refactor: consolidate lyrics builders, cancel registries, and priority plumbing

lib/providers/extension_provider.dart

@@ -1427,38 +1427,50 @@ class ExtensionNotifier extends Notifier<ExtensionState> {
     }
   }
 
+  /// Shared load path for the download/metadata priority lists: prefs first
+  /// (sanitized), falling back to backend defaults, then persist + push the
+  /// result back to the backend.
+  Future<List<String>> _loadPriorityList({
+    required String prefsKey,
+    required String label,
+    required List<String> Function(List<String>) sanitizeStored,
+    required List<String> Function(List<String>) sanitizeBackend,
+    required Future<List<String>> Function() fetchBackend,
+    required Future<void> Function(List<String>) pushBackend,
+  }) async {
+    final prefs = await SharedPreferences.getInstance();
+    final savedJson = prefs.getString(prefsKey);
+
+    List<String> priority;
+    if (savedJson != null) {
+      final saved = _tryDecodeStringListPreference(savedJson, prefsKey);
+      if (saved != null) {
+        priority = sanitizeStored(saved);
+        _log.d('Loaded $label from prefs: $priority');
+      } else {
+        await prefs.remove(prefsKey);
+        priority = sanitizeBackend(await fetchBackend());
+        _log.d('Recovered $label from defaults: $priority');
+      }
+    } else {
+      priority = sanitizeBackend(await fetchBackend());
+      _log.d('Using default $label: $priority');
+    }
+    await prefs.setString(prefsKey, jsonEncode(priority));
+    await pushBackend(priority);
+    return priority;
+  }
+
   Future<void> loadProviderPriority() async {
     try {
-      final prefs = await SharedPreferences.getInstance();
-      final savedJson = prefs.getString(_providerPriorityKey);
-
-      List<String> priority;
-      if (savedJson != null) {
-        final saved = _tryDecodeStringListPreference(
-          savedJson,
-          _providerPriorityKey,
-        );
-        if (saved != null) {
-          priority = _sanitizeDownloadProviderPriority(saved);
-          _log.d('Loaded provider priority from prefs: $priority');
-          await prefs.setString(_providerPriorityKey, jsonEncode(priority));
-          await PlatformBridge.setProviderPriority(priority);
-        } else {
-          await prefs.remove(_providerPriorityKey);
-          priority = await PlatformBridge.getProviderPriority();
-          priority = _sanitizeDownloadProviderPriority(priority);
-          await prefs.setString(_providerPriorityKey, jsonEncode(priority));
-          await PlatformBridge.setProviderPriority(priority);
-          _log.d('Recovered provider priority from defaults: $priority');
-        }
-      } else {
-        priority = await PlatformBridge.getProviderPriority();
-        priority = _sanitizeDownloadProviderPriority(priority);
-        await prefs.setString(_providerPriorityKey, jsonEncode(priority));
-        await PlatformBridge.setProviderPriority(priority);
-        _log.d('Using default provider priority: $priority');
-      }
-
+      final priority = await _loadPriorityList(
+        prefsKey: _providerPriorityKey,
+        label: 'provider priority',
+        sanitizeStored: _sanitizeDownloadProviderPriority,
+        sanitizeBackend: _sanitizeDownloadProviderPriority,
+        fetchBackend: PlatformBridge.getProviderPriority,
+        pushBackend: PlatformBridge.setProviderPriority,
+      );
       state = state.copyWith(providerPriority: priority);
     } catch (e) {
       _log.e('Failed to load provider priority: $e');
@@ -1502,51 +1514,16 @@ class ExtensionNotifier extends Notifier<ExtensionState> {
 
