chore: bump version to 3.0.0-alpha.4

- Add utils.hmacSHA1(key, message) for extensions
- Add artist type handling in track_provider for extension URL results
- Fix extension store not refreshing after uninstall
- Update CHANGELOG with new features and Spotify Web extension

.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

@@ -3,13 +3,13 @@ name: Release
 on:
   push:
     tags:
-      - 'v*'
+      - "v*"
   workflow_dispatch:
     inputs:
       version:
-        description: 'Version tag (e.g., v1.0.0)'
+        description: "Version tag (e.g., v1.0.0)"
         required: true
-        default: 'v1.0.0'
+        default: "v1.0.0"
 
 jobs:
   # Get version first (quick job)
@@ -28,7 +28,7 @@ jobs:
             VERSION="${GITHUB_REF#refs/tags/}"
           fi
           echo "version=$VERSION" >> $GITHUB_OUTPUT
-          
+
           # Check if version contains -preview, -beta, -rc, or -alpha (NOT -hotfix)
           VERSION_LOWER=$(echo "$VERSION" | tr '[:upper:]' '[:lower:]')
           if [[ "$VERSION_LOWER" == *"-preview"* ]] || [[ "$VERSION_LOWER" == *"-beta"* ]] || [[ "$VERSION_LOWER" == *"-rc"* ]] || [[ "$VERSION_LOWER" == *"-alpha"* ]]; then
@@ -43,7 +43,7 @@ jobs:
   build-android:
     runs-on: ubuntu-latest
     needs: get-version
-    
+
     steps:
       - name: Free disk space
         run: |
@@ -65,13 +65,13 @@ jobs:
       - name: Setup Java
         uses: actions/setup-java@v4
         with:
-          distribution: 'temurin'
-          java-version: '17'
+          distribution: "temurin"
+          java-version: "17"
 
       - name: Setup Go
         uses: actions/setup-go@v5
         with:
-          go-version: '1.21'
+          go-version: "1.21"
           cache-dependency-path: go_backend/go.sum
 
       # Cache Gradle for faster builds
@@ -89,15 +89,16 @@ jobs:
           # Use pre-installed Android SDK on GitHub runners
           echo "ANDROID_HOME=$ANDROID_HOME"
           echo "ANDROID_SDK_ROOT=$ANDROID_SDK_ROOT"
-          
+
           # 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: |
@@ -115,7 +116,7 @@ jobs:
       - name: Setup Flutter
         uses: subosito/flutter-action@v2
         with:
-          channel: 'stable'
+          channel: "stable"
           cache: true
 
       - name: Get Flutter dependencies
@@ -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: |
@@ -164,8 +165,8 @@ jobs:
 
   build-ios:
     runs-on: macos-latest
-    needs: get-version  # Only depends on version, NOT android build!
-    
+    needs: get-version # Only depends on version, NOT android build!
+
     steps:
       - name: Checkout repository
         uses: actions/checkout@v4
@@ -173,7 +174,7 @@ jobs:
       - name: Setup Go
         uses: actions/setup-go@v5
         with:
-          go-version: '1.21'
+          go-version: "1.21"
           cache-dependency-path: go_backend/go.sum
 
       # Cache CocoaPods
@@ -201,51 +202,51 @@ jobs:
         run: |
           ls -la ios/Frameworks/
           ls -la ios/Frameworks/Gobackend.xcframework/ || (echo "ERROR: XCFramework not found!" && exit 1)
-          
+
       - name: Add XCFramework to Xcode project
         run: |
           # Install xcodeproj gem for modifying Xcode project
           sudo gem install xcodeproj
-          
+
           # Create Ruby script to add framework
           cat > add_framework.rb << 'EOF'
           require 'xcodeproj'
-          
+
           project_path = 'ios/Runner.xcodeproj'
           project = Xcodeproj::Project.open(project_path)
-          
+
           # Get the main target
           target = project.targets.find { |t| t.name == 'Runner' }
-          
+
           # Get or create Frameworks group
           frameworks_group = project.main_group.find_subpath('Frameworks', true)
           frameworks_group ||= project.main_group.new_group('Frameworks')
-          
+
           # Add XCFramework reference
           framework_path = 'Frameworks/Gobackend.xcframework'
           framework_ref = frameworks_group.new_file(framework_path, :project)
-          
+
           # Add to frameworks build phase
           frameworks_build_phase = target.frameworks_build_phase
           frameworks_build_phase.add_file_reference(framework_ref)
-          
+
           # Add to embed frameworks build phase
           embed_phase = target.build_phases.find { |p| p.is_a?(Xcodeproj::Project::Object::PBXCopyFilesBuildPhase) && p.name == 'Embed Frameworks' }
           if embed_phase
             build_file = embed_phase.add_file_reference(framework_ref)
             build_file.settings = { 'ATTRIBUTES' => ['CodeSignOnCopy', 'RemoveHeadersOnCopy'] }
           end
-          
+
           project.save
           puts "Successfully added Gobackend.xcframework to Xcode project"
           EOF
-          
+
           ruby add_framework.rb
 
       - name: Setup Flutter
         uses: subosito/flutter-action@v2
         with:
-          channel: 'stable'
+          channel: "stable"
           cache: true
 
       # Swap pubspec for iOS build (includes ffmpeg_kit_flutter)
@@ -275,7 +276,7 @@ jobs:
         run: |
           # Build Flutter iOS without codesigning
           flutter build ios --release --no-codesign --config-only
-          
+
           # Use xcodebuild with code signing disabled
           cd ios
           xcodebuild -workspace Runner.xcworkspace \
@@ -300,7 +301,7 @@ jobs:
           # Use absolute path to avoid relative path issues
           zip -r $GITHUB_WORKSPACE/build/ios/ipa/SpotiFLAC-${VERSION}-ios-unsigned.ipa Payload
           rm -rf Payload
-          
+
       - name: Verify IPA created
         run: |
           ls -la build/ios/ipa/
@@ -321,7 +322,7 @@ jobs:
     needs: [get-version, build-android, build-ios]
     permissions:
       contents: write
-    
+
     steps:
       - name: Checkout repository
         uses: actions/checkout@v4
@@ -331,13 +332,13 @@ jobs:
         run: |
           VERSION=${{ needs.get-version.outputs.version }}
           VERSION_NUM=${VERSION#v}  # Remove 'v' prefix
-          
+
           echo "Looking for version: $VERSION_NUM"
-          
+
           # Extract changelog section for this version using sed
           # Find the line with version, then print until next version header or end
           CHANGELOG=$(sed -n "/^## \[$VERSION_NUM\]/,/^## \[/{ /^## \[$VERSION_NUM\]/d; /^## \[/d; p; }" CHANGELOG.md)
-          
+
           # If no changelog found, use default message
           if [ -z "$CHANGELOG" ]; then
             echo "No changelog found for version $VERSION_NUM"
@@ -345,7 +346,7 @@ jobs:
           else
             echo "Found changelog content"
           fi
-          
+
           # Save to file for multiline support
           echo "$CHANGELOG" > /tmp/changelog.txt
           echo "Extracted changelog:"
@@ -367,32 +368,34 @@ jobs:
         run: |
           VERSION=${{ needs.get-version.outputs.version }}
           cat > /tmp/release_body.txt << 'HEADER'
-          ## SpotiFLAC $VERSION
-          
-          Download Spotify tracks in FLAC quality from Tidal, Qobuz & Amazon Music.
-          
           ### What's New
           HEADER
-          
-          # Replace $VERSION in header
-          sed -i "s/\$VERSION/$VERSION/g" /tmp/release_body.txt
-          
+
           cat /tmp/changelog.txt >> /tmp/release_body.txt
+
+          REPO_OWNER="${{ github.repository_owner }}"
+          REPO_NAME="${{ github.event.repository.name }}"
           
           cat >> /tmp/release_body.txt << FOOTER
-          
+
           ---
-          
+
           ### Downloads
-          - **Android (arm64)**: \`SpotiFLAC-${VERSION}-arm64.apk\` (recommended)
-          - **Android (arm32)**: \`SpotiFLAC-${VERSION}-arm32.apk\` (older devices)
+
+          #### Android
+          - **arm64**: \`SpotiFLAC-${VERSION}-arm64.apk\` (recommended for modern devices)
+          - **arm32**: \`SpotiFLAC-${VERSION}-arm32.apk\` (older devices)
+
+          #### iOS
           - **iOS**: \`SpotiFLAC-${VERSION}-ios-unsigned.ipa\` (sideload required)
-          
+
           ### Installation
           **Android**: Enable "Install from unknown sources" and install the APK
           **iOS**: Use AltStore, Sideloadly, or similar tools to sideload the IPA
+
+          ![arm64](https://img.shields.io/github/downloads/${REPO_OWNER}/${REPO_NAME}/${VERSION}/SpotiFLAC-${VERSION}-arm64.apk?style=flat-square&logo=android&label=arm64&color=3DDC84) ![arm32](https://img.shields.io/github/downloads/${REPO_OWNER}/${REPO_NAME}/${VERSION}/SpotiFLAC-${VERSION}-arm32.apk?style=flat-square&logo=android&label=arm32&color=3DDC84) ![iOS](https://img.shields.io/github/downloads/${REPO_OWNER}/${REPO_NAME}/${VERSION}/SpotiFLAC-${VERSION}-ios-unsigned.ipa?style=flat-square&logo=apple&label=iOS&color=0078D6)
           FOOTER
-          
+
           echo "Release body:"
           cat /tmp/release_body.txt
 

.gitignore

@@ -13,6 +13,9 @@ Thumbs.db
 # Reference folder (development only)
 referensi/
 
+# Documentation (development only, published separately)
+docs/
+
 # Old spotiflac_android folder (moved to root)
 spotiflac_android/
 

CHANGELOG.md

@@ -1,5 +1,506 @@
 # Changelog
 
+## [3.0.0-alpha.4] - Upcoming
+
+### 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
+
+- **Spotify Web Extension** (example): New extension for Spotify 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 Spotify/Deezer 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 Spotify 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
+
+### Documentation
+
+- Updated `docs/EXTENSION_DEVELOPMENT.md`:
+  - Added thumbnail ratio customization section
+  - Added extension upgrade documentation
+  - Added settings fields table with `secret` field
+  - Added new troubleshooting entries
+  - Updated table of contents
+  - Updated changelog
+
+---
+
+## [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
+
+- **ISRC Metadata Missing:** Fixed an issue where ISRC codes were not being saved to the download history or embedded in file metadata for certain downloads. The backend now correctly propagates the ISRC found from streaming services (Tidal, Qobuz, Amazon) back to the application.
+- **Tidal Track/Disc Numbers:** Fixed missing Track Number and Disc Number in Tidal downloads. The downloader now prioritizes the actual metadata returned by Tidal over the potentially incomplete metadata from the initial search request.
+- **Concurrent Download Race Condition:** Fixed a potential race condition where temporary cover art files could overwrite each other during rapid concurrent downloads by adding randomization to temporary filenames.
+- **Qobuz Search Accuracy:** Reduced the duration tolerance for Qobuz search matches from 30s to 10s to prevent matching with incorrect versions/remixes.
+- **Metadata Enrichment Null Safety**: Fixed `type 'Null' is not a subtype of type 'String'` error
+  - Added proper null checks when parsing Go backend response
+  - Added type checking for track data before parsing
+- **Duration Calculation in Enrichment**: Fixed duration conversion bug
+  - Go backend returns `duration_ms` (milliseconds)
+  - Now properly converts to seconds for Track model
+
+### Changed
+
+- **Default Service Priority:** Updated the default download fallback order to **Tidal → Qobuz → Amazon**.
+  - Tidal is now the default download service (was Qobuz)
+  - Tidal has faster and more reliable ISRC matching
+  - Existing users need to change setting manually or clear app data
+- **Metadata Enrichment:** Improved metadata handling for Deezer tracks. If critical metadata (ISRC, Track Number) is missing from the initial search, the app now automatically fetches full details from the Deezer API before finding a source.
+
+### Added
+
+- **ISRC in History:** The Download History now reliably displays the ISRC code for downloaded tracks.
+- **Tidal Search Optimization:** Optimized Tidal search logic to immediately check for ISRC matches within search results, improving match speed and accuracy.
+  - Returns as soon as ISRC match is found in first query results
+  - Significantly faster for tracks with valid ISRC
+- **ISRC Enrichment for Search Results**: Tracks from Home search now fetch ISRC before download
+  - Search results don't include ISRC (for performance)
+  - ISRC is now fetched via metadata enrichment when download starts
+  - Ensures accurate track matching on all streaming services
+- **Deezer-to-Tidal Fallback:** Added native support for converting Deezer IDs to Tidal links via SongLink when using the fallback mechanism.
+- **Better Logging for Qobuz ISRC Search**: Added detailed logs for debugging
+  - Shows when ISRC search is attempted
+  - Shows number of results and exact ISRC matches found
+
+### Technical
+
+- Updated `go_backend/tidal.go`:
+  - Early exit optimization in `SearchTrackByMetadataWithISRC()`
+  - Deezer ID support in SongLink lookup
+- Updated `go_backend/qobuz.go`:
+  - Added logging for ISRC search flow
+  - Duration tolerance reduced from 30s to 10s
+- Updated `go_backend/exports.go`:
+  - Default service order changed to `[tidal, qobuz, amazon]`
+- Updated `lib/providers/download_queue_provider.dart`:
+  - ISRC-based enrichment condition
+  - Null-safe parsing of Go backend response
+- Updated `lib/services/platform_bridge.dart`:
+  - Null check for `getDeezerMetadata` result
+- Updated `lib/models/settings.dart`:
+  - Default service changed to `tidal`
+
+---
+
+## [2.1.7] - 2026-01-09
+
+### Added
+
+- **Special Thanks Section**: Added new "Special Thanks" section in About page to credit API creators
+  - **uimaxbai** - Creator of QQDL & HiFi API for Tidal downloads
+  - **sachinsenal0x64** - Original HiFi project creator, foundation of Tidal integration
+  - **DoubleDouble** - Amazing API for Amazon Music downloads
+  - **DAB Music** - The best Qobuz streaming API for Hi-Res downloads
+- **New Contributor**: Added Amonoman to Contributors section as the app logo creator
+
+### Fixed
+
+- **Missing PlatformBridge Import**: Fixed build errors in `home_tab.dart` and `playlist_screen.dart`
+  - Added missing `import 'package:spotiflac_android/services/platform_bridge.dart'`
+- **iOS Method Channel Crash**: Fixed "Method not implemented" crash when searching Deezer from iOS
+  - Implemented missing `searchDeezerAll` handler in `AppDelegate.swift`
+  - Ensures full compatibility with new Deezer integration features on iOS
+
+---
+
 ## [2.1.6] - 2026-01-08
 
 ### Added

README.md

@@ -1,5 +1,5 @@
 [![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/ca16289599f71b8e50d3726a8c64a202ea922a1893bcf21b9eca1a050736f1f5/)
+[![VirusTotal](https://img.shields.io/badge/VirusTotal-Safe-brightgreen?style=for-the-badge&logo=virustotal)](https://www.virustotal.com/gui/file/09c6260e9ebaf2ff0d15f30deda939642f41887f11aad602ac697cb37fa0308c/)
 
 <div align="center">
 
@@ -40,6 +40,31 @@ To use Spotify as your search source without hitting rate limits:
 4. Enter your Client ID and Secret
 5. Change **Search Source** to Spotify
 
+## Extensions (Alpha)
+
+> **Alpha Feature**: Extensions are now available in alpha. Some features may be unstable or change in future releases.
+
+SpotiFLAC supports extensions to add custom metadata and download providers. Extensions are written in JavaScript and run in a secure sandbox.
+
+### Features
+- **Metadata Providers**: Add new sources for track/album/artist search
+- **Download Providers**: Add new sources for audio downloads
+- **Custom Settings**: Extensions can have user-configurable settings
+- **Provider Priority**: Set the order in which providers are tried
+
+### Installing Extensions
+1. Download a `.spotiflac-ext` file
+2. Go to **Settings > Extensions**
+3. Tap **Install Extension** and select the file
+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](docs/EXTENSION_DEVELOPMENT.md) for complete documentation.
+
+### Example Extensions
+Sample extensions are available in the [docs/extensions_example](docs/extensions_example) folder:
+
 ## Other project
 
 ### [SpotiFLAC (Desktop)](https://github.com/afkarxyz/SpotiFLAC)

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

@@ -180,6 +180,13 @@ class MainActivity: FlutterActivity() {
                             }
                             result.success(null)
                         }
+                        "readFileMetadata" -> {
+                            val filePath = call.argument<String>("file_path") ?: ""
+                            val response = withContext(Dispatchers.IO) {
+                                Gobackend.readFileMetadata(filePath)
+                            }
+                            result.success(response)
+                        }
                         "startDownloadService" -> {
                             val trackName = call.argument<String>("track_name") ?: ""
                             val artistName = call.argument<String>("artist_name") ?: ""
@@ -211,6 +218,12 @@ 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) {
@@ -277,6 +290,346 @@ 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)
+                        }
+                        // 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) {

go_backend/amazon.go

@@ -18,7 +18,7 @@ import (
 // AmazonDownloader handles Amazon Music downloads using DoubleDouble service (same as PC)
 type AmazonDownloader struct {
 	client           *http.Client
-	regions          []string // us, eu regions for DoubleDouble service
+	regions          []string  // us, eu regions for DoubleDouble service
 	lastAPICallTime  time.Time // Rate limiting: track last API call
 	apiCallCount     int       // Rate limiting: counter per minute
 	apiCallResetTime time.Time // Rate limiting: reset time
@@ -52,46 +52,46 @@ type DoubleDoubleStatusResponse struct {
 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]
 	expectedFirst = strings.TrimSpace(expectedFirst)
-	
+
 	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
 	}
-	
+
 	// 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
 	}
-	
+
 	return false
 }
 
@@ -124,7 +124,7 @@ func (a *AmazonDownloader) waitForRateLimit() {
 	defer amazonRateLimitMu.Unlock()
 
 	now := time.Now()
-	
+
 	// Reset counter every minute
 	if now.Sub(a.apiCallResetTime) >= time.Minute {
 		a.apiCallCount = 0
@@ -135,7 +135,7 @@ 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()
@@ -148,7 +148,7 @@ 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)
 		}
 	}
@@ -170,19 +170,18 @@ func (a *AmazonDownloader) GetAvailableAPIs() []string {
 	return apis
 }
 
-
 // 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://
+		serviceBase, _ := base64.StdEncoding.DecodeString("aHR0cHM6Ly8=")               // https://
 		serviceDomain, _ := base64.StdEncoding.DecodeString("LmRvdWJsZWRvdWJsZS50b3A=") // .doubledouble.top
 		baseURL := fmt.Sprintf("%s%s%s", string(serviceBase), region, string(serviceDomain))
 
@@ -202,7 +201,7 @@ func (a *AmazonDownloader) downloadFromDoubleDoubleService(amazonURL, outputDir
 		req.Header.Set("User-Agent", getRandomUserAgent())
 
 		fmt.Println("[Amazon] Submitting download request...")
-		
+
 		// Retry logic for 429 errors (like PC version: 3 retries with 15s wait)
 		var resp *http.Response
 		maxRetries := 3
@@ -217,7 +216,7 @@ 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
 				}
@@ -256,7 +255,7 @@ 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)
@@ -311,7 +310,7 @@ 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" {
@@ -345,7 +344,6 @@ func (a *AmazonDownloader) downloadFromDoubleDoubleService(amazonURL, outputDir
 	return "", "", "", fmt.Errorf("all regions failed. Last error: %v", lastError)
 }
 
-
 // DownloadFile downloads a file from URL with User-Agent and progress tracking
 func (a *AmazonDownloader) DownloadFile(downloadURL, outputPath, itemID string) error {
 	// Initialize item progress (required for all downloads)
@@ -434,6 +432,7 @@ type AmazonDownloadResult struct {
 	ReleaseDate string
 	TrackNumber int
 	DiscNumber  int
+	ISRC        string
 }
 
 // downloadFromAmazon downloads a track using the request parameters
@@ -450,12 +449,12 @@ func downloadFromAmazon(req DownloadRequest) (AmazonDownloadResult, error) {
 	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
@@ -463,7 +462,7 @@ func downloadFromAmazon(req DownloadRequest) (AmazonDownloadResult, error) {
 	} else {
 		return AmazonDownloadResult{}, fmt.Errorf("no valid Spotify or Deezer ID provided for Amazon lookup")
 	}
-	
+
 	if err != nil {
 		return AmazonDownloadResult{}, fmt.Errorf("failed to check Amazon availability via SongLink: %w", err)
 	}
@@ -487,12 +486,12 @@ 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{}{
@@ -543,19 +542,38 @@ 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
+			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
+			GoLog("[Amazon] Using disc number from file: %d (request had: %d)\n", actualDiscNum, req.DiscNumber)
+		}
 	}
 
 	// Embed metadata using Spotify data (more accurate than DoubleDouble)
+	// But preserve track/disc numbers from file if they were better
 	metadata := Metadata{
 		Title:       req.TrackName,
 		Artist:      req.ArtistName,
 		Album:       req.AlbumName,
 		AlbumArtist: req.AlbumArtist,
 		Date:        req.ReleaseDate,
-		TrackNumber: req.TrackNumber,
+		TrackNumber: actualTrackNum,
 		TotalTracks: req.TotalTracks,
-		DiscNumber:  req.DiscNumber,
+		DiscNumber:  actualDiscNum,
 		ISRC:        req.ISRC,
 	}
 
@@ -563,7 +581,7 @@ 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 {
@@ -572,9 +590,9 @@ 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")
 		}
@@ -583,36 +601,50 @@ 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)
-		// Add to ISRC index for fast duplicate checking
-		AddToISRCIndex(req.OutputDir, req.ISRC, outputPath)
-		// Return 0 to indicate unknown quality
-		return AmazonDownloadResult{
-			FilePath:   outputPath,
-			BitDepth:   0,
-			SampleRate: 0,
-		}, nil
+		GoLog("[Amazon] Warning: couldn't read quality from file: %v\n", err)
+	} else {
+		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 {
+		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
+		}
 	}
-	
-	fmt.Printf("[Amazon] Actual quality: %d-bit/%dHz\n", quality.BitDepth, quality.SampleRate)
 
 	// Add to ISRC index for fast duplicate checking
 	AddToISRCIndex(req.OutputDir, req.ISRC, outputPath)
 
+	bitDepth := 0
+	sampleRate := 0
+	if err == nil {
+		bitDepth = quality.BitDepth
+		sampleRate = quality.SampleRate
+	}
+
 	return AmazonDownloadResult{
 		FilePath:    outputPath,
-		BitDepth:    quality.BitDepth,
-		SampleRate:  quality.SampleRate,
+		BitDepth:    bitDepth,
+		SampleRate:  sampleRate,
 		Title:       req.TrackName,
 		Artist:      req.ArtistName,
 		Album:       req.AlbumName,
 		ReleaseDate: req.ReleaseDate,
-		TrackNumber: req.TrackNumber,
-		DiscNumber:  req.DiscNumber,
+		TrackNumber: actualTrackNum,
+		DiscNumber:  actualDiscNum,
+		ISRC:        req.ISRC,
 	}, nil
 }

go_backend/deezer.go

@@ -19,9 +19,9 @@ 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
 )
@@ -58,27 +58,27 @@ 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 {
@@ -90,6 +90,7 @@ type deezerAlbumSimple struct {
 	CoverXL     string `json:"cover_xl"`
 	ReleaseDate string `json:"release_date"` // Sometimes at album level
 }
+
 // ... (skip other structs as they are fine/unchanged) ...
 
