refactor: migrate local library from in-memory list to database-backed pagination

Replace the full in-memory List<LocalLibraryItem> in LocalLibraryState
with a lightweight lookup index (ISRCs, matchKeys, filePathById) and
database-backed FutureProvider.family pagination providers.

Database changes:
- Add library schema v7 with normalized lookup columns (track_name_norm,
  artist_name_norm, album_name_norm, album_artist_norm, match_key,
  album_key) and corresponding indexes
- Backfill normalized columns on migration from v6
- Add getPage, getPageCount, getAlbumPage, getAlbumCount, getLookupIndex,
  getCoverPaths, getByFilePath, findFirstByTrackAndArtist DB methods

Provider changes:
- LocalLibraryState no longer holds items list; uses totalCount and
  loadedIndexVersion for change tracking
- Deprecate synchronous getByIsrc/findByTrackAndArtist (return null);
  add async findExistingAsync, getByIsrcAsync, getById on notifier
- Add localLibraryPageProvider, localLibraryAlbumPageProvider,
  localLibraryAllItemsProvider family providers for paginated access
- Add localLibraryCoverProvider and localLibraryFirstCoverProvider
  for async cover path resolution from DB

Screen migrations:
- album/artist/playlist screens use findExistingAsync for playback
- library_tracks_folder_screen uses async cover providers and
  existsInLibrary for local library indicator
- queue_tab watches localLibraryAllItemsProvider instead of state.items
- library_settings_page uses state.totalCount
- playback_provider uses findExistingAsync

Track metadata screen:
- Replace pushReplacement navigation with in-place state swap using
  AnimatedSwitcher for smooth cross-fade transitions on track swipe
- Add metadataLoadGeneration counter to prevent stale async callbacks
- Reset all transient state (lyrics, cover, file check) on track change

lib/providers/local_library_provider.dart

@@ -18,7 +18,6 @@ const _excludedDownloadedCountKey = 'local_library_excluded_downloaded_count';
 final _prefs = SharedPreferences.getInstance();
 
 class LocalLibraryState {
-  final List<LocalLibraryItem> items;
   final bool isScanning;
   final bool scanIsFinalizing;
   final double scanProgress;
@@ -27,14 +26,15 @@ class LocalLibraryState {
   final int scannedFiles;
   final int scanErrorCount;
   final bool scanWasCancelled;
+  final int totalCount;
+  final int loadedIndexVersion;
   final DateTime? lastScannedAt;
   final int excludedDownloadedCount;
   final Set<String> _trackKeySet;
-  final Map<String, LocalLibraryItem> _byIsrc;
-  final Map<String, LocalLibraryItem> _byTrackKey;
+  final Set<String> _isrcSet;
+  final Map<String, String> _filePathById;
 
   LocalLibraryState({
-    this.items = const [],
     this.isScanning = false,
     this.scanIsFinalizing = false,
     this.scanProgress = 0,
@@ -43,36 +43,30 @@ class LocalLibraryState {
     this.scannedFiles = 0,
     this.scanErrorCount = 0,
     this.scanWasCancelled = false,
+    this.totalCount = 0,
+    this.loadedIndexVersion = 0,
     this.lastScannedAt,
     this.excludedDownloadedCount = 0,
     Set<String>? trackKeySet,
-    Map<String, LocalLibraryItem>? byIsrc,
-    Map<String, LocalLibraryItem>? byTrackKey,
-  }) : _trackKeySet = trackKeySet ?? items.map((item) => item.matchKey).toSet(),
-       _byIsrc =
-           byIsrc ??
-           Map.fromEntries(
-             items
-                 .where((item) => item.isrc != null && item.isrc!.isNotEmpty)
-                 .map((item) => MapEntry(item.isrc!, item)),
-           ),
-       _byTrackKey =
-           byTrackKey ??
-           Map.fromEntries(items.map((item) => MapEntry(item.matchKey, item)));
+    Set<String>? isrcSet,
+    Map<String, String>? filePathById,
+  }) : _trackKeySet = trackKeySet ?? const <String>{},
+       _isrcSet = isrcSet ?? const <String>{},
+       _filePathById = filePathById ?? const <String, String>{};
 
-  bool hasIsrc(String isrc) => _byIsrc.containsKey(isrc);
+  @Deprecated(
+    'LocalLibraryState no longer owns full track rows. Use DB-backed page providers.',
+  )
+  List<LocalLibraryItem> get items => const <LocalLibraryItem>[];
+
+  bool hasIsrc(String isrc) => _isrcSet.contains(isrc);
 
   bool hasTrack(String trackName, String artistName) {
-    final key = '${trackName.toLowerCase()}|${artistName.toLowerCase()}';
+    final key = LibraryDatabase.matchKeyFor(trackName, artistName);
     return _trackKeySet.contains(key);
   }
 
-  LocalLibraryItem? getByIsrc(String isrc) => _byIsrc[isrc];
-
-  LocalLibraryItem? findByTrackAndArtist(String trackName, String artistName) {
-    final key = '${trackName.toLowerCase()}|${artistName.toLowerCase()}';
-    return _byTrackKey[key];
-  }
+  String? filePathForId(String id) => _filePathById[id];
 
   bool existsInLibrary({String? isrc, String? trackName, String? artistName}) {
     if (isrc != null && isrc.isNotEmpty && hasIsrc(isrc)) {
@@ -85,7 +79,6 @@ class LocalLibraryState {
   }
 
