v2.1.5: Fix progress bar and incomplete downloads

- Fix progress bar jumping from 1% to 100% (threshold-based updates)
- Fix incomplete downloads with temp file + size validation
- Applies to Tidal, Qobuz, and Amazon services

CHANGELOG.md

@@ -1,6 +1,6 @@
 # Changelog
 
-## [2.1.5-preview] - 2026-01-07
+## [2.1.5] - 2026-01-07
 
 ### Added
 - **Deezer as Alternative Metadata Source**: Choose between Deezer or Spotify for search
@@ -15,9 +15,22 @@
   - `[Search] Using metadata source: deezer/spotify for query: "..."`
   - `[FetchURL] Fetching track with Deezer fallback enabled...`
 
+### Fixed
+- **Progress Bar Not Updating**: Fixed bug where download progress jumped from 1% directly to 100%
+  - Progress now updates smoothly every 64KB of data received
+  - First progress update happens immediately when download starts
+- **Incomplete Downloads**: Fixed bug where interrupted downloads could result in corrupted/incomplete files
+  - Downloads now use temporary files (`.tmp`) during transfer
+  - File size is validated against server's Content-Length header
+  - Incomplete files are automatically deleted and error is reported
+  - Final file is only created after successful download completion
+  - Applies to all services: Tidal, Qobuz, and Amazon
+
 ### Technical
 - New settings field: `metadataSource` in `lib/models/settings.dart`
 - New UI: Search Source selector in Options Settings page
+- Improved `ItemProgressWriter` with threshold-based progress updates
+- Download functions now properly handle network interruptions
 
 ## [2.1.0] - 2026-01-06
 

go_backend/amazon.go

@@ -294,35 +294,63 @@ func (a *AmazonDownloader) DownloadFile(downloadURL, outputPath, itemID string)
 		return fmt.Errorf("download failed: HTTP %d", resp.StatusCode)
 	}
 
+	expectedSize := resp.ContentLength
 	// Set total bytes if available
-	if resp.ContentLength > 0 && itemID != "" {
-		SetItemBytesTotal(itemID, resp.ContentLength)
+	if expectedSize > 0 && itemID != "" {
+		SetItemBytesTotal(itemID, expectedSize)
 	}
 
-	out, err := os.Create(outputPath)
+	// Use temp file to avoid incomplete downloads
+	tempPath := outputPath + ".tmp"
+	out, err := os.Create(tempPath)
 	if err != nil {
 		return err
 	}
-	defer out.Close()
 
 	// Use buffered writer for better performance (256KB buffer)
 	bufWriter := bufio.NewWriterSize(out, 256*1024)
-	defer bufWriter.Flush()
 
 	// Use item progress writer with buffered output
-	var bytesWritten int64
+	var written int64
 	if itemID != "" {
 		pw := NewItemProgressWriter(bufWriter, itemID)
-		bytesWritten, err = io.Copy(pw, resp.Body)
+		written, err = io.Copy(pw, resp.Body)
 	} else {
 		// Fallback: direct copy without progress tracking
-		bytesWritten, err = io.Copy(bufWriter, resp.Body)
-	}
-	if err != nil {
-		return fmt.Errorf("failed to write file: %w", err)
+		written, err = io.Copy(bufWriter, resp.Body)
 	}
 
-	fmt.Printf("\r[Amazon] Downloaded: %.2f MB (Complete)\n", float64(bytesWritten)/(1024*1024))
+	// Flush buffer before checking for errors
+	flushErr := bufWriter.Flush()
+	closeErr := out.Close()
+
+	// Check for any errors
+	if err != nil {
+		os.Remove(tempPath)
+		return fmt.Errorf("download interrupted: %w", err)
+	}
+	if flushErr != nil {
+		os.Remove(tempPath)
+		return fmt.Errorf("failed to flush buffer: %w", flushErr)
+	}
+	if closeErr != nil {
+		os.Remove(tempPath)
+		return fmt.Errorf("failed to close file: %w", closeErr)
+	}
+
+	// Verify file size if Content-Length was provided
+	if expectedSize > 0 && written != expectedSize {
+		os.Remove(tempPath)
+		return fmt.Errorf("incomplete download: expected %d bytes, got %d bytes", expectedSize, written)
+	}
+
+	// Rename temp file to final path
+	if err := os.Rename(tempPath, outputPath); err != nil {
+		os.Remove(tempPath)
+		return fmt.Errorf("failed to rename temp file: %w", err)
+	}
+
+	fmt.Printf("\r[Amazon] Downloaded: %.2f MB (Complete)\n", float64(written)/(1024*1024))
 	return nil
 }
 