 // ... (in convertTrack) ...
@@ -113,7 +114,7 @@ func (c *DeezerClient) convertTrack(track deezerTrack) TrackMetadata {
 	if albumImage == "" {
 		albumImage = track.Album.Cover
 	}
-	
+
 	// Try to find release date
 	releaseDate := track.ReleaseDate
 	if releaseDate == "" {
@@ -137,17 +138,18 @@ 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 +166,17 @@ 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 +184,14 @@ 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 +203,28 @@ 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 +232,37 @@ 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 +277,7 @@ 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 +299,7 @@ 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 +327,12 @@ 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 +352,7 @@ 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 +418,7 @@ 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 +461,7 @@ 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 +525,7 @@ 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
@@ -522,7 +565,7 @@ 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()
@@ -535,20 +578,20 @@ 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 +599,24 @@ 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
 }
@@ -588,23 +631,21 @@ func (c *DeezerClient) GetTrackISRC(ctx context.Context, trackID string) (string
 		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 +728,7 @@ 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/extension_manager.go

@@ -0,0 +1,987 @@
+// 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 {
+	// Parse version parts
+	parts1 := strings.Split(strings.TrimPrefix(v1, "v"), ".")
+	parts2 := strings.Split(strings.TrimPrefix(v2, "v"), ".")
+
+	// Pad shorter version with zeros
+	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:"-"` // Goja VM instance (not serialized)
+	Enabled   bool               `json:"enabled"`
+	Error     string             `json:"error,omitempty"`
+	DataDir   string             `json:"data_dir"`   // Extension's data directory
+	SourceDir string             `json:"source_dir"` // Where extension files are extracted
+	IconPath  string             `json:"icon_path"`  // Full path to icon file (if exists)
+}
+
+// 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
+}
+
+// Global extension manager instance
+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
+
+	// Create directories if they don't exist
+	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()
+
+	// Find and read manifest.json
+	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")
+	}
+
+	// Parse and validate manifest
+	manifest, err := ParseManifest(manifestData)
+	if err != nil {
+		return nil, fmt.Errorf("Invalid extension manifest: %w", err)
+	}
+
+	// Check if extension already loaded - if so, try upgrade (check without holding lock for long)
+	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 {
+		// Check if this is an upgrade
+		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)
+		}
+	}
+
+	// Now acquire write lock for the rest of the operation
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	// Double-check extension wasn't added while we were waiting for lock
+	if _, exists := m.extensions[manifest.Name]; exists {
+		return nil, fmt.Errorf("Extension '%s' was installed by another process", manifest.DisplayName)
+	}
+
+	// Create extension directory
+	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
+	for _, file := range zipReader.File {
+		if file.FileInfo().IsDir() {
+			continue
+		}
+
+		// Get relative path within the zip
+		destPath := filepath.Join(extDir, filepath.Base(file.Name))
+
+		// Create destination file
+		destFile, err := os.Create(destPath)
+		if err != nil {
+			return nil, fmt.Errorf("failed to create file %s: %w", destPath, err)
+		}
+
+		// Copy content
+		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)
+		}
+	}
+
+	// Create data directory for extension
+	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)
+	}
+
+	// Create loaded extension
+	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 {
+	// Create new Goja runtime
+	vm := goja.New()
+	ext.VM = vm
+
+	// Read index.js
+	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)
+	}
+
+	// Create extension runtime and register sandboxed APIs
+	runtime := NewExtensionRuntime(ext)
+	runtime.RegisterAPIs(vm)
+	runtime.RegisterGoBackendAPIs(vm)
+
+	// Set up console.log for debugging
+	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)
+
+	// Set up registerExtension function
+	var registeredExtension goja.Value
+	vm.Set("registerExtension", func(call goja.FunctionCall) goja.Value {
+		if len(call.Arguments) > 0 {
+			registeredExtension = call.Arguments[0]
+			// Also set it as global 'extension' variable for later access
+			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() {
+			// Check if it's an extracted extension directory
+			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") {
+			// Load from package file
+			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()
+
+	// Read manifest
+	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)
+	}
+
+	// Check if index.js exists
+	indexPath := filepath.Join(dirPath, "index.js")
+	if _, err := os.Stat(indexPath); os.IsNotExist(err) {
+		return nil, fmt.Errorf("Extension is missing index.js file")
+	}
+
+	// Check if extension already loaded - skip if already exists (for directory loading on startup)
+	if _, exists := m.extensions[manifest.Name]; exists {
+		return nil, fmt.Errorf("Extension '%s' is already loaded", manifest.DisplayName)
+	}
+
+	// Create data directory for extension
+	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)
+	}
+
+	// Create loaded extension
+	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()
+
+	// Find and read manifest.json
+	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")
+	}
+
+	// Parse and validate manifest
+	newManifest, err := ParseManifest(manifestData)
+	if err != nil {
+		return nil, fmt.Errorf("Invalid extension manifest: %w", err)
+	}
+
+	// Check if extension exists
+	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)
+		}
+	}
+
+	// Recreate extension directory
+	if err := os.MkdirAll(extDir, 0755); err != nil {
+		return nil, fmt.Errorf("failed to create extension directory: %w", err)
+	}
+
+	// Extract all files from new package
+	for _, file := range zipReader.File {
+		if file.FileInfo().IsDir() {
+			continue
+		}
+
+		// Get relative path within the zip
+		destPath := filepath.Join(extDir, filepath.Base(file.Name))
+
+		// Create destination file
+		destFile, err := os.Create(destPath)
+		if err != nil {
+			return nil, fmt.Errorf("failed to create file %s: %w", destPath, err)
+		}
+
+		// Copy content
+		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)
+		}
+	}
+
+	// Create new loaded extension (reusing data directory, preserving enabled state)
+	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()
+
+	// Find and read manifest.json
+	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")
+	}
+
+	// Parse manifest
+	newManifest, err := ParseManifest(manifestData)
+	if err != nil {
+		return nil, fmt.Errorf("Invalid manifest: %w", err)
+	}
+
+	// Check if extension exists
+	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 {
+		// Compare versions
+		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 {
+		// Build permissions list
+		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"
+		}
+
+		// Check for icon file
+		iconPath := ""
+		if ext.Manifest.Icon != "" && ext.SourceDir != "" {
+			possibleIcon := filepath.Join(ext.SourceDir, ext.Manifest.Icon)
+			if _, err := os.Stat(possibleIcon); err == nil {
+				iconPath = possibleIcon
+			}
+		}
+		// Fallback: check for icon.png if not specified in manifest
+		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")
+	}
+
+	// Convert settings to JSON for passing to JS
+	settingsJSON, err := json.Marshal(settings)
+	if err != nil {
+		return fmt.Errorf("Failed to save settings")
+	}
+
+	// Call initialize function
+	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
+	}
+
+	// Check result
+	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
+	}
+
+	// Check result
+	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 +1,314 @@
+// 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
+}
+
+// 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 +1,269 @@
+// Package gobackend provides extension runtime with sandboxed execution
+package gobackend
+
+import (
+	"net/http"
+	"net/url"
+	"sync"
+	"time"
+
+	"github.com/dop251/goja"
+)
+
+// Global auth state for extensions (stores pending auth codes)
+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
+}
+
+// Global pending auth requests (Flutter polls this)
+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]
+}
+
+// ClearPendingAuthRequest clears pending auth request (called from Flutter after opening URL)
+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 {
+	// Create a cookie jar for this extension
+	jar, _ := newSimpleCookieJar()
+
+	client := &http.Client{
+		Timeout: 30 * time.Second,
+		Jar:     jar,
+	}
+
+	return &ExtensionRuntime{
+		extensionID: ext.ID,
+		manifest:    ext.Manifest,
+		settings:    make(map[string]interface{}),
+		httpClient:  client,
+		cookieJar:   jar,
+		dataDir:     ext.DataDir,
+		vm:          ext.VM,
+	}
+}
+
+// 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 +1,467 @@
+// Package gobackend provides File API for extension runtime
+package gobackend
+
+import (
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/dop251/goja"
+)
+
+// ==================== File API (Sandboxed) ====================
+
+// validatePath checks if the path is within the extension's data directory
+// For absolute paths (from download queue), it allows them if they're valid
+func (r *ExtensionRuntime) validatePath(path string) (string, error) {
+	// Clean and resolve the path
+	cleanPath := filepath.Clean(path)
+
+	// If path is absolute, allow it (for download queue paths)
+	// This is safe because the Go backend controls what paths are passed
+	if filepath.IsAbs(cleanPath) {
+		return cleanPath, nil
+	}
+
+	// For relative paths, join with data directory
+	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
+	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 +1,499 @@
+// 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()
+	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 +1,339 @@
+// 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")
+}
+
+// getEncryptionKey derives an encryption key from extension ID
+func (r *ExtensionRuntime) getEncryptionKey() []byte {
+	// Use SHA256 of extension ID + salt as encryption key
+	salt := "spotiflac-ext-cred-v1"
+	hash := sha256.Sum256([]byte(r.extensionID + salt))
+	return hash[:]
+}
+
+// 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 := r.getEncryptionKey()
+	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 := r.getEncryptionKey()
+	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 +1,219 @@
+package gobackend
+
+import (
+	"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",
+		},
+		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")
+	}
+}
+
+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")
+	}
+}

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"
 )
 
@@ -17,12 +22,12 @@ import (
 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
+	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
-	
+	chromePatch := rand.Intn(65) + 60     // Patch 60-125
+
 	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,
@@ -34,46 +39,48 @@ 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,
-	)
-}
+// Kept for potential future use
+// 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
-}
+// Kept for potential future use
+// 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  // 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
 )
 
 // Shared transport with connection pooling to prevent TCP exhaustion
@@ -91,9 +98,9 @@ var sharedTransport = &http.Transport{
 	ExpectContinueTimeout: 1 * time.Second,
 	DisableKeepAlives:     false, // Enable keep-alives for connection reuse
 	ForceAttemptHTTP2:     true,
-	WriteBufferSize:       64 * 1024,  // 64KB write buffer
-	ReadBufferSize:        64 * 1024,  // 64KB read buffer
-	DisableCompression:    true,       // FLAC is already compressed
+	WriteBufferSize:       64 * 1024, // 64KB write buffer
+	ReadBufferSize:        64 * 1024, // 64KB read buffer
+	DisableCompression:    true,      // FLAC is already compressed
 }
 
 // Shared HTTP client for general requests (reuses connections)
@@ -134,9 +141,15 @@ func 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 {
+		// Check for ISP blocking
+		CheckAndLogISPBlocking(err, req.URL.String(), "HTTP")
+	}
+	return resp, err
 }
 
 // RetryConfig holds configuration for retry logic
@@ -159,9 +172,11 @@ 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 +186,16 @@ 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 +216,43 @@ 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 +269,7 @@ 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 +343,172 @@ 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 +1,203 @@
+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 // Whether logging is enabled (controlled by Flutter)
+}
+
+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()
+
+	// Skip if logging is disabled (except for errors which are always logged)
+	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 {
+		// Remove oldest entry
+		lb.entries = lb.entries[1:]
+	}
+	lb.entries = append(lb.entries, entry)
+
+	// Also print to logcat for debugging
+	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)
+}
+
+// getSince returns log entries since the given index (internal use)
+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

@@ -250,29 +250,30 @@ 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

@@ -58,7 +58,7 @@ func EmbedMetadata(filePath string, metadata Metadata, coverPath string) error {
 	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 +66,15 @@ 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)
 	}
@@ -105,7 +105,7 @@ func EmbedMetadata(filePath string, metadata Metadata, coverPath string) error {
 						f.Meta = append(f.Meta[:i], f.Meta[i+1:]...)
 					}
 				}
-				
+
 				picture, err := flacpicture.NewFromImageData(
 					flacpicture.PictureTypeFrontCover,
 					"Front Cover",
@@ -162,7 +162,7 @@ func EmbedMetadataWithCoverData(filePath string, metadata Metadata, coverData []
 	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 +170,15 @@ 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)
 	}
@@ -204,7 +204,7 @@ func EmbedMetadataWithCoverData(filePath string, metadata Metadata, coverData []
 				f.Meta = append(f.Meta[:i], f.Meta[i+1:]...)
 			}
 		}
-		
+
 		picture, err := flacpicture.NewFromImageData(
 			flacpicture.PictureTypeFrontCover,
 			"Front Cover",
@@ -257,11 +257,30 @@ 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 != "" {
+					fmt.Sscanf(trackNum, "%d", &metadata.TrackNumber)
+				}
+			}
 
 			discNum := getComment(cmt, "DISCNUMBER")
 			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")
+			}
 
 			break
 		}
@@ -291,9 +310,14 @@ func setComment(cmt *flacvorbis.MetaDataBlockVorbisComment, key, value string) {
 }
 
 func getComment(cmt *flacvorbis.MetaDataBlockVorbisComment, key string) string {
+	keyUpper := strings.ToUpper(key) + "="
 	for _, comment := range cmt.Comments {
-		if len(comment) > len(key)+1 && comment[:len(key)+1] == key+"=" {
-			return comment[len(key)+1:]
+		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:]
+			}
 		}
 	}
 	return ""
@@ -356,13 +380,13 @@ 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] != "" {
@@ -376,8 +400,9 @@ 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
@@ -395,7 +420,7 @@ func GetAudioQuality(filePath string) (AudioQuality, error) {
 	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
@@ -422,12 +447,20 @@ func GetAudioQuality(filePath string) (AudioQuality, error) {
 		// Parse bits per sample (5 bits)
 		bitsPerSample := ((int(streamInfo[12]) & 0x01) << 4) | (int(streamInfo[13]) >> 4) + 1
 
+		// Parse total samples (36 bits: 4 bits from byte 13, all of bytes 14-17)
+		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
@@ -435,17 +468,16 @@ func GetAudioQuality(filePath string) (AudioQuality, error) {
 	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
 		return GetM4AQuality(filePath)
 	}
-	
+
 	return AudioQuality{}, fmt.Errorf("unsupported file format (not FLAC or M4A)")
 }
 
-
 // ========================================
 // M4A (MP4/AAC) Metadata Embedding
 // ========================================
@@ -468,16 +500,16 @@ func EmbedM4AMetadata(filePath string, metadata Metadata, coverData []byte) erro
 	// Find udta atom inside moov, or create one
 	moovSize := int(data[moovPos]<<24 | data[moovPos+1]<<16 | data[moovPos+2]<<8 | 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])
 		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])
@@ -495,7 +527,7 @@ 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:]...)
@@ -511,14 +543,14 @@ 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)
@@ -555,52 +587,52 @@ func findAtom(data []byte, name string, offset int) int {
 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)
@@ -610,7 +642,7 @@ 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
@@ -623,11 +655,11 @@ 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)
@@ -636,14 +668,14 @@ 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)
@@ -655,7 +687,7 @@ 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)
@@ -665,7 +697,7 @@ func buildTextAtom(name, value string) []byte {
 	atom[3] = byte(atomSize)
 	atom = append(atom, []byte(name)...)
 	atom = append(atom, dataAtom...)
-	
+
 	return atom
 }
 
@@ -682,7 +714,7 @@ 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)
@@ -692,7 +724,7 @@ func buildTrackNumberAtom(track, total int) []byte {
 	atom[3] = byte(atomSize)
 	atom = append(atom, []byte("trkn")...)
 	atom = append(atom, dataAtom...)
-	
+
 	return atom
 }
 
@@ -708,7 +740,7 @@ 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)
@@ -718,7 +750,7 @@ func buildDiscNumberAtom(disc, total int) []byte {
 	atom[3] = byte(atomSize)
 	atom = append(atom, []byte("disk")...)
 	atom = append(atom, dataAtom...)
-	
+
 	return atom
 }
 
@@ -729,7 +761,7 @@ func buildCoverAtom(coverData []byte) []byte {
 	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)
@@ -741,7 +773,7 @@ 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)
@@ -751,7 +783,7 @@ func buildCoverAtom(coverData []byte) []byte {
 	atom[3] = byte(atomSize)
 	atom = append(atom, []byte("covr")...)
 	atom = append(atom, dataAtom...)
-	
+
 	return atom
 }
 

go_backend/parallel.go

@@ -233,7 +233,7 @@ 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 {
@@ -272,7 +272,7 @@ 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
 	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"
@@ -204,11 +204,12 @@ 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 {
@@ -256,7 +257,7 @@ 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

@@ -12,6 +12,7 @@ import (
 	"path/filepath"
 	"strings"
 	"sync"
+	"time"
 )
 
 // QobuzDownloader handles Qobuz downloads
@@ -52,59 +53,235 @@ type QobuzTrack struct {
 func qobuzArtistsMatch(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]
 	expectedFirst = strings.TrimSpace(expectedFirst)
-	
+
 	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
 	}
-	
+
 	// 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)
+
+	// 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(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 {
+// 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 {
-		if r > 127 {
+		// 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 {
@@ -132,8 +309,8 @@ func (q *QobuzDownloader) GetAvailableAPIs() []string {
 	// Same APIs as PC version (referensi/backend/qobuz.go)
 	// Primary: dab.yeet.su, Fallback: dabmusic.xyz
 	encodedAPIs := []string{
-		"ZGFiLnllZXQuc3UvYXBpL3N0cmVhbT90cmFja0lkPQ==",     // dab.yeet.su/api/stream?trackId= (PRIMARY - same as PC)
-		"ZGFibXVzaWMueHl6L2FwaS9zdHJlYW0/dHJhY2tJZD0=",     // dabmusic.xyz/api/stream?trackId= (FALLBACK - same as PC)
+		"ZGFiLnllZXQuc3UvYXBpL3N0cmVhbT90cmFja0lkPQ==", // dab.yeet.su/api/stream?trackId= (PRIMARY - same as PC)
+		"ZGFibXVzaWMueHl6L2FwaS9zdHJlYW0/dHJhY2tJZD0=", // dabmusic.xyz/api/stream?trackId= (FALLBACK - same as PC)
 	}
 
 	var apis []string
@@ -194,6 +371,8 @@ 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) {
+	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)
 
@@ -221,6 +400,8 @@ func (q *QobuzDownloader) SearchTrackByISRCWithDuration(isrc string, expectedDur
 		return nil, err
 	}
 
+	GoLog("[Qobuz] ISRC search returned %d results\n", len(result.Tracks.Items))
+
 	// Find ISRC matches
 	var isrcMatches []*QobuzTrack
 	for i := range result.Tracks.Items {
@@ -229,6 +410,8 @@ func (q *QobuzDownloader) SearchTrackByISRCWithDuration(isrc string, expectedDur
 		}
 	}
 
+	GoLog("[Qobuz] Found %d exact ISRC matches\n", len(isrcMatches))
+
 	if len(isrcMatches) > 0 {
 		// Verify duration if provided
 		if expectedDurationSec > 0 {
@@ -238,27 +421,27 @@ func (q *QobuzDownloader) SearchTrackByISRCWithDuration(isrc string, expectedDur
 				if durationDiff < 0 {
 					durationDiff = -durationDiff
 				}
-				// Allow 30 seconds tolerance
-				if durationDiff <= 30 {
+				// Allow 10 seconds tolerance
+				if durationDiff <= 10 {
 					durationVerifiedMatches = append(durationVerifiedMatches, track)
 				}
 			}
-			
+
 			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)", 
+			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
 	}
 
@@ -281,6 +464,7 @@ 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")
 
@@ -312,7 +496,7 @@ 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)
 			}
 		}
 
@@ -342,7 +526,7 @@ 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)
 
@@ -353,7 +537,7 @@ 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
 		}
 
@@ -374,7 +558,7 @@ 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...)
 		}
 	}
@@ -383,16 +567,35 @@ 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
 			}
-			if durationDiff <= 30 {
+			if durationDiff <= 10 {
 				durationMatches = append(durationMatches, track)
 			}
 		}
@@ -401,24 +604,155 @@ 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)
+}
+
+// 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")
+	}
+
+	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 {
+		go func(api string) {
+			reqStart := time.Now()
+
+			client := &http.Client{
+				Timeout: 15 * time.Second,
+			}
+
+			reqURL := fmt.Sprintf("%s%d&quality=%s", api, trackID, quality)
+
+			req, err := http.NewRequest("GET", reqURL, nil)
+			if err != nil {
+				resultChan <- qobuzAPIResult{apiURL: api, err: err, duration: time.Since(reqStart)}
+				return
+			}
+
+			resp, err := client.Do(req)
+			if err != nil {
+				resultChan <- qobuzAPIResult{apiURL: api, err: err, duration: time.Since(reqStart)}
+				return
+			}
+			defer resp.Body.Close()
+
+			if resp.StatusCode != 200 {
+				resultChan <- qobuzAPIResult{apiURL: api, err: fmt.Errorf("HTTP %d", resp.StatusCode), duration: time.Since(reqStart)}
+				return
+			}
+
+			body, err := io.ReadAll(resp.Body)
+			if err != nil {
+				resultChan <- qobuzAPIResult{apiURL: api, err: err, duration: time.Since(reqStart)}
+				return
+			}
+
+			// 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
+			}
+
+			// 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(errorResp.Error), duration: time.Since(reqStart)}
+				return
+			}
+
+			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
+	var firstSuccess *qobuzAPIResult
+
+	for i := 0; i < len(apis); i++ {
+		result := <-resultChan
+		if result.err == nil && firstSuccess == nil {
+			firstSuccess = &result
+			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 firstSuccess.apiURL, firstSuccess.downloadURL, nil
+		} else if result.err != 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)
 }
 
