaximumSamplingRate * 1000) // Convert kHz to Hz
-	fmt.Printf("[Qobuz] Actual quality: %d-bit/%.1fkHz\n", actualBitDepth, track.MaximumSamplingRate)
+	GoLog("[Qobuz] Actual quality: %d-bit/%.1fkHz\n", actualBitDepth, track.MaximumSamplingRate)
 
-	// Get download URL using parallel API requests
 	downloadURL, err := downloader.GetDownloadURL(track.ID, qobuzQuality)
 	if err != nil {
 		return QobuzDownloadResult{}, fmt.Errorf("failed to get download URL: %w", err)
@@ -720,27 +1085,26 @@ func downloadFromQobuz(req DownloadRequest) (QobuzDownloadResult, error) {
 			req.TrackName,
 			req.ArtistName,
 			req.EmbedLyrics,
+			int64(req.DurationMS),
 		)
 	}()
 
 	// Download audio file with item ID for progress tracking
 	if err := downloader.DownloadFile(downloadURL, outputPath, req.ItemID); err != nil {
+		if errors.Is(err, ErrDownloadCancelled) {
+			return QobuzDownloadResult{}, ErrDownloadCancelled
+		}
 		return QobuzDownloadResult{}, fmt.Errorf("download failed: %w", err)
 	}
 
 	// Wait for parallel operations to complete
 	<-parallelDone
 
-	// Set progress to 100% and status to finalizing (before embedding)
-	// This makes the UI show "Finalizing..." while embedding happens
 	if req.ItemID != "" {
 		SetItemProgress(req.ItemID, 1.0, 0, 0)
 		SetItemFinalizing(req.ItemID)
 	}
 
-	// Embed metadata using parallel-fetched cover data
-	// Use metadata from the actual Qobuz track found (more accurate than request) but prefer
-	// requested Album Name to avoid ISRC version mismatches (e.g. Compilations vs Original)
 	albumName := track.Album.Title
 	if req.AlbumName != "" {
 		albumName = req.AlbumName
@@ -758,11 +1122,10 @@ func downloadFromQobuz(req DownloadRequest) (QobuzDownloadResult, error) {
 		ISRC:        track.ISRC,
 	}
 
-	// Use cover data from parallel fetch
 	var coverData []byte
 	if parallelResult != nil && parallelResult.CoverData != nil {
 		coverData = parallelResult.CoverData
-		fmt.Printf("[Qobuz] Using parallel-fetched cover (%d bytes)\n", len(coverData))
+		GoLog("[Qobuz] Using parallel-fetched cover (%d bytes)\n", len(coverData))
 	}
 
 	if err := EmbedMetadataWithCoverData(outputPath, metadata, coverData); err != nil {
@@ -771,9 +1134,9 @@ func downloadFromQobuz(req DownloadRequest) (QobuzDownloadResult, error) {
 
 	// Embed lyrics from parallel fetch
 	if req.EmbedLyrics && parallelResult != nil && parallelResult.LyricsLRC != "" {
-		fmt.Printf("[Qobuz] Embedding parallel-fetched lyrics (%d lines)...\n", len(parallelResult.LyricsData.Lines))
+		GoLog("[Qobuz] Embedding parallel-fetched lyrics (%d lines)...\n", len(parallelResult.LyricsData.Lines))
 		if embedErr := EmbedLyrics(outputPath, parallelResult.LyricsLRC); embedErr != nil {
-			fmt.Printf("[Qobuz] Warning: failed to embed lyrics: %v\n", embedErr)
+			GoLog("[Qobuz] Warning: failed to embed lyrics: %v\n", embedErr)
 		} else {
 			fmt.Println("[Qobuz] Lyrics embedded successfully")
 		}

go_backend/ratelimit.go

@@ -30,31 +30,25 @@ func (r *RateLimiter) WaitForSlot() {
 
 	now := time.Now()
 
-	// Remove timestamps outside the window
 	r.cleanOldTimestamps(now)
 
-	// If under limit, record and return immediately
 	if len(r.timestamps) < r.maxRequests {
 		r.timestamps = append(r.timestamps, now)
 		return
 	}
 
-	// Calculate wait time until oldest timestamp expires
 	oldestTimestamp := r.timestamps[0]
 	waitUntil := oldestTimestamp.Add(r.window)
 	waitDuration := waitUntil.Sub(now)
 
 	if waitDuration > 0 {
-		// Release lock while waiting
 		r.mu.Unlock()
 		time.Sleep(waitDuration)
 		r.mu.Lock()
 
-		// Clean again after waiting
 		r.cleanOldTimestamps(time.Now())
 	}
 
-	// Record this request
 	r.timestamps = append(r.timestamps, time.Now())
 }
 

go_backend/songlink.go

@@ -31,7 +31,6 @@ type TrackAvailability struct {
 }
 
 var (
-	// Global SongLink client instance for connection reuse
 	globalSongLinkClient *SongLinkClient
 	songLinkClientOnce   sync.Once
 )
@@ -40,7 +39,7 @@ var (
 func NewSongLinkClient() *SongLinkClient {
 	songLinkClientOnce.Do(func() {
 		globalSongLinkClient = &SongLinkClient{
-			client: NewHTTPClientWithTimeout(SongLinkTimeout), // 30s timeout
+			client: NewHTTPClientWithTimeout(SongLinkTimeout),
 		}
 	})
 	return globalSongLinkClient
@@ -48,15 +47,12 @@ func NewSongLinkClient() *SongLinkClient {
 
 // CheckTrackAvailability checks track availability on streaming platforms
 func (s *SongLinkClient) CheckTrackAvailability(spotifyTrackID string, isrc string) (*TrackAvailability, error) {
-	// Validate Spotify ID format (should be 22 characters alphanumeric)
 	if spotifyTrackID == "" {
 		return nil, fmt.Errorf("spotify track ID is empty")
 	}
 	
-	// Use global rate limiter - blocks until request is allowed
 	songLinkRateLimiter.WaitForSlot()
 
-	// Build API URL
 	spotifyBase, _ := base64.StdEncoding.DecodeString("aHR0cHM6Ly9vcGVuLnNwb3RpZnkuY29tL3RyYWNrLw==")
 	spotifyURL := fmt.Sprintf("%s%s", string(spotifyBase), spotifyTrackID)
 
@@ -68,7 +64,6 @@ func (s *SongLinkClient) CheckTrackAvailability(spotifyTrackID string, isrc stri
 		return nil, fmt.Errorf("failed to create request: %w", err)
 	}
 
-	// Use retry logic with User-Agent
 	retryConfig := DefaultRetryConfig()
 	resp, err := DoRequestWithRetry(s.client, req, retryConfig)
 	if err != nil {
@@ -76,7 +71,6 @@ func (s *SongLinkClient) CheckTrackAvailability(spotifyTrackID string, isrc stri
 	}
 	defer resp.Body.Close()
 
-	// Handle specific error codes
 	if resp.StatusCode == 400 {
 		return nil, fmt.Errorf("track not found on SongLink (invalid Spotify ID or track unavailable)")
 	}
@@ -109,27 +103,22 @@ func (s *SongLinkClient) CheckTrackAvailability(spotifyTrackID string, isrc stri
 		SpotifyID: spotifyTrackID,
 	}
 
-	// Check Tidal
 	if tidalLink, ok := songLinkResp.LinksByPlatform["tidal"]; ok && tidalLink.URL != "" {
 		availability.Tidal = true
 		availability.TidalURL = tidalLink.URL
 	}
 
-	// Check Amazon
 	if amazonLink, ok := songLinkResp.LinksByPlatform["amazonMusic"]; ok && amazonLink.URL != "" {
 		availability.Amazon = true
 		availability.AmazonURL = amazonLink.URL
 	}
 
-	// Check Deezer
 	if deezerLink, ok := songLinkResp.LinksByPlatform["deezer"]; ok && deezerLink.URL != "" {
 		availability.Deezer = true
 		availability.DeezerURL = deezerLink.URL
-		// Extract Deezer ID from URL (e.g., https://www.deezer.com/track/123456)
 		availability.DeezerID = extractDeezerIDFromURL(deezerLink.URL)
 	}
 
-	// Check Qobuz using ISRC (SongLink doesn't support Qobuz directly)
 	if isrc != "" {
 		availability.Qobuz = checkQobuzAvailability(isrc)
 	}
@@ -191,12 +180,9 @@ func checkQobuzAvailability(isrc string) bool {
 
 // extractDeezerIDFromURL extracts Deezer track/album/artist ID from URL
 func extractDeezerIDFromURL(deezerURL string) string {
-	// URL format: https://www.deezer.com/track/123456 or https://www.deezer.com/en/track/123456
 	parts := strings.Split(deezerURL, "/")
 	if len(parts) > 0 {
-		// Get the last part which should be the ID
 		lastPart := parts[len(parts)-1]
-		// Remove any query parameters
 		if idx := strings.Index(lastPart, "?"); idx > 0 {
 			lastPart = lastPart[:idx]
 		}
@@ -274,7 +260,6 @@ func (s *SongLinkClient) CheckAlbumAvailability(spotifyAlbumID string) (*AlbumAv
 		SpotifyID: spotifyAlbumID,
 	}
 
-	// Check Deezer
 	if deezerLink, ok := songLinkResp.LinksByPlatform["deezer"]; ok && deezerLink.URL != "" {
 		availability.Deezer = true
 		availability.DeezerURL = deezerLink.URL
@@ -309,13 +294,10 @@ func (s *SongLinkClient) CheckAvailabilityFromDeezer(deezerTrackID string) (*Tra
 		return nil, fmt.Errorf("deezer track ID is empty")
 	}
 	
-	// Use global rate limiter
 	songLinkRateLimiter.WaitForSlot()
 
-	// Build Deezer URL
 	deezerURL := fmt.Sprintf("https://www.deezer.com/track/%s", deezerTrackID)
 
-	// Build API URL using Deezer URL as source
 	apiBase, _ := base64.StdEncoding.DecodeString("aHR0cHM6Ly9hcGkuc29uZy5saW5rL3YxLWFscGhhLjEvbGlua3M/dXJsPQ==")
 	apiURL := fmt.Sprintf("%s%s&userCountry=US", string(apiBase), url.QueryEscape(deezerURL))
 
@@ -371,25 +353,20 @@ func (s *SongLinkClient) CheckAvailabilityFromDeezer(deezerTrackID string) (*Tra
 		DeezerID: deezerTrackID,
 	}
 
-	// Check Spotify
 	if spotifyLink, ok := songLinkResp.LinksByPlatform["spotify"]; ok && spotifyLink.URL != "" {
-		// Extract Spotify ID from URL
 		availability.SpotifyID = extractSpotifyIDFromURL(spotifyLink.URL)
 	}
 
-	// Check Tidal
 	if tidalLink, ok := songLinkResp.LinksByPlatform["tidal"]; ok && tidalLink.URL != "" {
 		availability.Tidal = true
 		availability.TidalURL = tidalLink.URL
 	}
 
-	// Check Amazon
 	if amazonLink, ok := songLinkResp.LinksByPlatform["amazonMusic"]; ok && amazonLink.URL != "" {
 		availability.Amazon = true
 		availability.AmazonURL = amazonLink.URL
 	}
 
-	// Check Deezer URL
 	if deezerLink, ok := songLinkResp.LinksByPlatform["deezer"]; ok && deezerLink.URL != "" {
 		availability.DeezerURL = deezerLink.URL
 	}
@@ -459,24 +436,20 @@ func (s *SongLinkClient) CheckAvailabilityByPlatform(platform, entityType, entit
 
 	availability := &TrackAvailability{}
 
-	// Check Spotify
 	if spotifyLink, ok := songLinkResp.LinksByPlatform["spotify"]; ok && spotifyLink.URL != "" {
 		availability.SpotifyID = extractSpotifyIDFromURL(spotifyLink.URL)
 	}
 
-	// Check Tidal
 	if tidalLink, ok := songLinkResp.LinksByPlatform["tidal"]; ok && tidalLink.URL != "" {
 		availability.Tidal = true
 		availability.TidalURL = tidalLink.URL
 	}
 
-	// Check Amazon
 	if amazonLink, ok := songLinkResp.LinksByPlatform["amazonMusic"]; ok && amazonLink.URL != "" {
 		availability.Amazon = true
 		availability.AmazonURL = amazonLink.URL
 	}
 
-	// Check Deezer
 	if deezerLink, ok := songLinkResp.LinksByPlatform["deezer"]; ok && deezerLink.URL != "" {
 		availability.Deezer = true
 		availability.DeezerURL = deezerLink.URL
@@ -488,10 +461,8 @@ func (s *SongLinkClient) CheckAvailabilityByPlatform(platform, entityType, entit
 
 // extractSpotifyIDFromURL extracts Spotify track ID from URL
 func extractSpotifyIDFromURL(spotifyURL string) string {
-	// URL format: https://open.spotify.com/track/0Jcij1eWd5bDMU5iPbxe2i
 	parts := strings.Split(spotifyURL, "/track/")
 	if len(parts) > 1 {
-		// Get the ID part and remove any query parameters
 		idPart := parts[1]
 		if idx := strings.Index(idPart, "?"); idx > 0 {
 			idPart = idPart[:idx]

go_backend/spotify.go

@@ -2,7 +2,6 @@ package gobackend
 
 import (
 	"context"
-	"encoding/base64"
 	"encoding/json"
 	"errors"
 	"fmt"
@@ -17,14 +16,14 @@ import (
 )
 
 const (
-	spotifyTokenURL     = "https://accounts.spotify.com/api/token"
-	playlistBaseURL     = "https://api.spotify.com/v1/playlists/%s"
-	albumBaseURL        = "https://api.spotify.com/v1/albums/%s"
-	trackBaseURL        = "https://api.spotify.com/v1/tracks/%s"
-	artistBaseURL       = "https://api.spotify.com/v1/artists/%s"
-	artistAlbumsURL     = "https://api.spotify.com/v1/artists/%s/albums"
-	searchBaseURL       = "https://api.spotify.com/v1/search"
-	
+	spotifyTokenURL = "https://accounts.spotify.com/api/token"
+	playlistBaseURL = "https://api.spotify.com/v1/playlists/%s"
+	albumBaseURL    = "https://api.spotify.com/v1/albums/%s"
+	trackBaseURL    = "https://api.spotify.com/v1/tracks/%s"
+	artistBaseURL   = "https://api.spotify.com/v1/artists/%s"
+	artistAlbumsURL = "https://api.spotify.com/v1/artists/%s/albums"
+	searchBaseURL   = "https://api.spotify.com/v1/search"
+
 	// Cache TTL settings
 	artistCacheTTL = 10 * time.Minute
 	searchCacheTTL = 5 * time.Minute
@@ -54,7 +53,7 @@ type SpotifyMetadataClient struct {
 	rng            *rand.Rand
 	rngMu          sync.Mutex
 	userAgent      string
-	
+
 	// Caches to reduce API calls
 	artistCache map[string]*cacheEntry // key: artistID
 	searchCache map[string]*cacheEntry // key: query+type
@@ -69,8 +68,10 @@ var (
 	credentialsMu      sync.RWMutex
 )
 
+// ErrNoSpotifyCredentials is returned when Spotify credentials are not configured
+var ErrNoSpotifyCredentials = errors.New("Spotify credentials not configured. Please set your own Client ID and Secret in Settings, or use Deezer as metadata source (free, no credentials required)")
+
 // SetSpotifyCredentials sets custom Spotify API credentials
-// Pass empty strings to use default credentials
 func SetSpotifyCredentials(clientID, clientSecret string) {
 	credentialsMu.Lock()
 	defer credentialsMu.Unlock()
@@ -78,42 +79,53 @@ func SetSpotifyCredentials(clientID, clientSecret string) {
 	customClientSecret = clientSecret
 }
 
-// getCredentials returns the current credentials (custom or default)
-func getCredentials() (string, string) {
+// HasSpotifyCredentials checks if Spotify credentials are configured
+func HasSpotifyCredentials() bool {
 	credentialsMu.RLock()
 	defer credentialsMu.RUnlock()
-	
+
 	if customClientID != "" && customClientSecret != "" {
-		return customClientID, customClientSecret
-	}
-	
-	// Fall back to default credentials
-	clientID := os.Getenv("SPOTIFY_CLIENT_ID")
-	if clientID == "" {
-		if decoded, err := base64.StdEncoding.DecodeString("NWY1NzNjOTYyMDQ5NGJhZTg3ODkwYzBmMDhhNjAyOTM="); err == nil {
-			clientID = string(decoded)
-		}
+		return true
 	}
 
-	clientSecret := os.Getenv("SPOTIFY_CLIENT_SECRET")
-	if clientSecret == "" {
-		if decoded, err := base64.StdEncoding.DecodeString("MjEyNDc2ZDliMGYzNDcyZWFhNzYyZDkwYjE5YjBiYTg="); err == nil {
-			clientSecret = string(decoded)
-		}
+	if os.Getenv("SPOTIFY_CLIENT_ID") != "" && os.Getenv("SPOTIFY_CLIENT_SECRET") != "" {
+		return true
 	}
-	
-	return clientID, clientSecret
+
+	return false
+}
+
+// getCredentials returns the current credentials or error if not configured
+func getCredentials() (string, string, error) {
+	credentialsMu.RLock()
+	defer credentialsMu.RUnlock()
+
+	if customClientID != "" && customClientSecret != "" {
+		return customClientID, customClientSecret, nil
+	}
+
+	clientID := os.Getenv("SPOTIFY_CLIENT_ID")
+	clientSecret := os.Getenv("SPOTIFY_CLIENT_SECRET")
+
+	if clientID != "" && clientSecret != "" {
+		return clientID, clientSecret, nil
+	}
+
+	return "", "", ErrNoSpotifyCredentials
 }
 