go_backend/progress.go

@@ -195,39 +195,38 @@ func getDownloadDir() string {
 }
 
 // ItemProgressWriter wraps io.Writer to track download progress for a specific item
-// Uses buffered writing for better performance
 type ItemProgressWriter struct {
-	writer  interface{ Write([]byte) (int, error) }
-	itemID  string
-	current int64
-	buffer  []byte
-	bufPos  int
+	writer       interface{ Write([]byte) (int, error) }
+	itemID       string
+	current      int64
+	lastReported int64 // Track last reported bytes for threshold-based updates
 }
 
-const progressWriterBufferSize = 256 * 1024 // 256KB buffer for faster writes
+const progressUpdateThreshold = 64 * 1024 // Update progress every 64KB
 
 // NewItemProgressWriter creates a new progress writer for a specific item
 func NewItemProgressWriter(w interface{ Write([]byte) (int, error) }, itemID string) *ItemProgressWriter {
 	return &ItemProgressWriter{
-		writer:  w,
-		itemID:  itemID,
-		current: 0,
-		buffer:  make([]byte, progressWriterBufferSize),
-		bufPos:  0,
+		writer:       w,
+		itemID:       itemID,
+		current:      0,
+		lastReported: 0,
 	}
 }
 
-// Write implements io.Writer with buffering
+// Write implements io.Writer with threshold-based progress updates
 func (pw *ItemProgressWriter) Write(p []byte) (int, error) {
 	n, err := pw.writer.Write(p)
 	if err != nil {
 		return n, err
 	}
 	pw.current += int64(n)
-	
-	// Update progress less frequently (every 64KB) to reduce lock contention
-	if pw.current%(64*1024) == 0 || pw.current == 0 {
+
+	// Update progress when we've received at least 64KB since last update
+	// Also update on first write to show download has started
+	if pw.lastReported == 0 || pw.current-pw.lastReported >= progressUpdateThreshold {
 		SetItemBytesReceived(pw.itemID, pw.current)
+		pw.lastReported = pw.current
 	}
 	return n, nil
 }

go_backend/qobuz.go

@@ -473,30 +473,63 @@ func (q *QobuzDownloader) DownloadFile(downloadURL, outputPath, itemID string) e
 		return fmt.Errorf("download failed: HTTP %d", resp.StatusCode)
 	}
 
+	expectedSize := resp.ContentLength
 	// Set total bytes if available
-	if resp.ContentLength > 0 && itemID != "" {
-		SetItemBytesTotal(itemID, resp.ContentLength)
+	if expectedSize > 0 && itemID != "" {
+		SetItemBytesTotal(itemID, expectedSize)
 	}
 
-	out, err := os.Create(outputPath)
+	// Use temp file to avoid incomplete downloads
+	tempPath := outputPath + ".tmp"
+	out, err := os.Create(tempPath)
 	if err != nil {
 		return err
 	}
-	defer out.Close()
 
 	// Use buffered writer for better performance (256KB buffer)
 	bufWriter := bufio.NewWriterSize(out, 256*1024)
-	defer bufWriter.Flush()
 