 // getQobuzDownloadURLSequential requests download URL from APIs sequentially
@@ -437,7 +771,7 @@ func getQobuzDownloadURLSequential(apis []string, trackID int64, quality string)
 		// The apiURL already includes the path, just append trackID and quality
 		reqURL := fmt.Sprintf("%s%d&quality=%s", apiURL, trackID, quality)
 
-		fmt.Printf("[Qobuz] Trying: %s\n", reqURL)
+		GoLog("[Qobuz] Trying: %s\n", reqURL)
 
 		req, err := http.NewRequest("GET", reqURL, nil)
 		if err != nil {
@@ -482,7 +816,7 @@ func getQobuzDownloadURLSequential(apis []string, trackID int64, quality string)
 		}
 
 		if result.URL != "" {
-			fmt.Printf("[Qobuz] Got download URL from: %s\n", apiURL)
+			GoLog("[Qobuz] Got download URL from: %s\n", apiURL)
 			return apiURL, result.URL, nil
 		}
 
@@ -492,14 +826,16 @@ func getQobuzDownloadURLSequential(apis []string, trackID int64, quality string)
 	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)
+	// Use parallel approach - request from all APIs simultaneously
+	_, downloadURL, err := getQobuzDownloadURLParallel(apis, trackID, quality)
 	if err != nil {
 		return "", err
 	}
@@ -592,6 +928,7 @@ type QobuzDownloadResult struct {
 	ReleaseDate string
 	TrackNumber int
 	DiscNumber  int
+	ISRC        string
 }
 
 // downloadFromQobuz downloads a track using the request parameters
@@ -612,11 +949,11 @@ func downloadFromQobuz(req DownloadRequest) (QobuzDownloadResult, error) {
 	// OPTIMIZATION: Check cache first for track ID
 	if 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
 			}
 		}
@@ -624,21 +961,28 @@ func downloadFromQobuz(req DownloadRequest) (QobuzDownloadResult, error) {
 
 	// Strategy 1: Search by ISRC with duration verification
 	if track == nil && 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
 		}
@@ -653,7 +997,7 @@ 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)
 	}
@@ -687,12 +1031,12 @@ 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)
@@ -731,11 +1075,17 @@ func downloadFromQobuz(req DownloadRequest) (QobuzDownloadResult, error) {
 	}
 
 	// Embed metadata using parallel-fetched cover data
-	// Use metadata from the actual Qobuz track found (more accurate than request)
+	// 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
+	}
+
 	metadata := Metadata{
 		Title:       track.Title,
 		Artist:      track.Performer.Name,
-		Album:       track.Album.Title,
+		Album:       albumName,
 		AlbumArtist: req.AlbumArtist, // Qobuz track struct might not have this handy, keep req or check album struct
 		Date:        track.Album.ReleaseDate,
 		TrackNumber: track.TrackNumber,
@@ -748,7 +1098,7 @@ func downloadFromQobuz(req DownloadRequest) (QobuzDownloadResult, error) {
 	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 {
@@ -757,9 +1107,9 @@ 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")
 		}
@@ -780,5 +1130,6 @@ func downloadFromQobuz(req DownloadRequest) (QobuzDownloadResult, error) {
 		ReleaseDate: track.Album.ReleaseDate,
 		TrackNumber: track.TrackNumber,
 		DiscNumber:  req.DiscNumber, // Qobuz track struct limitations
+		ISRC:        track.ISRC,
 	}, nil
 }

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()
@@ -78,39 +79,56 @@ 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()
-	
+
+	// Check custom credentials first
 	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)
-		}
+	// Check environment variables
+	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()
+
+	// Check custom credentials first
+	if customClientID != "" && customClientSecret != "" {
+		return customClientID, customClientSecret, nil
+	}
+
+	// Check environment variables
+	clientID := os.Getenv("SPOTIFY_CLIENT_ID")
+	clientSecret := os.Getenv("SPOTIFY_CLIENT_SECRET")
+
+	if clientID != "" && clientSecret != "" {
+		return clientID, clientSecret, nil
+	}
+
+	// No credentials available
+	return "", "", ErrNoSpotifyCredentials
 }
 
 // NewSpotifyMetadataClient creates a new Spotify client
-func NewSpotifyMetadataClient() *SpotifyMetadataClient {
-	src := rand.NewSource(time.Now().UnixNano())
+// Returns error if credentials are not configured
+func NewSpotifyMetadataClient() (*SpotifyMetadataClient, error) {
+	// Get credentials - will error if not configured
+	clientID, clientSecret, err := getCredentials()
+	if err != nil {
+		return nil, err
+	}
 
-	// Get credentials (custom or default)
-	clientID, clientSecret := getCredentials()
+	src := rand.NewSource(time.Now().UnixNano())
 
 	c := &SpotifyMetadataClient{
 		httpClient:   NewHTTPClientWithTimeout(15 * time.Second), // Use shared transport for connection pooling
@@ -122,7 +140,7 @@ func NewSpotifyMetadataClient() *SpotifyMetadataClient {
 		albumCache:   make(map[string]*cacheEntry),
 	}
 	c.userAgent = c.randomUserAgent()
-	return c
+	return c, nil
 }
 
 // TrackMetadata represents track information
@@ -140,6 +158,7 @@ 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 +178,7 @@ 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 +303,7 @@ 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 +352,14 @@ 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 +384,7 @@ func (c *SpotifyMetadataClient) SearchTracks(ctx context.Context, query string,
 			DiscNumber:  track.DiscNumber,
 			ExternalURL: track.ExternalURL.Spotify,
 			ISRC:        track.ExternalID.ISRC,
+			AlbumType:   track.Album.AlbumType,
 		})
 	}
 
@@ -373,7 +395,7 @@ func (c *SpotifyMetadataClient) SearchTracks(ctx context.Context, query string,
 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() {
@@ -388,24 +410,24 @@ 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
 	}
@@ -430,6 +452,7 @@ 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,
 		})
 	}
 
@@ -438,7 +461,7 @@ func (c *SpotifyMetadataClient) SearchAll(ctx context.Context, query string, tra
 	if artistCount > artistLimit {
 		artistCount = artistLimit
 	}
-	
+
 	for i := 0; i < artistCount; i++ {
 		artist := response.Artists.Items[i]
 		result.Artists = append(result.Artists, SearchArtistResult{
@@ -534,7 +557,7 @@ 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 +586,7 @@ 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),
@@ -602,23 +625,23 @@ 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 +649,15 @@ 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 +691,7 @@ 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 +718,7 @@ 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 {
@@ -755,10 +778,10 @@ 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"`
@@ -941,15 +964,15 @@ 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.xcodeproj/project.pbxproj

@@ -427,7 +427,7 @@
 			isa = XCBuildConfiguration;
 			buildSettings = {
 				ALWAYS_SEARCH_USER_PATHS = NO;
-				ASSETCATALOG_COMPILER_GENERATE_SWIFT_ASSET_SYMBOL_EXTENSIONS = YES;
+				ASSETCATALOG_COMPILER_GENERATE_SWIFT_ASSET_SYMBOL_EXTENSIONS = AppIcon;
 				CLANG_ANALYZER_NONNULL = YES;
 				CLANG_CXX_LANGUAGE_STANDARD = "gnu++0x";
 				CLANG_CXX_LIBRARY = "libc++";
@@ -484,7 +484,7 @@
 			isa = XCBuildConfiguration;
 			buildSettings = {
 				ALWAYS_SEARCH_USER_PATHS = NO;
-				ASSETCATALOG_COMPILER_GENERATE_SWIFT_ASSET_SYMBOL_EXTENSIONS = YES;
+				ASSETCATALOG_COMPILER_GENERATE_SWIFT_ASSET_SYMBOL_EXTENSIONS = AppIcon;
 				CLANG_ANALYZER_NONNULL = YES;
 				CLANG_CXX_LANGUAGE_STANDARD = "gnu++0x";
 				CLANG_CXX_LIBRARY = "libc++";

ios/Runner/AppDelegate.swift

@@ -181,6 +181,342 @@ import Gobackend  // Import Go framework
             GobackendCleanupConnections()
             return nil
             
+        case "readFileMetadata":
+            let args = call.arguments as! [String: Any]
+            let filePath = args["file_path"] as! String
+            let response = GobackendReadFileMetadata(filePath, &error)
+            if let error = error { throw error }
+            return response
+            
+        case "searchDeezerAll":
+            let args = call.arguments as! [String: Any]
+            let query = args["query"] as! String
+            let trackLimit = args["track_limit"] as? Int ?? 15
+            let artistLimit = args["artist_limit"] as? Int ?? 3
+            let response = GobackendSearchDeezerAll(query, Int(trackLimit), Int(artistLimit), &error)
+            if let error = error { throw error }
+            return response
+
+        case "getDeezerMetadata":
+            let args = call.arguments as! [String: Any]
+            let resourceType = args["resource_type"] as! String
+            let resourceId = args["resource_id"] as! String
+            let response = GobackendGetDeezerMetadata(resourceType, resourceId, &error)
+            if let error = error { throw error }
+            return response
+
+        case "parseDeezerUrl":
+            let args = call.arguments as! [String: Any]
+            let url = args["url"] as! String
+            let response = GobackendParseDeezerURLExport(url, &error)
+            if let error = error { throw error }
+            return response
+
+        case "searchDeezerByISRC":
+            let args = call.arguments as! [String: Any]
+            let isrc = args["isrc"] as! String
+            let response = GobackendSearchDeezerByISRC(isrc, &error)
+            if let error = error { throw error }
+            return response
+
+        case "convertSpotifyToDeezer":
+            let args = call.arguments as! [String: Any]
+            let resourceType = args["resource_type"] as! String
+            let spotifyId = args["spotify_id"] as! String
+            let response = GobackendConvertSpotifyToDeezer(resourceType, spotifyId, &error)
+            if let error = error { throw error }
+            return response
+
+        case "getSpotifyMetadataWithFallback":
+            let args = call.arguments as! [String: Any]
+            let url = args["url"] as! String
+            let response = GobackendGetSpotifyMetadataWithDeezerFallback(url, &error)
+            if let error = error { throw error }
+            return response
+            
+        case "preWarmTrackCache":
+            let args = call.arguments as! [String: Any]
+            let tracksJson = args["tracks"] as! String
+            let _ = GobackendPreWarmTrackCacheJSON(tracksJson, &error)
+            if let error = error { throw error }
+            return nil
+            
+        case "getTrackCacheSize":
+            let response = GobackendGetTrackCacheSize()
+            return response
+            
+        case "clearTrackCache":
+            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
+            
+        // 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
+            
         default:
             throw NSError(
                 domain: "SpotiFLAC",

ios/Runner/Assets.xcassets/AppIcon.appiconset/Contents.json

@@ -1,122 +1 @@
-{
-  "images" : [
-    {
-      "size" : "20x20",
-      "idiom" : "iphone",
-      "filename" : "Icon-App-20x20@2x.png",
-      "scale" : "2x"
-    },
-    {
-      "size" : "20x20",
-      "idiom" : "iphone",
-      "filename" : "Icon-App-20x20@3x.png",
-      "scale" : "3x"
-    },
-    {
-      "size" : "29x29",
-      "idiom" : "iphone",
-      "filename" : "Icon-App-29x29@1x.png",
-      "scale" : "1x"
-    },
-    {
-      "size" : "29x29",
-      "idiom" : "iphone",
-      "filename" : "Icon-App-29x29@2x.png",
-      "scale" : "2x"
-    },
-    {
-      "size" : "29x29",
-      "idiom" : "iphone",
-      "filename" : "Icon-App-29x29@3x.png",
-      "scale" : "3x"
-    },
-    {
-      "size" : "40x40",
-      "idiom" : "iphone",
-      "filename" : "Icon-App-40x40@2x.png",
-      "scale" : "2x"
-    },
-    {
-      "size" : "40x40",
-      "idiom" : "iphone",
-      "filename" : "Icon-App-40x40@3x.png",
-      "scale" : "3x"
-    },
-    {
-      "size" : "60x60",
-      "idiom" : "iphone",
-      "filename" : "Icon-App-60x60@2x.png",
-      "scale" : "2x"
-    },
-    {
-      "size" : "60x60",
-      "idiom" : "iphone",
-      "filename" : "Icon-App-60x60@3x.png",
-      "scale" : "3x"
-    },
-    {
-      "size" : "20x20",
-      "idiom" : "ipad",
-      "filename" : "Icon-App-20x20@1x.png",
-      "scale" : "1x"
-    },
-    {
-      "size" : "20x20",
-      "idiom" : "ipad",
-      "filename" : "Icon-App-20x20@2x.png",
-      "scale" : "2x"
-    },
-    {
-      "size" : "29x29",
-      "idiom" : "ipad",
-      "filename" : "Icon-App-29x29@1x.png",
-      "scale" : "1x"
-    },
-    {
-      "size" : "29x29",
-      "idiom" : "ipad",
-      "filename" : "Icon-App-29x29@2x.png",
-      "scale" : "2x"
-    },
-    {
-      "size" : "40x40",
-      "idiom" : "ipad",
-      "filename" : "Icon-App-40x40@1x.png",
-      "scale" : "1x"
-    },
-    {
-      "size" : "40x40",
-      "idiom" : "ipad",
-      "filename" : "Icon-App-40x40@2x.png",
-      "scale" : "2x"
-    },
-    {
-      "size" : "76x76",
-      "idiom" : "ipad",
-      "filename" : "Icon-App-76x76@1x.png",
-      "scale" : "1x"
-    },
-    {
-      "size" : "76x76",
-      "idiom" : "ipad",
-      "filename" : "Icon-App-76x76@2x.png",
-      "scale" : "2x"
-    },
-    {
-      "size" : "83.5x83.5",
-      "idiom" : "ipad",
-      "filename" : "Icon-App-83.5x83.5@2x.png",
-      "scale" : "2x"
-    },
-    {
-      "size" : "1024x1024",
-      "idiom" : "ios-marketing",
-      "filename" : "Icon-App-1024x1024@1x.png",
-      "scale" : "1x"
-    }
-  ],
-  "info" : {
-    "version" : 1,
-    "author" : "xcode"
-  }
-}
+{"images":[{"size":"20x20","idiom":"iphone","filename":"Icon-App-20x20@2x.png","scale":"2x"},{"size":"20x20","idiom":"iphone","filename":"Icon-App-20x20@3x.png","scale":"3x"},{"size":"29x29","idiom":"iphone","filename":"Icon-App-29x29@1x.png","scale":"1x"},{"size":"29x29","idiom":"iphone","filename":"Icon-App-29x29@2x.png","scale":"2x"},{"size":"29x29","idiom":"iphone","filename":"Icon-App-29x29@3x.png","scale":"3x"},{"size":"40x40","idiom":"iphone","filename":"Icon-App-40x40@2x.png","scale":"2x"},{"size":"40x40","idiom":"iphone","filename":"Icon-App-40x40@3x.png","scale":"3x"},{"size":"57x57","idiom":"iphone","filename":"Icon-App-57x57@1x.png","scale":"1x"},{"size":"57x57","idiom":"iphone","filename":"Icon-App-57x57@2x.png","scale":"2x"},{"size":"60x60","idiom":"iphone","filename":"Icon-App-60x60@2x.png","scale":"2x"},{"size":"60x60","idiom":"iphone","filename":"Icon-App-60x60@3x.png","scale":"3x"},{"size":"20x20","idiom":"ipad","filename":"Icon-App-20x20@1x.png","scale":"1x"},{"size":"20x20","idiom":"ipad","filename":"Icon-App-20x20@2x.png","scale":"2x"},{"size":"29x29","idiom":"ipad","filename":"Icon-App-29x29@1x.png","scale":"1x"},{"size":"29x29","idiom":"ipad","filename":"Icon-App-29x29@2x.png","scale":"2x"},{"size":"40x40","idiom":"ipad","filename":"Icon-App-40x40@1x.png","scale":"1x"},{"size":"40x40","idiom":"ipad","filename":"Icon-App-40x40@2x.png","scale":"2x"},{"size":"50x50","idiom":"ipad","filename":"Icon-App-50x50@1x.png","scale":"1x"},{"size":"50x50","idiom":"ipad","filename":"Icon-App-50x50@2x.png","scale":"2x"},{"size":"72x72","idiom":"ipad","filename":"Icon-App-72x72@1x.png","scale":"1x"},{"size":"72x72","idiom":"ipad","filename":"Icon-App-72x72@2x.png","scale":"2x"},{"size":"76x76","idiom":"ipad","filename":"Icon-App-76x76@1x.png","scale":"1x"},{"size":"76x76","idiom":"ipad","filename":"Icon-App-76x76@2x.png","scale":"2x"},{"size":"83.5x83.5","idiom":"ipad","filename":"Icon-App-83.5x83.5@2x.png","scale":"2x"},{"size":"1024x1024","idiom":"ios-marketing","filename":"Icon-App-1024x1024@1x.png","scale":"1x"}],"info":{"version":1,"author":"xcode"}}

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 = '2.1.6';
-  static const String buildNumber = '44';
+  static const String version = '3.0.0-alpha.4';
+  static const String buildNumber = '53';
   static const String fullVersion = '$version+$buildNumber';
   
   

lib/main.dart

@@ -1,7 +1,10 @@
+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';
 
@@ -24,14 +27,42 @@ 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) {
+  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';
+      
+      // Create directories if needed
+      await Directory(extensionsDir).create(recursive: true);
+      await Directory(dataDir).create(recursive: true);
+      
+      // Initialize extension system
+      await ref.read(extensionProvider.notifier).initialize(extensionsDir, dataDir);
+    } catch (e) {
+      debugPrint('Failed to initialize extensions: $e');
+    }
+  }
+
+  @override
+  Widget build(BuildContext context) {
     // Eagerly initialize download history provider to load from storage
     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

@@ -18,14 +18,20 @@ 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 bool showExtensionStore; // Show Extension Store tab in navigation
 
   const AppSettings({
-    this.defaultService = 'qobuz',
+    this.defaultService = 'tidal',
     this.audioQuality = 'LOSSLESS',
     this.filenameFormat = '{title} - {artist}',
     this.downloadDirectory = '',
@@ -39,11 +45,17 @@ 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.showExtensionStore = true, // Default: show store
   });
 
   AppSettings copyWith({
@@ -61,11 +73,17 @@ 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? separateSingles,
+    bool? showExtensionStore,
   }) {
     return AppSettings(
       defaultService: defaultService ?? this.defaultService,
@@ -82,11 +100,17 @@ 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: searchProvider ?? this.searchProvider,
+      separateSingles: separateSingles ?? this.separateSingles,
+      showExtensionStore: showExtensionStore ?? this.showExtensionStore,
     );
   }
 

lib/models/settings.g.dart

@@ -7,7 +7,7 @@ part of 'settings.dart';
 // **************************************************************************
 
 AppSettings _$AppSettingsFromJson(Map<String, dynamic> json) => AppSettings(
-  defaultService: json['defaultService'] as String? ?? 'qobuz',
+  defaultService: json['defaultService'] as String? ?? 'tidal',
   audioQuality: json['audioQuality'] as String? ?? 'LOSSLESS',
   filenameFormat: json['filenameFormat'] as String? ?? '{title} - {artist}',
   downloadDirectory: json['downloadDirectory'] as String? ?? '',
@@ -21,12 +21,18 @@ AppSettings _$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,
+  showExtensionStore: json['showExtensionStore'] as bool? ?? true,
 );
 
 Map<String, dynamic> _$AppSettingsToJson(AppSettings instance) =>
@@ -45,9 +51,15 @@ Map<String, dynamic> _$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,
+      'showExtensionStore': instance.showExtensionStore,
     };

lib/models/track.dart

@@ -18,6 +18,8 @@ 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)
 
   const Track({
     required this.id,
@@ -33,10 +35,18 @@ class Track {
     this.releaseDate,
     this.deezerId,
     this.availability,
+    this.source,
+    this.albumType,
   });
 
+  /// Check if this track is a single (based on album_type metadata)
+  bool get isSingle => albumType == 'single' || albumType == 'ep';
+
   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 +24,8 @@ 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?,
 );
 
 Map<String, dynamic> _$TrackToJson(Track instance) => <String, dynamic>{
@@ -40,6 +42,8 @@ Map<String, dynamic> _$TrackToJson(Track instance) => <String, dynamic>{
   'releaseDate': instance.releaseDate,
   'deezerId': instance.deezerId,
   'availability': instance.availability,
+  'source': instance.source,
+  'albumType': instance.albumType,
 };
 
 ServiceAvailability _$ServiceAvailabilityFromJson(Map<String, dynamic> json) =>

lib/providers/extension_provider.dart

@@ -0,0 +1,715 @@
+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 custom dimensions specified, use them
+    if (thumbnailWidth != null && thumbnailHeight != null) {
+      return (thumbnailWidth!.toDouble(), thumbnailHeight!.toDouble());
+    }
+    
+    // Otherwise use ratio presets
+    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');
+      
+      // Get extension info before updating state
+      final ext = state.extensions.where((e) => e.id == extensionId).firstOrNull;
+      
+      // Update local state
+      final extensions = state.extensions.map((e) {
+        if (e.id == extensionId) {
+          return e.copyWith(enabled: enabled);
+        }
+        return e;
+      }).toList();
+      
+      state = state.copyWith(extensions: extensions);
+      
+      // If disabling an extension, reset related settings
+      if (!enabled && ext != null) {
+        final settings = ref.read(settingsProvider);
+        
+        // If this extension was the search provider, clear it and reset to Deezer
+        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 this extension was the default download service, reset to Tidal
+        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/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';
@@ -26,6 +27,9 @@ class SettingsNotifier extends Notifier<AppSettings> {
       