 // NewSpotifyMetadataClient creates a new Spotify client
-func NewSpotifyMetadataClient() *SpotifyMetadataClient {
+// Returns error if credentials are not configured
+func NewSpotifyMetadataClient() (*SpotifyMetadataClient, error) {
+	clientID, clientSecret, err := getCredentials()
+	if err != nil {
+		return nil, err
+	}
+
 	src := rand.NewSource(time.Now().UnixNano())
 
-	// Get credentials (custom or default)
-	clientID, clientSecret := getCredentials()
-
 	c := &SpotifyMetadataClient{
-		httpClient:   NewHTTPClientWithTimeout(15 * time.Second), // Use shared transport for connection pooling
+		httpClient:   NewHTTPClientWithTimeout(15 * time.Second),
 		clientID:     clientID,
 		clientSecret: clientSecret,
 		rng:          rand.New(src),
@@ -122,7 +134,7 @@ func NewSpotifyMetadataClient() *SpotifyMetadataClient {
 		albumCache:   make(map[string]*cacheEntry),
 	}
 	c.userAgent = c.randomUserAgent()
-	return c
+	return c, nil
 }
 
 // TrackMetadata represents track information
@@ -140,6 +152,7 @@ type TrackMetadata struct {
 	DiscNumber  int    `json:"disc_number,omitempty"`
 	ExternalURL string `json:"external_urls"`
 	ISRC        string `json:"isrc"`
+	AlbumType   string `json:"album_type,omitempty"` // album, single, ep, compilation
 }
 
 // AlbumTrackMetadata holds per-track info for album/playlist
@@ -159,6 +172,7 @@ type AlbumTrackMetadata struct {
 	ISRC        string `json:"isrc"`
 	AlbumID     string `json:"album_id,omitempty"`
 	AlbumURL    string `json:"album_url,omitempty"`
+	AlbumType   string `json:"album_type,omitempty"` // album, single, ep, compilation
 }
 
 // AlbumInfoMetadata holds album information
@@ -283,6 +297,7 @@ type albumSimplified struct {
 	Images      []image     `json:"images"`
 	ExternalURL externalURL `json:"external_urls"`
 	Artists     []artist    `json:"artists"`
+	AlbumType   string      `json:"album_type"` // album, single, compilation
 }
 
 type trackFull struct {
@@ -331,14 +346,14 @@ func (c *SpotifyMetadataClient) SearchTracks(ctx context.Context, query string,
 	}
 
 	searchURL := fmt.Sprintf("%s?q=%s&type=track&limit=%d", searchBaseURL, url.QueryEscape(query), limit)
-	
+
 	var response struct {
 		Tracks struct {
 			Items []trackFull `json:"items"`
 			Total int         `json:"total"`
 		} `json:"tracks"`
 	}
-	
+
 	if err := c.getJSON(ctx, searchURL, token, &response); err != nil {
 		return nil, err
 	}
@@ -363,6 +378,7 @@ func (c *SpotifyMetadataClient) SearchTracks(ctx context.Context, query string,
 			DiscNumber:  track.DiscNumber,
 			ExternalURL: track.ExternalURL.Spotify,
 			ISRC:        track.ExternalID.ISRC,
+			AlbumType:   track.Album.AlbumType,
 		})
 	}
 
@@ -371,10 +387,8 @@ func (c *SpotifyMetadataClient) SearchTracks(ctx context.Context, query string,
 
 // SearchAll searches for tracks and artists on Spotify
 func (c *SpotifyMetadataClient) SearchAll(ctx context.Context, query string, trackLimit, artistLimit int) (*SearchAllResult, error) {
-	// Create cache key
 	cacheKey := fmt.Sprintf("all:%s:%d:%d", query, trackLimit, artistLimit)
-	
-	// Check cache first
+
 	c.cacheMu.RLock()
 	if entry, ok := c.searchCache[cacheKey]; ok && !entry.isExpired() {
 		c.cacheMu.RUnlock()
@@ -388,24 +402,24 @@ func (c *SpotifyMetadataClient) SearchAll(ctx context.Context, query string, tra
 	}
 
 	searchURL := fmt.Sprintf("%s?q=%s&type=track,artist&limit=%d", searchBaseURL, url.QueryEscape(query), trackLimit)
-	
+
 	var response struct {
 		Tracks struct {
 			Items []trackFull `json:"items"`
 		} `json:"tracks"`
 		Artists struct {
 			Items []struct {
-				ID         string  `json:"id"`
-				Name       string  `json:"name"`
-				Images     []image `json:"images"`
-				Followers  struct {
+				ID        string  `json:"id"`
+				Name      string  `json:"name"`
+				Images    []image `json:"images"`
+				Followers struct {
 					Total int `json:"total"`
 				} `json:"followers"`
 				Popularity int `json:"popularity"`
 			} `json:"items"`
 		} `json:"artists"`
 	}
-	
+
 	if err := c.getJSON(ctx, searchURL, token, &response); err != nil {
 		return nil, err
 	}
@@ -430,15 +444,15 @@ func (c *SpotifyMetadataClient) SearchAll(ctx context.Context, query string, tra
 			DiscNumber:  track.DiscNumber,
 			ExternalURL: track.ExternalURL.Spotify,
 			ISRC:        track.ExternalID.ISRC,
+			AlbumType:   track.Album.AlbumType,
 		})
 	}
 
-	// Limit artists to artistLimit
 	artistCount := len(response.Artists.Items)
 	if artistCount > artistLimit {
 		artistCount = artistLimit
 	}
-	
+
 	for i := 0; i < artistCount; i++ {
 		artist := response.Artists.Items[i]
 		result.Artists = append(result.Artists, SearchArtistResult{
@@ -450,7 +464,6 @@ func (c *SpotifyMetadataClient) SearchAll(ctx context.Context, query string, tra
 		})
 	}
 
-	// Store in cache
 	c.cacheMu.Lock()
 	c.searchCache[cacheKey] = &cacheEntry{
 		data:      result,
@@ -487,7 +500,6 @@ func (c *SpotifyMetadataClient) fetchTrack(ctx context.Context, trackID, token s
 }
 
 func (c *SpotifyMetadataClient) fetchAlbum(ctx context.Context, albumID, token string) (*AlbumResponsePayload, error) {
-	// Check cache first
 	c.cacheMu.RLock()
 	if entry, ok := c.albumCache[albumID]; ok && !entry.isExpired() {
 		c.cacheMu.RUnlock()
@@ -534,7 +546,7 @@ func (c *SpotifyMetadataClient) fetchAlbum(ctx context.Context, albumID, token s
 	// Collect all tracks (including paginated)
 	allTrackItems := data.Tracks.Items
 	nextURL := data.Tracks.Next
-	
+
 	// Fetch remaining tracks using pagination (no limit)
 	for nextURL != "" {
 		var pageData struct {
@@ -563,7 +575,7 @@ func (c *SpotifyMetadataClient) fetchAlbum(ctx context.Context, albumID, token s
 	tracks := make([]AlbumTrackMetadata, 0, len(allTrackItems))
 	for _, item := range allTrackItems {
 		isrc := isrcMap[item.ID]
-		
+
 		tracks = append(tracks, AlbumTrackMetadata{
 			SpotifyID:   item.ID,
 			Artists:     joinArtists(item.Artists),
@@ -587,7 +599,6 @@ func (c *SpotifyMetadataClient) fetchAlbum(ctx context.Context, albumID, token s
 		TrackList: tracks,
 	}
 
-	// Store in cache
 	c.cacheMu.Lock()
 	c.albumCache[albumID] = &cacheEntry{
 		data:      result,
@@ -602,23 +613,23 @@ func (c *SpotifyMetadataClient) fetchAlbum(ctx context.Context, albumID, token s
 // Similar to Deezer implementation for consistency
 func (c *SpotifyMetadataClient) fetchISRCsParallel(ctx context.Context, trackIDs []string, token string) map[string]string {
 	const maxParallelISRC = 10 // Max concurrent ISRC fetches
-	
+
 	result := make(map[string]string)
 	var resultMu sync.Mutex
-	
+
 	if len(trackIDs) == 0 {
 		return result
 	}
-	
+
 	// Use semaphore to limit concurrent requests
 	sem := make(chan struct{}, maxParallelISRC)
 	var wg sync.WaitGroup
-	
+
 	for _, trackID := range trackIDs {
 		wg.Add(1)
 		go func(id string) {
 			defer wg.Done()
-			
+
 			// Acquire semaphore
 			select {
 			case sem <- struct{}{}:
@@ -626,15 +637,15 @@ func (c *SpotifyMetadataClient) fetchISRCsParallel(ctx context.Context, trackIDs
 			case <-ctx.Done():
 				return
 			}
-			
+
 			isrc := c.fetchTrackISRC(ctx, id, token)
-			
+
 			resultMu.Lock()
 			result[id] = isrc
 			resultMu.Unlock()
 		}(trackID)
 	}
-	
+
 	wg.Wait()
 	return result
 }
@@ -668,7 +679,7 @@ func (c *SpotifyMetadataClient) fetchPlaylist(ctx context.Context, playlistID, t
 
 	// Pre-allocate with expected capacity
 	tracks := make([]AlbumTrackMetadata, 0, data.Tracks.Total)
-	
+
 	// Add first batch of tracks
 	for _, item := range data.Tracks.Items {
 		if item.Track == nil {
@@ -695,7 +706,7 @@ func (c *SpotifyMetadataClient) fetchPlaylist(ctx context.Context, playlistID, t
 
 	// Fetch remaining tracks using pagination (NO LIMIT - fetch all tracks)
 	nextURL := data.Tracks.Next
-	
+
 	for nextURL != "" {
 		var pageData struct {
 			Items []struct {
@@ -745,7 +756,6 @@ func (c *SpotifyMetadataClient) fetchPlaylist(ctx context.Context, playlistID, t
 }
 
 func (c *SpotifyMetadataClient) fetchArtist(ctx context.Context, artistID, token string) (*ArtistResponsePayload, error) {
-	// Check cache first
 	c.cacheMu.RLock()
 	if entry, ok := c.artistCache[artistID]; ok && !entry.isExpired() {
 		c.cacheMu.RUnlock()
@@ -755,10 +765,10 @@ func (c *SpotifyMetadataClient) fetchArtist(ctx context.Context, artistID, token
 
 	// Fetch artist info
 	var artistData struct {
-		ID         string  `json:"id"`
-		Name       string  `json:"name"`
-		Images     []image `json:"images"`
-		Followers  struct {
+		ID        string  `json:"id"`
+		Name      string  `json:"name"`
+		Images    []image `json:"images"`
+		Followers struct {
 			Total int `json:"total"`
 		} `json:"followers"`
 		Popularity int `json:"popularity"`
@@ -833,7 +843,6 @@ func (c *SpotifyMetadataClient) fetchArtist(ctx context.Context, artistID, token
 		Albums:     albums,
 	}
 
-	// Store in cache
 	c.cacheMu.Lock()
 	c.artistCache[artistID] = &cacheEntry{
 		data:      result,
@@ -941,15 +950,15 @@ func (c *SpotifyMetadataClient) randomUserAgent() string {
 	defer c.rngMu.Unlock()
 
 	// Use Mac User-Agent format (same as PC version)
-	macMajor := c.rng.Intn(4) + 11    // 11-14
-	macMinor := c.rng.Intn(5) + 4     // 4-8
-	webkitMajor := c.rng.Intn(7) + 530 // 530-536
-	webkitMinor := c.rng.Intn(7) + 30  // 30-36
-	chromeMajor := c.rng.Intn(25) + 80 // 80-104
+	macMajor := c.rng.Intn(4) + 11         // 11-14
+	macMinor := c.rng.Intn(5) + 4          // 4-8
+	webkitMajor := c.rng.Intn(7) + 530     // 530-536
+	webkitMinor := c.rng.Intn(7) + 30      // 30-36
+	chromeMajor := c.rng.Intn(25) + 80     // 80-104
 	chromeBuild := c.rng.Intn(1500) + 3000 // 3000-4499
-	chromePatch := c.rng.Intn(65) + 60 // 60-124
-	safariMajor := c.rng.Intn(7) + 530 // 530-536
-	safariMinor := c.rng.Intn(6) + 30  // 30-35
+	chromePatch := c.rng.Intn(65) + 60     // 60-124
+	safariMajor := c.rng.Intn(7) + 530     // 530-536
+	safariMinor := c.rng.Intn(6) + 30      // 30-35
 
 	return fmt.Sprintf(
 		"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_%d_%d) AppleWebKit/%d.%d (KHTML, like Gecko) Chrome/%d.0.%d.%d Safari/%d.%d",

ios/Runner/AppDelegate.swift

@@ -120,6 +120,12 @@ import Gobackend  // Import Go framework
             let itemId = args["item_id"] as! String
             GobackendClearItemProgress(itemId)
             return nil
+
+        case "cancelDownload":
+            let args = call.arguments as! [String: Any]
+            let itemId = args["item_id"] as! String
+            GobackendCancelDownload(itemId)
+            return nil
             
         case "setDownloadDirectory":
             let args = call.arguments as! [String: Any]
@@ -155,7 +161,8 @@ import Gobackend  // Import Go framework
             let spotifyId = args["spotify_id"] as! String
             let trackName = args["track_name"] as! String
             let artistName = args["artist_name"] as! String
-            let response = GobackendFetchLyrics(spotifyId, trackName, artistName, &error)
+            let durationMs = args["duration_ms"] as? Int64 ?? 0
+            let response = GobackendFetchLyrics(spotifyId, trackName, artistName, durationMs, &error)
             if let error = error { throw error }
             return response
             
@@ -165,7 +172,8 @@ import Gobackend  // Import Go framework
             let trackName = args["track_name"] as! String
             let artistName = args["artist_name"] as! String
             let filePath = args["file_path"] as? String ?? ""
-            let response = GobackendGetLyricsLRC(spotifyId, trackName, artistName, filePath, &error)
+            let durationMs = args["duration_ms"] as? Int64 ?? 0
+            let response = GobackendGetLyricsLRC(spotifyId, trackName, artistName, filePath, durationMs, &error)
             if let error = error { throw error }
             return response
             
@@ -249,6 +257,339 @@ import Gobackend  // Import Go framework
             GobackendClearTrackCache()
             return nil
             