   Future<void> loadMetadataProviderPriority() async {
     try {
-      final prefs = await SharedPreferences.getInstance();
-      final savedJson = prefs.getString(_metadataProviderPriorityKey);
-
-      List<String> priority;
-      if (savedJson != null) {
-        final saved = _tryDecodeStringListPreference(
-          savedJson,
-          _metadataProviderPriorityKey,
-        );
-        if (saved != null) {
-          priority = _sanitizeMetadataProviderPriority(
-            _replaceRetiredBuiltInMetadataProviders(saved),
-          );
-          _log.d('Loaded metadata provider priority from prefs: $priority');
-          await prefs.setString(
-            _metadataProviderPriorityKey,
-            jsonEncode(priority),
-          );
-          await PlatformBridge.setMetadataProviderPriority(priority);
-        } else {
-          await prefs.remove(_metadataProviderPriorityKey);
-          final backendPriority =
-              await PlatformBridge.getMetadataProviderPriority();
-          priority = _sanitizeMetadataProviderPriority(backendPriority);
-          await prefs.setString(
-            _metadataProviderPriorityKey,
-            jsonEncode(priority),
-          );
-          await PlatformBridge.setMetadataProviderPriority(priority);
-          _log.d(
-            'Recovered metadata provider priority from defaults: $priority',
-          );
-        }
-      } else {
-        final backendPriority =
-            await PlatformBridge.getMetadataProviderPriority();
-        priority = _sanitizeMetadataProviderPriority(backendPriority);
-        _log.d('Using default metadata provider priority: $priority');
-        await prefs.setString(
-          _metadataProviderPriorityKey,
-          jsonEncode(priority),
-        );
-        await PlatformBridge.setMetadataProviderPriority(priority);
-      }
-
+      final priority = await _loadPriorityList(
+        prefsKey: _metadataProviderPriorityKey,
+        label: 'metadata provider priority',
+        sanitizeStored: (saved) => _sanitizeMetadataProviderPriority(
+          _replaceRetiredBuiltInMetadataProviders(saved),
+        ),
+        sanitizeBackend: _sanitizeMetadataProviderPriority,
+        fetchBackend: PlatformBridge.getMetadataProviderPriority,
+        pushBackend: PlatformBridge.setMetadataProviderPriority,
+      );
       state = state.copyWith(metadataProviderPriority: priority);
     } catch (e) {
       _log.e('Failed to load metadata provider priority: $e');

lib/providers/repo_provider.dart

@@ -364,15 +364,33 @@ class RepoNotifier extends Notifier<RepoState> {
     String extensionsDir,
   ) {
     return _runSerialized(
-      () => _installExtensionInternal(extensionId, tempDir, extensionsDir),
+      () => _downloadAndApplyExtension(
+        extensionId,
+        tempDir,
+        action: 'install',
+        apply: (notifier, path) => notifier.installExtension(path),
+      ),
     );
   }
 
-  Future<bool> _installExtensionInternal(
+  Future<bool> updateExtension(String extensionId, String tempDir) {
+    return _runSerialized(
+      () => _downloadAndApplyExtension(
+        extensionId,
+        tempDir,
+        action: 'update',
+        apply: (notifier, path) => notifier.upgradeExtension(path),
+      ),
+    );
+  }
+
+  Future<bool> _downloadAndApplyExtension(
     String extensionId,
-    String tempDir,
-    String extensionsDir,
-  ) async {
+    String tempDir, {
+    required String action,
+    required Future<bool> Function(ExtensionNotifier notifier, String path)
+    apply,
+  }) async {
     state = state.copyWith(
       isDownloading: true,
       downloadingId: extensionId,
@@ -386,64 +404,21 @@ class RepoNotifier extends Notifier<RepoState> {
         tempDir,
       );
 
-      _log.i('Installing extension from: $downloadPath');
-      final extNotifier = ref.read(extensionProvider.notifier);
-      final success = await extNotifier.installExtension(downloadPath);
+      _log.i('Applying $action from: $downloadPath');
+      final success = await apply(
+        ref.read(extensionProvider.notifier),
+        downloadPath,
+      );
 
       if (success) {
-        _log.i('Extension installed: $extensionId');
+        _log.i('Extension $action succeeded: $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;
-    }
-  }
-
-  Future<bool> updateExtension(String extensionId, String tempDir) {
-    return _runSerialized(
-      () => _updateExtensionInternal(extensionId, tempDir),
-    );
-  }
-
-  Future<bool> _updateExtensionInternal(
-    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.downloadRepoExtension(
-        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');
+      _log.e('Failed to $action extension: $e');
       state = state.copyWith(
         isDownloading: false,
         clearDownloadingId: true,

lib/screens/downloaded_album_screen.dart

@@ -23,6 +23,7 @@ import 'package:spotiflac_android/screens/selection_mode_mixin.dart';
 import 'package:spotiflac_android/screens/track_metadata_screen.dart';
 import 'package:spotiflac_android/services/downloaded_embedded_cover_resolver.dart';
 import 'package:spotiflac_android/widgets/album_scaffold_body.dart';
+import 'package:spotiflac_android/widgets/cached_cover_image.dart';
 import 'package:spotiflac_android/widgets/album_track_tile.dart';
 import 'package:spotiflac_android/widgets/animation_utils.dart';
 import 'package:spotiflac_android/widgets/destructive_selection_button.dart';
@@ -206,7 +207,7 @@ class _DownloadedAlbumScreenState extends ConsumerState<DownloadedAlbumScreen>
     required int navigationIndex,
   }) async {
     final navigator = Navigator.of(context);
-    _precacheCover(item.coverUrl);
+    precacheCoverImage(context, item.coverUrl);
     final beforeModTime =
         await DownloadedEmbeddedCoverResolver.readFileModTimeMillis(
           item.filePath,
@@ -230,28 +231,6 @@ class _DownloadedAlbumScreenState extends ConsumerState<DownloadedAlbumScreen>
     );
   }
 