       // Apply Spotify credentials to Go backend on load
       _applySpotifyCredentials();
+      
+      // Sync logging state
+      LogBuffer.loggingEnabled = state.enableLogging;
     }
   }
 
@@ -56,18 +60,16 @@ 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 && 
+    // Only apply if both fields are set
+    if (state.spotifyClientId.isNotEmpty && 
         state.spotifyClientSecret.isNotEmpty) {
       await PlatformBridge.setSpotifyCredentials(
         state.spotifyClientId,
         state.spotifyClientSecret,
       );
-    } else {
-      // Clear to use default
-      await PlatformBridge.setSpotifyCredentials('', '');
     }
+    // Note: If credentials are empty, Spotify API will return error
+    // User should use Deezer as metadata source instead
   }
 
   void setDefaultService(String service) {
@@ -144,6 +146,11 @@ 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 +194,33 @@ class SettingsNotifier extends Notifier<AppSettings> {
     state = state.copyWith(metadataSource: source);
     _saveSettings();
   }
+
+  void setSearchProvider(String? provider) {
+    state = state.copyWith(searchProvider: provider);
+    _saveSettings();
+  }
+
+  void setEnableLogging(bool enabled) {
+    state = state.copyWith(enableLogging: enabled);
+    _saveSettings();
+    // Sync logging state to LogBuffer
+    LogBuffer.loggingEnabled = enabled;
+  }
+
+  void setUseExtensionProviders(bool enabled) {
+    state = state.copyWith(useExtensionProviders: enabled);
+    _saveSettings();
+  }
+
+  void setSeparateSingles(bool enabled) {
+    state = state.copyWith(separateSingles: enabled);
+    _saveSettings();
+  }
+
+  void setShowExtensionStore(bool enabled) {
+    state = state.copyWith(showExtensionStore: enabled);
+    _saveSettings();
+  }
 }
 
 final settingsProvider = NotifierProvider<SettingsNotifier, AppSettings>(

lib/providers/store_provider.dart

@@ -0,0 +1,286 @@
+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/extension_provider.dart';
+
+final _log = AppLogger('StoreProvider');
+
+/// Extension categories
+class StoreCategory {
+  static const String metadata = 'metadata';
+  static const String download = 'download';
+  static const String utility = 'utility';
+  static const String lyrics = 'lyrics';
+  static const String integration = 'integration';
+
+  static const List<String> all = [metadata, download, utility, lyrics, integration];
+
+  static String getDisplayName(String category) {
+    switch (category) {
+      case metadata:
+        return 'Metadata';
+      case download:
+        return 'Download';
+      case utility:
+        return 'Utility';
+      case lyrics:
+        return 'Lyrics';
+      case integration:
+        return 'Integration';
+      default:
+        return category;
+    }
+  }
+}
+
+/// Represents an extension in the store
+class StoreExtension {
+  final String id;
+  final String name;
+  final String displayName;
+  final String version;
+  final String author;
+  final String description;
+  final String downloadUrl;
+  final String? iconUrl;
+  final String category;
+  final List<String> tags;
+  final int downloads;
+  final String updatedAt;
+  final String? minAppVersion;
+  final bool isInstalled;
+  final String? installedVersion;
+  final bool hasUpdate;
+
+  const StoreExtension({
+    required this.id,
+    required this.name,
+    required this.displayName,
+    required this.version,
+    required this.author,
+    required this.description,
+    required this.downloadUrl,
+    this.iconUrl,
+    required this.category,
+    this.tags = const [],
+    this.downloads = 0,
+    required this.updatedAt,
+    this.minAppVersion,
+    this.isInstalled = false,
+    this.installedVersion,
+    this.hasUpdate = false,
+  });
+
+  factory StoreExtension.fromJson(Map<String, dynamic> json) {
+    return StoreExtension(
+      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? ?? '',
+      downloadUrl: json['download_url'] as String? ?? '',
+      iconUrl: json['icon_url'] as String?,
+      category: json['category'] as String? ?? 'utility',
+      tags: (json['tags'] as List<dynamic>?)?.cast<String>() ?? [],
+      downloads: json['downloads'] as int? ?? 0,
+      updatedAt: json['updated_at'] as String? ?? '',
+      minAppVersion: json['min_app_version'] as String?,
+      isInstalled: json['is_installed'] as bool? ?? false,
+      installedVersion: json['installed_version'] as String?,
+      hasUpdate: json['has_update'] as bool? ?? false,
+    );
+  }
+}
+
+/// State for extension store
+class StoreState {
+  final List<StoreExtension> extensions;
+  final String? selectedCategory;
+  final String searchQuery;
+  final bool isLoading;
+  final bool isDownloading;
+  final String? downloadingId;
+  final String? error;
+  final bool isInitialized;
+
+  const StoreState({
+    this.extensions = const [],
+    this.selectedCategory,
+    this.searchQuery = '',
+    this.isLoading = false,
+    this.isDownloading = false,
+    this.downloadingId,
+    this.error,
+    this.isInitialized = false,
+  });
+
+  StoreState copyWith({
+    List<StoreExtension>? extensions,
+    String? selectedCategory,
+    bool clearCategory = false,
+    String? searchQuery,
+    bool? isLoading,
+    bool? isDownloading,
+    String? downloadingId,
+    bool clearDownloadingId = false,
+    String? error,
+    bool clearError = false,
+    bool? isInitialized,
+  }) {
+    return StoreState(
+      extensions: extensions ?? this.extensions,
+      selectedCategory: clearCategory ? null : (selectedCategory ?? this.selectedCategory),
+      searchQuery: searchQuery ?? this.searchQuery,
+      isLoading: isLoading ?? this.isLoading,
+      isDownloading: isDownloading ?? this.isDownloading,
+      downloadingId: clearDownloadingId ? null : (downloadingId ?? this.downloadingId),
+      error: clearError ? null : (error ?? this.error),
+      isInitialized: isInitialized ?? this.isInitialized,
+    );
+  }
+
+  /// Get filtered extensions based on category and search
+  List<StoreExtension> get filteredExtensions {
+    var result = extensions;
+
+    if (selectedCategory != null) {
+      result = result.where((e) => e.category == selectedCategory).toList();
+    }
+
+    if (searchQuery.isNotEmpty) {
+      final query = searchQuery.toLowerCase();
+      result = result.where((e) =>
+        e.name.toLowerCase().contains(query) ||
+        e.displayName.toLowerCase().contains(query) ||
+        e.description.toLowerCase().contains(query) ||
+        e.author.toLowerCase().contains(query) ||
+        e.tags.any((t) => t.toLowerCase().contains(query))
+      ).toList();
+    }
+
+    return result;
+  }
+}
+
+/// Provider for managing extension store
+class StoreNotifier extends Notifier<StoreState> {
+  @override
+  StoreState build() {
+    return const StoreState();
+  }
+
+  /// Initialize the store
+  Future<void> initialize(String cacheDir) async {
+    if (state.isInitialized) return;
+
+    state = state.copyWith(isLoading: true, clearError: true);
+
+    try {
+      await PlatformBridge.initExtensionStore(cacheDir);
+      await refresh();
+      state = state.copyWith(isInitialized: true, isLoading: false);
+      _log.i('Extension store initialized');
+    } catch (e) {
+      _log.e('Failed to initialize store: $e');
+      state = state.copyWith(isLoading: false, error: e.toString());
+    }
+  }
+
+  /// Refresh extensions from store
+  Future<void> refresh({bool forceRefresh = false}) async {
+    state = state.copyWith(isLoading: true, clearError: true);
+
+    try {
+      final extensions = await PlatformBridge.getStoreExtensions(forceRefresh: forceRefresh);
+      state = state.copyWith(
+        extensions: extensions.map((e) => StoreExtension.fromJson(e)).toList(),
+        isLoading: false,
+      );
+      _log.d('Loaded ${state.extensions.length} extensions from store');
+    } catch (e) {
+      _log.e('Failed to refresh store: $e');
+      state = state.copyWith(isLoading: false, error: e.toString());
+    }
+  }
+
+  /// Set category filter
+  void setCategory(String? category) {
+    if (category == null) {
+      state = state.copyWith(clearCategory: true);
+    } else {
+      state = state.copyWith(selectedCategory: category);
+    }
+  }
+
+  /// Set search query
+  void setSearchQuery(String query) {
+    state = state.copyWith(searchQuery: query);
+  }
+
+  /// Clear search
+  void clearSearch() {
+    state = state.copyWith(searchQuery: '', clearCategory: true);
+  }
+
+  /// Download and install extension
+  Future<bool> installExtension(String extensionId, String tempDir, String extensionsDir) async {
+    state = state.copyWith(isDownloading: true, downloadingId: extensionId, clearError: true);
+
+    try {
+      _log.i('Downloading extension: $extensionId');
+      final downloadPath = await PlatformBridge.downloadStoreExtension(extensionId, tempDir);
+
+      _log.i('Installing extension from: $downloadPath');
+      final extNotifier = ref.read(extensionProvider.notifier);
+      final success = await extNotifier.installExtension(downloadPath);
+
+      if (success) {
+        _log.i('Extension installed: $extensionId');
+        await refresh();
+      }
+
+      state = state.copyWith(isDownloading: false, clearDownloadingId: true);
+      return success;
+    } catch (e) {
+      _log.e('Failed to install extension: $e');
+      state = state.copyWith(isDownloading: false, clearDownloadingId: true, error: e.toString());
+      return false;
+    }
+  }
+
+  /// Update an installed extension
+  Future<bool> updateExtension(String extensionId, String tempDir) async {
+    state = state.copyWith(isDownloading: true, downloadingId: extensionId, clearError: true);
+
+    try {
+      _log.i('Downloading update for: $extensionId');
+      final downloadPath = await PlatformBridge.downloadStoreExtension(extensionId, tempDir);
+
+      _log.i('Upgrading extension from: $downloadPath');
+      final extNotifier = ref.read(extensionProvider.notifier);
+      final success = await extNotifier.upgradeExtension(downloadPath);
+
+      if (success) {
+        _log.i('Extension updated: $extensionId');
+        await refresh();
+      }
+
+      state = state.copyWith(isDownloading: false, clearDownloadingId: true);
+      return success;
+    } catch (e) {
+      _log.e('Failed to update extension: $e');
+      state = state.copyWith(isDownloading: false, clearDownloadingId: true, error: e.toString());
+      return false;
+    }
+  }
+
+  /// Clear error
+  void clearError() {
+    state = state.copyWith(clearError: true);
+  }
+}
+
+final storeProvider = NotifierProvider<StoreNotifier, StoreState>(
+  StoreNotifier.new,
+);

lib/providers/track_provider.dart

@@ -1,6 +1,11 @@
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:spotiflac_android/models/track.dart';
 import 'package:spotiflac_android/services/platform_bridge.dart';
+import 'package:spotiflac_android/utils/logger.dart';
+import 'package:spotiflac_android/providers/settings_provider.dart';
+import 'package:spotiflac_android/providers/extension_provider.dart';
+
+final _log = AppLogger('TrackProvider');
 
 class TrackState {
   final List<Track> tracks;
@@ -15,6 +20,7 @@ class TrackState {
   final List<ArtistAlbum>? artistAlbums; // For artist page
   final List<SearchArtist>? searchArtists; // For search results
   final bool hasSearchText; // For back button handling
+  final String? searchExtensionId; // Extension ID used for current search results
 
   const TrackState({
     this.tracks = const [],
@@ -29,6 +35,7 @@ class TrackState {
     this.artistAlbums,
     this.searchArtists,
     this.hasSearchText = false,
+    this.searchExtensionId,
   });
 
   bool get hasContent => tracks.isNotEmpty || artistAlbums != null || (searchArtists != null && searchArtists!.isNotEmpty);
@@ -46,6 +53,7 @@ class TrackState {
     List<ArtistAlbum>? artistAlbums,
     List<SearchArtist>? searchArtists,
     bool? hasSearchText,
+    String? searchExtensionId,
   }) {
     return TrackState(
       tracks: tracks ?? this.tracks,
@@ -60,6 +68,7 @@ class TrackState {
       artistAlbums: artistAlbums ?? this.artistAlbums,
       searchArtists: searchArtists ?? this.searchArtists,
       hasSearchText: hasSearchText ?? this.hasSearchText,
+      searchExtensionId: searchExtensionId,
     );
   }
 }
@@ -122,6 +131,59 @@ class TrackNotifier extends Notifier<TrackState> {
     state = TrackState(isLoading: true, hasSearchText: state.hasSearchText);
 
     try {
+      // First, check if any extension can handle this URL
+      final extensionHandler = await PlatformBridge.findURLHandler(url);
+      if (extensionHandler != null) {
+        _log.i('Found extension URL handler: $extensionHandler for URL: $url');
+        final result = await PlatformBridge.handleURLWithExtension(url);
+        if (!_isRequestValid(requestId)) return;
+        
+        if (result != null) {
+          final type = result['type'] as String?;
+          final extensionId = result['extension_id'] as String?;
+          
+          if (type == 'track' && result['track'] != null) {
+            final trackData = result['track'] as Map<String, dynamic>;
+            final track = _parseSearchTrack(trackData, source: extensionId);
+            state = TrackState(
+              tracks: [track],
+              isLoading: false,
+              coverUrl: track.coverUrl,
+              searchExtensionId: extensionId,
+            );
+            return;
+          } else if ((type == 'album' || type == 'playlist') && result['tracks'] != null) {
+            final trackList = result['tracks'] as List<dynamic>;
+            final tracks = trackList.map((t) => _parseSearchTrack(t as Map<String, dynamic>, source: extensionId)).toList();
+            state = TrackState(
+              tracks: tracks,
+              isLoading: false,
+              albumId: result['album']?['id'] as String?,
+              albumName: result['name'] as String? ?? result['album']?['name'] as String?,
+              playlistName: type == 'playlist' ? result['name'] as String? : null,
+              coverUrl: result['cover_url'] as String?,
+              searchExtensionId: extensionId,
+            );
+            return;
+          } else if (type == 'artist' && result['artist'] != null) {
+            final artistData = result['artist'] as Map<String, dynamic>;
+            final albumsList = artistData['albums'] as List<dynamic>? ?? [];
+            final albums = albumsList.map((a) => _parseArtistAlbum(a as Map<String, dynamic>)).toList();
+            state = TrackState(
+              tracks: [],
+              isLoading: false,
+              artistId: artistData['id'] as String?,
+              artistName: artistData['name'] as String?,
+              coverUrl: artistData['image_url'] as String? ?? artistData['images'] as String?,
+              artistAlbums: albums,
+              searchExtensionId: extensionId,
+            );
+            return;
+          }
+        }
+      }
+      
+      // No extension handler found, try Spotify URL parsing
       final parsed = await PlatformBridge.parseSpotifyUrl(url);
       if (!_isRequestValid(requestId)) return; // Request cancelled
       
@@ -207,31 +269,109 @@ class TrackNotifier extends Notifier<TrackState> {
     state = TrackState(isLoading: true, hasSearchText: state.hasSearchText);
 
     try {
+      // Check if extension providers should be used for search
+      final settings = ref.read(settingsProvider);
+      final extensionState = ref.read(extensionProvider);
+      final hasActiveMetadataExtensions = extensionState.extensions.any(
+        (e) => e.enabled && e.hasMetadataProvider,
+      );
+      final useExtensions = settings.useExtensionProviders && hasActiveMetadataExtensions;
+
       // Use Deezer or Spotify based on settings
       final source = metadataSource ?? 'deezer';
       
-      // Debug log to show which source is being used
-      // ignore: avoid_print
-      print('[Search] Using metadata source: $source for query: "$query"');
+      _log.i('Search started: source=$source, query="$query", useExtensions=$useExtensions');
       
       Map<String, dynamic> results;
-      if (source == 'deezer') {
-        results = await PlatformBridge.searchDeezerAll(query, trackLimit: 20, artistLimit: 5);
-        // ignore: avoid_print
-        print('[Search] Deezer returned ${(results['tracks'] as List?)?.length ?? 0} tracks');
-      } else {
-        results = await PlatformBridge.searchSpotifyAll(query, trackLimit: 20, artistLimit: 5);
-        // ignore: avoid_print
-        print('[Search] Spotify returned ${(results['tracks'] as List?)?.length ?? 0} tracks');
+      List<Track> extensionTracks = [];
+      
+      // Try extension providers first if enabled
+      if (useExtensions) {
+        try {
+          _log.d('Calling extension search API...');
+          final extResults = await PlatformBridge.searchTracksWithExtensions(query, limit: 20);
+          _log.i('Extensions returned ${extResults.length} tracks');
+          
+          // Parse extension results
+          for (final t in extResults) {
+            try {
+              extensionTracks.add(_parseSearchTrack(t));
+            } catch (e) {
+              _log.e('Failed to parse extension track: $e', e);
+            }
+          }
+        } catch (e) {
+          _log.w('Extension search failed, falling back to built-in: $e');
+        }
       }
       
-      if (!_isRequestValid(requestId)) return; // Request cancelled
+      // Also search with built-in providers
+      if (source == 'deezer') {
+        _log.d('Calling Deezer search API...');
+        results = await PlatformBridge.searchDeezerAll(query, trackLimit: 20, artistLimit: 5);
+        _log.i('Deezer returned ${(results['tracks'] as List?)?.length ?? 0} tracks, ${(results['artists'] as List?)?.length ?? 0} artists');
+      } else {
+        _log.d('Calling Spotify search API...');
+        results = await PlatformBridge.searchSpotifyAll(query, trackLimit: 20, artistLimit: 5);
+        _log.i('Spotify returned ${(results['tracks'] as List?)?.length ?? 0} tracks, ${(results['artists'] as List?)?.length ?? 0} artists');
+      }
+      
+      if (!_isRequestValid(requestId)) {
+        _log.w('Search request cancelled (requestId=$requestId)');
+        return;
+      }
       
       final trackList = results['tracks'] as List<dynamic>? ?? [];
       final artistList = results['artists'] as List<dynamic>? ?? [];
       
-      final tracks = trackList.map((t) => _parseSearchTrack(t as Map<String, dynamic>)).toList();
-      final artists = artistList.map((a) => _parseSearchArtist(a as Map<String, dynamic>)).toList();
+      _log.d('Raw results: ${trackList.length} tracks, ${artistList.length} artists');
+      
+      // Parse tracks with error handling per item
+      final tracks = <Track>[];
+      
+      // Add extension tracks first (they have priority)
+      tracks.addAll(extensionTracks);
+      
+      // Add built-in provider tracks, avoiding duplicates by ISRC
+      final existingIsrcs = extensionTracks
+          .where((t) => t.isrc != null && t.isrc!.isNotEmpty)
+          .map((t) => t.isrc!)
+          .toSet();
+      
+      for (int i = 0; i < trackList.length; i++) {
+        final t = trackList[i];
+        try {
+          if (t is Map<String, dynamic>) {
+            final track = _parseSearchTrack(t);
+            // Skip if we already have this track from extensions
+            if (track.isrc != null && existingIsrcs.contains(track.isrc)) {
+              continue;
+            }
+            tracks.add(track);
+          } else {
+            _log.w('Track[$i] is not a Map: ${t.runtimeType}');
+          }
+        } catch (e) {
+          _log.e('Failed to parse track[$i]: $e', e);
+        }
+      }
+      
+      // Parse artists with error handling per item
+      final artists = <SearchArtist>[];
+      for (int i = 0; i < artistList.length; i++) {
+        final a = artistList[i];
+        try {
+          if (a is Map<String, dynamic>) {
+            artists.add(_parseSearchArtist(a));
+          } else {
+            _log.w('Artist[$i] is not a Map: ${a.runtimeType}');
+          }
+        } catch (e) {
+          _log.e('Failed to parse artist[$i]: $e', e);
+        }
+      }
+      
+      _log.i('Search complete: ${tracks.length} tracks (${extensionTracks.length} from extensions), ${artists.length} artists parsed successfully');
       
       state = TrackState(
         tracks: tracks,
@@ -239,9 +379,56 @@ class TrackNotifier extends Notifier<TrackState> {
         isLoading: false,
         hasSearchText: state.hasSearchText,
       );
-    } catch (e) {
-      if (!_isRequestValid(requestId)) return; // Request cancelled
-      // Preserve hasSearchText on error so user stays on search screen
+    } catch (e, stackTrace) {
+      if (!_isRequestValid(requestId)) return;
+      _log.e('Search failed: $e', e, stackTrace);
+      state = TrackState(isLoading: false, error: e.toString(), hasSearchText: state.hasSearchText);
+    }
+  }
+
+  /// Perform custom search using a specific extension
+  Future<void> customSearch(String extensionId, String query, {Map<String, dynamic>? options}) async {
+    // Increment request ID to cancel any pending requests
+    final requestId = ++_currentRequestId;
+
+    // Preserve hasSearchText during search
+    state = TrackState(isLoading: true, hasSearchText: state.hasSearchText);
+
+    try {
+      _log.i('Custom search started: extension=$extensionId, query="$query"');
+      
+      final results = await PlatformBridge.customSearchWithExtension(extensionId, query, options: options);
+      
+      if (!_isRequestValid(requestId)) {
+        _log.w('Custom search request cancelled (requestId=$requestId)');
+        return;
+      }
+      
+      _log.i('Custom search returned ${results.length} tracks');
+      
+      // Parse tracks with error handling per item, setting source to extension ID
+      final tracks = <Track>[];
+      for (int i = 0; i < results.length; i++) {
+        final t = results[i];
+        try {
+          tracks.add(_parseSearchTrack(t, source: extensionId));
+        } catch (e) {
+          _log.e('Failed to parse custom search track[$i]: $e', e);
+        }
+      }
+      
+      _log.i('Custom search complete: ${tracks.length} tracks parsed (source=$extensionId)');
+      
+      state = TrackState(
+        tracks: tracks,
+        searchArtists: [], // Custom search doesn't return artists
+        isLoading: false,
+        hasSearchText: state.hasSearchText,
+        searchExtensionId: extensionId, // Store which extension was used
+      );
+    } catch (e, stackTrace) {
+      if (!_isRequestValid(requestId)) return;
+      _log.e('Custom search failed: $e', e, stackTrace);
       state = TrackState(isLoading: false, error: e.toString(), hasSearchText: state.hasSearchText);
     }
   }
@@ -309,19 +496,30 @@ class TrackNotifier extends Notifier<TrackState> {
     );
   }
 