+        case "setSpotifyCredentials":
+            let args = call.arguments as! [String: Any]
+            let clientId = args["client_id"] as! String
+            let clientSecret = args["client_secret"] as! String
+            GobackendSetSpotifyAPICredentials(clientId, clientSecret)
+            return nil
+            
+        case "hasSpotifyCredentials":
+            let hasCredentials = GobackendCheckSpotifyCredentials()
+            return hasCredentials
+            
+        // Log methods
+        case "getLogs":
+            let response = GobackendGetLogs()
+            return response
+            
+        case "getLogsSince":
+            let args = call.arguments as! [String: Any]
+            let index = args["index"] as? Int ?? 0
+            let response = GobackendGetLogsSince(Int(index))
+            return response
+            
+        case "clearLogs":
+            GobackendClearLogs()
+            return nil
+            
+        case "getLogCount":
+            let response = GobackendGetLogCount()
+            return response
+            
+        case "setLoggingEnabled":
+            let args = call.arguments as! [String: Any]
+            let enabled = args["enabled"] as? Bool ?? false
+            GobackendSetLoggingEnabled(enabled)
+            return nil
+            
+        // Extension System methods
+        case "initExtensionSystem":
+            let args = call.arguments as! [String: Any]
+            let extensionsDir = args["extensions_dir"] as! String
+            let dataDir = args["data_dir"] as! String
+            GobackendInitExtensionSystem(extensionsDir, dataDir, &error)
+            if let error = error { throw error }
+            return nil
+            
+        case "loadExtensionsFromDir":
+            let args = call.arguments as! [String: Any]
+            let dirPath = args["dir_path"] as! String
+            let response = GobackendLoadExtensionsFromDir(dirPath, &error)
+            if let error = error { throw error }
+            return response
+            
+        case "loadExtensionFromPath":
+            let args = call.arguments as! [String: Any]
+            let filePath = args["file_path"] as! String
+            let response = GobackendLoadExtensionFromPath(filePath, &error)
+            if let error = error { throw error }
+            return response
+            
+        case "unloadExtension":
+            let args = call.arguments as! [String: Any]
+            let extensionId = args["extension_id"] as! String
+            GobackendUnloadExtensionByID(extensionId, &error)
+            if let error = error { throw error }
+            return nil
+            
+        case "getInstalledExtensions":
+            let response = GobackendGetInstalledExtensions(&error)
+            if let error = error { throw error }
+            return response
+            
+        case "setExtensionEnabled":
+            let args = call.arguments as! [String: Any]
+            let extensionId = args["extension_id"] as! String
+            let enabled = args["enabled"] as? Bool ?? false
+            GobackendSetExtensionEnabledByID(extensionId, enabled, &error)
+            if let error = error { throw error }
+            return nil
+            
+        case "setProviderPriority":
+            let args = call.arguments as! [String: Any]
+            let priorityJson = args["priority"] as! String
+            GobackendSetProviderPriorityJSON(priorityJson, &error)
+            if let error = error { throw error }
+            return nil
+            
+        case "getProviderPriority":
+            let response = GobackendGetProviderPriorityJSON(&error)
+            if let error = error { throw error }
+            return response
+            
+        case "setMetadataProviderPriority":
+            let args = call.arguments as! [String: Any]
+            let priorityJson = args["priority"] as! String
+            GobackendSetMetadataProviderPriorityJSON(priorityJson, &error)
+            if let error = error { throw error }
+            return nil
+            
+        case "getMetadataProviderPriority":
+            let response = GobackendGetMetadataProviderPriorityJSON(&error)
+            if let error = error { throw error }
+            return response
+            
+        case "getExtensionSettings":
+            let args = call.arguments as! [String: Any]
+            let extensionId = args["extension_id"] as! String
+            let response = GobackendGetExtensionSettingsJSON(extensionId, &error)
+            if let error = error { throw error }
+            return response
+            
+        case "setExtensionSettings":
+            let args = call.arguments as! [String: Any]
+            let extensionId = args["extension_id"] as! String
+            let settingsJson = args["settings"] as! String
+            GobackendSetExtensionSettingsJSON(extensionId, settingsJson, &error)
+            if let error = error { throw error }
+            return nil
+            
+        case "searchTracksWithExtensions":
+            let args = call.arguments as! [String: Any]
+            let query = args["query"] as! String
+            let limit = args["limit"] as? Int ?? 20
+            let response = GobackendSearchTracksWithExtensionsJSON(query, Int(limit), &error)
+            if let error = error { throw error }
+            return response
+            
+        case "downloadWithExtensions":
+            let requestJson = call.arguments as! String
+            let response = GobackendDownloadWithExtensionsJSON(requestJson, &error)
+            if let error = error { throw error }
+            return response
+            
+        case "removeExtension":
+            let args = call.arguments as! [String: Any]
+            let extensionId = args["extension_id"] as! String
+            GobackendRemoveExtensionByID(extensionId, &error)
+            if let error = error { throw error }
+            return nil
+            
+        case "upgradeExtension":
+            let args = call.arguments as! [String: Any]
+            let filePath = args["file_path"] as! String
+            let response = GobackendUpgradeExtensionFromPath(filePath, &error)
+            if let error = error { throw error }
+            return response
+            
+        case "checkExtensionUpgrade":
+            let args = call.arguments as! [String: Any]
+            let filePath = args["file_path"] as! String
+            let response = GobackendCheckExtensionUpgradeFromPath(filePath, &error)
+            if let error = error { throw error }
+            return response
+            
+        case "cleanupExtensions":
+            GobackendCleanupExtensions()
+            return nil
+            
+        // Extension Auth API
+        case "getExtensionPendingAuth":
+            let args = call.arguments as! [String: Any]
+            let extensionId = args["extension_id"] as! String
+            let response = GobackendGetExtensionPendingAuthJSON(extensionId, &error)
+            if let error = error { throw error }
+            return response
+            
+        case "setExtensionAuthCode":
+            let args = call.arguments as! [String: Any]
+            let extensionId = args["extension_id"] as! String
+            let authCode = args["auth_code"] as! String
+            GobackendSetExtensionAuthCodeByID(extensionId, authCode)
+            return nil
+            
+        case "setExtensionTokens":
+            let args = call.arguments as! [String: Any]
+            let extensionId = args["extension_id"] as! String
+            let accessToken = args["access_token"] as! String
+            let refreshToken = args["refresh_token"] as? String ?? ""
+            let expiresIn = args["expires_in"] as? Int ?? 0
+            GobackendSetExtensionTokensByID(extensionId, accessToken, refreshToken, Int(expiresIn))
+            return nil
+            
+        case "clearExtensionPendingAuth":
+            let args = call.arguments as! [String: Any]
+            let extensionId = args["extension_id"] as! String
+            GobackendClearExtensionPendingAuthByID(extensionId)
+            return nil
+            
+        case "isExtensionAuthenticated":
+            let args = call.arguments as! [String: Any]
+            let extensionId = args["extension_id"] as! String
+            let response = GobackendIsExtensionAuthenticatedByID(extensionId)
+            return response
+            
+        case "getAllPendingAuthRequests":
+            let response = GobackendGetAllPendingAuthRequestsJSON(&error)
+            if let error = error { throw error }
+            return response
+            
+        // Extension FFmpeg API
+        case "getPendingFFmpegCommand":
+            let args = call.arguments as! [String: Any]
+            let commandId = args["command_id"] as! String
+            let response = GobackendGetPendingFFmpegCommandJSON(commandId, &error)
+            if let error = error { throw error }
+            return response
+            
+        case "setFFmpegCommandResult":
+            let args = call.arguments as! [String: Any]
+            let commandId = args["command_id"] as! String
+            let success = args["success"] as? Bool ?? false
+            let output = args["output"] as? String ?? ""
+            let errorMsg = args["error"] as? String ?? ""
+            GobackendSetFFmpegCommandResult(commandId, success, output, errorMsg)
+            return nil
+            
+        case "getAllPendingFFmpegCommands":
+            let response = GobackendGetAllPendingFFmpegCommandsJSON(&error)
+            if let error = error { throw error }
+            return response
+            
+        // Extension Custom Search API
+        case "customSearchWithExtension":
+            let args = call.arguments as! [String: Any]
+            let extensionId = args["extension_id"] as! String
+            let query = args["query"] as! String
+            let optionsJson = args["options"] as? String ?? ""
+            let response = GobackendCustomSearchWithExtensionJSON(extensionId, query, optionsJson, &error)
+            if let error = error { throw error }
+            return response
+            
+        case "getSearchProviders":
+            let response = GobackendGetSearchProvidersJSON(&error)
+            if let error = error { throw error }
+            return response
+            
+        // Extension URL Handler API
+        case "handleURLWithExtension":
+            let args = call.arguments as! [String: Any]
+            let url = args["url"] as! String
+            let response = GobackendHandleURLWithExtensionJSON(url, &error)
+            if let error = error { throw error }
+            return response
+            
+        case "findURLHandler":
+            let args = call.arguments as! [String: Any]
+            let url = args["url"] as! String
+            let response = GobackendFindURLHandlerJSON(url)
+            return response
+            
+        case "getURLHandlers":
+            let response = GobackendGetURLHandlersJSON(&error)
+            if let error = error { throw error }
+            return response
+            
+        case "getAlbumWithExtension":
+            let args = call.arguments as! [String: Any]
+            let extensionId = args["extension_id"] as! String
+            let albumId = args["album_id"] as! String
+            let response = GobackendGetAlbumWithExtensionJSON(extensionId, albumId, &error)
+            if let error = error { throw error }
+            return response
+            
+        case "getPlaylistWithExtension":
+            let args = call.arguments as! [String: Any]
+            let extensionId = args["extension_id"] as! String
+            let playlistId = args["playlist_id"] as! String
+            let response = GobackendGetPlaylistWithExtensionJSON(extensionId, playlistId, &error)
+            if let error = error { throw error }
+            return response
+            
+        case "getArtistWithExtension":
+            let args = call.arguments as! [String: Any]
+            let extensionId = args["extension_id"] as! String
+            let artistId = args["artist_id"] as! String
+            let response = GobackendGetArtistWithExtensionJSON(extensionId, artistId, &error)
+            if let error = error { throw error }
+            return response
+            
+        // Extension Post-Processing API
+        case "runPostProcessing":
+            let args = call.arguments as! [String: Any]
+            let filePath = args["file_path"] as! String
+            let metadataJson = args["metadata"] as? String ?? ""
+            let response = GobackendRunPostProcessingJSON(filePath, metadataJson, &error)
+            if let error = error { throw error }
+            return response
+            
+        case "getPostProcessingProviders":
+            let response = GobackendGetPostProcessingProvidersJSON(&error)
+            if let error = error { throw error }
+            return response
+            
+        // Extension Store
+        case "initExtensionStore":
+            let args = call.arguments as! [String: Any]
+            let cacheDir = args["cache_dir"] as! String
+            GobackendInitExtensionStoreJSON(cacheDir, &error)
+            if let error = error { throw error }
+            return nil
+            
+        case "getStoreExtensions":
+            let args = call.arguments as! [String: Any]
+            let forceRefresh = args["force_refresh"] as? Bool ?? false
+            let response = GobackendGetStoreExtensionsJSON(forceRefresh, &error)
+            if let error = error { throw error }
+            return response
+            
+        case "searchStoreExtensions":
+            let args = call.arguments as! [String: Any]
+            let query = args["query"] as? String ?? ""
+            let category = args["category"] as? String ?? ""
+            let response = GobackendSearchStoreExtensionsJSON(query, category, &error)
+            if let error = error { throw error }
+            return response
+            
+        case "getStoreCategories":
+            let response = GobackendGetStoreCategoriesJSON(&error)
+            if let error = error { throw error }
+            return response
+            
+        case "downloadStoreExtension":
+            let args = call.arguments as! [String: Any]
+            let extensionId = args["extension_id"] as! String
+            let destDir = args["dest_dir"] as! String
+            let response = GobackendDownloadStoreExtensionJSON(extensionId, destDir, &error)
+            if let error = error { throw error }
+            return response
+            
+        case "clearStoreCache":
+            GobackendClearStoreCacheJSON(&error)
+            if let error = error { throw error }
+            return nil
+            
         default:
             throw NSError(
                 domain: "SpotiFLAC",

ios/Runner/Info.plist

@@ -4,6 +4,23 @@
 <dict>
 	<key>CFBundleDevelopmentRegion</key>
 	<string>$(DEVELOPMENT_LANGUAGE)</string>
+	<key>CFBundleLocalizations</key>
+	<array>
+		<string>en</string>
+		<string>de</string>
+		<string>es</string>
+		<string>fr</string>
+		<string>hi</string>
+		<string>id</string>
+		<string>ja</string>
+		<string>ko</string>
+		<string>nl</string>
+		<string>pt</string>
+		<string>ru</string>
+		<string>zh</string>
+		<string>zh-Hans</string>
+		<string>zh-Hant</string>
+	</array>
 	<key>CFBundleDisplayName</key>
 	<string>SpotiFLAC</string>
 	<key>CFBundleExecutable</key>

l10n.yaml

@@ -0,0 +1,6 @@
+arb-dir: lib/l10n/arb
+template-arb-file: app_en.arb
+output-localization-file: app_localizations.dart
+output-class: AppLocalizations
+output-dir: lib/l10n
+nullable-getter: false

lib/app.dart

@@ -1,13 +1,14 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:flutter_localizations/flutter_localizations.dart';
 import 'package:go_router/go_router.dart';
 import 'package:spotiflac_android/screens/main_shell.dart';
 import 'package:spotiflac_android/screens/setup_screen.dart';
 import 'package:spotiflac_android/providers/settings_provider.dart';
 import 'package:spotiflac_android/theme/dynamic_color_wrapper.dart';
+import 'package:spotiflac_android/l10n/app_localizations.dart';
 
 final _routerProvider = Provider<GoRouter>((ref) {
-  // Only watch isFirstLaunch to prevent router rebuild on other settings changes
   final isFirstLaunch = ref.watch(settingsProvider.select((s) => s.isFirstLaunch));
   
   return GoRouter(
@@ -31,6 +32,12 @@ class SpotiFLACApp extends ConsumerWidget {
   @override
   Widget build(BuildContext context, WidgetRef ref) {
     final router = ref.watch(_routerProvider);
+    final localeString = ref.watch(settingsProvider.select((s) => s.locale));
+    
+    Locale? locale;
+    if (localeString != 'system') {
+      locale = Locale(localeString);
+    }
     
     return DynamicColorWrapper(
       builder: (lightTheme, darkTheme, themeMode) {
@@ -43,6 +50,14 @@ class SpotiFLACApp extends ConsumerWidget {
           themeAnimationDuration: const Duration(milliseconds: 300),
           themeAnimationCurve: Curves.easeInOut,
           routerConfig: router,
+          locale: locale,
+          localizationsDelegates: const [
+            AppLocalizations.delegate,
+            GlobalMaterialLocalizations.delegate,
+            GlobalWidgetsLocalizations.delegate,
+            GlobalCupertinoLocalizations.delegate,
+          ],
+          supportedLocales: AppLocalizations.supportedLocales,
         );
       },
     );

lib/constants/app_info.dart

@@ -1,8 +1,8 @@
 /// App version and info constants
 /// Update version here only - all other files will reference this
 class AppInfo {
-  static const String version = '2.2.0';
-  static const String buildNumber = '46';
+  static const String version = '3.1.1';
+  static const String buildNumber = '60';
   static const String fullVersion = '$version+$buildNumber';
   
   