 	// Use item progress writer with buffered output
+	var written int64
 	if itemID != "" {
 		progressWriter := NewItemProgressWriter(bufWriter, itemID)
-		_, err = io.Copy(progressWriter, resp.Body)
+		written, err = io.Copy(progressWriter, resp.Body)
 	} else {
 		// Fallback: direct copy without progress tracking
-		_, err = io.Copy(bufWriter, resp.Body)
+		written, err = io.Copy(bufWriter, resp.Body)
 	}
-	return err
+
+	// Flush buffer before checking for errors
+	flushErr := bufWriter.Flush()
+	closeErr := out.Close()
+
+	// Check for any errors
+	if err != nil {
+		os.Remove(tempPath)
+		return fmt.Errorf("download interrupted: %w", err)
+	}
+	if flushErr != nil {
+		os.Remove(tempPath)
+		return fmt.Errorf("failed to flush buffer: %w", flushErr)
+	}
+	if closeErr != nil {
+		os.Remove(tempPath)
+		return fmt.Errorf("failed to close file: %w", closeErr)
+	}
+
+	// Verify file size if Content-Length was provided
+	if expectedSize > 0 && written != expectedSize {
+		os.Remove(tempPath)
+		return fmt.Errorf("incomplete download: expected %d bytes, got %d bytes", expectedSize, written)
+	}
+
+	// Rename temp file to final path
+	if err := os.Rename(tempPath, outputPath); err != nil {
+		os.Remove(tempPath)
+		return fmt.Errorf("failed to rename temp file: %w", err)
+	}
+
+	return nil
 }
 
 // QobuzDownloadResult contains download result with quality info

go_backend/tidal.go

@@ -746,30 +746,63 @@ func (t *TidalDownloader) DownloadFile(downloadURL, outputPath, itemID string) e
 		return fmt.Errorf("download failed: HTTP %d", resp.StatusCode)
 	}
 
+	expectedSize := resp.ContentLength
 	// Set total bytes if available
-	if resp.ContentLength > 0 && itemID != "" {
-		SetItemBytesTotal(itemID, resp.ContentLength)
+	if expectedSize > 0 && itemID != "" {
+		SetItemBytesTotal(itemID, expectedSize)
 	}
 
-	out, err := os.Create(outputPath)
+	// Use temp file to avoid incomplete downloads
+	tempPath := outputPath + ".tmp"
+	out, err := os.Create(tempPath)
 	if err != nil {
 		return err
 	}
-	defer out.Close()
 
 	// Use buffered writer for better performance (256KB buffer)
 	bufWriter := bufio.NewWriterSize(out, 256*1024)
-	defer bufWriter.Flush()
 
 	// Use item progress writer with buffered output
+	var written int64
 	if itemID != "" {
 		progressWriter := NewItemProgressWriter(bufWriter, itemID)
-		_, err = io.Copy(progressWriter, resp.Body)
+		written, err = io.Copy(progressWriter, resp.Body)
 	} else {
 		// Fallback: direct copy without progress tracking
-		_, err = io.Copy(bufWriter, resp.Body)
+		written, err = io.Copy(bufWriter, resp.Body)
 	}
-	return err
+
+	// Flush buffer before checking for errors
+	flushErr := bufWriter.Flush()
+	closeErr := out.Close()
+
+	// Check for any errors
+	if err != nil {
+		os.Remove(tempPath)
+		return fmt.Errorf("download interrupted: %w", err)
+	}
+	if flushErr != nil {
+		os.Remove(tempPath)
+		return fmt.Errorf("failed to flush buffer: %w", flushErr)
+	}
+	if closeErr != nil {
+		os.Remove(tempPath)
+		return fmt.Errorf("failed to close file: %w", closeErr)
+	}
+
+	// Verify file size if Content-Length was provided
+	if expectedSize > 0 && written != expectedSize {
+		os.Remove(tempPath)
+		return fmt.Errorf("incomplete download: expected %d bytes, got %d bytes", expectedSize, written)
+	}
+
+	// Rename temp file to final path
+	if err := os.Rename(tempPath, outputPath); err != nil {
+		os.Remove(tempPath)
+		return fmt.Errorf("failed to rename temp file: %w", err)
+	}
+
+	return nil
 }
 
 func (t *TidalDownloader) downloadFromManifest(manifestB64, outputPath, itemID string) error {
@@ -805,26 +838,52 @@ func (t *TidalDownloader) downloadFromManifest(manifestB64, outputPath, itemID s
 			return fmt.Errorf("download failed with status %d", resp.StatusCode)
 		}
 