-  Track _parseSearchTrack(Map<String, dynamic> data) {
+  Track _parseSearchTrack(Map<String, dynamic> data, {String? source}) {
+    // Handle duration_ms which might be int or double
+    int durationMs = 0;
+    final durationValue = data['duration_ms'];
+    if (durationValue is int) {
+      durationMs = durationValue;
+    } else if (durationValue is double) {
+      durationMs = durationValue.toInt();
+    }
+    
     return Track(
-      id: data['spotify_id'] as String? ?? '',
-      name: data['name'] as String? ?? '',
-      artistName: data['artists'] as String? ?? '',
-      albumName: data['album_name'] as String? ?? '',
-      albumArtist: data['album_artist'] as String?,
-      coverUrl: data['images'] as String?,
-      isrc: data['isrc'] as String?,
-      duration: ((data['duration_ms'] as int? ?? 0) / 1000).round(),
+      id: (data['spotify_id'] ?? data['id'] ?? '').toString(),
+      name: (data['name'] ?? '').toString(),
+      artistName: (data['artists'] ?? data['artist'] ?? '').toString(),
+      albumName: (data['album_name'] ?? data['album'] ?? '').toString(),
+      albumArtist: data['album_artist']?.toString(),
+      coverUrl: data['images']?.toString(),
+      isrc: data['isrc']?.toString(),
+      duration: (durationMs / 1000).round(),
       trackNumber: data['track_number'] as int?,
       discNumber: data['disc_number'] as int?,
-      releaseDate: data['release_date'] as String?,
+      releaseDate: data['release_date']?.toString(),
+      source: source ?? data['source']?.toString() ?? data['provider_id']?.toString(),
+      albumType: data['album_type']?.toString(),
     );
   }
 

lib/screens/album_screen.dart

@@ -7,6 +7,7 @@ import 'package:spotiflac_android/models/download_item.dart';
 import 'package:spotiflac_android/providers/download_queue_provider.dart';
 import 'package:spotiflac_android/providers/settings_provider.dart';
 import 'package:spotiflac_android/services/platform_bridge.dart';
+import 'package:spotiflac_android/widgets/download_service_picker.dart';
 
 /// Simple in-memory cache for album tracks
 class _AlbumCache {
@@ -316,10 +317,16 @@ class _AlbumScreenState extends ConsumerState<AlbumScreen> {
   void _downloadTrack(BuildContext context, Track track) {
     final settings = ref.read(settingsProvider);
     if (settings.askQualityBeforeDownload) {
-      _showQualityPicker(context, (quality, service) {
-        ref.read(downloadQueueProvider.notifier).addToQueue(track, service, qualityOverride: quality);
-        ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text('Added "${track.name}" to queue')));
-      }, trackName: track.name, artistName: track.artistName, coverUrl: track.coverUrl);
+      DownloadServicePicker.show(
+        context,
+        trackName: track.name,
+        artistName: track.artistName,
+        coverUrl: track.coverUrl,
+        onSelect: (quality, service) {
+          ref.read(downloadQueueProvider.notifier).addToQueue(track, service, qualityOverride: quality);
+          ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text('Added "${track.name}" to queue')));
+        },
+      );
     } else {
       ref.read(downloadQueueProvider.notifier).addToQueue(track, settings.defaultService);
       ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text('Added "${track.name}" to queue')));
@@ -331,84 +338,21 @@ class _AlbumScreenState extends ConsumerState<AlbumScreen> {
     if (tracks == null || tracks.isEmpty) return;
     final settings = ref.read(settingsProvider);
     if (settings.askQualityBeforeDownload) {
-      _showQualityPicker(context, (quality, service) {
-        ref.read(downloadQueueProvider.notifier).addMultipleToQueue(tracks, service, qualityOverride: quality);
-        ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text('Added ${tracks.length} tracks to queue')));
-      }, trackName: '${tracks.length} tracks', artistName: widget.albumName);
+      DownloadServicePicker.show(
+        context,
+        trackName: '${tracks.length} tracks',
+        artistName: widget.albumName,
+        onSelect: (quality, service) {
+          ref.read(downloadQueueProvider.notifier).addMultipleToQueue(tracks, service, qualityOverride: quality);
+          ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text('Added ${tracks.length} tracks to queue')));
+        },
+      );
     } else {
       ref.read(downloadQueueProvider.notifier).addMultipleToQueue(tracks, settings.defaultService);
       ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text('Added ${tracks.length} tracks to queue')));
     }
   }
 
-  void _showQualityPicker(BuildContext context, void Function(String quality, String service) onSelect, {String? trackName, String? artistName, String? coverUrl}) {
-    final colorScheme = Theme.of(context).colorScheme;
-    final settings = ref.read(settingsProvider);
-    String selectedService = settings.defaultService;
-    
-    showModalBottomSheet(
-      context: context,
-      backgroundColor: colorScheme.surfaceContainerHigh,
-      shape: const RoundedRectangleBorder(borderRadius: BorderRadius.vertical(top: Radius.circular(28))),
-      isScrollControlled: true,
-      builder: (context) => StatefulBuilder(
-        builder: (context, setModalState) => SafeArea(
-          child: SingleChildScrollView(
-            child: Column(
-              mainAxisSize: MainAxisSize.min,
-              crossAxisAlignment: CrossAxisAlignment.start,
-              children: [
-                if (trackName != null) ...[
-                  _TrackInfoHeader(trackName: trackName, artistName: artistName, coverUrl: coverUrl),
-                  Divider(height: 1, color: colorScheme.outlineVariant.withValues(alpha: 0.5)),
-                ] else ...[
-                  const SizedBox(height: 8),
-                  Center(child: Container(width: 40, height: 4, decoration: BoxDecoration(color: colorScheme.onSurfaceVariant.withValues(alpha: 0.4), borderRadius: BorderRadius.circular(2)))),
-                ],
-                // Service selector
-                Padding(
-                  padding: const EdgeInsets.fromLTRB(24, 16, 24, 8),
-                  child: Text('Download From', style: Theme.of(context).textTheme.titleMedium?.copyWith(fontWeight: FontWeight.bold)),
-                ),
-                Padding(
-                  padding: const EdgeInsets.symmetric(horizontal: 20),
-                  child: Row(
-                    children: [
-                      _ServiceChip(label: 'Tidal', isSelected: selectedService == 'tidal', onTap: () => setModalState(() => selectedService = 'tidal')),
-                      const SizedBox(width: 8),
-                      _ServiceChip(label: 'Qobuz', isSelected: selectedService == 'qobuz', onTap: () => setModalState(() => selectedService = 'qobuz')),
-                      const SizedBox(width: 8),
-                      _ServiceChip(label: 'Amazon', isSelected: selectedService == 'amazon', onTap: () => setModalState(() => selectedService = 'amazon')),
-                    ],
-                  ),
-                ),
-                Padding(
-                  padding: const EdgeInsets.fromLTRB(24, 16, 24, 8),
-                  child: Text('Select Quality', style: Theme.of(context).textTheme.titleMedium?.copyWith(fontWeight: FontWeight.bold)),
-                ),
-                // Disclaimer
-                Padding(
-                  padding: const EdgeInsets.fromLTRB(24, 0, 24, 12),
-                  child: Text(
-                    'Actual quality depends on track availability. Hi-Res may not be available for all tracks.',
-                    style: Theme.of(context).textTheme.bodySmall?.copyWith(
-                      color: colorScheme.onSurfaceVariant,
-                      fontStyle: FontStyle.italic,
-                    ),
-                  ),
-                ),
-                _QualityOption(title: 'FLAC Lossless', subtitle: '16-bit / 44.1kHz', icon: Icons.music_note, onTap: () { Navigator.pop(context); onSelect('LOSSLESS', selectedService); }),
-                _QualityOption(title: 'Hi-Res FLAC', subtitle: '24-bit / up to 96kHz', icon: Icons.high_quality, onTap: () { Navigator.pop(context); onSelect('HI_RES', selectedService); }),
-                _QualityOption(title: 'Hi-Res FLAC Max', subtitle: '24-bit / up to 192kHz', icon: Icons.four_k, onTap: () { Navigator.pop(context); onSelect('HI_RES_LOSSLESS', selectedService); }),
-                const SizedBox(height: 16),
-              ],
-            ),
-          ),
-        ),
-      ),
-    );
-  }
-
   /// Build error widget with special handling for rate limit (429)
   Widget _buildErrorWidget(String error, ColorScheme colorScheme) {
     final isRateLimit = error.contains('429') || 
@@ -473,148 +417,6 @@ class _AlbumScreenState extends ConsumerState<AlbumScreen> {
   }
 }
 
-class _QualityOption extends StatelessWidget {
-  final String title;
-  final String subtitle;
-  final IconData icon;
-  final VoidCallback onTap;
-
-  const _QualityOption({required this.title, required this.subtitle, required this.icon, required this.onTap});
-
-  @override
-  Widget build(BuildContext context) {
-    final colorScheme = Theme.of(context).colorScheme;
-    return ListTile(
-      contentPadding: const EdgeInsets.symmetric(horizontal: 24, vertical: 4),
-      leading: Container(padding: const EdgeInsets.all(10), decoration: BoxDecoration(color: colorScheme.primaryContainer, borderRadius: BorderRadius.circular(12)), child: Icon(icon, color: colorScheme.onPrimaryContainer, size: 20)),
-      title: Text(title, style: const TextStyle(fontWeight: FontWeight.w500)),
-      subtitle: Text(subtitle, style: TextStyle(color: colorScheme.onSurfaceVariant)),
-      onTap: onTap,
-    );
-  }
-}
-
-class _ServiceChip extends StatelessWidget {
-  final String label;
-  final bool isSelected;
-  final VoidCallback onTap;
-  const _ServiceChip({required this.label, required this.isSelected, required this.onTap});
-
-  @override
-  Widget build(BuildContext context) {
-    final colorScheme = Theme.of(context).colorScheme;
-    return Expanded(
-      child: GestureDetector(
-        onTap: onTap,
-        child: AnimatedContainer(
-          duration: const Duration(milliseconds: 200),
-          padding: const EdgeInsets.symmetric(vertical: 10),
-          decoration: BoxDecoration(
-            color: isSelected ? colorScheme.primaryContainer : colorScheme.surfaceContainerHighest,
-            borderRadius: BorderRadius.circular(12),
-            border: isSelected ? null : Border.all(color: colorScheme.outlineVariant.withValues(alpha: 0.5)),
-          ),
-          child: Text(
-            label,
-            textAlign: TextAlign.center,
-            style: TextStyle(
-              fontWeight: isSelected ? FontWeight.w600 : FontWeight.normal,
-              color: isSelected ? colorScheme.onPrimaryContainer : colorScheme.onSurfaceVariant,
-            ),
-          ),
-        ),
-      ),
-    );
-  }
-}
-
-class _TrackInfoHeader extends StatefulWidget {
-  final String trackName;
-  final String? artistName;
-  final String? coverUrl;
-  const _TrackInfoHeader({required this.trackName, this.artistName, this.coverUrl});
-
-  @override
-  State<_TrackInfoHeader> createState() => _TrackInfoHeaderState();
-}
-
-class _TrackInfoHeaderState extends State<_TrackInfoHeader> {
-  bool _expanded = false;
-  bool _isOverflowing = false;
-
-  @override
-  Widget build(BuildContext context) {
-    final colorScheme = Theme.of(context).colorScheme;
-    return Material(
-      color: Colors.transparent,
-      child: InkWell(
-        onTap: _isOverflowing ? () => setState(() => _expanded = !_expanded) : null,
-        borderRadius: const BorderRadius.only(topLeft: Radius.circular(28), topRight: Radius.circular(28)),
-        child: Column(
-          children: [
-            const SizedBox(height: 8),
-            Container(width: 40, height: 4, decoration: BoxDecoration(color: colorScheme.onSurfaceVariant.withValues(alpha: 0.4), borderRadius: BorderRadius.circular(2))),
-            Padding(
-              padding: const EdgeInsets.fromLTRB(16, 12, 16, 12),
-              child: Row(
-                children: [
-                  ClipRRect(
-                    borderRadius: BorderRadius.circular(8),
-                    child: widget.coverUrl != null
-                        ? Image.network(widget.coverUrl!, width: 56, height: 56, fit: BoxFit.cover,
-                            errorBuilder: (_, e, s) => Container(width: 56, height: 56, color: colorScheme.surfaceContainerHighest, child: Icon(Icons.music_note, color: colorScheme.onSurfaceVariant)))
-                        : Container(width: 56, height: 56, color: colorScheme.surfaceContainerHighest, child: Icon(Icons.music_note, color: colorScheme.onSurfaceVariant)),
-                  ),
-                  const SizedBox(width: 12),
-                  Expanded(
-                    child: LayoutBuilder(
-                      builder: (context, constraints) {
-                        final titleStyle = Theme.of(context).textTheme.titleMedium?.copyWith(fontWeight: FontWeight.w600);
-                        final titleSpan = TextSpan(text: widget.trackName, style: titleStyle);
-                        final titlePainter = TextPainter(text: titleSpan, maxLines: 1, textDirection: TextDirection.ltr)..layout(maxWidth: constraints.maxWidth);
-                        final titleOverflows = titlePainter.didExceedMaxLines;
-                        
-                        WidgetsBinding.instance.addPostFrameCallback((_) {
-                          if (mounted && _isOverflowing != titleOverflows) {
-                            setState(() => _isOverflowing = titleOverflows);
-                          }
-                        });
-                        
-                        return Column(
-                          crossAxisAlignment: CrossAxisAlignment.start,
-                          children: [
-                            Text(
-                              widget.trackName,
-                              style: titleStyle,
-                              maxLines: _expanded ? 10 : 1,
-                              overflow: _expanded ? TextOverflow.visible : TextOverflow.ellipsis,
-                            ),
-                            if (widget.artistName != null) ...[
-                              const SizedBox(height: 2),
-                              Text(
-                                widget.artistName!,
-                                style: Theme.of(context).textTheme.bodyMedium?.copyWith(color: colorScheme.onSurfaceVariant),
-                                maxLines: _expanded ? 3 : 1,
-                                overflow: _expanded ? TextOverflow.visible : TextOverflow.ellipsis,
-                              ),
-                            ],
-                          ],
-                        );
-                      },
-                    ),
-                  ),
-                  if (_isOverflowing || _expanded)
-                    Icon(_expanded ? Icons.expand_less : Icons.expand_more, color: colorScheme.onSurfaceVariant, size: 20),
-                ],
-              ),
-            ),
-          ],
-        ),
-      ),
-    );
-  }
-}
-
 /// Separate Consumer widget for each track - only rebuilds when this specific track's status changes
 class _AlbumTrackItem extends ConsumerWidget {
   final Track track;

lib/screens/artist_screen.dart

@@ -159,6 +159,11 @@ class _ArtistScreenState extends ConsumerState<ArtistScreen> {
   }
 
   Widget _buildAppBar(BuildContext context, ColorScheme colorScheme) {
+    // Validate image URL - must be non-null, non-empty, and have a valid host
+    final hasValidImage = widget.coverUrl != null && 
+                          widget.coverUrl!.isNotEmpty &&
+                          Uri.tryParse(widget.coverUrl!)?.hasAuthority == true;
+    
     return SliverAppBar(
       expandedHeight: 280,
       pinned: true,
@@ -169,8 +174,15 @@ class _ArtistScreenState extends ConsumerState<ArtistScreen> {
         background: Stack(
           fit: StackFit.expand,
           children: [
-            if (widget.coverUrl != null)
-              CachedNetworkImage(imageUrl: widget.coverUrl!, fit: BoxFit.cover, color: Colors.black.withValues(alpha: 0.5), colorBlendMode: BlendMode.darken, memCacheWidth: 600),
+            if (hasValidImage)
+              CachedNetworkImage(
+                imageUrl: widget.coverUrl!, 
+                fit: BoxFit.cover, 
+                color: Colors.black.withValues(alpha: 0.5), 
+                colorBlendMode: BlendMode.darken, 
+                memCacheWidth: 600,
+                errorWidget: (context, url, error) => Container(color: colorScheme.surfaceContainerHighest),
+              ),
             Container(
               decoration: BoxDecoration(
                 gradient: LinearGradient(
@@ -192,8 +204,16 @@ class _ArtistScreenState extends ConsumerState<ArtistScreen> {
                     boxShadow: [BoxShadow(color: Colors.black.withValues(alpha: 0.3), blurRadius: 20, offset: const Offset(0, 10))],
                   ),
                   child: ClipOval(
-                    child: widget.coverUrl != null
-                        ? CachedNetworkImage(imageUrl: widget.coverUrl!, fit: BoxFit.cover, memCacheWidth: 280)
+                    child: hasValidImage
+                        ? CachedNetworkImage(
+                            imageUrl: widget.coverUrl!, 
+                            fit: BoxFit.cover, 
+                            memCacheWidth: 280,
+                            errorWidget: (context, url, error) => Container(
+                              color: colorScheme.surfaceContainerHighest, 
+                              child: Icon(Icons.person, size: 48, color: colorScheme.onSurfaceVariant),
+                            ),
+                          )
                         : Container(color: colorScheme.surfaceContainerHighest, child: Icon(Icons.person, size: 48, color: colorScheme.onSurfaceVariant)),
                   ),
                 ),