lib/l10n/arb/app_id.arb

@@ -0,0 +1,681 @@
+{
+  "@@locale": "id",
+  "@@last_modified": "2026-01-16",
+
+  "appName": "SpotiFLAC",
+  "appDescription": "Unduh lagu Spotify dalam kualitas lossless dari Tidal, Qobuz, dan Amazon Music.",
+
+  "navHome": "Beranda",
+  "navHistory": "Riwayat",
+  "navSettings": "Pengaturan",
+  "navStore": "Toko",
+
+  "homeTitle": "Beranda",
+  "homeSearchHint": "Tempel URL Spotify atau cari...",
+  "homeSearchHintExtension": "Cari dengan {extensionName}...",
+  "homeSubtitle": "Tempel link Spotify atau cari berdasarkan nama",
+  "homeSupports": "Mendukung: URL Track, Album, Playlist, Artis",
+  "homeRecent": "Terbaru",
+
+  "historyTitle": "Riwayat",
+  "historyDownloading": "Mengunduh ({count})",
+  "historyDownloaded": "Terunduh",
+  "historyFilterAll": "Semua",
+  "historyFilterAlbums": "Album",
+  "historyFilterSingles": "Single",
+  "historyTracksCount": "{count, plural, =1{1 lagu} other{{count} lagu}}",
+  "historyAlbumsCount": "{count, plural, =1{1 album} other{{count} album}}",
+  "historyNoDownloads": "Tidak ada riwayat unduhan",
+  "historyNoDownloadsSubtitle": "Lagu yang diunduh akan muncul di sini",
+  "historyNoAlbums": "Tidak ada unduhan album",
+  "historyNoAlbumsSubtitle": "Unduh beberapa lagu dari album untuk melihatnya di sini",
+  "historyNoSingles": "Tidak ada unduhan single",
+  "historyNoSinglesSubtitle": "Unduhan lagu satuan akan muncul di sini",
+
+  "settingsTitle": "Pengaturan",
+  "settingsDownload": "Unduhan",
+  "settingsAppearance": "Tampilan",
+  "settingsOptions": "Opsi",
+  "settingsExtensions": "Ekstensi",
+  "settingsAbout": "Tentang",
+
+  "downloadTitle": "Unduhan",
+  "downloadLocation": "Lokasi Unduhan",
+  "downloadLocationSubtitle": "Pilih tempat menyimpan file",
+  "downloadLocationDefault": "Lokasi default",
+  "downloadDefaultService": "Layanan Default",
+  "downloadDefaultServiceSubtitle": "Layanan yang digunakan untuk unduhan",
+  "downloadDefaultQuality": "Kualitas Default",
+  "downloadAskQuality": "Tanya Kualitas Sebelum Unduh",
+  "downloadAskQualitySubtitle": "Tampilkan pemilih kualitas untuk setiap unduhan",
+  "downloadFilenameFormat": "Format Nama File",
+  "downloadFolderOrganization": "Organisasi Folder",
+  "downloadSeparateSingles": "Pisahkan Single",
+  "downloadSeparateSinglesSubtitle": "Letakkan lagu satuan di folder terpisah",
+
+  "qualityBest": "Terbaik",
+  "qualityFlac": "FLAC",
+  "quality320": "320 kbps",
+  "quality128": "128 kbps",
+
+  "appearanceTitle": "Tampilan",
+  "appearanceTheme": "Tema",
+  "appearanceThemeSystem": "Sistem",
+  "appearanceThemeLight": "Terang",
+  "appearanceThemeDark": "Gelap",
+  "appearanceDynamicColor": "Warna Dinamis",
+  "appearanceDynamicColorSubtitle": "Gunakan warna dari wallpaper Anda",
+  "appearanceAccentColor": "Warna Aksen",
+  "appearanceHistoryView": "Tampilan Riwayat",
+  "appearanceHistoryViewList": "Daftar",
+  "appearanceHistoryViewGrid": "Grid",
+
+  "optionsTitle": "Opsi",
+  "optionsSearchSource": "Sumber Pencarian",
+  "optionsPrimaryProvider": "Provider Utama",
+  "optionsPrimaryProviderSubtitle": "Layanan yang digunakan saat mencari berdasarkan nama lagu.",
+  "optionsUsingExtension": "Menggunakan ekstensi: {extensionName}",
+  "optionsSwitchBack": "Ketuk Deezer atau Spotify untuk beralih dari ekstensi",
+  "optionsAutoFallback": "Auto Fallback",
+  "optionsAutoFallbackSubtitle": "Coba layanan lain jika unduhan gagal",
+  "optionsUseExtensionProviders": "Gunakan Provider Ekstensi",
+  "optionsUseExtensionProvidersOn": "Ekstensi akan dicoba terlebih dahulu",
+  "optionsUseExtensionProvidersOff": "Hanya menggunakan provider bawaan",
+  "optionsEmbedLyrics": "Sematkan Lirik",
+  "optionsEmbedLyricsSubtitle": "Sematkan lirik sinkron ke file FLAC",
+  "optionsMaxQualityCover": "Cover Kualitas Maksimal",
+  "optionsMaxQualityCoverSubtitle": "Unduh cover art resolusi tertinggi",
+  "optionsConcurrentDownloads": "Unduhan Bersamaan",
+  "optionsConcurrentSequential": "Berurutan (1 per waktu)",
+  "optionsConcurrentParallel": "{count} unduhan paralel",
+  "optionsConcurrentWarning": "Unduhan paralel dapat memicu pembatasan rate",
+  "optionsExtensionStore": "Toko Ekstensi",
+  "optionsExtensionStoreSubtitle": "Tampilkan tab Toko di navigasi",
+  "optionsCheckUpdates": "Periksa Pembaruan",
+  "optionsCheckUpdatesSubtitle": "Beritahu saat versi baru tersedia",
+  "optionsUpdateChannel": "Saluran Pembaruan",
+  "optionsUpdateChannelStable": "Hanya rilis stabil",
+  "optionsUpdateChannelPreview": "Dapatkan rilis preview",
+  "optionsUpdateChannelWarning": "Preview mungkin mengandung bug atau fitur belum lengkap",
+  "optionsClearHistory": "Hapus Riwayat Unduhan",
+  "optionsClearHistorySubtitle": "Hapus semua lagu dari riwayat",
+  "optionsDetailedLogging": "Log Detail",
+  "optionsDetailedLoggingOn": "Log detail sedang direkam",
+  "optionsDetailedLoggingOff": "Aktifkan untuk laporan bug",
+  "optionsSpotifyCredentials": "Kredensial Spotify",
+  "optionsSpotifyCredentialsConfigured": "Client ID: {clientId}...",
+  "optionsSpotifyCredentialsRequired": "Diperlukan - ketuk untuk mengatur",
+  "optionsSpotifyWarning": "Spotify memerlukan kredensial API Anda sendiri. Dapatkan gratis dari developer.spotify.com",
+
+  "extensionsTitle": "Ekstensi",
+  "extensionsInstalled": "Ekstensi Terpasang",
+  "extensionsNone": "Tidak ada ekstensi terpasang",
+  "extensionsNoneSubtitle": "Pasang ekstensi dari tab Toko",
+  "extensionsEnabled": "Aktif",
+  "extensionsDisabled": "Nonaktif",
+  "extensionsVersion": "Versi {version}",
+  "extensionsAuthor": "oleh {author}",
+  "extensionsUninstall": "Copot",
+  "extensionsSetAsSearch": "Jadikan Provider Pencarian",
+
+  "storeTitle": "Toko Ekstensi",
+  "storeSearch": "Cari ekstensi...",
+  "storeInstall": "Pasang",
+  "storeInstalled": "Terpasang",
+  "storeUpdate": "Perbarui",
+
+  "aboutTitle": "Tentang",
+  "aboutContributors": "Kontributor",
+  "aboutMobileDeveloper": "Pengembang versi mobile",
+  "aboutOriginalCreator": "Pencipta SpotiFLAC asli",
+  "aboutLogoArtist": "Seniman berbakat yang membuat logo aplikasi kami yang indah!",
+  "aboutSpecialThanks": "Terima Kasih Khusus",
+  "aboutLinks": "Tautan",
+  "aboutMobileSource": "Kode sumber mobile",
+  "aboutPCSource": "Kode sumber PC",
+  "aboutReportIssue": "Laporkan masalah",
+  "aboutReportIssueSubtitle": "Laporkan masalah yang Anda temui",
+  "aboutFeatureRequest": "Permintaan fitur",
+  "aboutFeatureRequestSubtitle": "Sarankan fitur baru untuk aplikasi",
+  "aboutSupport": "Dukungan",
+  "aboutBuyMeCoffee": "Traktir saya kopi",
+  "aboutBuyMeCoffeeSubtitle": "Dukung pengembangan di Ko-fi",
+  "aboutApp": "Aplikasi",
+  "aboutVersion": "Versi",
+
+  "albumTitle": "Album",
+  "albumTracks": "{count, plural, =1{1 lagu} other{{count} lagu}}",
+  "albumDownloadAll": "Unduh Semua",
+  "albumDownloadRemaining": "Unduh Sisanya",
+
+  "playlistTitle": "Playlist",
+  "artistTitle": "Artis",
+  "artistAlbums": "Album",
+  "artistSingles": "Single & EP",
+
+  "trackMetadataTitle": "Info Lagu",
+  "trackMetadataArtist": "Artis",
+  "trackMetadataAlbum": "Album",
+  "trackMetadataDuration": "Durasi",
+  "trackMetadataQuality": "Kualitas",
+  "trackMetadataPath": "Lokasi File",
+  "trackMetadataDownloadedAt": "Diunduh",
+  "trackMetadataService": "Layanan",
+  "trackMetadataPlay": "Putar",
+  "trackMetadataShare": "Bagikan",
+  "trackMetadataDelete": "Hapus",
+  "trackMetadataRedownload": "Unduh ulang",
+  "trackMetadataOpenFolder": "Buka Folder",
+
+  "setupTitle": "Selamat Datang di SpotiFLAC",
+  "setupSubtitle": "Mari mulai pengaturan",
+  "setupStoragePermission": "Izin Penyimpanan",
+  "setupStoragePermissionSubtitle": "Diperlukan untuk menyimpan file unduhan",
+  "setupStoragePermissionGranted": "Izin diberikan",
+  "setupStoragePermissionDenied": "Izin ditolak",
+  "setupGrantPermission": "Berikan Izin",
+  "setupDownloadLocation": "Lokasi Unduhan",
+  "setupChooseFolder": "Pilih Folder",
+  "setupContinue": "Lanjutkan",
+  "setupSkip": "Lewati untuk sekarang",
+
+  "dialogCancel": "Batal",
+  "dialogOk": "OK",
+  "dialogSave": "Simpan",
+  "dialogDelete": "Hapus",
+  "dialogRetry": "Coba Lagi",
+  "dialogClose": "Tutup",
+  "dialogYes": "Ya",
+  "dialogNo": "Tidak",
+  "dialogClear": "Hapus",
+  "dialogConfirm": "Konfirmasi",
+  "dialogDone": "Selesai",
+
+  "dialogClearHistoryTitle": "Hapus Riwayat",
+  "dialogClearHistoryMessage": "Apakah Anda yakin ingin menghapus semua riwayat unduhan? Ini tidak dapat dibatalkan.",
+  "dialogDeleteSelectedTitle": "Hapus yang Dipilih",
+  "dialogDeleteSelectedMessage": "Hapus {count} {count, plural, =1{lagu} other{lagu}} dari riwayat?\n\nIni juga akan menghapus file dari penyimpanan.",
+  "dialogImportPlaylistTitle": "Impor Playlist",
+  "dialogImportPlaylistMessage": "Ditemukan {count} lagu di CSV. Tambahkan ke antrian unduhan?",
+
+  "snackbarAddedToQueue": "Menambahkan \"{trackName}\" ke antrian",
+  "snackbarAddedTracksToQueue": "Menambahkan {count} lagu ke antrian",
+  "snackbarAlreadyDownloaded": "\"{trackName}\" sudah diunduh",
+  "snackbarHistoryCleared": "Riwayat dihapus",
+  "snackbarCredentialsSaved": "Kredensial disimpan",
+  "snackbarCredentialsCleared": "Kredensial dihapus",
+  "snackbarDeletedTracks": "Menghapus {count} {count, plural, =1{lagu} other{lagu}}",
+  "snackbarCannotOpenFile": "Tidak dapat membuka file: {error}",
+  "snackbarFillAllFields": "Harap isi semua field",
+  "snackbarViewQueue": "Lihat Antrian",
+
+  "errorRateLimited": "Dibatasi",
+  "errorRateLimitedMessage": "Terlalu banyak permintaan. Harap tunggu sebentar sebelum mencari lagi.",
+  "errorFailedToLoad": "Gagal memuat {item}",
+  "errorNoTracksFound": "Tidak ada lagu ditemukan",
+  "errorMissingExtensionSource": "Tidak dapat memuat {item}: sumber ekstensi tidak ada",
+
+  "statusQueued": "Mengantri",
+  "statusDownloading": "Mengunduh",
+  "statusFinalizing": "Menyelesaikan",
+  "statusCompleted": "Selesai",
+  "statusFailed": "Gagal",
+  "statusSkipped": "Dilewati",
+  "statusPaused": "Dijeda",
+
+  "actionPause": "Jeda",
+  "actionResume": "Lanjutkan",
+  "actionCancel": "Batal",
+  "actionStop": "Hentikan",
+  "actionSelect": "Pilih",
+  "actionSelectAll": "Pilih Semua",
+  "actionDeselect": "Batal Pilih",
+  "actionPaste": "Tempel",
+  "actionImportCsv": "Impor CSV",
+  "actionRemoveCredentials": "Hapus Kredensial",
+  "actionSaveCredentials": "Simpan Kredensial",
+
+  "selectionSelected": "{count} dipilih",
+  "selectionAllSelected": "Semua lagu dipilih",
+  "selectionTapToSelect": "Ketuk lagu untuk memilih",
+  "selectionDeleteTracks": "Hapus {count} {count, plural, =1{lagu} other{lagu}}",
+  "selectionSelectToDelete": "Pilih lagu untuk dihapus",
+
+  "progressFetchingMetadata": "Mengambil metadata... {current}/{total}",
+  "progressReadingCsv": "Membaca CSV...",
+
+  "searchSongs": "Lagu",
+  "searchArtists": "Artis",
+  "searchAlbums": "Album",
+  "searchPlaylists": "Playlist",
+
+  "tooltipPlay": "Putar",
+  "tooltipCancel": "Batal",
+  "tooltipStop": "Hentikan",
+  "tooltipRetry": "Coba Lagi",
+  "tooltipRemove": "Hapus",
+  "tooltipClear": "Hapus",
+  "tooltipPaste": "Tempel",
+
+  "filenameFormat": "Format Nama File",
+  "filenameFormatPreview": "Pratinjau: {preview}",
+  "folderOrganization": "Organisasi Folder",
+  "folderOrganizationNone": "Tanpa organisasi",
+  "folderOrganizationByArtist": "Berdasarkan Artis",
+  "folderOrganizationByAlbum": "Berdasarkan Album",
+  "folderOrganizationByArtistAlbum": "Artis/Album",
+
+  "updateAvailable": "Pembaruan Tersedia",
+  "updateNewVersion": "Versi {version} tersedia",
+  "updateDownload": "Unduh",
+  "updateLater": "Nanti",
+  "updateChangelog": "Log Perubahan",
+
+  "providerPriority": "Prioritas Provider",
+  "providerPrioritySubtitle": "Seret untuk mengatur ulang provider unduhan",
+  "metadataProviderPriority": "Prioritas Provider Metadata",
+  "metadataProviderPrioritySubtitle": "Urutan yang digunakan saat mengambil metadata lagu",
+
+  "logTitle": "Log",
+  "logCopy": "Salin Log",
+  "logClear": "Hapus Log",
+  "logShare": "Bagikan Log",
+  "logEmpty": "Belum ada log",
+  "logCopied": "Log disalin ke clipboard",
+
+  "credentialsTitle": "Kredensial Spotify",
+  "credentialsDescription": "Masukkan Client ID dan Secret Anda untuk menggunakan kuota aplikasi Spotify Anda sendiri.",
+  "credentialsClientId": "Client ID",
+  "credentialsClientIdHint": "Tempel Client ID",
+  "credentialsClientSecret": "Client Secret",
+  "credentialsClientSecretHint": "Tempel Client Secret",
+
+  "channelStable": "Stabil",
+  "channelPreview": "Preview",
+
+  "sectionSearchSource": "Sumber Pencarian",
+  "sectionDownload": "Unduhan",
+  "sectionPerformance": "Performa",
+  "sectionApp": "Aplikasi",
+  "sectionData": "Data",
+  "sectionDebug": "Debug",
+  "sectionService": "Layanan",
+  "sectionAudioQuality": "Kualitas Audio",
+  "sectionFileSettings": "Pengaturan File",
+  "sectionColor": "Warna",
+  "sectionTheme": "Tema",
+  "sectionLayout": "Tata Letak",
+  "sectionLanguage": "Bahasa",
+
+  "appearanceLanguage": "Bahasa Aplikasi",
+  "appearanceLanguageSubtitle": "Pilih bahasa yang kamu inginkan",
+  "languageSystem": "Bawaan Sistem",
+  "languageEnglish": "English",
+  "languageIndonesian": "Bahasa Indonesia",
+
+  "settingsAppearanceSubtitle": "Tema, warna, tampilan",
+  "settingsDownloadSubtitle": "Layanan, kualitas, format nama file",
+  "settingsOptionsSubtitle": "Fallback, lirik, cover art, pembaruan",
+  "settingsExtensionsSubtitle": "Kelola provider unduhan",
+  "settingsLogsSubtitle": "Lihat log aplikasi untuk debugging",
+
+  "loadingSharedLink": "Memuat link yang dibagikan...",
+  "pressBackAgainToExit": "Tekan kembali sekali lagi untuk keluar",
+
+  "artistReleases": "{count, plural, =1{1 rilis} other{{count} rilis}}",
+  "artistCompilations": "Kompilasi",
+  "artistPopular": "Populer",
+  "artistMonthlyListeners": "{count} pendengar bulanan",
+
+  "tracksHeader": "Lagu",
+  "downloadAllCount": "Unduh Semua ({count})",
+  "tracksCount": "{count, plural, =1{1 lagu} other{{count} lagu}}",
+
+  "setupStorageAccessRequired": "Akses Penyimpanan Diperlukan",
+  "setupStorageAccessMessage": "SpotiFLAC membutuhkan izin \"Akses semua file\" untuk menyimpan file musik ke folder pilihan Anda.",
+  "setupStorageAccessMessageAndroid11": "Android 11+ memerlukan izin \"Akses semua file\" untuk menyimpan file ke folder unduhan pilihan Anda.",
+  "setupOpenSettings": "Buka Pengaturan",
+  "setupPermissionDeniedMessage": "Izin ditolak. Harap berikan semua izin untuk melanjutkan.",
+  "setupPermissionRequired": "Izin {permissionType} Diperlukan",
+  "setupPermissionRequiredMessage": "Izin {permissionType} diperlukan untuk pengalaman terbaik. Anda dapat mengubahnya nanti di Pengaturan.",
+  "setupSelectDownloadFolder": "Pilih Folder Unduhan",
+  "setupUseDefaultFolder": "Gunakan Folder Default?",
+  "setupNoFolderSelected": "Tidak ada folder dipilih. Apakah Anda ingin menggunakan folder Musik default?",
+  "setupUseDefault": "Gunakan Default",
+  "setupDownloadLocationTitle": "Lokasi Unduhan",
+  "setupDownloadLocationIosMessage": "Di iOS, unduhan disimpan ke folder Documents aplikasi. Anda dapat mengaksesnya melalui aplikasi Files.",
+  "setupAppDocumentsFolder": "Folder Documents Aplikasi",
+  "setupAppDocumentsFolderSubtitle": "Direkomendasikan - dapat diakses via aplikasi Files",
+  "setupChooseFromFiles": "Pilih dari Files",
+  "setupChooseFromFilesSubtitle": "Pilih lokasi iCloud atau lainnya",
+  "setupIosEmptyFolderWarning": "Batasan iOS: Folder kosong tidak dapat dipilih. Pilih folder dengan minimal satu file.",
+  "setupDownloadInFlac": "Unduh lagu Spotify dalam format FLAC",
+  "setupStepStorage": "Penyimpanan",
+  "setupStepNotification": "Notifikasi",
+  "setupStepFolder": "Folder",
+  "setupStepSpotify": "Spotify",
+  "setupStepPermission": "Izin",
+  "setupStorageGranted": "Izin Penyimpanan Diberikan!",
+  "setupStorageRequired": "Izin Penyimpanan Diperlukan",