+		expectedSize := resp.ContentLength
 		// Set total bytes for progress tracking
-		if resp.ContentLength > 0 && itemID != "" {
-			SetItemBytesTotal(itemID, resp.ContentLength)
+		if expectedSize > 0 && itemID != "" {
+			SetItemBytesTotal(itemID, expectedSize)
 		}
 
-		out, err := os.Create(outputPath)
+		// Use temp file to avoid incomplete downloads
+		tempPath := outputPath + ".tmp"
+		out, err := os.Create(tempPath)
 		if err != nil {
 			return fmt.Errorf("failed to create file: %w", err)
 		}
-		defer out.Close()
 
 		// Use item progress writer
+		var written int64
 		if itemID != "" {
 			progressWriter := NewItemProgressWriter(out, itemID)
-			_, err = io.Copy(progressWriter, resp.Body)
+			written, err = io.Copy(progressWriter, resp.Body)
 		} else {
-			// Fallback: direct copy without progress tracking
-			_, err = io.Copy(out, resp.Body)
+			written, err = io.Copy(out, resp.Body)
 		}
-		return err
+
+		closeErr := out.Close()
+
+		if err != nil {
+			os.Remove(tempPath)
+			return fmt.Errorf("download interrupted: %w", err)
+		}
+		if closeErr != nil {
+			os.Remove(tempPath)
+			return fmt.Errorf("failed to close file: %w", closeErr)
+		}
+
+		// Verify file size if Content-Length was provided
+		if expectedSize > 0 && written != expectedSize {
+			os.Remove(tempPath)
+			return fmt.Errorf("incomplete download: expected %d bytes, got %d bytes", expectedSize, written)
+		}
+
+		// Rename temp file to final path
+		if err := os.Rename(tempPath, outputPath); err != nil {
+			os.Remove(tempPath)
+			return fmt.Errorf("failed to rename temp file: %w", err)
+		}
+
+		return nil
 	}
 
 	// DASH format - download segments to temporary file

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 = '2.1.5-preview';
-  static const String buildNumber = '42';
+  static const String version = '2.1.5';
+  static const String buildNumber = '43';
   static const String fullVersion = '$version+$buildNumber';
   
   

lib/providers/settings_provider.dart

@@ -5,6 +5,8 @@ import 'package:spotiflac_android/models/settings.dart';
 import 'package:spotiflac_android/services/platform_bridge.dart';
 
 const _settingsKey = 'app_settings';
+const _migrationVersionKey = 'settings_migration_version';
+const _currentMigrationVersion = 1; // Increment this when adding new migrations
 
 class SettingsNotifier extends Notifier<AppSettings> {
   @override
@@ -18,11 +20,32 @@ class SettingsNotifier extends Notifier<AppSettings> {
     final json = prefs.getString(_settingsKey);
     if (json != null) {
       state = AppSettings.fromJson(jsonDecode(json));
+      
+      // Run migrations if needed
+      await _runMigrations(prefs);
+      
       // Apply Spotify credentials to Go backend on load
       _applySpotifyCredentials();
     }
   }
 
+  /// Run one-time migrations for settings
+  Future<void> _runMigrations(SharedPreferences prefs) async {
+    final lastMigration = prefs.getInt(_migrationVersionKey) ?? 0;
+    
+    if (lastMigration < 1) {
+      // Migration 1: Set metadataSource to 'deezer' for existing users
+      // This ensures users updating from older versions get Deezer as default
+      state = state.copyWith(metadataSource: 'deezer');
+      await _saveSettings();
+    }
+    
+    // Save current migration version
+    if (lastMigration < _currentMigrationVersion) {
+      await prefs.setInt(_migrationVersionKey, _currentMigrationVersion);
+    }
+  }
+
   Future<void> _saveSettings() async {
     final prefs = await SharedPreferences.getInstance();
     await prefs.setString(_settingsKey, jsonEncode(state.toJson()));

pubspec.yaml

@@ -1,7 +1,7 @@
 name: spotiflac_android
 description: Download Spotify tracks in FLAC from Tidal, Qobuz & Amazon Music
 publish_to: 'none'
-version: 2.1.5-preview+42
+version: 2.1.5+43
 
 environment:
   sdk: ^3.10.0