lib/screens/downloaded_album_screen.dart

@@ -0,0 +1,573 @@
+import 'dart:io';
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:cached_network_image/cached_network_image.dart';
+import 'package:open_filex/open_filex.dart';
+import 'package:spotiflac_android/providers/download_queue_provider.dart';
+import 'package:spotiflac_android/screens/track_metadata_screen.dart';
+
+/// Screen to display downloaded tracks from a specific album
+class DownloadedAlbumScreen extends ConsumerStatefulWidget {
+  final String albumName;
+  final String artistName;
+  final String? coverUrl;
+
+  const DownloadedAlbumScreen({
+    super.key,
+    required this.albumName,
+    required this.artistName,
+    this.coverUrl,
+  });
+
+  @override
+  ConsumerState<DownloadedAlbumScreen> createState() => _DownloadedAlbumScreenState();
+}
+
+class _DownloadedAlbumScreenState extends ConsumerState<DownloadedAlbumScreen> {
+  // Multi-select state
+  bool _isSelectionMode = false;
+  final Set<String> _selectedIds = {};
+
+  /// Get tracks for this album from history provider (reactive)
+  List<DownloadHistoryItem> _getAlbumTracks(List<DownloadHistoryItem> allItems) {
+    return allItems.where((item) {
+      final itemKey = '${item.albumName}|${item.albumArtist ?? item.artistName}';
+      final albumKey = '${widget.albumName}|${widget.artistName}';
+      return itemKey == albumKey;
+    }).toList()
+      ..sort((a, b) {
+        final aNum = a.trackNumber ?? 999;
+        final bNum = b.trackNumber ?? 999;
+        if (aNum != bNum) return aNum.compareTo(bNum);
+        return a.trackName.compareTo(b.trackName);
+      });
+  }
+
+  void _enterSelectionMode(String itemId) {
+    HapticFeedback.mediumImpact();
+    setState(() {
+      _isSelectionMode = true;
+      _selectedIds.add(itemId);
+    });
+  }
+
+  void _exitSelectionMode() {
+    setState(() {
+      _isSelectionMode = false;
+      _selectedIds.clear();
+    });
+  }
+
+  void _toggleSelection(String itemId) {
+    setState(() {
+      if (_selectedIds.contains(itemId)) {
+        _selectedIds.remove(itemId);
+        if (_selectedIds.isEmpty) {
+          _isSelectionMode = false;
+        }
+      } else {
+        _selectedIds.add(itemId);
+      }
+    });
+  }
+
+  void _selectAll(List<DownloadHistoryItem> tracks) {
+    setState(() {
+      _selectedIds.addAll(tracks.map((e) => e.id));
+    });
+  }
+
+  Future<void> _deleteSelected(List<DownloadHistoryItem> currentTracks) async {
+    final count = _selectedIds.length;
+    final confirmed = await showDialog<bool>(
+      context: context,
+      builder: (ctx) => AlertDialog(
+        title: const Text('Delete Selected'),
+        content: Text('Delete $count ${count == 1 ? 'track' : 'tracks'} from this album?\n\nThis will also delete the files from storage.'),
+        actions: [
+          TextButton(
+            onPressed: () => Navigator.pop(ctx, false),
+            child: const Text('Cancel'),
+          ),
+          FilledButton(
+            onPressed: () => Navigator.pop(ctx, true),
+            style: FilledButton.styleFrom(
+              backgroundColor: Theme.of(context).colorScheme.error,
+            ),
+            child: const Text('Delete'),
+          ),
+        ],
+      ),
+    );
+
+    if (confirmed == true && mounted) {
+      final historyNotifier = ref.read(downloadHistoryProvider.notifier);
+      final idsToDelete = _selectedIds.toList();
+      
+      int deletedCount = 0;
+      for (final id in idsToDelete) {
+        final item = currentTracks.where((e) => e.id == id).firstOrNull;
+        if (item != null) {
+          try {
+            final file = File(item.filePath);
+            if (await file.exists()) {
+              await file.delete();
+            }
+          } catch (_) {}
+          historyNotifier.removeFromHistory(id);
+          deletedCount++;
+        }
+      }
+      
+      _exitSelectionMode();
+      
+      if (mounted) {
+        ScaffoldMessenger.of(context).showSnackBar(
+          SnackBar(content: Text('Deleted $deletedCount ${deletedCount == 1 ? 'track' : 'tracks'}')),
+        );
+      }
+    }
+  }
+
+  Future<void> _openFile(String filePath) async {
+    try {
+      await OpenFilex.open(filePath);
+    } catch (e) {
+      if (mounted) {
+        ScaffoldMessenger.of(context).showSnackBar(
+          SnackBar(content: Text('Cannot open file: $e')),
+        );
+      }
+    }
+  }
+
+  void _navigateToMetadataScreen(DownloadHistoryItem item) {
+    Navigator.push(context, PageRouteBuilder(
+      transitionDuration: const Duration(milliseconds: 300),
+      reverseTransitionDuration: const Duration(milliseconds: 250),
+      pageBuilder: (context, animation, secondaryAnimation) => TrackMetadataScreen(item: item),
+      transitionsBuilder: (context, animation, secondaryAnimation, child) => FadeTransition(opacity: animation, child: child),
+    ));
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final colorScheme = Theme.of(context).colorScheme;
+    final bottomPadding = MediaQuery.of(context).padding.bottom;
+    
+    // Watch history and get tracks for this album (reactive!)
+    final allHistoryItems = ref.watch(downloadHistoryProvider.select((s) => s.items));
+    final tracks = _getAlbumTracks(allHistoryItems);
+    
+    // Auto-pop if album has less than 2 tracks (no longer an "album")
+    if (tracks.length < 2) {
+      WidgetsBinding.instance.addPostFrameCallback((_) {
+        if (mounted) Navigator.pop(context);
+      });
+      return const SizedBox.shrink();
+    }
+    
+    // Clean up selected IDs that no longer exist
+    final validIds = tracks.map((t) => t.id).toSet();
+    _selectedIds.removeWhere((id) => !validIds.contains(id));
+    if (_selectedIds.isEmpty && _isSelectionMode) {
+      WidgetsBinding.instance.addPostFrameCallback((_) {
+        if (mounted) setState(() => _isSelectionMode = false);
+      });
+    }
+
+    return PopScope(
+      canPop: !_isSelectionMode,
+      onPopInvokedWithResult: (didPop, result) {
+        if (!didPop && _isSelectionMode) {
+          _exitSelectionMode();
+        }
+      },
+      child: Scaffold(
+        body: Stack(
+          children: [
+            CustomScrollView(
+              slivers: [
+                _buildAppBar(context, colorScheme),
+                _buildInfoCard(context, colorScheme, tracks),
+                _buildTrackListHeader(context, colorScheme, tracks),
+                _buildTrackList(context, colorScheme, tracks),
+                SliverToBoxAdapter(child: SizedBox(height: _isSelectionMode ? 120 : 32)),
+              ],
+            ),
+            
+            // Bottom Selection Action Bar
+            AnimatedPositioned(
+              duration: const Duration(milliseconds: 250),
+              curve: Curves.easeOutCubic,
+              left: 0,
+              right: 0,
+              bottom: _isSelectionMode ? 0 : -(200 + bottomPadding),
+              child: _buildSelectionBottomBar(context, colorScheme, tracks, bottomPadding),
+            ),
+          ],
+        ),
+      ),
+    );
+  }
+
+  Widget _buildAppBar(BuildContext context, ColorScheme colorScheme) {
+    return SliverAppBar(
+      expandedHeight: 280,
+      pinned: true,
+      stretch: true,
+      backgroundColor: colorScheme.surface,
+      surfaceTintColor: Colors.transparent,
+      flexibleSpace: FlexibleSpaceBar(
+        background: Stack(
+          fit: StackFit.expand,
+          children: [
+            if (widget.coverUrl != null)
+              CachedNetworkImage(
+                imageUrl: widget.coverUrl!,
+                fit: BoxFit.cover,
+                color: Colors.black.withValues(alpha: 0.5),
+                colorBlendMode: BlendMode.darken,
+                memCacheWidth: 600,
+              ),
+            Container(
+              decoration: BoxDecoration(
+                gradient: LinearGradient(
+                  begin: Alignment.topCenter,
+                  end: Alignment.bottomCenter,
+                  colors: [
+                    Colors.transparent,
+                    colorScheme.surface.withValues(alpha: 0.8),
+                    colorScheme.surface,
+                  ],
+                  stops: const [0.0, 0.7, 1.0],
+                ),
+              ),
+            ),
+            Center(
+              child: Padding(
+                padding: const EdgeInsets.only(top: 60),
+                child: Container(
+                  width: 140,
+                  height: 140,
+                  decoration: BoxDecoration(
+                    borderRadius: BorderRadius.circular(16),
+                    boxShadow: [
+                      BoxShadow(
+                        color: Colors.black.withValues(alpha: 0.3),
+                        blurRadius: 20,
+                        offset: const Offset(0, 10),
+                      ),
+                    ],
+                  ),
+                  child: ClipRRect(
+                    borderRadius: BorderRadius.circular(16),
+                    child: widget.coverUrl != null
+                        ? CachedNetworkImage(imageUrl: widget.coverUrl!, fit: BoxFit.cover, memCacheWidth: 280)
+                        : Container(
+                            color: colorScheme.surfaceContainerHighest,
+                            child: Icon(Icons.album, size: 48, color: colorScheme.onSurfaceVariant),
+                          ),
+                  ),
+                ),
+              ),
+            ),
+          ],
+        ),
+        stretchModes: const [StretchMode.zoomBackground, StretchMode.blurBackground],
+      ),
+      leading: IconButton(
+        icon: Container(
+          padding: const EdgeInsets.all(8),
+          decoration: BoxDecoration(color: colorScheme.surface.withValues(alpha: 0.8), shape: BoxShape.circle),
+          child: Icon(Icons.arrow_back, color: colorScheme.onSurface),
+        ),
+        onPressed: () => Navigator.pop(context),
+      ),
+    );
+  }
+
+  Widget _buildInfoCard(BuildContext context, ColorScheme colorScheme, List<DownloadHistoryItem> tracks) {
+    return SliverToBoxAdapter(
+      child: Padding(
+        padding: const EdgeInsets.all(16),
+        child: Card(
+          elevation: 0,
+          color: colorScheme.surfaceContainerLow,
+          shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(20)),
+          child: Padding(
+            padding: const EdgeInsets.all(20),
+            child: Column(
+              crossAxisAlignment: CrossAxisAlignment.start,
+              children: [
+                Text(
+                  widget.albumName,
+                  style: Theme.of(context).textTheme.headlineSmall?.copyWith(fontWeight: FontWeight.bold, color: colorScheme.onSurface),
+                ),
+                const SizedBox(height: 4),
+                Text(
+                  widget.artistName,
+                  style: Theme.of(context).textTheme.bodyLarge?.copyWith(color: colorScheme.onSurfaceVariant),
+                ),
+                const SizedBox(height: 12),
+                Row(
+                  children: [
+                    Container(
+                      padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 6),
+                      decoration: BoxDecoration(color: colorScheme.primaryContainer, borderRadius: BorderRadius.circular(20)),
+                      child: Row(
+                        mainAxisSize: MainAxisSize.min,
+                        children: [
+                          Icon(Icons.download_done, size: 14, color: colorScheme.onPrimaryContainer),
+                          const SizedBox(width: 4),
+                          Text('${tracks.length} downloaded', style: TextStyle(color: colorScheme.onPrimaryContainer, fontWeight: FontWeight.w600, fontSize: 12)),
+                        ],
+                      ),
+                    ),
+                    const SizedBox(width: 8),
+                    if (_getCommonQuality(tracks) != null)
+                      Container(
+                        padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 6),
+                        decoration: BoxDecoration(
+                          color: _getCommonQuality(tracks)!.startsWith('24') 
+                              ? colorScheme.tertiaryContainer 
+                              : colorScheme.surfaceContainerHighest,
+                          borderRadius: BorderRadius.circular(20),
+                        ),
+                        child: Text(
+                          _getCommonQuality(tracks)!,
+                          style: TextStyle(
+                            color: _getCommonQuality(tracks)!.startsWith('24') 
+                                ? colorScheme.onTertiaryContainer 
+                                : colorScheme.onSurfaceVariant,
+                            fontWeight: FontWeight.w600,
+                            fontSize: 12,
+                          ),
+                        ),
+                      ),
+                  ],
+                ),
+              ],
+            ),
+          ),
+        ),
+      ),
+    );
+  }
+
+  String? _getCommonQuality(List<DownloadHistoryItem> tracks) {
+    if (tracks.isEmpty) return null;
+    final firstQuality = tracks.first.quality;
+    if (firstQuality == null) return null;
+    for (final track in tracks) {
+      if (track.quality != firstQuality) return null;
+    }
+    return firstQuality;
+  }
+
+  Widget _buildTrackListHeader(BuildContext context, ColorScheme colorScheme, List<DownloadHistoryItem> tracks) {
+    return SliverToBoxAdapter(
+      child: Padding(
+        padding: const EdgeInsets.fromLTRB(20, 8, 20, 8),
+        child: Row(
+          children: [
+            Icon(Icons.queue_music, size: 20, color: colorScheme.primary),
+            const SizedBox(width: 8),
+            Text('Tracks', style: Theme.of(context).textTheme.titleMedium?.copyWith(fontWeight: FontWeight.w600, color: colorScheme.onSurface)),
+            const Spacer(),
+            if (!_isSelectionMode)
+              TextButton.icon(
+                onPressed: tracks.isNotEmpty ? () => _enterSelectionMode(tracks.first.id) : null,
+                icon: const Icon(Icons.checklist, size: 18),
+                label: const Text('Select'),
+                style: TextButton.styleFrom(visualDensity: VisualDensity.compact),
+              ),
+          ],
+        ),
+      ),
+    );
+  }
+
+  Widget _buildTrackList(BuildContext context, ColorScheme colorScheme, List<DownloadHistoryItem> tracks) {
+    return SliverList(
+      delegate: SliverChildBuilderDelegate(
+        (context, index) {
+          final track = tracks[index];
+          return KeyedSubtree(
+            key: ValueKey(track.id),
+            child: _buildTrackItem(context, colorScheme, track),
+          );
+        },
+        childCount: tracks.length,
+      ),
+    );
+  }
+
+  Widget _buildTrackItem(BuildContext context, ColorScheme colorScheme, DownloadHistoryItem track) {
+    final isSelected = _selectedIds.contains(track.id);
+    
+    return Padding(
+      padding: const EdgeInsets.symmetric(horizontal: 8),
+      child: Card(
+        elevation: 0,
+        color: isSelected ? colorScheme.primaryContainer.withValues(alpha: 0.3) : Colors.transparent,
+        margin: const EdgeInsets.symmetric(vertical: 2),
+        child: ListTile(
+          shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(12)),
+          onTap: _isSelectionMode 
+              ? () => _toggleSelection(track.id)
+              : () => _navigateToMetadataScreen(track),
+          onLongPress: _isSelectionMode ? null : () => _enterSelectionMode(track.id),
+          leading: Row(
+            mainAxisSize: MainAxisSize.min,
+            children: [
+              if (_isSelectionMode) ...[
+                Container(
+                  width: 24,
+                  height: 24,
+                  decoration: BoxDecoration(
+                    color: isSelected ? colorScheme.primary : Colors.transparent,
+                    shape: BoxShape.circle,
+                    border: Border.all(color: isSelected ? colorScheme.primary : colorScheme.outline, width: 2),
+                  ),
+                  child: isSelected 
+                      ? Icon(Icons.check, color: colorScheme.onPrimary, size: 16)
+                      : null,
+                ),
+                const SizedBox(width: 12),
+              ],
+              SizedBox(
+                width: 24,
+                child: Text(
+                  track.trackNumber?.toString() ?? '-',
+                  style: Theme.of(context).textTheme.bodyMedium?.copyWith(
+                    color: colorScheme.onSurfaceVariant,
+                    fontWeight: FontWeight.w500,
+                  ),
+                  textAlign: TextAlign.center,
+                ),
+              ),
+            ],
+          ),
+          title: Text(
+            track.trackName,
+            maxLines: 1,
+            overflow: TextOverflow.ellipsis,
+            style: Theme.of(context).textTheme.bodyLarge?.copyWith(fontWeight: FontWeight.w500),
+          ),
+          subtitle: Text(
+            track.artistName,
+            maxLines: 1,
+            overflow: TextOverflow.ellipsis,
+            style: TextStyle(color: colorScheme.onSurfaceVariant),
+          ),
+          trailing: _isSelectionMode ? null : IconButton(
+            onPressed: () => _openFile(track.filePath),
+            icon: Icon(Icons.play_arrow, color: colorScheme.primary),
+            style: IconButton.styleFrom(
+              backgroundColor: colorScheme.primaryContainer.withValues(alpha: 0.3),
+            ),
+          ),
+        ),
+      ),
+    );
+  }
+
+  Widget _buildSelectionBottomBar(BuildContext context, ColorScheme colorScheme, List<DownloadHistoryItem> tracks, double bottomPadding) {
+    final selectedCount = _selectedIds.length;
+    final allSelected = selectedCount == tracks.length && tracks.isNotEmpty;
+    
+    return Container(
+      decoration: BoxDecoration(
+        color: colorScheme.surfaceContainerHigh,
+        borderRadius: const BorderRadius.vertical(top: Radius.circular(28)),
+        boxShadow: [
+          BoxShadow(
+            color: Colors.black.withValues(alpha: 0.15),
+            blurRadius: 12,
+            offset: const Offset(0, -4),
+          ),
+        ],
+      ),
+      child: SafeArea(
+        top: false,
+        child: Padding(
+          padding: EdgeInsets.fromLTRB(16, 16, 16, bottomPadding > 0 ? 8 : 16),
+          child: Column(
+            mainAxisSize: MainAxisSize.min,
+            children: [
+              Container(
+                width: 32,
+                height: 4,
+                margin: const EdgeInsets.only(bottom: 16),
+                decoration: BoxDecoration(
+                  color: colorScheme.outlineVariant,
+                  borderRadius: BorderRadius.circular(2),
+                ),
+              ),
+              Row(
+                children: [
+                  IconButton.filledTonal(
+                    onPressed: _exitSelectionMode,
+                    icon: const Icon(Icons.close),
+                    style: IconButton.styleFrom(
+                      backgroundColor: colorScheme.surfaceContainerHighest,
+                    ),
+                  ),
+                  const SizedBox(width: 12),
+                  Expanded(
+                    child: Column(
+                      crossAxisAlignment: CrossAxisAlignment.start,
+                      children: [
+                        Text(
+                          '$selectedCount selected',
+                          style: Theme.of(context).textTheme.titleMedium?.copyWith(fontWeight: FontWeight.bold),
+                        ),
+                        Text(
+                          allSelected ? 'All tracks selected' : 'Tap tracks to select',
+                          style: Theme.of(context).textTheme.bodySmall?.copyWith(color: colorScheme.onSurfaceVariant),
+                        ),
+                      ],
+                    ),
+                  ),
+                  TextButton.icon(
+                    onPressed: () {
+                      if (allSelected) {
+                        _exitSelectionMode();
+                      } else {
+                        _selectAll(tracks);
+                      }
+                    },
+                    icon: Icon(allSelected ? Icons.deselect : Icons.select_all, size: 20),
+                    label: Text(allSelected ? 'Deselect' : 'Select All'),
+                    style: TextButton.styleFrom(foregroundColor: colorScheme.primary),
+                  ),
+                ],
+              ),
+              const SizedBox(height: 16),
+              SizedBox(
+                width: double.infinity,
+                child: FilledButton.icon(
+                  onPressed: selectedCount > 0 ? () => _deleteSelected(tracks) : null,
+                  icon: const Icon(Icons.delete_outline),
+                  label: Text(
+                    selectedCount > 0 
+                        ? 'Delete $selectedCount ${selectedCount == 1 ? 'track' : 'tracks'}'
+                        : 'Select tracks to delete',
+                  ),
+                  style: FilledButton.styleFrom(
+                    backgroundColor: selectedCount > 0 ? colorScheme.error : colorScheme.surfaceContainerHighest,
+                    foregroundColor: selectedCount > 0 ? colorScheme.onError : colorScheme.onSurfaceVariant,
+                    padding: const EdgeInsets.symmetric(vertical: 16),
+                    shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(16)),
+                  ),
+                ),
+              ),
+            ],
+          ),
+        ),
+      ),
+    );
+  }
+}

lib/screens/home_tab.dart

@@ -8,11 +8,14 @@ import 'package:spotiflac_android/models/track.dart';
 import 'package:spotiflac_android/providers/track_provider.dart';
 import 'package:spotiflac_android/providers/download_queue_provider.dart';
 import 'package:spotiflac_android/providers/settings_provider.dart';
+import 'package:spotiflac_android/providers/extension_provider.dart';
 import 'package:spotiflac_android/screens/track_metadata_screen.dart';
 import 'package:spotiflac_android/screens/album_screen.dart';
 import 'package:spotiflac_android/screens/artist_screen.dart';
+import 'package:spotiflac_android/services/csv_import_service.dart';
 import 'package:spotiflac_android/screens/playlist_screen.dart';
 import 'package:spotiflac_android/models/download_item.dart';
+import 'package:spotiflac_android/widgets/download_service_picker.dart';
 
 class HomeTab extends ConsumerStatefulWidget {
   const HomeTab({super.key});
@@ -77,12 +80,21 @@ class _HomeTabState extends ConsumerState<HomeTab> with AutomaticKeepAliveClient
   }
 
   Future<void> _performSearch(String query) async {
-    // Skip if same query already searched
-    if (_lastSearchQuery == query) return;
-    _lastSearchQuery = query;
-    
     final settings = ref.read(settingsProvider);
-    await ref.read(trackProvider.notifier).search(query, metadataSource: settings.metadataSource);
+    final searchProvider = settings.searchProvider;
+    
+    // Skip if same query already searched with same provider
+    final searchKey = '${searchProvider ?? 'default'}:$query';
+    if (_lastSearchQuery == searchKey) return;
+    _lastSearchQuery = searchKey;
+    
+    if (searchProvider != null && searchProvider.isNotEmpty) {
+      // Use custom search from extension
+      await ref.read(trackProvider.notifier).customSearch(searchProvider, query);
+    } else {
+      // Use default search (Deezer/Spotify)
+      await ref.read(trackProvider.notifier).search(query, metadataSource: settings.metadataSource);
+    }
     ref.read(settingsProvider.notifier).setHasSearchedBefore();
   }
 
@@ -172,10 +184,16 @@ class _HomeTabState extends ConsumerState<HomeTab> with AutomaticKeepAliveClient
       final settings = ref.read(settingsProvider);
       
       if (settings.askQualityBeforeDownload) {
-        _showQualityPicker(context, (quality, service) {
-          ref.read(downloadQueueProvider.notifier).addToQueue(track, service, qualityOverride: quality);
-          ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text('Added "${track.name}" to queue')));
-        }, trackName: track.name, artistName: track.artistName, coverUrl: track.coverUrl);
+        DownloadServicePicker.show(
+          context,
+          trackName: track.name,
+          artistName: track.artistName,
+          coverUrl: track.coverUrl,
+          onSelect: (quality, service) {
+            ref.read(downloadQueueProvider.notifier).addToQueue(track, service, qualityOverride: quality);
+            ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text('Added "${track.name}" to queue')));
+          },
+        );
       } else {
         ref.read(downloadQueueProvider.notifier).addToQueue(track, settings.defaultService);
         ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text('Added "${track.name}" to queue')));
@@ -183,87 +201,103 @@ class _HomeTabState extends ConsumerState<HomeTab> with AutomaticKeepAliveClient
     }
   }
 
-  void _showQualityPicker(BuildContext context, void Function(String quality, String service) onSelect, {String? trackName, String? artistName, String? coverUrl}) {
-    final colorScheme = Theme.of(context).colorScheme;
-    final settings = ref.read(settingsProvider);
-    String selectedService = settings.defaultService;
+  Future<void> _importCsv(BuildContext context, WidgetRef ref) async {
+    // Show loading dialog with progress
+    int currentProgress = 0;
+    int totalTracks = 0;
     