+  "setupStorageDescription": "SpotiFLAC membutuhkan izin penyimpanan untuk menyimpan file musik yang diunduh.",
+  "setupNotificationGranted": "Izin Notifikasi Diberikan!",
+  "setupNotificationEnable": "Aktifkan Notifikasi",
+  "setupNotificationDescription": "Dapatkan pemberitahuan saat unduhan selesai atau membutuhkan perhatian.",
+  "setupFolderSelected": "Folder Unduhan Dipilih!",
+  "setupFolderChoose": "Pilih Folder Unduhan",
+  "setupFolderDescription": "Pilih folder tempat musik yang diunduh akan disimpan.",
+  "setupChangeFolder": "Ubah Folder",
+  "setupSelectFolder": "Pilih Folder",
+  "setupSpotifyApiOptional": "Spotify API (Opsional)",
+  "setupSpotifyApiDescription": "Tambahkan kredensial Spotify API untuk hasil pencarian lebih baik dan akses ke konten eksklusif Spotify.",
+  "setupUseSpotifyApi": "Gunakan Spotify API",
+  "setupEnterCredentialsBelow": "Masukkan kredensial Anda di bawah",
+  "setupUsingDeezer": "Menggunakan Deezer (tidak perlu akun)",
+  "setupEnterClientId": "Masukkan Spotify Client ID",
+  "setupEnterClientSecret": "Masukkan Spotify Client Secret",
+  "setupGetFreeCredentials": "Dapatkan kredensial API gratis dari Spotify Developer Dashboard.",
+  "setupEnableNotifications": "Aktifkan Notifikasi",
+
+  "dialogImport": "Impor",
+  "dialogDiscard": "Buang",
+  "dialogRemove": "Hapus",
+  "dialogUninstall": "Copot",
+  "dialogDiscardChanges": "Buang Perubahan?",
+  "dialogUnsavedChanges": "Anda memiliki perubahan yang belum disimpan. Apakah Anda ingin membuangnya?",
+  "dialogDownloadFailed": "Unduhan Gagal",
+  "dialogTrackLabel": "Lagu:",
+  "dialogArtistLabel": "Artis:",
+  "dialogErrorLabel": "Error:",
+  "dialogClearAll": "Hapus Semua",
+  "dialogClearAllDownloads": "Apakah Anda yakin ingin menghapus semua unduhan?",
+  "dialogRemoveFromDevice": "Hapus dari perangkat?",
+  "dialogRemoveExtension": "Hapus Ekstensi",
+  "dialogRemoveExtensionMessage": "Apakah Anda yakin ingin menghapus ekstensi ini? Tindakan ini tidak dapat dibatalkan.",
+  "dialogUninstallExtension": "Copot Ekstensi?",
+  "dialogUninstallExtensionMessage": "Apakah Anda yakin ingin menghapus {extensionName}?",
+
+  "snackbarFailedToLoad": "Gagal memuat: {error}",
+  "snackbarUrlCopied": "URL {platform} disalin ke clipboard",
+  "snackbarFileNotFound": "File tidak ditemukan",
+  "snackbarSelectExtFile": "Harap pilih file .spotiflac-ext",
+  "snackbarProviderPrioritySaved": "Prioritas provider disimpan",
+  "snackbarMetadataProviderSaved": "Prioritas provider metadata disimpan",
+  "snackbarExtensionInstalled": "{extensionName} terpasang.",
+  "snackbarExtensionUpdated": "{extensionName} diperbarui.",
+  "snackbarFailedToInstall": "Gagal memasang ekstensi",
+  "snackbarFailedToUpdate": "Gagal memperbarui ekstensi",
+
+  "storeFilterAll": "Semua",
+  "storeFilterMetadata": "Metadata",
+  "storeFilterDownload": "Unduhan",
+  "storeFilterUtility": "Utilitas",
+  "storeFilterLyrics": "Lirik",
+  "storeFilterIntegration": "Integrasi",
+  "storeClearFilters": "Hapus filter",
+  "storeNoResults": "Tidak ada ekstensi ditemukan",
+
+  "extensionProviderPriority": "Prioritas Provider",
+  "extensionInstallButton": "Pasang Ekstensi",
+  "extensionDefaultProvider": "Default (Deezer/Spotify)",
+  "extensionDefaultProviderSubtitle": "Gunakan pencarian bawaan",
+  "extensionAuthor": "Pembuat",
+  "extensionId": "ID",
+  "extensionError": "Error",
+  "extensionCapabilities": "Kemampuan",
+  "extensionMetadataProvider": "Provider Metadata",
+  "extensionDownloadProvider": "Provider Unduhan",
+  "extensionLyricsProvider": "Provider Lirik",
+  "extensionUrlHandler": "Penanganan URL",
+  "extensionQualityOptions": "Opsi Kualitas",
+  "extensionPostProcessingHooks": "Hook Pasca-Pemrosesan",
+  "extensionPermissions": "Izin",
+  "extensionSettings": "Pengaturan",
+  "extensionRemoveButton": "Hapus Ekstensi",
+  "extensionUpdated": "Diperbarui",
+  "extensionMinAppVersion": "Versi App Minimum",
+
+  "qualityFlacLossless": "FLAC Lossless",
+  "qualityFlacLosslessSubtitle": "16-bit / 44.1kHz",
+  "qualityHiResFlac": "Hi-Res FLAC",
+  "qualityHiResFlacSubtitle": "24-bit / hingga 96kHz",
+  "qualityHiResFlacMax": "Hi-Res FLAC Max",
+  "qualityHiResFlacMaxSubtitle": "24-bit / hingga 192kHz",
+  "qualityNote": "Kualitas sebenarnya tergantung ketersediaan lagu dari layanan",
+
+  "downloadAskBeforeDownload": "Tanya Sebelum Unduh",
+  "downloadDirectory": "Direktori Unduhan",
+  "downloadSeparateSinglesFolder": "Folder Singles Terpisah",
+  "downloadAlbumFolderStructure": "Struktur Folder Album",
+  "downloadSaveFormat": "Simpan Format",
+  "downloadSelectService": "Pilih Layanan",
+  "downloadSelectQuality": "Pilih Kualitas",
+  "downloadFrom": "Unduh Dari",
+  "downloadDefaultQualityLabel": "Kualitas Default",
+  "downloadBestAvailable": "Terbaik tersedia",
+
+  "folderNone": "Tidak ada",
+  "folderNoneSubtitle": "Simpan semua file langsung ke folder unduhan",
+  "folderArtist": "Artis",
+  "folderArtistSubtitle": "Nama Artis/namafile",
+  "folderAlbum": "Album",
+  "folderAlbumSubtitle": "Nama Album/namafile",
+  "folderArtistAlbum": "Artis/Album",
+  "folderArtistAlbumSubtitle": "Nama Artis/Nama Album/namafile",
+
+  "serviceTidal": "Tidal",
+  "serviceQobuz": "Qobuz",
+  "serviceAmazon": "Amazon",
+  "serviceDeezer": "Deezer",
+  "serviceSpotify": "Spotify",
+
+  "logSearchHint": "Cari log...",
+  "logFilterLevel": "Level",
+  "logFilterSection": "Filter",
+  "logShareLogs": "Bagikan log",
+  "logClearLogs": "Hapus log",
+  "logClearLogsTitle": "Hapus Log",
+  "logClearLogsMessage": "Apakah Anda yakin ingin menghapus semua log?",
+  "logIspBlocking": "PEMBLOKIRAN ISP TERDETEKSI",
+  "logRateLimited": "DIBATASI",
+  "logNetworkError": "ERROR JARINGAN",
+  "logTrackNotFound": "LAGU TIDAK DITEMUKAN",
+
+  "appearanceAmoledDark": "AMOLED Gelap",
+  "appearanceAmoledDarkSubtitle": "Latar belakang hitam murni",
+  "appearanceChooseAccentColor": "Pilih Warna Aksen",
+  "appearanceChooseTheme": "Mode Tema",
+
+  "updateStartingDownload": "Memulai unduhan...",
+  "updateDownloadFailed": "Unduhan gagal",
+  "updateFailedMessage": "Gagal mengunduh pembaruan",
+  "updateNewVersionReady": "Versi baru sudah siap",
+  "updateCurrent": "Saat ini",
+  "updateNew": "Baru",
+  "updateDownloading": "Mengunduh...",
+  "updateWhatsNew": "Yang Baru",
+  "updateDownloadInstall": "Unduh & Pasang",
+  "updateDontRemind": "Jangan ingatkan",
+
+  "trackCopyFilePath": "Salin lokasi file",
+  "trackRemoveFromDevice": "Hapus dari perangkat",
+  "trackLoadLyrics": "Muat Lirik",
+
+  "dateToday": "Hari ini",
+  "dateYesterday": "Kemarin",
+  "dateDaysAgo": "{count} hari lalu",
+  "dateWeeksAgo": "{count} minggu lalu",
+  "dateMonthsAgo": "{count} bulan lalu",
+
+  "concurrentSequential": "Berurutan",
+  "concurrentParallel2": "2 Paralel",
+  "concurrentParallel3": "3 Paralel",
+
+  "filenameAvailablePlaceholders": "Placeholder yang tersedia:",
+  "filenameHint": "{artist} - {title}",
+
+  "tapToSeeError": "Ketuk untuk melihat detail error",
+
+  "setupProceedToNextStep": "Anda dapat melanjutkan ke langkah berikutnya.",
+  "setupNotificationProgressDescription": "Anda akan menerima notifikasi progres unduhan.",
+  "setupNotificationBackgroundDescription": "Dapatkan notifikasi tentang progres dan penyelesaian unduhan. Ini membantu Anda melacak unduhan saat aplikasi di latar belakang.",
+  "setupSkipForNow": "Lewati untuk sekarang",
+  "setupBack": "Kembali",
+  "setupNext": "Lanjut",
+  "setupGetStarted": "Mulai",
+  "setupSkipAndStart": "Lewati & Mulai",
+  "setupAllowAccessToManageFiles": "Harap aktifkan \"Izinkan akses untuk mengelola semua file\" di layar berikutnya.",
+  "setupGetCredentialsFromSpotify": "Dapatkan kredensial dari developer.spotify.com",
+
+  "trackMetadata": "Metadata",
+  "trackFileInfo": "Info File",
+  "trackLyrics": "Lirik",
+  "trackFileNotFound": "File tidak ditemukan",
+  "trackOpenInDeezer": "Buka di Deezer",
+  "trackOpenInSpotify": "Buka di Spotify",
+  "trackTrackName": "Nama lagu",
+  "trackArtist": "Artis",
+  "trackAlbumArtist": "Artis album",
+  "trackAlbum": "Album",
+  "trackTrackNumber": "Nomor lagu",
+  "trackDiscNumber": "Nomor disc",
+  "trackDuration": "Durasi",
+  "trackAudioQuality": "Kualitas audio",
+  "trackReleaseDate": "Tanggal rilis",
+  "trackDownloaded": "Diunduh",
+  "trackCopyLyrics": "Salin lirik",
+  "trackLyricsNotAvailable": "Lirik tidak tersedia untuk lagu ini",
+  "trackLyricsTimeout": "Permintaan timeout. Coba lagi nanti.",
+  "trackLyricsLoadFailed": "Gagal memuat lirik",
+  "trackCopiedToClipboard": "Disalin ke clipboard",
+  "trackDeleteConfirmTitle": "Hapus dari perangkat?",
+  "trackDeleteConfirmMessage": "Ini akan menghapus file unduhan secara permanen dan menghapusnya dari riwayat Anda.",
+  "trackCannotOpen": "Tidak dapat membuka: {message}",
+
+  "logFilterBySeverity": "Filter log berdasarkan tingkat keparahan",
+  "logNoLogsYet": "Belum ada log",
+  "logNoLogsYetSubtitle": "Log akan muncul di sini saat Anda menggunakan aplikasi",
+  "logIssueSummary": "Ringkasan Masalah",
+  "logIspBlockingDescription": "ISP Anda mungkin memblokir akses ke layanan unduhan",
+  "logIspBlockingSuggestion": "Coba gunakan VPN atau ubah DNS ke 1.1.1.1 atau 8.8.8.8",
+  "logRateLimitedDescription": "Terlalu banyak permintaan ke layanan",
+  "logRateLimitedSuggestion": "Tunggu beberapa menit sebelum mencoba lagi",
+  "logNetworkErrorDescription": "Masalah koneksi terdeteksi",
+  "logNetworkErrorSuggestion": "Periksa koneksi internet Anda",
+  "logTrackNotFoundDescription": "Beberapa lagu tidak dapat ditemukan di layanan unduhan",
+  "logTrackNotFoundSuggestion": "Lagu mungkin tidak tersedia dalam kualitas lossless",
+  "logTotalErrors": "Total error: {count}",
+  "logAffected": "Terpengaruh: {domains}",
+  "logEntriesFiltered": "Entri ({count} difilter)",
+  "logEntries": "Entri ({count})",
+
+  "extensionsProviderPrioritySection": "Prioritas Provider",
+  "extensionsInstalledSection": "Ekstensi Terpasang",
+  "extensionsNoExtensions": "Tidak ada ekstensi terpasang",
+  "extensionsNoExtensionsSubtitle": "Pasang file .spotiflac-ext untuk menambahkan provider baru",
+  "extensionsInstallButton": "Pasang Ekstensi",
+  "extensionsInfoTip": "Ekstensi dapat menambahkan provider metadata dan unduhan baru. Hanya pasang ekstensi dari sumber terpercaya.",
+  "extensionsInstalledSuccess": "Ekstensi berhasil dipasang",
+  "extensionsDownloadPriority": "Prioritas Unduhan",
+  "extensionsDownloadPrioritySubtitle": "Atur urutan layanan unduhan",
+  "extensionsNoDownloadProvider": "Tidak ada ekstensi dengan provider unduhan",
+  "extensionsMetadataPriority": "Prioritas Metadata",
+  "extensionsMetadataPrioritySubtitle": "Atur urutan sumber pencarian & metadata",
+  "extensionsNoMetadataProvider": "Tidak ada ekstensi dengan provider metadata",
+  "extensionsSearchProvider": "Provider Pencarian",
+  "extensionsNoCustomSearch": "Tidak ada ekstensi dengan pencarian kustom",
+  "extensionsSearchProviderDescription": "Pilih layanan yang digunakan untuk mencari lagu",
+  "extensionsCustomSearch": "Pencarian kustom",
+  "extensionsErrorLoading": "Error memuat ekstensi",
+
+  "extensionCustomTrackMatching": "Pencocokan Lagu Kustom",
+  "extensionPostProcessing": "Pasca-Pemrosesan",
+  "extensionHooksAvailable": "{count} hook tersedia",
+  "extensionPatternsCount": "{count} pola",
+  "extensionStrategy": "Strategi: {strategy}",
+
+  "aboutDoubleDouble": "DoubleDouble",
+  "aboutDoubleDoubleDesc": "API luar biasa untuk unduhan Amazon Music. Terima kasih sudah membuatnya gratis!",
+  "aboutDabMusic": "DAB Music",
+  "aboutDabMusicDesc": "API streaming Qobuz terbaik. Unduhan Hi-Res tidak akan mungkin tanpa ini!",
+
+  "queueTitle": "Antrian Unduhan",
+  "queueClearAll": "Hapus Semua",
+  "queueClearAllMessage": "Apakah Anda yakin ingin menghapus semua unduhan?",
+
+  "albumFolderArtistAlbum": "Artis / Album",
+  "albumFolderArtistAlbumSubtitle": "Albums/Nama Artis/Nama Album/",
+  "albumFolderArtistYearAlbum": "Artis / [Tahun] Album",
+  "albumFolderArtistYearAlbumSubtitle": "Albums/Nama Artis/[2005] Nama Album/",
+  "albumFolderAlbumOnly": "Album Saja",
+  "albumFolderAlbumOnlySubtitle": "Albums/Nama Album/",
+  "albumFolderYearAlbum": "[Tahun] Album",
+  "albumFolderYearAlbumSubtitle": "Albums/[2005] Nama Album/",
+
+  "downloadedAlbumDeleteSelected": "Hapus yang Dipilih",
+  "downloadedAlbumDeleteMessage": "Hapus {count} {count, plural, =1{lagu} other{lagu}} dari album ini?\n\nIni juga akan menghapus file dari penyimpanan.",
+
+  "utilityFunctions": "Fungsi Utilitas",
+
+  "aboutMobileDeveloper": "Pengembang versi mobile",
+  "aboutOriginalCreator": "Pembuat SpotiFLAC asli",
+  "aboutLogoArtist": "Seniman berbakat yang membuat logo aplikasi kita yang indah!",
+  "aboutBinimumDesc": "Pembuat QQDL & HiFi API. Tanpa API ini, unduhan Tidal tidak akan ada!",
+  "aboutSachinsenalDesc": "Pembuat proyek HiFi asli. Fondasi dari integrasi Tidal!",
+  "aboutMobileSource": "Kode sumber mobile",
+  "aboutPCSource": "Kode sumber PC",
+  "aboutReportIssue": "Laporkan masalah",
+  "aboutReportIssueSubtitle": "Laporkan masalah yang Anda temui",
+  "aboutFeatureRequest": "Permintaan fitur",
+  "aboutFeatureRequestSubtitle": "Sarankan fitur baru untuk aplikasi",
+  "aboutBuyMeCoffee": "Belikan saya kopi",
+  "aboutBuyMeCoffeeSubtitle": "Dukung pengembangan di Ko-fi",
+  "aboutVersion": "Versi",
+  "aboutAppDescription": "Unduh lagu Spotify dalam kualitas lossless dari Tidal, Qobuz, dan Amazon Music.",
+
+  "providerPriorityTitle": "Prioritas Provider",
+  "providerPriorityDescription": "Seret untuk mengatur ulang urutan provider unduhan. Aplikasi akan mencoba provider dari atas ke bawah saat mengunduh lagu.",
+  "providerPriorityInfo": "Jika lagu tidak tersedia di provider pertama, aplikasi akan otomatis mencoba yang berikutnya.",
+  "providerBuiltIn": "Bawaan",
+  "providerExtension": "Ekstensi",
+
+  "metadataProviderPriorityTitle": "Prioritas Metadata",
+  "metadataProviderPriorityDescription": "Seret untuk mengatur ulang urutan provider metadata. Aplikasi akan mencoba provider dari atas ke bawah saat mencari lagu dan mengambil metadata.",
+  "metadataProviderPriorityInfo": "Deezer tidak memiliki batas rate dan direkomendasikan sebagai utama. Spotify mungkin membatasi rate setelah banyak permintaan.",
+  "metadataNoRateLimits": "Tidak ada batas rate",
+  "metadataMayRateLimit": "Mungkin dibatasi rate",
+
+  "queueEmpty": "Tidak ada unduhan dalam antrian",
+  "queueEmptySubtitle": "Tambahkan lagu dari layar beranda",
+  "queueClearCompleted": "Hapus yang selesai",
+  "queueDownloadFailed": "Unduhan Gagal",
+  "queueTrackLabel": "Lagu:",
+  "queueArtistLabel": "Artis:",
+  "queueErrorLabel": "Error:",
+  "queueUnknownError": "Error tidak diketahui",
+
+  "downloadedAlbumTracksHeader": "Lagu",
+  "downloadedAlbumDownloadedCount": "{count} diunduh",
+  "downloadedAlbumSelectedCount": "{count} dipilih",
+  "downloadedAlbumAllSelected": "Semua lagu dipilih",
+  "downloadedAlbumTapToSelect": "Ketuk lagu untuk memilih",
+  "downloadedAlbumDeleteCount": "Hapus {count} {count, plural, =1{lagu} other{lagu}}",
+  "downloadedAlbumSelectToDelete": "Pilih lagu untuk dihapus",
+
+  "folderOrganizationDescription": "Atur file yang diunduh ke dalam folder",
+  "folderOrganizationNone": "Tidak ada",
+  "folderOrganizationNoneSubtitle": "Semua file di folder unduhan",
+  "folderOrganizationByArtist": "Berdasarkan Artis",
+  "folderOrganizationByArtistSubtitle": "Folder terpisah untuk setiap artis",
+  "folderOrganizationByAlbum": "Berdasarkan Album",
+  "folderOrganizationByAlbumSubtitle": "Folder terpisah untuk setiap album",
+  "folderOrganizationByArtistAlbum": "Berdasarkan Artis & Album",
+  "folderOrganizationByArtistAlbumSubtitle": "Folder bersarang untuk artis dan album",
+
+  "recentTypeArtist": "Artis",
+  "recentTypeAlbum": "Album",
+  "recentTypeSong": "Lagu",
+  "recentTypePlaylist": "Playlist",
+
+  "recentPlaylistInfo": "Playlist: {name}",
+  "errorGeneric": "Error: {message}"
+}