-  void _precacheCover(String? url) {
-    if (url == null || url.isEmpty) return;
-    if (!url.startsWith('http://') && !url.startsWith('https://')) {
-      return;
-    }
-    final dpr = MediaQuery.devicePixelRatioOf(
-      context,
-    ).clamp(1.0, 3.0).toDouble();
-    final targetSize = (360 * dpr).round().clamp(512, 1024).toInt();
-    precacheImage(
-      ResizeImage(
-        CachedNetworkImageProvider(
-          url,
-          cacheManager: CoverCacheManager.instance,
-        ),
-        width: targetSize,
-        height: targetSize,
-      ),
-      context,
-    );
-  }
-
   @override
   Widget build(BuildContext context) {
     final colorScheme = Theme.of(context).colorScheme;

lib/screens/home_tab.dart

@@ -2359,7 +2359,7 @@ class _HomeTabState extends ConsumerState<HomeTab>
     int? navigationIndex,
   }) async {
     final navigator = Navigator.of(context);
-    _precacheCover(item.coverUrl);
+    precacheCoverImage(context, item.coverUrl);
     final beforeModTime =
         await DownloadedEmbeddedCoverResolver.readFileModTimeMillis(
           item.filePath,
@@ -2382,25 +2382,6 @@ class _HomeTabState extends ConsumerState<HomeTab>
     );
   }
 
-  void _precacheCover(String? url) {
-    if (url == null || url.isEmpty) return;
-    if (!url.startsWith('http://') && !url.startsWith('https://')) {
-      return;
-    }
-    final dpr = MediaQuery.devicePixelRatioOf(
-      context,
-    ).clamp(1.0, 3.0).toDouble();
-    final targetSize = (360 * dpr).round().clamp(512, 1024).toInt();
-    precacheImage(
-      ResizeImage(
-        cachedCoverImageProvider(url),
-        width: targetSize,
-        height: targetSize,
-      ),
-      context,
-    );
-  }
-
   Widget _buildErrorWidget(String error, ColorScheme colorScheme) {
     final l10n = context.l10n;
     final isRateLimit =

lib/screens/queue_tab_navigation.dart

@@ -93,25 +93,6 @@ extension _QueueTabNavigation on _QueueTabState {
     );
   }
 
-  void _precacheCover(String? url) {
-    if (url == null || url.isEmpty) return;
-    if (!url.startsWith('http://') && !url.startsWith('https://')) {
-      return;
-    }
-    final dpr = MediaQuery.devicePixelRatioOf(
-      context,
-    ).clamp(1.0, 3.0).toDouble();
-    final targetSize = (360 * dpr).round().clamp(512, 1024).toInt();
-    precacheImage(
-      ResizeImage(
-        cachedCoverImageProvider(url),
-        width: targetSize,
-        height: targetSize,
-      ),
-      context,
-    );
-  }
-
   Future<void> _navigateToMetadataScreen(DownloadItem item) async {
     final historyItem = ref
         .read(downloadHistoryProvider)
@@ -131,7 +112,7 @@ extension _QueueTabNavigation on _QueueTabState {
         );
 
     final navigator = Navigator.of(context);
-    _precacheCover(historyItem.coverUrl);
+    precacheCoverImage(context, historyItem.coverUrl);
     _searchFocusNode.unfocus();
     final beforeModTime = await _readFileModTimeMillis(historyItem.filePath);
     if (!mounted) return;
@@ -159,7 +140,7 @@ extension _QueueTabNavigation on _QueueTabState {
     int? navigationIndex,
   }) async {
     final navigator = Navigator.of(context);
-    _precacheCover(item.coverUrl);
+    precacheCoverImage(context, item.coverUrl);
     _searchFocusNode.unfocus();
     final beforeModTime = await _readFileModTimeMillis(item.filePath);
     if (!mounted) return;

lib/widgets/cached_cover_image.dart

@@ -180,6 +180,25 @@ CachedNetworkImageProvider cachedCoverImageProvider(String url) {
   );
 }
 
+/// Pre-warms the cover cache at the metadata-screen display size so the hero
+/// transition doesn't pop in a low-res frame. Http(s) URLs only.
+void precacheCoverImage(BuildContext context, String? url) {
+  if (url == null || url.isEmpty) return;
+  if (!url.startsWith('http://') && !url.startsWith('https://')) {
+    return;
+  }
+  final dpr = MediaQuery.devicePixelRatioOf(context).clamp(1.0, 3.0).toDouble();
+  final targetSize = (360 * dpr).round().clamp(512, 1024).toInt();
+  precacheImage(
+    ResizeImage(
+      cachedCoverImageProvider(url),
+      width: targetSize,
+      height: targetSize,
+    ),
+    context,
+  );
+}
+
 int coverImageCacheExtent(
   BuildContext context,
   double logicalSize, {