-    showModalBottomSheet(
-      context: context,
-      backgroundColor: colorScheme.surfaceContainerHigh,
-      shape: const RoundedRectangleBorder(borderRadius: BorderRadius.vertical(top: Radius.circular(28))),
-      isScrollControlled: true,
-      builder: (context) => StatefulBuilder(
-        builder: (context, setModalState) => SafeArea(
-          child: SingleChildScrollView(
-            child: Column(
-              mainAxisSize: MainAxisSize.min,
-              crossAxisAlignment: CrossAxisAlignment.start,
-              children: [
-                if (trackName != null) ...[
-                  _TrackInfoHeader(trackName: trackName, artistName: artistName, coverUrl: coverUrl),
-                  Divider(height: 1, color: colorScheme.outlineVariant.withValues(alpha: 0.5)),
-                ] else ...[
-                  const SizedBox(height: 8),
-                  Center(child: Container(width: 40, height: 4, decoration: BoxDecoration(color: colorScheme.onSurfaceVariant.withValues(alpha: 0.4), borderRadius: BorderRadius.circular(2)))),
+    // Use StatefulBuilder to update dialog content
+    bool dialogShown = false;
+    StateSetter? setDialogState;
+    
+    void showProgressDialog() {
+      if (dialogShown || !mounted) return;
+      dialogShown = true;
+      showDialog(
+        context: this.context,
+        barrierDismissible: false,
+        builder: (dialogCtx) => StatefulBuilder(
+          builder: (dialogCtx, setState) {
+            setDialogState = setState;
+            return AlertDialog(
+              content: Column(
+                mainAxisSize: MainAxisSize.min,
+                children: [
+                  const CircularProgressIndicator(),
+                  const SizedBox(height: 16),
+                  Text(
+                    totalTracks > 0 
+                        ? 'Fetching metadata... $currentProgress/$totalTracks'
+                        : 'Reading CSV...',
+                  ),
                 ],
-                // Service selector
-                Padding(
-                  padding: const EdgeInsets.fromLTRB(24, 16, 24, 8),
-                  child: Text('Download From', style: Theme.of(context).textTheme.titleMedium?.copyWith(fontWeight: FontWeight.bold)),
-                ),
-                Padding(
-                  padding: const EdgeInsets.symmetric(horizontal: 20),
-                  child: Row(
-                    children: [
-                      _ServiceChip(label: 'Tidal', isSelected: selectedService == 'tidal', onTap: () => setModalState(() => selectedService = 'tidal')),
-                      const SizedBox(width: 8),
-                      _ServiceChip(label: 'Qobuz', isSelected: selectedService == 'qobuz', onTap: () => setModalState(() => selectedService = 'qobuz')),
-                      const SizedBox(width: 8),
-                      _ServiceChip(label: 'Amazon', isSelected: selectedService == 'amazon', onTap: () => setModalState(() => selectedService = 'amazon')),
-                    ],
-                  ),
-                ),
-                Padding(
-                  padding: const EdgeInsets.fromLTRB(24, 16, 24, 8),
-                  child: Text('Select Quality', style: Theme.of(context).textTheme.titleMedium?.copyWith(fontWeight: FontWeight.bold)),
-                ),
-                // Disclaimer
-                Padding(
-                  padding: const EdgeInsets.fromLTRB(24, 0, 24, 12),
-                  child: Text(
-                    'Actual quality depends on track availability. Hi-Res may not be available for all tracks.',
-                    style: Theme.of(context).textTheme.bodySmall?.copyWith(
-                      color: colorScheme.onSurfaceVariant,
-                      fontStyle: FontStyle.italic,
-                    ),
-                  ),
-                ),
-                _QualityPickerOption(
-                  title: 'FLAC Lossless',
-                  subtitle: '16-bit / 44.1kHz',
-                  icon: Icons.music_note,
-                  onTap: () { Navigator.pop(context); onSelect('LOSSLESS', selectedService); },
-                ),
-                _QualityPickerOption(
-                  title: 'Hi-Res FLAC',
-                  subtitle: '24-bit / up to 96kHz',
-                  icon: Icons.high_quality,
-                  onTap: () { Navigator.pop(context); onSelect('HI_RES', selectedService); },
-                ),
-                _QualityPickerOption(
-                  title: 'Hi-Res FLAC Max',
-                  subtitle: '24-bit / up to 192kHz',
-                  icon: Icons.four_k,
-                  onTap: () { Navigator.pop(context); onSelect('HI_RES_LOSSLESS', selectedService); },
-                ),
-                const SizedBox(height: 16),
-              ],
-            ),
-          ),
+              ),
+            );
+          },
         ),
-      ),
+      );
+    }
+    
+    final tracks = await CsvImportService.pickAndParseCsv(
+      onProgress: (current, total) {
+        currentProgress = current;
+        totalTracks = total;
+        if (!dialogShown && total > 0) {
+          showProgressDialog();
+        }
+        setDialogState?.call(() {});
+      },
     );
+    
+    // Close progress dialog
+    if (dialogShown && mounted) {
+      Navigator.of(this.context).pop();
+    }
+    
+    if (tracks.isNotEmpty) {
+      final settings = ref.read(settingsProvider);
+      
+      if (!mounted) return;
+      
+      // Optionally show confirmation dialog
+      final confirmed = await showDialog<bool>(
+        context: this.context,
+        builder: (dialogCtx) => AlertDialog(
+          title: const Text('Import Playlist'),
+          content: Text('Found ${tracks.length} tracks in CSV. Add them to download queue?'),
+          actions: [
+            TextButton(
+              onPressed: () => Navigator.pop(dialogCtx, false),
+              child: const Text('Cancel'),
+            ),
+            FilledButton(
+              onPressed: () => Navigator.pop(dialogCtx, true),
+              child: const Text('Import'),
+            ),
+          ],
+        ),
+      );
+
+      if (confirmed == true) {
+        ref.read(downloadQueueProvider.notifier).addMultipleToQueue(tracks, settings.defaultService);
+        if (mounted) {
+           ScaffoldMessenger.of(this.context).showSnackBar(
+            SnackBar(
+              content: Text('Added ${tracks.length} tracks to queue'),
+              action: SnackBarAction(
+                label: 'View Queue',
+                onPressed: () {
+                   // Navigate to queue tab (handled by main_shell index)
+                   // We don't have direct access to set index here easily without provider
+                },
+              ),
+            ),
+          );
+        }
+      }
+    } else {
+       // Only show error if pick was not cancelled (handled inside service logging usually, but maybe show snackbar if file empty)
+    }
   }
 
   @override
@@ -286,9 +320,14 @@ class _HomeTabState extends ConsumerState<HomeTab> with AutomaticKeepAliveClient
     final error = ref.watch(trackProvider.select((s) => s.error));
     final hasSearchedBefore = ref.watch(settingsProvider.select((s) => s.hasSearchedBefore));
     
+    // Watch extension state to update search hint when extensions load/change
+    ref.watch(extensionProvider.select((s) => s.isInitialized));
+    ref.watch(extensionProvider.select((s) => s.extensions));
+    
     final colorScheme = Theme.of(context).colorScheme;
     final hasResults = _isTyping || tracks.isNotEmpty || (searchArtists != null && searchArtists.isNotEmpty) || isLoading;
     final screenHeight = MediaQuery.of(context).size.height;
+    final topPadding = MediaQuery.of(context).padding.top;
     final historyItems = ref.watch(downloadHistoryProvider.select((s) => s.items));
 
     return Scaffold(
@@ -297,24 +336,32 @@ class _HomeTabState extends ConsumerState<HomeTab> with AutomaticKeepAliveClient
         slivers: [
           // App Bar - always present
           SliverAppBar(
-            expandedHeight: 130,
+            expandedHeight: 120 + topPadding,
             collapsedHeight: kToolbarHeight,
             floating: false,
             pinned: true,
             backgroundColor: colorScheme.surface,
             surfaceTintColor: Colors.transparent,
             automaticallyImplyLeading: false,
-            flexibleSpace: FlexibleSpaceBar(
-              expandedTitleScale: 1.3,
-              titlePadding: const EdgeInsets.only(left: 24, bottom: 16),
-              title: Text(
-                'Home',
-                style: TextStyle(
-                  fontSize: 28,
-                  fontWeight: FontWeight.bold,
-                  color: colorScheme.onSurface,
-                ),
-              ),
+            flexibleSpace: LayoutBuilder(
+              builder: (context, constraints) {
+                final maxHeight = 120 + topPadding;
+                final minHeight = kToolbarHeight + topPadding;
+                final expandRatio = ((constraints.maxHeight - minHeight) / (maxHeight - minHeight)).clamp(0.0, 1.0);
+                
+                return FlexibleSpaceBar(
+                  expandedTitleScale: 1.0,
+                  titlePadding: const EdgeInsets.only(left: 24, bottom: 16),
+                  title: Text(
+                    'Home',
+                    style: TextStyle(
+                      fontSize: 20 + (14 * expandRatio), // 20 -> 34
+                      fontWeight: FontWeight.bold,
+                      color: colorScheme.onSurface,
+                    ),
+                  ),
+                );
+              },
             ),
           ),
           
@@ -329,12 +376,27 @@ class _HomeTabState extends ConsumerState<HomeTab> with AutomaticKeepAliveClient
                       children: [
                         SizedBox(height: screenHeight * 0.06),
                         Container(
-                          padding: const EdgeInsets.all(24),
+                          width: 96,
+                          height: 96,
                           decoration: BoxDecoration(
-                            color: colorScheme.primaryContainer.withValues(alpha: 0.3),
+                            color: colorScheme.primary,
                             shape: BoxShape.circle,
                           ),
-                          child: Icon(Icons.music_note, size: 48, color: colorScheme.primary),
+                          child: Image.asset(
+                            'assets/images/logo-transparant.png',
+                            color: colorScheme.onPrimary, // Tint with onPrimary color
+                            fit: BoxFit.contain,
+                            errorBuilder: (_, _, _) => ClipRRect(
+                              // Fallback to original logo if transparent one is missing
+                              borderRadius: BorderRadius.circular(24),
+                              child: Image.asset(
+                                'assets/images/logo.png',
+                                width: 96,
+                                height: 96,
+                                fit: BoxFit.cover,
+                              ),
+                            ),
+                          ),
                         ),
                         const SizedBox(height: 16),
                         Text(
@@ -651,6 +713,11 @@ class _HomeTabState extends ConsumerState<HomeTab> with AutomaticKeepAliveClient
   }
 
   Widget _buildArtistCard(SearchArtist artist, ColorScheme colorScheme) {
+    // Validate image URL - must be non-null, non-empty, and have a valid host
+    final hasValidImage = artist.imageUrl != null && 
+                          artist.imageUrl!.isNotEmpty &&
+                          Uri.tryParse(artist.imageUrl!)?.hasAuthority == true;
+    
     return GestureDetector(
       onTap: () => _navigateToArtist(artist.id, artist.name, artist.imageUrl),
       child: Container(
@@ -666,12 +733,17 @@ class _HomeTabState extends ConsumerState<HomeTab> with AutomaticKeepAliveClient
                 color: colorScheme.surfaceContainerHighest,
               ),
               child: ClipOval(
-                child: artist.imageUrl != null
+                child: hasValidImage
                     ? CachedNetworkImage(
                         imageUrl: artist.imageUrl!,
                         fit: BoxFit.cover,
                         memCacheWidth: 200,
                         memCacheHeight: 200,
+                        errorWidget: (context, url, error) => Icon(
+                          Icons.person,
+                          color: colorScheme.onSurfaceVariant,
+                          size: 44,
+                        ),
                       )
                     : Icon(Icons.person, color: colorScheme.onSurfaceVariant, size: 44),
               ),
@@ -703,6 +775,32 @@ class _HomeTabState extends ConsumerState<HomeTab> with AutomaticKeepAliveClient
     ));
   }
 
+  /// Get search hint based on selected provider
+  String _getSearchHint() {
+    final settings = ref.read(settingsProvider);
+    final searchProvider = settings.searchProvider;
+    final extState = ref.read(extensionProvider);
+    
+    // If extension system not initialized yet, show default hint
+    if (!extState.isInitialized) {
+      return 'Paste Spotify URL or search...';
+    }
+    
+    if (searchProvider != null && searchProvider.isNotEmpty) {
+      final ext = extState.extensions.where((e) => e.id == searchProvider).firstOrNull;
+      // Only show extension placeholder if extension exists AND is enabled
+      if (ext != null && ext.enabled) {
+        if (ext.searchBehavior?.placeholder != null) {
+          return ext.searchBehavior!.placeholder!;
+        }
+        return 'Search with ${ext.displayName}...';
+      }
+      // Extension not found or disabled - clear the search provider setting
+      // and return default hint
+    }
+    return 'Paste Spotify URL or search...';
+  }
+
   Widget _buildSearchBar(ColorScheme colorScheme) {
     final hasText = _urlController.text.isNotEmpty;
     
@@ -711,7 +809,7 @@ class _HomeTabState extends ConsumerState<HomeTab> with AutomaticKeepAliveClient
       focusNode: _searchFocusNode,
       autofocus: false,
       decoration: InputDecoration(
-        hintText: 'Paste Spotify URL or search...',
+        hintText: _getSearchHint(),
         filled: true,
         fillColor: colorScheme.surfaceContainerHighest,
         border: OutlineInputBorder(
@@ -736,12 +834,18 @@ class _HomeTabState extends ConsumerState<HomeTab> with AutomaticKeepAliveClient
                 onPressed: _clearAndRefresh,
                 tooltip: 'Clear',
               )
-            else
+            else ...[
+              IconButton(
+                icon: const Icon(Icons.file_upload_outlined),
+                onPressed: () => _importCsv(context, ref),
+                tooltip: 'Import CSV',
+              ),
               IconButton(
                 icon: const Icon(Icons.paste),
                 onPressed: _pasteFromClipboard,
                 tooltip: 'Paste',
               ),
+            ],
           ],
         ),
         contentPadding: const EdgeInsets.symmetric(horizontal: 20, vertical: 16),
@@ -771,147 +875,6 @@ class _HomeTabState extends ConsumerState<HomeTab> with AutomaticKeepAliveClient
 
 }
 
-class _QualityPickerOption extends StatelessWidget {
-  final String title;
-  final String subtitle;
-  final IconData icon;
-  final VoidCallback onTap;
-  const _QualityPickerOption({required this.title, required this.subtitle, required this.icon, required this.onTap});
-
-  @override
-  Widget build(BuildContext context) {
-    final colorScheme = Theme.of(context).colorScheme;
-    return ListTile(
-      contentPadding: const EdgeInsets.symmetric(horizontal: 24, vertical: 4),
-      leading: Container(padding: const EdgeInsets.all(10), decoration: BoxDecoration(color: colorScheme.primaryContainer, borderRadius: BorderRadius.circular(12)), child: Icon(icon, color: colorScheme.onPrimaryContainer, size: 20)),
-      title: Text(title, style: const TextStyle(fontWeight: FontWeight.w500)),
-      subtitle: Text(subtitle, style: TextStyle(color: colorScheme.onSurfaceVariant)),
-      onTap: onTap,
-    );
-  }
-}
-
-class _ServiceChip extends StatelessWidget {
-  final String label;
-  final bool isSelected;
-  final VoidCallback onTap;
-  const _ServiceChip({required this.label, required this.isSelected, required this.onTap});
-
-  @override
-  Widget build(BuildContext context) {
-    final colorScheme = Theme.of(context).colorScheme;
-    return Expanded(
-      child: GestureDetector(
-        onTap: onTap,
-        child: AnimatedContainer(
-          duration: const Duration(milliseconds: 200),
-          padding: const EdgeInsets.symmetric(vertical: 10),
-          decoration: BoxDecoration(
-            color: isSelected ? colorScheme.primaryContainer : colorScheme.surfaceContainerHighest,
-            borderRadius: BorderRadius.circular(12),
-            border: isSelected ? null : Border.all(color: colorScheme.outlineVariant.withValues(alpha: 0.5)),
-          ),
-          child: Text(
-            label,
-            textAlign: TextAlign.center,
-            style: TextStyle(
-              fontWeight: isSelected ? FontWeight.w600 : FontWeight.normal,
-              color: isSelected ? colorScheme.onPrimaryContainer : colorScheme.onSurfaceVariant,
-            ),
-          ),
-        ),
-      ),
-    );
-  }
-}
-
-class _TrackInfoHeader extends StatefulWidget {
-  final String trackName;
-  final String? artistName;
-  final String? coverUrl;
-  const _TrackInfoHeader({required this.trackName, this.artistName, this.coverUrl});
-
-  @override
-  State<_TrackInfoHeader> createState() => _TrackInfoHeaderState();
-}
-
-class _TrackInfoHeaderState extends State<_TrackInfoHeader> {
-  bool _expanded = false;
-  bool _isOverflowing = false;
-
-  @override
-  Widget build(BuildContext context) {
-    final colorScheme = Theme.of(context).colorScheme;
-    return Material(
-      color: Colors.transparent,
-      child: InkWell(
-        onTap: _isOverflowing ? () => setState(() => _expanded = !_expanded) : null,
-        borderRadius: const BorderRadius.only(topLeft: Radius.circular(28), topRight: Radius.circular(28)),
-        child: Column(
-          children: [
-            const SizedBox(height: 8),
-            Container(width: 40, height: 4, decoration: BoxDecoration(color: colorScheme.onSurfaceVariant.withValues(alpha: 0.4), borderRadius: BorderRadius.circular(2))),
-            Padding(
-              padding: const EdgeInsets.fromLTRB(16, 12, 16, 12),
-              child: Row(
-                children: [
-                  ClipRRect(
-                    borderRadius: BorderRadius.circular(8),
-                    child: widget.coverUrl != null
-                        ? Image.network(widget.coverUrl!, width: 56, height: 56, fit: BoxFit.cover,
-                            errorBuilder: (_, e, s) => Container(width: 56, height: 56, color: colorScheme.surfaceContainerHighest, child: Icon(Icons.music_note, color: colorScheme.onSurfaceVariant)))
-                        : Container(width: 56, height: 56, color: colorScheme.surfaceContainerHighest, child: Icon(Icons.music_note, color: colorScheme.onSurfaceVariant)),
-                  ),
-                  const SizedBox(width: 12),
-                  Expanded(
-                    child: LayoutBuilder(
-                      builder: (context, constraints) {
-                        final titleStyle = Theme.of(context).textTheme.titleMedium?.copyWith(fontWeight: FontWeight.w600);
-                        final titleSpan = TextSpan(text: widget.trackName, style: titleStyle);
-                        final titlePainter = TextPainter(text: titleSpan, maxLines: 1, textDirection: TextDirection.ltr)..layout(maxWidth: constraints.maxWidth);
-                        final titleOverflows = titlePainter.didExceedMaxLines;
-                        
-                        WidgetsBinding.instance.addPostFrameCallback((_) {
-                          if (mounted && _isOverflowing != titleOverflows) {
-                            setState(() => _isOverflowing = titleOverflows);
-                          }
-                        });
-                        
-                        return Column(
-                          crossAxisAlignment: CrossAxisAlignment.start,
-                          children: [
-                            Text(
-                              widget.trackName,
-                              style: titleStyle,
-                              maxLines: _expanded ? 10 : 1,
-                              overflow: _expanded ? TextOverflow.visible : TextOverflow.ellipsis,
-                            ),
-                            if (widget.artistName != null) ...[
-                              const SizedBox(height: 2),
-                              Text(
-                                widget.artistName!,
-                                style: Theme.of(context).textTheme.bodyMedium?.copyWith(color: colorScheme.onSurfaceVariant),
-                                maxLines: _expanded ? 3 : 1,
-                                overflow: _expanded ? TextOverflow.visible : TextOverflow.ellipsis,
-                              ),
-                            ],
-                          ],
-                        );
-                      },
-                    ),
-                  ),
-                  if (_isOverflowing || _expanded)
-                    Icon(_expanded ? Icons.expand_less : Icons.expand_more, color: colorScheme.onSurfaceVariant, size: 20),
-                ],
-              ),
-            ),
-          ],
-        ),
-      ),
-    );
-  }
-}
-
 /// Separate Consumer widget for each track item - only rebuilds when this specific track's status changes
 class _TrackItemWithStatus extends ConsumerWidget {
   final Track track;
@@ -941,6 +904,28 @@ class _TrackItemWithStatus extends ConsumerWidget {
       return state.isDownloaded(track.id);
     }));
     
+    // Get thumbnail size from extension if track is from extension
+    double thumbWidth = 56;
+    double thumbHeight = 56;
+    
+    // Get extension ID from track.source or from TrackState.searchExtensionId
+    final trackState = ref.watch(trackProvider);
+    final extensionId = track.source ?? trackState.searchExtensionId;
+    
+    if (extensionId != null && extensionId.isNotEmpty) {
+      final extState = ref.watch(extensionProvider);
+      final extension = extState.extensions.where((e) => e.id == extensionId).firstOrNull;
+      if (extension?.searchBehavior != null) {
+        final size = extension!.searchBehavior!.getThumbnailSize(defaultSize: 56);
+        thumbWidth = size.$1;
+        thumbHeight = size.$2;
+        // Debug: log only when using custom size
+        if (thumbWidth != 56 || thumbHeight != 56) {
+          debugPrint('[Thumbnail] ${track.name}: using ${thumbWidth.toInt()}x${thumbHeight.toInt()} from ${extension.id}');
+        }
+      }
+    }
+    
     final isQueued = queueItem != null;
     final isDownloading = queueItem?.status == DownloadStatus.downloading;
     final isFinalizing = queueItem?.status == DownloadStatus.finalizing;
@@ -961,21 +946,21 @@ class _TrackItemWithStatus extends ConsumerWidget {
             padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 10),
             child: Row(
               children: [
-                // Album art
+                // Album art with dynamic size based on extension config
                 ClipRRect(
                   borderRadius: BorderRadius.circular(10),
                   child: track.coverUrl != null
                       ? CachedNetworkImage(
                           imageUrl: track.coverUrl!,
-                          width: 56,
-                          height: 56,
+                          width: thumbWidth,
+                          height: thumbHeight,
                           fit: BoxFit.cover,
-                          memCacheWidth: 112,
-                          memCacheHeight: 112,
+                          memCacheWidth: (thumbWidth * 2).toInt(),
+                          memCacheHeight: (thumbHeight * 2).toInt(),
                         )
                       : Container(
-                          width: 56,
-                          height: 56,
+                          width: thumbWidth,
+                          height: thumbHeight,
                           color: colorScheme.surfaceContainerHighest,
                           child: Icon(Icons.music_note, color: colorScheme.onSurfaceVariant),
                         ),
@@ -1012,7 +997,7 @@ class _TrackItemWithStatus extends ConsumerWidget {
           Divider(
             height: 1,
             thickness: 1,
-            indent: 80,
+            indent: thumbWidth + 24, // Adjust divider indent based on thumbnail width
             endIndent: 12,
             color: colorScheme.outlineVariant.withValues(alpha: 0.3),
           ),

lib/screens/main_shell.dart

@@ -6,6 +6,7 @@ import 'package:spotiflac_android/providers/download_queue_provider.dart';
 import 'package:spotiflac_android/providers/settings_provider.dart';
 import 'package:spotiflac_android/providers/track_provider.dart';
 import 'package:spotiflac_android/screens/home_tab.dart';
+import 'package:spotiflac_android/screens/store_tab.dart';
 import 'package:spotiflac_android/screens/queue_tab.dart';
 import 'package:spotiflac_android/screens/settings/settings_tab.dart';
 import 'package:spotiflac_android/services/share_intent_service.dart';
@@ -62,6 +63,9 @@ class _MainShellState extends ConsumerState<MainShell> {
   }
 
   void _handleSharedUrl(String url) {
+    // Pop any existing screens (Album, Artist, Settings sub-pages) to return to root
+    Navigator.of(context).popUntil((route) => route.isFirst);
+    
     // Navigate to Home tab
     if (_currentIndex != 0) {
       _onNavTap(0);
@@ -169,6 +173,7 @@ class _MainShellState extends ConsumerState<MainShell> {
   Widget build(BuildContext context) {
     final queueState = ref.watch(downloadQueueProvider.select((s) => s.queuedCount));
     final trackState = ref.watch(trackProvider);
+    final showStore = ref.watch(settingsProvider.select((s) => s.showExtensionStore));
     