lib/l10n/l10n.dart

@@ -0,0 +1,11 @@
+import 'package:flutter/material.dart';
+import 'package:spotiflac_android/l10n/app_localizations.dart';
+
+export 'package:spotiflac_android/l10n/app_localizations.dart';
+
+/// Extension to easily access AppLocalizations from BuildContext
+extension AppLocalizationsX on BuildContext {
+  /// Get the AppLocalizations instance
+  /// Usage: context.l10n.navHome
+  AppLocalizations get l10n => AppLocalizations.of(this);
+}

lib/l10n/supported_locales.dart

@@ -0,0 +1,48 @@
+// GENERATED FILE - DO NOT EDIT
+// Generated by: dart run tool/check_translations.dart 0
+// Only languages with >= 0% translation completion are included.
+// Translation is measured by comparing VALUES (not just key existence).
+//
+// To regenerate, run: dart run tool/check_translations.dart 0
+
+import 'package:flutter/widgets.dart';
+
+/// Minimum translation completion threshold used to filter languages.
+const int translationThreshold = 0;
+
+/// List of locales that meet the translation threshold.
+/// Only these languages will be available in the app.
+const List<Locale> filteredSupportedLocales = <Locale>[
+  Locale('en'),
+  Locale('ru'),
+  Locale('id'),
+  Locale('ja'),
+  Locale('de'),
+  Locale('es'),
+  Locale('fr'),
+  Locale('hi'),
+  Locale('ko'),
+  Locale('nl'),
+  Locale('pt'),
+  Locale('zh'),
+  Locale('zh', 'CN'),
+  Locale('zh', 'TW'),
+];
+
+/// Set of locale codes for quick lookup.
+const Set<String> filteredLocaleCodes = <String>{
+  'en',
+  'ru',
+  'id',
+  'ja',
+  'de',
+  'es',
+  'fr',
+  'hi',
+  'ko',
+  'nl',
+  'pt',
+  'zh',
+  'zh_CN',
+  'zh_TW',
+};

lib/main.dart

@@ -1,17 +1,18 @@
+import 'dart:io';
 import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:path_provider/path_provider.dart';
 import 'package:spotiflac_android/app.dart';
 import 'package:spotiflac_android/providers/download_queue_provider.dart';
+import 'package:spotiflac_android/providers/extension_provider.dart';
 import 'package:spotiflac_android/services/notification_service.dart';
 import 'package:spotiflac_android/services/share_intent_service.dart';
 
 void main() async {
   WidgetsFlutterBinding.ensureInitialized();
   
-  // Initialize notification service
   await NotificationService().initialize();
   
-  // Initialize share intent service
   await ShareIntentService().initialize();
   
   runApp(
@@ -24,14 +25,39 @@ void main() async {
 }
 
 /// Widget to eagerly initialize providers that need to load data on startup
-class _EagerInitialization extends ConsumerWidget {
+class _EagerInitialization extends ConsumerStatefulWidget {
   const _EagerInitialization({required this.child});
   final Widget child;
 
   @override
-  Widget build(BuildContext context, WidgetRef ref) {
-    // Eagerly initialize download history provider to load from storage
+  ConsumerState<_EagerInitialization> createState() => _EagerInitializationState();
+}
+
+class _EagerInitializationState extends ConsumerState<_EagerInitialization> {
+  @override
+  void initState() {
+    super.initState();
+    _initializeExtensions();
+  }
+
+  Future<void> _initializeExtensions() async {
+    try {
+      final appDir = await getApplicationDocumentsDirectory();
+      final extensionsDir = '${appDir.path}/extensions';
+      final dataDir = '${appDir.path}/extension_data';
+      
+      await Directory(extensionsDir).create(recursive: true);
+      await Directory(dataDir).create(recursive: true);
+      
+      await ref.read(extensionProvider.notifier).initialize(extensionsDir, dataDir);
+    } catch (e) {
+      debugPrint('Failed to initialize extensions: $e');
+    }
+  }
+
+  @override
+  Widget build(BuildContext context) {
     ref.watch(downloadHistoryProvider);
-    return child;
+    return widget.child;
   }
 }

lib/models/download_item.dart

@@ -19,6 +19,7 @@ enum DownloadErrorType {
   notFound,    // Track not found on any service
   rateLimit,   // Rate limited by service
   network,     // Network/connection error
+  permission,  // File/folder permission error
 }
 
 @JsonSerializable()
@@ -88,6 +89,8 @@ class DownloadItem {
         return 'Rate limit reached, try again later';
       case DownloadErrorType.network:
         return 'Connection failed, check your internet';
+      case DownloadErrorType.permission:
+        return 'Cannot write to folder, check storage permission';
       default:
         return error ?? 'An error occurred';
     }

lib/models/download_item.g.dart

@@ -51,4 +51,5 @@ const _$DownloadErrorTypeEnumMap = {
   DownloadErrorType.notFound: 'notFound',
   DownloadErrorType.rateLimit: 'rateLimit',
   DownloadErrorType.network: 'network',
+  DownloadErrorType.permission: 'permission',
 };

lib/models/settings.dart

@@ -18,11 +18,19 @@ class AppSettings {
   final bool hasSearchedBefore; // Hide helper text after first search
   final String folderOrganization; // none, artist, album, artist_album
   final String historyViewMode; // list, grid
+  final String historyFilterMode; // all, albums, singles
   final bool askQualityBeforeDownload; // Show quality picker before each download
   final String spotifyClientId; // Custom Spotify client ID (empty = use default)
   final String spotifyClientSecret; // Custom Spotify client secret (empty = use default)
   final bool useCustomSpotifyCredentials; // Whether to use custom credentials (if set)
   final String metadataSource; // spotify, deezer - source for search and metadata
+  final bool enableLogging; // Enable detailed logging for debugging
+  final bool useExtensionProviders; // Use extension providers for downloads when available
+  final String? searchProvider; // null/empty = default (Deezer/Spotify), otherwise extension ID
+  final bool separateSingles; // Separate singles/EPs into their own folder
+  final String albumFolderStructure; // artist_album, album_only, artist_year_album, year_album
+  final bool showExtensionStore; // Show Extension Store tab in navigation
+  final String locale; // App language: 'system', 'en', 'id', etc.
 
   const AppSettings({
     this.defaultService = 'tidal',
@@ -39,11 +47,19 @@ class AppSettings {
     this.hasSearchedBefore = false, // Default: show helper text
     this.folderOrganization = 'none', // Default: no folder organization
     this.historyViewMode = 'grid', // Default: grid view
+    this.historyFilterMode = 'all', // Default: show all
     this.askQualityBeforeDownload = true, // Default: ask quality before download
     this.spotifyClientId = '', // Default: use built-in credentials
     this.spotifyClientSecret = '', // Default: use built-in credentials
     this.useCustomSpotifyCredentials = true, // Default: use custom if set
     this.metadataSource = 'deezer', // Default: Deezer (no rate limit)
+    this.enableLogging = false, // Default: disabled for performance
+    this.useExtensionProviders = true, // Default: use extensions when available
+    this.searchProvider, // Default: null (use Deezer/Spotify)
+    this.separateSingles = false, // Default: disabled
+    this.albumFolderStructure = 'artist_album', // Default: Albums/Artist/Album
+    this.showExtensionStore = true, // Default: show store
+    this.locale = 'system', // Default: follow system language
   });
 
   AppSettings copyWith({
@@ -61,11 +77,20 @@ class AppSettings {
     bool? hasSearchedBefore,
     String? folderOrganization,
     String? historyViewMode,
+    String? historyFilterMode,
     bool? askQualityBeforeDownload,
     String? spotifyClientId,
     String? spotifyClientSecret,
     bool? useCustomSpotifyCredentials,
     String? metadataSource,
+    bool? enableLogging,
+    bool? useExtensionProviders,
+    String? searchProvider,
+    bool clearSearchProvider = false, // Set to true to clear searchProvider to null
+    bool? separateSingles,
+    String? albumFolderStructure,
+    bool? showExtensionStore,
+    String? locale,
   }) {
     return AppSettings(
       defaultService: defaultService ?? this.defaultService,
@@ -82,11 +107,19 @@ class AppSettings {
       hasSearchedBefore: hasSearchedBefore ?? this.hasSearchedBefore,
       folderOrganization: folderOrganization ?? this.folderOrganization,
       historyViewMode: historyViewMode ?? this.historyViewMode,
+      historyFilterMode: historyFilterMode ?? this.historyFilterMode,
       askQualityBeforeDownload: askQualityBeforeDownload ?? this.askQualityBeforeDownload,
       spotifyClientId: spotifyClientId ?? this.spotifyClientId,
       spotifyClientSecret: spotifyClientSecret ?? this.spotifyClientSecret,
       useCustomSpotifyCredentials: useCustomSpotifyCredentials ?? this.useCustomSpotifyCredentials,
       metadataSource: metadataSource ?? this.metadataSource,
+      enableLogging: enableLogging ?? this.enableLogging,
+      useExtensionProviders: useExtensionProviders ?? this.useExtensionProviders,
+      searchProvider: clearSearchProvider ? null : (searchProvider ?? this.searchProvider),
+      separateSingles: separateSingles ?? this.separateSingles,
+      albumFolderStructure: albumFolderStructure ?? this.albumFolderStructure,
+      showExtensionStore: showExtensionStore ?? this.showExtensionStore,
+      locale: locale ?? this.locale,
     );
   }
 

lib/models/settings.g.dart

@@ -21,12 +21,21 @@ AppSettings _$AppSettingsFromJson(Map<String, dynamic> json) => AppSettings(
   hasSearchedBefore: json['hasSearchedBefore'] as bool? ?? false,
   folderOrganization: json['folderOrganization'] as String? ?? 'none',
   historyViewMode: json['historyViewMode'] as String? ?? 'grid',
+  historyFilterMode: json['historyFilterMode'] as String? ?? 'all',
   askQualityBeforeDownload: json['askQualityBeforeDownload'] as bool? ?? true,
   spotifyClientId: json['spotifyClientId'] as String? ?? '',
   spotifyClientSecret: json['spotifyClientSecret'] as String? ?? '',
   useCustomSpotifyCredentials:
       json['useCustomSpotifyCredentials'] as bool? ?? true,
   metadataSource: json['metadataSource'] as String? ?? 'deezer',
+  enableLogging: json['enableLogging'] as bool? ?? false,
+  useExtensionProviders: json['useExtensionProviders'] as bool? ?? true,
+  searchProvider: json['searchProvider'] as String?,
+  separateSingles: json['separateSingles'] as bool? ?? false,
+  albumFolderStructure:
+      json['albumFolderStructure'] as String? ?? 'artist_album',
+  showExtensionStore: json['showExtensionStore'] as bool? ?? true,
+  locale: json['locale'] as String? ?? 'system',
 );
 
 Map<String, dynamic> _$AppSettingsToJson(AppSettings instance) =>
@@ -45,9 +54,17 @@ Map<String, dynamic> _$AppSettingsToJson(AppSettings instance) =>
       'hasSearchedBefore': instance.hasSearchedBefore,
       'folderOrganization': instance.folderOrganization,
       'historyViewMode': instance.historyViewMode,
+      'historyFilterMode': instance.historyFilterMode,
       'askQualityBeforeDownload': instance.askQualityBeforeDownload,
       'spotifyClientId': instance.spotifyClientId,
       'spotifyClientSecret': instance.spotifyClientSecret,
       'useCustomSpotifyCredentials': instance.useCustomSpotifyCredentials,
       'metadataSource': instance.metadataSource,
+      'enableLogging': instance.enableLogging,
+      'useExtensionProviders': instance.useExtensionProviders,
+      'searchProvider': instance.searchProvider,
+      'separateSingles': instance.separateSingles,
+      'albumFolderStructure': instance.albumFolderStructure,
+      'showExtensionStore': instance.showExtensionStore,
+      'locale': instance.locale,
     };

lib/models/track.dart

@@ -18,6 +18,9 @@ class Track {
   final String? releaseDate;
   final String? deezerId;
   final ServiceAvailability? availability;
+  final String? source; // Extension ID that provided this track (null for built-in sources)
+  final String? albumType; // album, single, ep, compilation (from metadata API)
+  final String? itemType; // track, album, playlist - for extension search results
 
   const Track({
     required this.id,
@@ -33,10 +36,31 @@ class Track {
     this.releaseDate,
     this.deezerId,
     this.availability,
+    this.source,
+    this.albumType,
+    this.itemType,
   });
 
+  /// Check if this track is a single (based on album_type metadata)
+  bool get isSingle => albumType == 'single' || albumType == 'ep';
+  
+  /// Check if this is an album item (not a track)
+  bool get isAlbumItem => itemType == 'album';
+  
+  /// Check if this is a playlist item (not a track)
+  bool get isPlaylistItem => itemType == 'playlist';
+  
+  /// Check if this is an artist item (not a track)
+  bool get isArtistItem => itemType == 'artist';
+  
+  /// Check if this is a collection (album, playlist, or artist)
+  bool get isCollection => isAlbumItem || isPlaylistItem || isArtistItem;
+
   factory Track.fromJson(Map<String, dynamic> json) => _$TrackFromJson(json);
   Map<String, dynamic> toJson() => _$TrackToJson(this);
+  
+  /// Check if this track is from an extension
+  bool get isFromExtension => source != null && source!.isNotEmpty;
 }
 
 @JsonSerializable()

lib/models/track.g.dart

@@ -24,6 +24,9 @@ Track _$TrackFromJson(Map<String, dynamic> json) => Track(
       : ServiceAvailability.fromJson(
           json['availability'] as Map<String, dynamic>,
         ),
+  source: json['source'] as String?,
+  albumType: json['albumType'] as String?,
+  itemType: json['itemType'] as String?,
 );
 
 Map<String, dynamic> _$TrackToJson(Track instance) => <String, dynamic>{
@@ -40,6 +43,9 @@ Map<String, dynamic> _$TrackToJson(Track instance) => <String, dynamic>{
   'releaseDate': instance.releaseDate,
   'deezerId': instance.deezerId,
   'availability': instance.availability,
+  'source': instance.source,
+  'albumType': instance.albumType,
+  'itemType': instance.itemType,
 };
 