     // Check if keyboard is visible (bottom inset > 0 means keyboard is showing)
     final isKeyboardVisible = MediaQuery.of(context).viewInsets.bottom > 0;
@@ -182,6 +187,57 @@ class _MainShellState extends ConsumerState<MainShell> {
                    !trackState.isLoading &&
                    !isKeyboardVisible;
 
+    // Build tabs and destinations based on settings
+    final tabs = <Widget>[
+      const HomeTab(),
+      const QueueTab(),
+      if (showStore) const StoreTab(),
+      const SettingsTab(),
+    ];
+
+    final destinations = <NavigationDestination>[
+      const NavigationDestination(
+        icon: Icon(Icons.home_outlined),
+        selectedIcon: Icon(Icons.home),
+        label: 'Home',
+      ),
+      NavigationDestination(
+        icon: Badge(
+          isLabelVisible: queueState > 0,
+          label: Text('$queueState'),
+          child: const Icon(Icons.history_outlined),
+        ),
+        selectedIcon: Badge(
+          isLabelVisible: queueState > 0,
+          label: Text('$queueState'),
+          child: const Icon(Icons.history),
+        ),
+        label: 'History',
+      ),
+      if (showStore)
+        const NavigationDestination(
+          icon: Icon(Icons.store_outlined),
+          selectedIcon: Icon(Icons.store),
+          label: 'Store',
+        ),
+      const NavigationDestination(
+        icon: Icon(Icons.settings_outlined),
+        selectedIcon: Icon(Icons.settings),
+        label: 'Settings',
+      ),
+    ];
+
+    // Clamp current index if tabs changed
+    final maxIndex = tabs.length - 1;
+    if (_currentIndex > maxIndex) {
+      WidgetsBinding.instance.addPostFrameCallback((_) {
+        if (mounted) {
+          setState(() => _currentIndex = maxIndex);
+          _pageController.jumpToPage(maxIndex);
+        }
+      });
+    }
+
     return PopScope(
       canPop: canPop,
       onPopInvokedWithResult: (didPop, result) async {
@@ -199,44 +255,16 @@ class _MainShellState extends ConsumerState<MainShell> {
           controller: _pageController,
           onPageChanged: _onPageChanged,
           physics: const BouncingScrollPhysics(),
-          children: const [
-            HomeTab(),
-            QueueTab(),
-            SettingsTab(),
-          ],
+          children: tabs,
         ),
         bottomNavigationBar: NavigationBar(
-          selectedIndex: _currentIndex,
+          selectedIndex: _currentIndex.clamp(0, maxIndex),
           onDestinationSelected: _onNavTap,
           animationDuration: const Duration(milliseconds: 200),
           backgroundColor: Theme.of(context).brightness == Brightness.dark
               ? Color.alphaBlend(Colors.white.withValues(alpha: 0.05), Theme.of(context).colorScheme.surface)
               : Color.alphaBlend(Colors.black.withValues(alpha: 0.03), Theme.of(context).colorScheme.surface),
-          destinations: [
-            const NavigationDestination(
-              icon: Icon(Icons.home_outlined),
-              selectedIcon: Icon(Icons.home),
-              label: 'Home',
-            ),
-            NavigationDestination(
-              icon: Badge(
-                isLabelVisible: queueState > 0,
-                label: Text('$queueState'),
-                child: const Icon(Icons.history_outlined),
-              ),
-              selectedIcon: Badge(
-                isLabelVisible: queueState > 0,
-                label: Text('$queueState'),
-                child: const Icon(Icons.history),
-              ),
-              label: 'History',
-            ),
-            const NavigationDestination(
-              icon: Icon(Icons.settings_outlined),
-              selectedIcon: Icon(Icons.settings),
-              label: 'Settings',
-            ),
-          ],
+          destinations: destinations,
         ),
       ),
     );

lib/screens/playlist_screen.dart

@@ -6,6 +6,7 @@ import 'package:spotiflac_android/models/track.dart';
 import 'package:spotiflac_android/models/download_item.dart';
 import 'package:spotiflac_android/providers/download_queue_provider.dart';
 import 'package:spotiflac_android/providers/settings_provider.dart';
+import 'package:spotiflac_android/widgets/download_service_picker.dart';
 
 /// Playlist detail screen with Material Expressive 3 design
 class PlaylistScreen extends ConsumerWidget {
@@ -168,10 +169,16 @@ class PlaylistScreen extends ConsumerWidget {
   void _downloadTrack(BuildContext context, WidgetRef ref, Track track) {
     final settings = ref.read(settingsProvider);
     if (settings.askQualityBeforeDownload) {
-      _showQualityPicker(context, ref, (quality, service) {
-        ref.read(downloadQueueProvider.notifier).addToQueue(track, service, qualityOverride: quality);
-        ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text('Added "${track.name}" to queue')));
-      }, trackName: track.name, artistName: track.artistName, coverUrl: track.coverUrl);
+      DownloadServicePicker.show(
+        context,
+        trackName: track.name,
+        artistName: track.artistName,
+        coverUrl: track.coverUrl,
+        onSelect: (quality, service) {
+          ref.read(downloadQueueProvider.notifier).addToQueue(track, service, qualityOverride: quality);
+          ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text('Added "${track.name}" to queue')));
+        },
+      );
     } else {
       ref.read(downloadQueueProvider.notifier).addToQueue(track, settings.defaultService);
       ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text('Added "${track.name}" to queue')));
@@ -182,222 +189,20 @@ class PlaylistScreen extends ConsumerWidget {
     if (tracks.isEmpty) return;
     final settings = ref.read(settingsProvider);
     if (settings.askQualityBeforeDownload) {
-      _showQualityPicker(context, ref, (quality, service) {
-        ref.read(downloadQueueProvider.notifier).addMultipleToQueue(tracks, service, qualityOverride: quality);
-        ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text('Added ${tracks.length} tracks to queue')));
-      }, trackName: '${tracks.length} tracks', artistName: playlistName);
+      DownloadServicePicker.show(
+        context,
+        trackName: '${tracks.length} tracks',
+        artistName: playlistName,
+        onSelect: (quality, service) {
+          ref.read(downloadQueueProvider.notifier).addMultipleToQueue(tracks, service, qualityOverride: quality);
+          ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text('Added ${tracks.length} tracks to queue')));
+        },
+      );
     } else {
       ref.read(downloadQueueProvider.notifier).addMultipleToQueue(tracks, settings.defaultService);
       ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text('Added ${tracks.length} tracks to queue')));
     }
   }
-
-  void _showQualityPicker(BuildContext context, WidgetRef ref, void Function(String quality, String service) onSelect, {String? trackName, String? artistName, String? coverUrl}) {
-    final colorScheme = Theme.of(context).colorScheme;
-    final settings = ref.read(settingsProvider);
-    String selectedService = settings.defaultService;
-    
-    showModalBottomSheet(
-      context: context,
-      backgroundColor: colorScheme.surfaceContainerHigh,
-      shape: const RoundedRectangleBorder(borderRadius: BorderRadius.vertical(top: Radius.circular(28))),
-      isScrollControlled: true,
-      builder: (context) => StatefulBuilder(
-        builder: (context, setModalState) => SafeArea(
-          child: SingleChildScrollView(
-            child: Column(
-              mainAxisSize: MainAxisSize.min,
-              crossAxisAlignment: CrossAxisAlignment.start,
-              children: [
-                if (trackName != null) ...[
-                  _TrackInfoHeader(trackName: trackName, artistName: artistName, coverUrl: coverUrl),
-                  Divider(height: 1, color: colorScheme.outlineVariant.withValues(alpha: 0.5)),
-                ] else ...[
-                  const SizedBox(height: 8),
-                  Center(child: Container(width: 40, height: 4, decoration: BoxDecoration(color: colorScheme.onSurfaceVariant.withValues(alpha: 0.4), borderRadius: BorderRadius.circular(2)))),
-                ],
-                // Service selector
-                Padding(
-                  padding: const EdgeInsets.fromLTRB(24, 16, 24, 8),
-                  child: Text('Download From', style: Theme.of(context).textTheme.titleMedium?.copyWith(fontWeight: FontWeight.bold)),
-                ),
-                Padding(
-                  padding: const EdgeInsets.symmetric(horizontal: 20),
-                  child: Row(
-                    children: [
-                      _ServiceChip(label: 'Tidal', isSelected: selectedService == 'tidal', onTap: () => setModalState(() => selectedService = 'tidal')),
-                      const SizedBox(width: 8),
-                      _ServiceChip(label: 'Qobuz', isSelected: selectedService == 'qobuz', onTap: () => setModalState(() => selectedService = 'qobuz')),
-                      const SizedBox(width: 8),
-                      _ServiceChip(label: 'Amazon', isSelected: selectedService == 'amazon', onTap: () => setModalState(() => selectedService = 'amazon')),
-                    ],
-                  ),
-                ),
-                Padding(padding: const EdgeInsets.fromLTRB(24, 16, 24, 8), child: Text('Select Quality', style: Theme.of(context).textTheme.titleMedium?.copyWith(fontWeight: FontWeight.bold))),
-                // Disclaimer
-                Padding(
-                  padding: const EdgeInsets.fromLTRB(24, 0, 24, 12),
-                  child: Text(
-                    'Actual quality depends on track availability. Hi-Res may not be available for all tracks.',
-                    style: Theme.of(context).textTheme.bodySmall?.copyWith(
-                      color: colorScheme.onSurfaceVariant,
-                      fontStyle: FontStyle.italic,
-                    ),
-                  ),
-                ),
-                _QualityOption(title: 'FLAC Lossless', subtitle: '16-bit / 44.1kHz', icon: Icons.music_note, onTap: () { Navigator.pop(context); onSelect('LOSSLESS', selectedService); }),
-                _QualityOption(title: 'Hi-Res FLAC', subtitle: '24-bit / up to 96kHz', icon: Icons.high_quality, onTap: () { Navigator.pop(context); onSelect('HI_RES', selectedService); }),
-                _QualityOption(title: 'Hi-Res FLAC Max', subtitle: '24-bit / up to 192kHz', icon: Icons.four_k, onTap: () { Navigator.pop(context); onSelect('HI_RES_LOSSLESS', selectedService); }),
-                const SizedBox(height: 16),
-              ],
-            ),
-          ),
-        ),
-      ),
-    );
-  }
-}
-
-class _QualityOption extends StatelessWidget {
-  final String title;
-  final String subtitle;
-  final IconData icon;
-  final VoidCallback onTap;
-
-  const _QualityOption({required this.title, required this.subtitle, required this.icon, required this.onTap});
-
-  @override
-  Widget build(BuildContext context) {
-    final colorScheme = Theme.of(context).colorScheme;
-    return ListTile(
-      contentPadding: const EdgeInsets.symmetric(horizontal: 24, vertical: 4),
-      leading: Container(padding: const EdgeInsets.all(10), decoration: BoxDecoration(color: colorScheme.primaryContainer, borderRadius: BorderRadius.circular(12)), child: Icon(icon, color: colorScheme.onPrimaryContainer, size: 20)),
-      title: Text(title, style: const TextStyle(fontWeight: FontWeight.w500)),
-      subtitle: Text(subtitle, style: TextStyle(color: colorScheme.onSurfaceVariant)),
-      onTap: onTap,
-    );
-  }
-}
-
-class _ServiceChip extends StatelessWidget {
-  final String label;
-  final bool isSelected;
-  final VoidCallback onTap;
-  const _ServiceChip({required this.label, required this.isSelected, required this.onTap});
-
-  @override
-  Widget build(BuildContext context) {
-    final colorScheme = Theme.of(context).colorScheme;
-    return Expanded(
-      child: GestureDetector(
-        onTap: onTap,
-        child: AnimatedContainer(
-          duration: const Duration(milliseconds: 200),
-          padding: const EdgeInsets.symmetric(vertical: 10),
-          decoration: BoxDecoration(
-            color: isSelected ? colorScheme.primaryContainer : colorScheme.surfaceContainerHighest,
-            borderRadius: BorderRadius.circular(12),
-            border: isSelected ? null : Border.all(color: colorScheme.outlineVariant.withValues(alpha: 0.5)),
-          ),
-          child: Text(
-            label,
-            textAlign: TextAlign.center,
-            style: TextStyle(
-              fontWeight: isSelected ? FontWeight.w600 : FontWeight.normal,
-              color: isSelected ? colorScheme.onPrimaryContainer : colorScheme.onSurfaceVariant,
-            ),
-          ),
-        ),
-      ),
-    );
-  }
-}
-
-class _TrackInfoHeader extends StatefulWidget {
-  final String trackName;
-  final String? artistName;
-  final String? coverUrl;
-  const _TrackInfoHeader({required this.trackName, this.artistName, this.coverUrl});
-
-  @override
-  State<_TrackInfoHeader> createState() => _TrackInfoHeaderState();
-}
-
-class _TrackInfoHeaderState extends State<_TrackInfoHeader> {
-  bool _expanded = false;
-  bool _isOverflowing = false;
-
-  @override
-  Widget build(BuildContext context) {
-    final colorScheme = Theme.of(context).colorScheme;
-    return Material(
-      color: Colors.transparent,
-      child: InkWell(
-        onTap: _isOverflowing ? () => setState(() => _expanded = !_expanded) : null,
-        borderRadius: const BorderRadius.only(topLeft: Radius.circular(28), topRight: Radius.circular(28)),
-        child: Column(
-          children: [
-            const SizedBox(height: 8),
-            Container(width: 40, height: 4, decoration: BoxDecoration(color: colorScheme.onSurfaceVariant.withValues(alpha: 0.4), borderRadius: BorderRadius.circular(2))),
-            Padding(
-              padding: const EdgeInsets.fromLTRB(16, 12, 16, 12),
-              child: Row(
-                children: [
-                  ClipRRect(
-                    borderRadius: BorderRadius.circular(8),
-                    child: widget.coverUrl != null
-                        ? Image.network(widget.coverUrl!, width: 56, height: 56, fit: BoxFit.cover,
-                            errorBuilder: (_, e, s) => Container(width: 56, height: 56, color: colorScheme.surfaceContainerHighest, child: Icon(Icons.music_note, color: colorScheme.onSurfaceVariant)))
-                        : Container(width: 56, height: 56, color: colorScheme.surfaceContainerHighest, child: Icon(Icons.music_note, color: colorScheme.onSurfaceVariant)),
-                  ),
-                  const SizedBox(width: 12),
-                  Expanded(
-                    child: LayoutBuilder(
-                      builder: (context, constraints) {
-                        final titleStyle = Theme.of(context).textTheme.titleMedium?.copyWith(fontWeight: FontWeight.w600);
-                        final titleSpan = TextSpan(text: widget.trackName, style: titleStyle);
-                        final titlePainter = TextPainter(text: titleSpan, maxLines: 1, textDirection: TextDirection.ltr)..layout(maxWidth: constraints.maxWidth);
-                        final titleOverflows = titlePainter.didExceedMaxLines;
-                        
-                        WidgetsBinding.instance.addPostFrameCallback((_) {
-                          if (mounted && _isOverflowing != titleOverflows) {
-                            setState(() => _isOverflowing = titleOverflows);
-                          }
-                        });
-                        
-                        return Column(
-                          crossAxisAlignment: CrossAxisAlignment.start,
-                          children: [
-                            Text(
-                              widget.trackName,
-                              style: titleStyle,
-                              maxLines: _expanded ? 10 : 1,
-                              overflow: _expanded ? TextOverflow.visible : TextOverflow.ellipsis,
-                            ),
-                            if (widget.artistName != null) ...[
-                              const SizedBox(height: 2),
-                              Text(
-                                widget.artistName!,
-                                style: Theme.of(context).textTheme.bodyMedium?.copyWith(color: colorScheme.onSurfaceVariant),
-                                maxLines: _expanded ? 3 : 1,
-                                overflow: _expanded ? TextOverflow.visible : TextOverflow.ellipsis,
-                              ),
-                            ],
-                          ],
-                        );
-                      },
-                    ),
-                  ),
-                  if (_isOverflowing || _expanded)
-                    Icon(_expanded ? Icons.expand_less : Icons.expand_more, color: colorScheme.onSurfaceVariant, size: 20),
-                ],
-              ),
-            ),
-          ],
-        ),
-      ),
-    );
-  }
 }
 
 /// Separate Consumer widget for each track - only rebuilds when this specific track's status changes

lib/screens/settings/about_page.dart

@@ -78,6 +78,49 @@ class AboutPage extends StatelessWidget {
                   name: AppInfo.originalAuthor,
                   description: 'Creator of the original SpotiFLAC',
                   githubUsername: AppInfo.originalAuthor,
+                  showDivider: true,
+                ),
+                _ContributorItem(
+                  name: 'Amonoman',
+                  description: 'The talented artist who created our beautiful app logo!',
+                  githubUsername: 'Amonoman',
+                  showDivider: false,
+                ),
+              ],
+            ),
+          ),
+
+          // Special Thanks section
+          const SliverToBoxAdapter(
+            child: SettingsSectionHeader(title: 'Special Thanks'),
+          ),
+          SliverToBoxAdapter(
+            child: SettingsGroup(
+              children: [
+                _ContributorItem(
+                  name: 'uimaxbai',
+                  description: 'The creator of QQDL & HiFi API. Without this API, Tidal downloads wouldn\'t exist!',
+                  githubUsername: 'uimaxbai',
+                  showDivider: true,
+                ),
+                _ContributorItem(
+                  name: 'sachinsenal0x64',
+                  description: 'The original HiFi project creator. The foundation of Tidal integration!',
+                  githubUsername: 'sachinsenal0x64',
+                  showDivider: true,
+                ),
+                _AboutSettingsItem(
+                  icon: Icons.cloud_outlined,
+                  title: 'DoubleDouble',
+                  subtitle: 'Amazing API for Amazon Music downloads. Thank you for making it free!',
+                  onTap: () => _launchUrl('https://doubledouble.top'),
+                  showDivider: true,
+                ),
+                _AboutSettingsItem(
+                  icon: Icons.music_note_outlined,
+                  title: 'DAB Music',
+                  subtitle: 'The best Qobuz streaming API. Hi-Res downloads wouldn\'t be possible without this!',
+                  onTap: () => _launchUrl('https://dabmusic.xyz'),
                   showDivider: false,
                 ),
               ],
@@ -206,30 +249,26 @@ class _AppHeaderCard extends StatelessWidget {
       padding: const EdgeInsets.all(24),
       child: Column(
         children: [
+          // App logo
           // App logo
           Container(
             width: 88,
             height: 88,
             decoration: BoxDecoration(
-              color: colorScheme.primaryContainer,
-              borderRadius: BorderRadius.circular(24),
-              boxShadow: [
-                BoxShadow(
-                  color: colorScheme.primary.withValues(alpha: 0.2),
-                  blurRadius: 16,
-                  offset: const Offset(0, 4),
-                ),
-              ],
+              color: colorScheme.primary,
+              shape: BoxShape.circle,
             ),
-            child: ClipRRect(
-              borderRadius: BorderRadius.circular(24),
-              child: Image.asset(
-                'assets/images/logo.png',
-                fit: BoxFit.cover,
-                errorBuilder: (_, _, _) => Icon(
-                  Icons.music_note,
-                  size: 48,
-                  color: colorScheme.onPrimaryContainer,
+            child: Image.asset(
+              'assets/images/logo-transparant.png',
+              color: colorScheme.onPrimary, // Tint with onPrimary color
+              fit: BoxFit.contain,
+              errorBuilder: (_, _, _) => ClipRRect(
+                borderRadius: BorderRadius.circular(24),
+                child: Image.asset(
+                  'assets/images/logo.png',
+                  width: 88,
+                  height: 88,
+                  fit: BoxFit.cover,
                 ),
               ),
             ),
@@ -374,3 +413,80 @@ class _ContributorItem extends StatelessWidget {
     await launchUrl(uri, mode: LaunchMode.inAppBrowserView);
   }
 }
+
+/// Settings item with 40x40 icon area to align with contributor avatars
+class _AboutSettingsItem extends StatelessWidget {
+  final IconData icon;
+  final String title;
+  final String? subtitle;
+  final VoidCallback? onTap;
+  final bool showDivider;
+
+  const _AboutSettingsItem({
+    required this.icon,
+    required this.title,
+    this.subtitle,
+    this.onTap,
+    this.showDivider = true,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    final colorScheme = Theme.of(context).colorScheme;
+    
+    return Column(
+      mainAxisSize: MainAxisSize.min,
+      children: [
+        InkWell(
+          onTap: onTap,
+          splashColor: colorScheme.primary.withValues(alpha: 0.12),
+          highlightColor: colorScheme.primary.withValues(alpha: 0.08),
+          child: Padding(
+            padding: const EdgeInsets.symmetric(horizontal: 20, vertical: 12),
+            child: Row(
+              children: [
+                // Icon with 40x40 size to match avatar
+                SizedBox(
+                  width: 40,
+                  height: 40,
+                  child: Icon(icon, color: colorScheme.onSurfaceVariant, size: 24),
+                ),
+                const SizedBox(width: 16),
+                Expanded(
+                  child: Column(
+                    crossAxisAlignment: CrossAxisAlignment.start,
+                    children: [
+                      Text(
+                        title,
+                        style: Theme.of(context).textTheme.bodyLarge,
+                      ),
+                      if (subtitle != null) ...[
+                        const SizedBox(height: 2),
+                        Text(
+                          subtitle!,
+                          style: Theme.of(context).textTheme.bodyMedium?.copyWith(
+                            color: colorScheme.onSurfaceVariant,
+                          ),
+                        ),
+                      ],
+                    ],
+                  ),
+                ),
+                if (onTap != null)
+                  Icon(Icons.chevron_right, color: colorScheme.onSurfaceVariant),
+              ],
+            ),
+          ),
+        ),
+        if (showDivider)
+          Divider(
+            height: 1,
+            thickness: 1,
+            indent: 76, // 20 + 40 + 16 = 76 (same as contributor item)
+            endIndent: 20,
+            color: colorScheme.outlineVariant.withValues(alpha: 0.3),
+          ),
+      ],
+    );
+  }
+}