 ServiceAvailability _$ServiceAvailabilityFromJson(Map<String, dynamic> json) =>

lib/providers/extension_provider.dart

@@ -0,0 +1,708 @@
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:spotiflac_android/services/platform_bridge.dart';
+import 'package:spotiflac_android/utils/logger.dart';
+import 'package:spotiflac_android/providers/settings_provider.dart';
+
+final _log = AppLogger('ExtensionProvider');
+
+/// Represents an installed extension
+class Extension {
+  final String id;
+  final String name;
+  final String displayName;
+  final String version;
+  final String author;
+  final String description;
+  final bool enabled;
+  final String status; // 'loaded', 'error', 'disabled'
+  final String? errorMessage;
+  final String? iconPath; // Path to extension icon
+  final List<String> permissions;
+  final List<ExtensionSetting> settings;
+  final List<QualityOption> qualityOptions; // Custom quality options for download providers
+  final bool hasMetadataProvider;
+  final bool hasDownloadProvider;
+  final bool skipMetadataEnrichment; // If true, use metadata from extension instead of enriching
+  final SearchBehavior? searchBehavior; // Custom search behavior
+  final URLHandler? urlHandler; // Custom URL handling
+  final TrackMatching? trackMatching; // Custom track matching
+  final PostProcessing? postProcessing; // Post-processing hooks
+
+  const Extension({
+    required this.id,
+    required this.name,
+    required this.displayName,
+    required this.version,
+    required this.author,
+    required this.description,
+    required this.enabled,
+    required this.status,
+    this.errorMessage,
+    this.iconPath,
+    this.permissions = const [],
+    this.settings = const [],
+    this.qualityOptions = const [],
+    this.hasMetadataProvider = false,
+    this.hasDownloadProvider = false,
+    this.skipMetadataEnrichment = false,
+    this.searchBehavior,
+    this.urlHandler,
+    this.trackMatching,
+    this.postProcessing,
+  });
+
+  factory Extension.fromJson(Map<String, dynamic> json) {
+    return Extension(
+      id: json['id'] as String? ?? '',
+      name: json['name'] as String? ?? '',
+      displayName: json['display_name'] as String? ?? json['name'] as String? ?? '',
+      version: json['version'] as String? ?? '0.0.0',
+      author: json['author'] as String? ?? 'Unknown',
+      description: json['description'] as String? ?? '',
+      enabled: json['enabled'] as bool? ?? false,
+      status: json['status'] as String? ?? 'loaded',
+      errorMessage: json['error_message'] as String?,
+      iconPath: json['icon_path'] as String?,
+      permissions: (json['permissions'] as List<dynamic>?)?.cast<String>() ?? [],
+      settings: (json['settings'] as List<dynamic>?)
+          ?.map((s) => ExtensionSetting.fromJson(s as Map<String, dynamic>))
+          .toList() ?? [],
+      qualityOptions: (json['quality_options'] as List<dynamic>?)
+          ?.map((q) => QualityOption.fromJson(q as Map<String, dynamic>))
+          .toList() ?? [],
+      hasMetadataProvider: json['has_metadata_provider'] as bool? ?? false,
+      hasDownloadProvider: json['has_download_provider'] as bool? ?? false,
+      skipMetadataEnrichment: json['skip_metadata_enrichment'] as bool? ?? false,
+      searchBehavior: json['search_behavior'] != null 
+          ? SearchBehavior.fromJson(json['search_behavior'] as Map<String, dynamic>)
+          : null,
+      urlHandler: json['url_handler'] != null
+          ? URLHandler.fromJson(json['url_handler'] as Map<String, dynamic>)
+          : null,
+      trackMatching: json['track_matching'] != null
+          ? TrackMatching.fromJson(json['track_matching'] as Map<String, dynamic>)
+          : null,
+      postProcessing: json['post_processing'] != null
+          ? PostProcessing.fromJson(json['post_processing'] as Map<String, dynamic>)
+          : null,
+    );
+  }
+
+  Extension copyWith({
+    String? id,
+    String? name,
+    String? displayName,
+    String? version,
+    String? author,
+    String? description,
+    bool? enabled,
+    String? status,
+    String? errorMessage,
+    String? iconPath,
+    List<String>? permissions,
+    List<ExtensionSetting>? settings,
+    List<QualityOption>? qualityOptions,
+    bool? hasMetadataProvider,
+    bool? hasDownloadProvider,
+    bool? skipMetadataEnrichment,
+    SearchBehavior? searchBehavior,
+    URLHandler? urlHandler,
+    TrackMatching? trackMatching,
+    PostProcessing? postProcessing,
+  }) {
+    return Extension(
+      id: id ?? this.id,
+      name: name ?? this.name,
+      displayName: displayName ?? this.displayName,
+      version: version ?? this.version,
+      author: author ?? this.author,
+      description: description ?? this.description,
+      enabled: enabled ?? this.enabled,
+      status: status ?? this.status,
+      errorMessage: errorMessage ?? this.errorMessage,
+      iconPath: iconPath ?? this.iconPath,
+      permissions: permissions ?? this.permissions,
+      settings: settings ?? this.settings,
+      qualityOptions: qualityOptions ?? this.qualityOptions,
+      hasMetadataProvider: hasMetadataProvider ?? this.hasMetadataProvider,
+      hasDownloadProvider: hasDownloadProvider ?? this.hasDownloadProvider,
+      skipMetadataEnrichment: skipMetadataEnrichment ?? this.skipMetadataEnrichment,
+      searchBehavior: searchBehavior ?? this.searchBehavior,
+      urlHandler: urlHandler ?? this.urlHandler,
+      trackMatching: trackMatching ?? this.trackMatching,
+      postProcessing: postProcessing ?? this.postProcessing,
+    );
+  }
+
+  bool get hasCustomSearch => searchBehavior?.enabled ?? false;
+  bool get hasURLHandler => urlHandler?.enabled ?? false;
+  bool get hasCustomMatching => trackMatching?.customMatching ?? false;
+  bool get hasPostProcessing => postProcessing?.enabled ?? false;
+}
+
+/// Custom search behavior configuration
+class SearchBehavior {
+  final bool enabled;
+  final String? placeholder;
+  final bool primary;
+  final String? icon;
+  final String? thumbnailRatio; // "square" (1:1), "wide" (16:9), "portrait" (2:3)
+  final int? thumbnailWidth;
+  final int? thumbnailHeight;
+
+  const SearchBehavior({
+    required this.enabled,
+    this.placeholder,
+    this.primary = false,
+    this.icon,
+    this.thumbnailRatio,
+    this.thumbnailWidth,
+    this.thumbnailHeight,
+  });
+
+  factory SearchBehavior.fromJson(Map<String, dynamic> json) {
+    return SearchBehavior(
+      enabled: json['enabled'] as bool? ?? false,
+      placeholder: json['placeholder'] as String?,
+      primary: json['primary'] as bool? ?? false,
+      icon: json['icon'] as String?,
+      thumbnailRatio: json['thumbnailRatio'] as String?,
+      thumbnailWidth: json['thumbnailWidth'] as int?,
+      thumbnailHeight: json['thumbnailHeight'] as int?,
+    );
+  }
+
+  /// Get thumbnail size based on configuration
+  /// Returns (width, height) tuple
+  (double, double) getThumbnailSize({double defaultSize = 56}) {
+    if (thumbnailWidth != null && thumbnailHeight != null) {
+      return (thumbnailWidth!.toDouble(), thumbnailHeight!.toDouble());
+    }
+    
+    switch (thumbnailRatio) {
+      case 'wide': // 16:9 - YouTube style
+        return (defaultSize * 16 / 9, defaultSize);
+      case 'portrait': // 2:3 - Poster style
+        return (defaultSize * 2 / 3, defaultSize);
+      case 'square': // 1:1 - Album art style
+      default:
+        return (defaultSize, defaultSize);
+    }
+  }
+}
+
+/// Custom track matching configuration
+class TrackMatching {
+  final bool customMatching;
+  final String? strategy; // "isrc", "name", "duration", "custom"
+  final int durationTolerance; // in seconds
+
+  const TrackMatching({
+    required this.customMatching,
+    this.strategy,
+    this.durationTolerance = 3,
+  });
+
+  factory TrackMatching.fromJson(Map<String, dynamic> json) {
+    return TrackMatching(
+      customMatching: json['customMatching'] as bool? ?? false,
+      strategy: json['strategy'] as String?,
+      durationTolerance: json['durationTolerance'] as int? ?? 3,
+    );
+  }
+}
+
+/// Post-processing configuration
+class PostProcessing {
+  final bool enabled;
+  final List<PostProcessingHook> hooks;
+
+  const PostProcessing({
+    required this.enabled,
+    this.hooks = const [],
+  });
+
+  factory PostProcessing.fromJson(Map<String, dynamic> json) {
+    return PostProcessing(
+      enabled: json['enabled'] as bool? ?? false,
+      hooks: (json['hooks'] as List<dynamic>?)
+          ?.map((h) => PostProcessingHook.fromJson(h as Map<String, dynamic>))
+          .toList() ?? [],
+    );
+  }
+}
+
+/// URL handler configuration for custom URL patterns
+class URLHandler {
+  final bool enabled;
+  final List<String> patterns;
+
+  const URLHandler({
+    required this.enabled,
+    this.patterns = const [],
+  });
+
+  factory URLHandler.fromJson(Map<String, dynamic> json) {
+    return URLHandler(
+      enabled: json['enabled'] as bool? ?? false,
+      patterns: (json['patterns'] as List<dynamic>?)?.cast<String>() ?? [],
+    );
+  }
+
+  /// Check if a URL matches any of the patterns
+  bool matchesURL(String url) {
+    if (!enabled || patterns.isEmpty) return false;
+    final lowerUrl = url.toLowerCase();
+    for (final pattern in patterns) {
+      if (lowerUrl.contains(pattern.toLowerCase())) {
+        return true;
+      }
+    }
+    return false;
+  }
+}
+
+/// A post-processing hook
+class PostProcessingHook {
+  final String id;
+  final String name;
+  final String? description;
+  final bool defaultEnabled;
+  final List<String> supportedFormats;
+
+  const PostProcessingHook({
+    required this.id,
+    required this.name,
+    this.description,
+    this.defaultEnabled = false,
+    this.supportedFormats = const [],
+  });
+
+  factory PostProcessingHook.fromJson(Map<String, dynamic> json) {
+    return PostProcessingHook(
+      id: json['id'] as String? ?? '',
+      name: json['name'] as String? ?? '',
+      description: json['description'] as String?,
+      defaultEnabled: json['defaultEnabled'] as bool? ?? false,
+      supportedFormats: (json['supportedFormats'] as List<dynamic>?)?.cast<String>() ?? [],
+    );
+  }
+}
+
+/// Represents a quality option for download providers
+class QualityOption {
+  final String id;
+  final String label;
+  final String? description;
+  final List<QualitySpecificSetting> settings; // Quality-specific settings
+
+  const QualityOption({
+    required this.id,
+    required this.label,
+    this.description,
+    this.settings = const [],
+  });
+
+  factory QualityOption.fromJson(Map<String, dynamic> json) {
+    return QualityOption(
+      id: json['id'] as String? ?? '',
+      label: json['label'] as String? ?? '',
+      description: json['description'] as String?,
+      settings: (json['settings'] as List<dynamic>?)
+          ?.map((s) => QualitySpecificSetting.fromJson(s as Map<String, dynamic>))
+          .toList() ?? [],
+    );
+  }
+}
+
+/// Represents a setting that's specific to a quality option
+class QualitySpecificSetting {
+  final String key;
+  final String label;
+  final String type; // 'string', 'number', 'boolean', 'select'
+  final dynamic defaultValue;
+  final String? description;
+  final List<String>? options; // For select type
+  final bool required;
+  final bool secret;
+
+  const QualitySpecificSetting({
+    required this.key,
+    required this.label,
+    required this.type,
+    this.defaultValue,
+    this.description,
+    this.options,
+    this.required = false,
+    this.secret = false,
+  });
+
+  factory QualitySpecificSetting.fromJson(Map<String, dynamic> json) {
+    return QualitySpecificSetting(
+      key: json['key'] as String? ?? '',
+      label: json['label'] as String? ?? '',
+      type: json['type'] as String? ?? 'string',
+      defaultValue: json['default'],
+      description: json['description'] as String?,
+      options: (json['options'] as List<dynamic>?)?.cast<String>(),
+      required: json['required'] as bool? ?? false,
+      secret: json['secret'] as bool? ?? false,
+    );
+  }
+}
+
+/// Represents a setting field for an extension
+class ExtensionSetting {
+  final String key;
+  final String label;
+  final String type; // 'string', 'number', 'boolean', 'select'
+  final dynamic defaultValue;
+  final String? description;
+  final List<String>? options; // For select type
+  final bool required;
+
+  const ExtensionSetting({
+    required this.key,
+    required this.label,
+    required this.type,
+    this.defaultValue,
+    this.description,
+    this.options,
+    this.required = false,
+  });
+
+  factory ExtensionSetting.fromJson(Map<String, dynamic> json) {
+    return ExtensionSetting(
+      key: json['key'] as String? ?? '',
+      label: json['label'] as String? ?? '',
+      type: json['type'] as String? ?? 'string',
+      defaultValue: json['default'],
+      description: json['description'] as String?,
+      options: (json['options'] as List<dynamic>?)?.cast<String>(),
+      required: json['required'] as bool? ?? false,
+    );
+  }
+}
+
+/// State for extension management
+class ExtensionState {
+  final List<Extension> extensions;
+  final List<String> providerPriority;
+  final List<String> metadataProviderPriority;
+  final bool isLoading;
+  final String? error;
+  final bool isInitialized;
+
+  const ExtensionState({
+    this.extensions = const [],
+    this.providerPriority = const [],
+    this.metadataProviderPriority = const [],
+    this.isLoading = false,
+    this.error,
+    this.isInitialized = false,
+  });
+
+  ExtensionState copyWith({
+    List<Extension>? extensions,
+    List<String>? providerPriority,
+    List<String>? metadataProviderPriority,
+    bool? isLoading,
+    String? error,
+    bool? isInitialized,
+  }) {
+    return ExtensionState(
+      extensions: extensions ?? this.extensions,
+      providerPriority: providerPriority ?? this.providerPriority,
+      metadataProviderPriority: metadataProviderPriority ?? this.metadataProviderPriority,
+      isLoading: isLoading ?? this.isLoading,
+      error: error,
+      isInitialized: isInitialized ?? this.isInitialized,
+    );
+  }
+}
+
+
+/// Provider for managing extensions
+class ExtensionNotifier extends Notifier<ExtensionState> {
+  @override
+  ExtensionState build() {
+    return const ExtensionState();
+  }
+
+  /// Initialize the extension system
+  Future<void> initialize(String extensionsDir, String dataDir) async {
+    if (state.isInitialized) return;
+    
+    state = state.copyWith(isLoading: true, error: null);
+    
+    try {
+      await PlatformBridge.initExtensionSystem(extensionsDir, dataDir);
+      await loadExtensions(extensionsDir);
+      await loadProviderPriority();
+      await loadMetadataProviderPriority();
+      state = state.copyWith(isInitialized: true, isLoading: false);
+      _log.i('Extension system initialized');
+    } catch (e) {
+      _log.e('Failed to initialize extension system: $e');
+      state = state.copyWith(isLoading: false, error: e.toString());
+    }
+  }
+
+  /// Load all extensions from directory
+  Future<void> loadExtensions(String dirPath) async {
+    state = state.copyWith(isLoading: true, error: null);
+    
+    try {
+      final result = await PlatformBridge.loadExtensionsFromDir(dirPath);
+      _log.d('Load extensions result: $result');
+      await refreshExtensions();
+      state = state.copyWith(isLoading: false);
+    } catch (e) {
+      _log.e('Failed to load extensions: $e');
+      state = state.copyWith(isLoading: false, error: e.toString());
+    }
+  }
+
+  /// Refresh the list of installed extensions
+  Future<void> refreshExtensions() async {
+    try {
+      final list = await PlatformBridge.getInstalledExtensions();
+      final extensions = list.map((e) => Extension.fromJson(e)).toList();
+      state = state.copyWith(extensions: extensions);
+      _log.d('Loaded ${extensions.length} extensions');
+      
+      // Log search behavior for extensions that have it
+      for (final ext in extensions) {
+        if (ext.searchBehavior != null) {
+          _log.d('Extension ${ext.id}: thumbnailRatio=${ext.searchBehavior!.thumbnailRatio}');
+        }
+      }
+    } catch (e) {
+      _log.e('Failed to refresh extensions: $e');
+      state = state.copyWith(error: e.toString());
+    }
+  }
+
+  /// Clear any error state
+  void clearError() {
+    state = state.copyWith(error: null);
+  }
+
+  /// Install extension from file (auto-upgrades if already installed with newer version)
+  Future<bool> installExtension(String filePath) async {
+    state = state.copyWith(isLoading: true, error: null);
+    
+    try {
+      final result = await PlatformBridge.loadExtensionFromPath(filePath);
+      _log.i('Installed extension: ${result['name']}');
+      await refreshExtensions();
+      state = state.copyWith(isLoading: false);
+      return true;
+    } catch (e) {
+      _log.e('Failed to install extension: $e');
+      state = state.copyWith(isLoading: false, error: e.toString());
+      return false;
+    }
+  }
+
+  /// Check if a package file is an upgrade for an existing extension
+  /// Returns: {extension_id, current_version, new_version, can_upgrade, is_installed}
+  Future<Map<String, dynamic>> checkExtensionUpgrade(String filePath) async {
+    try {
+      return await PlatformBridge.checkExtensionUpgrade(filePath);
+    } catch (e) {
+      _log.e('Failed to check extension upgrade: $e');
+      return {'error': e.toString()};
+    }
+  }
+
+  /// Upgrade an existing extension from a new package file
+  Future<bool> upgradeExtension(String filePath) async {
+    state = state.copyWith(isLoading: true, error: null);
+    
+    try {
+      final result = await PlatformBridge.upgradeExtension(filePath);
+      _log.i('Upgraded extension: ${result['display_name']} to v${result['version']}');
+      await refreshExtensions();
+      state = state.copyWith(isLoading: false);
+      return true;
+    } catch (e) {
+      _log.e('Failed to upgrade extension: $e');
+      state = state.copyWith(isLoading: false, error: e.toString());
+      return false;
+    }
+  }
+
+  /// Uninstall/remove an extension
+  Future<bool> removeExtension(String extensionId) async {
+    state = state.copyWith(isLoading: true, error: null);
+    
+    try {
+      await PlatformBridge.removeExtension(extensionId);
+      _log.i('Removed extension: $extensionId');
+      await refreshExtensions();
+      state = state.copyWith(isLoading: false);
+      return true;
+    } catch (e) {
+      _log.e('Failed to remove extension: $e');
+      state = state.copyWith(isLoading: false, error: e.toString());
+      return false;
+    }
+  }
+
+  /// Enable or disable an extension
+  Future<void> setExtensionEnabled(String extensionId, bool enabled) async {
+    try {
+      await PlatformBridge.setExtensionEnabled(extensionId, enabled);
+      _log.d('Set extension $extensionId enabled: $enabled');
+      
+      final ext = state.extensions.where((e) => e.id == extensionId).firstOrNull;
+      
+      final extensions = state.extensions.map((e) {
+        if (e.id == extensionId) {
+          return e.copyWith(enabled: enabled);
+        }
+        return e;
+      }).toList();
+      
+      state = state.copyWith(extensions: extensions);
+      
+      if (!enabled && ext != null) {
+        final settings = ref.read(settingsProvider);
+        
+        if (settings.searchProvider == extensionId) {
+          ref.read(settingsProvider.notifier).setSearchProvider(null);
+          ref.read(settingsProvider.notifier).setMetadataSource('deezer');
+          _log.d('Cleared search provider and reset to Deezer because extension $extensionId was disabled');
+        }
+        
+        if (ext.hasDownloadProvider && settings.defaultService == extensionId) {
+          ref.read(settingsProvider.notifier).setDefaultService('tidal');
+          _log.d('Reset default service to Tidal because extension $extensionId was disabled');
+        }
+      }
+    } catch (e) {
+      _log.e('Failed to set extension enabled: $e');
+      state = state.copyWith(error: e.toString());
+    }
+  }
+
+  /// Get settings for an extension
+  Future<Map<String, dynamic>> getExtensionSettings(String extensionId) async {
+    try {
+      return await PlatformBridge.getExtensionSettings(extensionId);
+    } catch (e) {
+      _log.e('Failed to get extension settings: $e');
+      return {};
+    }
+  }
+
+  /// Update settings for an extension
+  Future<void> setExtensionSettings(String extensionId, Map<String, dynamic> settings) async {
+    try {
+      await PlatformBridge.setExtensionSettings(extensionId, settings);
+      _log.d('Updated settings for extension: $extensionId');
+    } catch (e) {
+      _log.e('Failed to set extension settings: $e');
+      state = state.copyWith(error: e.toString());
+    }
+  }
+
+  /// Load provider priority order
+  Future<void> loadProviderPriority() async {
+    try {
+      final priority = await PlatformBridge.getProviderPriority();
+      state = state.copyWith(providerPriority: priority);
+    } catch (e) {
+      _log.e('Failed to load provider priority: $e');
+    }
+  }
+
+  /// Set provider priority order
+  Future<void> setProviderPriority(List<String> priority) async {
+    try {
+      await PlatformBridge.setProviderPriority(priority);
+      state = state.copyWith(providerPriority: priority);
+      _log.d('Updated provider priority: $priority');
+    } catch (e) {
+      _log.e('Failed to set provider priority: $e');
+      state = state.copyWith(error: e.toString());
+    }
+  }
+
+  /// Load metadata provider priority order
+  Future<void> loadMetadataProviderPriority() async {
+    try {
+      final priority = await PlatformBridge.getMetadataProviderPriority();
+      state = state.copyWith(metadataProviderPriority: priority);
+    } catch (e) {
+      _log.e('Failed to load metadata provider priority: $e');
+    }
+  }
+
+  /// Set metadata provider priority order
+  Future<void> setMetadataProviderPriority(List<String> priority) async {
+    try {
+      await PlatformBridge.setMetadataProviderPriority(priority);
+      state = state.copyWith(metadataProviderPriority: priority);
+      _log.d('Updated metadata provider priority: $priority');
+    } catch (e) {
+      _log.e('Failed to set metadata provider priority: $e');
+      state = state.copyWith(error: e.toString());
+    }
+  }
+
+  /// Cleanup all extensions (call on app close)
+  Future<void> cleanup() async {
+    try {
+      await PlatformBridge.cleanupExtensions();
+      _log.d('Extensions cleaned up');
+    } catch (e) {
+      _log.e('Failed to cleanup extensions: $e');
+    }
+  }
+
+  /// Get extension by ID
+  Extension? getExtension(String extensionId) {
+    try {
+      return state.extensions.firstWhere((ext) => ext.id == extensionId);
+    } catch (_) {
+      return null;
+    }
+  }
+
+  /// Get all enabled extensions
+  List<Extension> get enabledExtensions {
+    return state.extensions.where((ext) => ext.enabled).toList();
+  }
+
+  /// Get all download providers (built-in + extensions)
+  List<String> getAllDownloadProviders() {
+    final providers = ['tidal', 'qobuz', 'amazon'];
+    for (final ext in state.extensions) {
+      if (ext.enabled && ext.hasDownloadProvider) {
+        providers.add(ext.id);
+      }
+    }
+    return providers;
+  }
+
+  /// Get all metadata providers (built-in + extensions)
+  List<String> getAllMetadataProviders() {
+    final providers = ['deezer', 'spotify'];
+    for (final ext in state.extensions) {
+      if (ext.enabled && ext.hasMetadataProvider) {
+        providers.add(ext.id);
+      }
+    }
+    return providers;
+  }
+  /// Get all extensions that provide custom search
+  List<Extension> get searchProviders {
+    return state.extensions.where((ext) => ext.enabled && ext.hasCustomSearch).toList();
+  }
+}
+
+final extensionProvider = NotifierProvider<ExtensionNotifier, ExtensionState>(
+  ExtensionNotifier.new,
+);

lib/providers/recent_access_provider.dart

@@ -0,0 +1,242 @@
+import 'dart:convert';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:shared_preferences/shared_preferences.dart';
+
+const _recentAccessKey = 'recent_access_history';
+const _maxRecentItems = 20;
+
+/// Types of items that can be accessed
+enum RecentAccessType {
+  artist,
+  album,
+  track,
+  playlist,
+}
+
+/// Represents a recently accessed item
+class RecentAccessItem {
+  final String id;
+  final String name;
+  final String? subtitle; // Artist name for tracks/albums, null for artists
+  final String? imageUrl;
+  final RecentAccessType type;
+  final DateTime accessedAt;
+  final String? providerId; // Extension ID or 'deezer' for built-in
+
+  const RecentAccessItem({
+    required this.id,
+    required this.name,
+    this.subtitle,
+    this.imageUrl,
+    required this.type,
+    required this.accessedAt,
+    this.providerId,
+  });
+
+  Map<String, dynamic> toJson() => {
+    'id': id,
+    'name': name,
+    'subtitle': subtitle,
+    'imageUrl': imageUrl,
+    'type': type.name,
+    'accessedAt': accessedAt.toIso8601String(),
+    'providerId': providerId,
+  };
+
+  factory RecentAccessItem.fromJson(Map<String, dynamic> json) {
+    return RecentAccessItem(
+      id: json['id'] as String,
+      name: json['name'] as String,
+      subtitle: json['subtitle'] as String?,
+      imageUrl: json['imageUrl'] as String?,
+      type: RecentAccessType.values.firstWhere(
+        (e) => e.name == json['type'],
+        orElse: () => RecentAccessType.track,
+      ),
+      accessedAt: DateTime.parse(json['accessedAt'] as String),
+      providerId: json['providerId'] as String?,
+    );
+  }
+
+  /// Create a unique key for deduplication
+  String get uniqueKey => '${type.name}:${providerId ?? 'default'}:$id';
+
+  @override
+  bool operator ==(Object other) =>
+      identical(this, other) ||
+      other is RecentAccessItem &&
+          runtimeType == other.runtimeType &&
+          uniqueKey == other.uniqueKey;
+
+  @override
+  int get hashCode => uniqueKey.hashCode;
+}
+
+/// State for recent access history
+class RecentAccessState {
+  final List<RecentAccessItem> items;
+  final bool isLoaded;
+
+  const RecentAccessState({
+    this.items = const [],
+    this.isLoaded = false,
+  });
+
+  RecentAccessState copyWith({
+    List<RecentAccessItem>? items,
+    bool? isLoaded,
+  }) {
+    return RecentAccessState(
+      items: items ?? this.items,
+      isLoaded: isLoaded ?? this.isLoaded,
+    );
+  }
+}
+
+/// Provider for managing recent access history
+class RecentAccessNotifier extends Notifier<RecentAccessState> {
+  @override
+  RecentAccessState build() {
+    _loadHistory();
+    return const RecentAccessState();
+  }
+
+  Future<void> _loadHistory() async {
+    final prefs = await SharedPreferences.getInstance();
+    final json = prefs.getString(_recentAccessKey);
+    if (json != null) {
+      try {
+        final List<dynamic> decoded = jsonDecode(json);
+        final items = decoded
+            .map((e) => RecentAccessItem.fromJson(e as Map<String, dynamic>))
+            .toList();
+        state = state.copyWith(items: items, isLoaded: true);
+      } catch (e) {
+        state = state.copyWith(isLoaded: true);
+      }
+    } else {
+      state = state.copyWith(isLoaded: true);
+    }
+  }
+
+  Future<void> _saveHistory() async {
+    final prefs = await SharedPreferences.getInstance();
+    final json = jsonEncode(state.items.map((e) => e.toJson()).toList());
+    await prefs.setString(_recentAccessKey, json);
+  }
+
+  /// Record an access to an artist
+  void recordArtistAccess({
+    required String id,
+    required String name,
+    String? imageUrl,
+    String? providerId,
+  }) {
+    _recordAccess(RecentAccessItem(
+      id: id,
+      name: name,
+      imageUrl: imageUrl,
+      type: RecentAccessType.artist,
+      accessedAt: DateTime.now(),
+      providerId: providerId,
+    ));
+  }
+
+  /// Record an access to an album
+  void recordAlbumAccess({
+    required String id,
+    required String name,
+    String? artistName,
+    String? imageUrl,
+    String? providerId,
+  }) {
+    _recordAccess(RecentAccessItem(
+      id: id,
+      name: name,
+      subtitle: artistName,
+      imageUrl: imageUrl,
+      type: RecentAccessType.album,
+      accessedAt: DateTime.now(),
+      providerId: providerId,
+    ));
+  }
+
+  /// Record an access to a track
+  void recordTrackAccess({
+    required String id,
+    required String name,
+    String? artistName,
+    String? imageUrl,
+    String? providerId,
+  }) {
+    _recordAccess(RecentAccessItem(
+      id: id,
+      name: name,
+      subtitle: artistName,
+      imageUrl: imageUrl,
+      type: RecentAccessType.track,
+      accessedAt: DateTime.now(),
+      providerId: providerId,
+    ));
+  }
+
+  /// Record an access to a playlist
+  void recordPlaylistAccess({
+    required String id,
+    required String name,
+    String? ownerName,
+    String? imageUrl,
+    String? providerId,
+  }) {
+    _recordAccess(RecentAccessItem(
+      id: id,
+      name: name,
+      subtitle: ownerName,
+      imageUrl: imageUrl,
+      type: RecentAccessType.playlist,
+      accessedAt: DateTime.now(),
+      providerId: providerId,
+    ));
+  }
+
+  void _recordAccess(RecentAccessItem item) {
+    // ignore: avoid_print
+    print('[RecentAccess] Recording: ${item.type.name} - ${item.name} (${item.id})');
+    
+    final updatedItems = state.items
+        .where((e) => e.uniqueKey != item.uniqueKey)
+        .toList();
+    
+    updatedItems.insert(0, item);
+    
+    if (updatedItems.length > _maxRecentItems) {
+      updatedItems.removeRange(_maxRecentItems, updatedItems.length);
+    }
+    
+    state = state.copyWith(items: updatedItems);
+    _saveHistory();
+    
+    // ignore: avoid_print
+    print('[RecentAccess] Total items now: ${updatedItems.length}');
+  }
+
+  /// Remove a specific item from history
+  void removeItem(RecentAccessItem item) {
+    final updatedItems = state.items
+        .where((e) => e.uniqueKey != item.uniqueKey)
+        .toList();
+    state = state.copyWith(items: updatedItems);
+    _saveHistory();
+  }
+
+  /// Clear all history
+  void clearHistory() {
+    state = state.copyWith(items: []);
+    _saveHistory();
+  }
+}
+
+/// Provider instance
+final recentAccessProvider = NotifierProvider<RecentAccessNotifier, RecentAccessState>(
+  RecentAccessNotifier.new,
+);

lib/providers/settings_provider.dart

@@ -3,6 +3,7 @@ import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:shared_preferences/shared_preferences.dart';
 import 'package:spotiflac_android/models/settings.dart';
 import 'package:spotiflac_android/services/platform_bridge.dart';
+import 'package:spotiflac_android/utils/logger.dart';
 
 const _settingsKey = 'app_settings';
 const _migrationVersionKey = 'settings_migration_version';
@@ -21,11 +22,11 @@ class SettingsNotifier extends Notifier<AppSettings> {
     if (json != null) {
       state = AppSettings.fromJson(jsonDecode(json));
       
-      // Run migrations if needed
       await _runMigrations(prefs);
       
-      // Apply Spotify credentials to Go backend on load
       _applySpotifyCredentials();
+      
+      LogBuffer.loggingEnabled = state.enableLogging;
     }
   }
 
@@ -34,16 +35,12 @@ class SettingsNotifier extends Notifier<AppSettings> {
     final lastMigration = prefs.getInt(_migrationVersionKey) ?? 0;
     
     if (lastMigration < 1) {
-      // Migration 1: Set metadataSource to 'deezer' for existing users
-      // Only apply if user hasn't enabled custom Spotify credentials
-      // (users with custom credentials likely prefer Spotify)
       if (!state.useCustomSpotifyCredentials) {
         state = state.copyWith(metadataSource: 'deezer');
         await _saveSettings();
       }
     }
     
-    // Save current migration version
     if (lastMigration < _currentMigrationVersion) {
       await prefs.setInt(_migrationVersionKey, _currentMigrationVersion);
     }
@@ -56,17 +53,12 @@ class SettingsNotifier extends Notifier<AppSettings> {
 
   /// Apply current Spotify credentials to Go backend
   Future<void> _applySpotifyCredentials() async {
-    // Only apply custom credentials if enabled and both fields are set
-    if (state.useCustomSpotifyCredentials && 
-        state.spotifyClientId.isNotEmpty && 
+    if (state.spotifyClientId.isNotEmpty && 
         state.spotifyClientSecret.isNotEmpty) {
       await PlatformBridge.setSpotifyCredentials(
         state.spotifyClientId,
         state.spotifyClientSecret,
       );
-    } else {
-      // Clear to use default
-      await PlatformBridge.setSpotifyCredentials('', '');
     }
   }
 
@@ -111,7 +103,6 @@ class SettingsNotifier extends Notifier<AppSettings> {
   }
 
   void setConcurrentDownloads(int count) {
-    // Clamp between 1 and 3
     final clamped = count.clamp(1, 3);
     state = state.copyWith(concurrentDownloads: clamped);
     _saveSettings();
@@ -144,6 +135,11 @@ class SettingsNotifier extends Notifier<AppSettings> {
     _saveSettings();
   }
 
+  void setHistoryFilterMode(String mode) {
+    state = state.copyWith(historyFilterMode: mode);
+    _saveSettings();
+  }
+
   void setAskQualityBeforeDownload(bool enabled) {
     state = state.copyWith(askQualityBeforeDownload: enabled);
     _saveSettings();
@@ -187,6 +183,46 @@ class SettingsNotifier extends Notifier<AppSettings> {
     state = state.copyWith(metadataSource: source);
     _saveSettings();
   }
+
+  void setSearchProvider(String? provider) {
+    if (provider == null || provider.isEmpty) {
+      state = state.copyWith(clearSearchProvider: true);
+    } else {
+      state = state.copyWith(searchProvider: provider);
+    }
+    _saveSettings();
+  }
+
+  void setEnableLogging(bool enabled) {
+    state = state.copyWith(enableLogging: enabled);
+    _saveSettings();
+    LogBuffer.loggingEnabled = enabled;
+  }
+
+  void setUseExtensionProviders(bool enabled) {
+    state = state.copyWith(useExtensionProviders: enabled);
+    _saveSettings();
+  }
+
+  void setSeparateSingles(bool enabled) {
+    state = state.copyWith(separateSingles: enabled);
+    _saveSettings();
+  }
+
+  void setAlbumFolderStructure(String structure) {
+    state = state.copyWith(albumFolderStructure: structure);
+    _saveSettings();
+  }
+
+  void setShowExtensionStore(bool enabled) {
+    state = state.copyWith(showExtensionStore: enabled);
+    _saveSettings();
+  }
+
+  void setLocale(String locale) {
+    state = state.copyWith(locale: locale);
+    _saveSettings();
+  }
 }
 
 final settingsProvider = NotifierProvider<SettingsNotifier, AppSettings>(