   LocalLibraryState copyWith({
-    List<LocalLibraryItem>? items,
     bool? isScanning,
     bool? scanIsFinalizing,
     double? scanProgress,
@@ -94,14 +87,15 @@ class LocalLibraryState {
     int? scannedFiles,
     int? scanErrorCount,
     bool? scanWasCancelled,
+    int? totalCount,
+    int? loadedIndexVersion,
     DateTime? lastScannedAt,
     int? excludedDownloadedCount,
+    Set<String>? trackKeySet,
+    Set<String>? isrcSet,
+    Map<String, String>? filePathById,
   }) {
-    final nextItems = items ?? this.items;
-    final keepDerivedIndex = identical(nextItems, this.items);
-
     return LocalLibraryState(
-      items: nextItems,
       isScanning: isScanning ?? this.isScanning,
       scanIsFinalizing: scanIsFinalizing ?? this.scanIsFinalizing,
       scanProgress: scanProgress ?? this.scanProgress,
@@ -110,12 +104,14 @@ class LocalLibraryState {
       scannedFiles: scannedFiles ?? this.scannedFiles,
       scanErrorCount: scanErrorCount ?? this.scanErrorCount,
       scanWasCancelled: scanWasCancelled ?? this.scanWasCancelled,
+      totalCount: totalCount ?? this.totalCount,
+      loadedIndexVersion: loadedIndexVersion ?? this.loadedIndexVersion,
       lastScannedAt: lastScannedAt ?? this.lastScannedAt,
       excludedDownloadedCount:
           excludedDownloadedCount ?? this.excludedDownloadedCount,
-      trackKeySet: keepDerivedIndex ? _trackKeySet : null,
-      byIsrc: keepDerivedIndex ? _byIsrc : null,
-      byTrackKey: keepDerivedIndex ? _byTrackKey : null,
+      trackKeySet: trackKeySet ?? _trackKeySet,
+      isrcSet: isrcSet ?? _isrcSet,
+      filePathById: filePathById ?? _filePathById,
     );
   }
 }
@@ -169,12 +165,11 @@ class LocalLibraryNotifier extends Notifier<LocalLibraryState> {
     _isLoaded = true;
 
     try {
-      final dbItemsFuture = _db.getAll();
+      final countFuture = _db.getCount();
+      final indexFuture = _db.getLookupIndex();
       final prefsFuture = _prefs;
-      final jsonList = await dbItemsFuture;
-      final items = jsonList
-          .map((e) => LocalLibraryItem.fromJson(e))
-          .toList(growable: false);
+      final count = await countFuture;
+      final lookupIndex = await indexFuture;
 
       DateTime? lastScannedAt;
       var excludedDownloadedCount = 0;
@@ -188,12 +183,16 @@ class LocalLibraryNotifier extends Notifier<LocalLibraryState> {
       }
 
       state = state.copyWith(
-        items: items,
+        totalCount: count,
+        loadedIndexVersion: state.loadedIndexVersion + 1,
         lastScannedAt: lastScannedAt,
         excludedDownloadedCount: excludedDownloadedCount,
+        trackKeySet: lookupIndex.matchKeys,
+        isrcSet: lookupIndex.isrcs,
+        filePathById: lookupIndex.filePathById,
       );
       _log.i(
-        'Loaded ${items.length} items from library database, lastScannedAt: '
+        'Loaded local library summary: $count items, lastScannedAt: '
         '$lastScannedAt, excludedDownloadedCount: $excludedDownloadedCount',
       );
       _hasLoadedFromDatabase = true;
@@ -212,6 +211,27 @@ class LocalLibraryNotifier extends Notifier<LocalLibraryState> {
     await _ensureLoadedFromDatabase();
   }
 
+  Future<void> _refreshSummaryFromStorage({
+    DateTime? lastScannedAt,
+    int? excludedDownloadedCount,
+  }) async {
+    final countFuture = _db.getCount();
+    final indexFuture = _db.getLookupIndex();
+    final count = await countFuture;
+    final index = await indexFuture;
+    state = state.copyWith(
+      totalCount: count,
+      loadedIndexVersion: state.loadedIndexVersion + 1,
+      lastScannedAt: lastScannedAt,
+      excludedDownloadedCount: excludedDownloadedCount,
+      trackKeySet: index.matchKeys,
+      isrcSet: index.isrcs,
+      filePathById: index.filePathById,
+    );
+    _hasLoadedFromDatabase = true;
+    _isLoaded = true;
+  }
+
   bool _isDownloadedPath(String? filePath, Set<String> downloadedPathKeys) {
     if (filePath == null || filePath.isEmpty || downloadedPathKeys.isEmpty) {
       return false;
@@ -225,31 +245,6 @@ class LocalLibraryNotifier extends Notifier<LocalLibraryState> {
     return false;
   }
 
-  Future<Map<String, LocalLibraryItem>> _currentItemsByPathForIncrementalScan(
-    Map<String, int> existingFiles,
-  ) async {
-    await _ensureLoadedFromDatabase();
-
-    final loadedItems = state.items;
-    if (loadedItems.isNotEmpty || existingFiles.isEmpty) {
-      return <String, LocalLibraryItem>{
-        for (final item in loadedItems) item.filePath: item,
-      };
-    }
-
-    // Rare fallback: if provider state failed to warm while the database has
-    // rows, preserve correctness instead of applying a diff to an empty base.
-    _log.w(
-      'Library state is empty while database has ${existingFiles.length} files; '
-      'loading incremental scan baseline from database',
-    );
-    final existingJson = await _db.getAll();
-    return <String, LocalLibraryItem>{
-      for (final item in existingJson.map(LocalLibraryItem.fromJson))
-        item.filePath: item,
-    };
-  }
-
   Future<void> startScan(
     String folderPath, {
     bool forceFullScan = false,
@@ -376,7 +371,6 @@ class LocalLibraryNotifier extends Notifier<LocalLibraryState> {
         }
 
         await _db.replaceAll(items.map((e) => e.toJson()).toList());
-        final persistedItems = [...items]..sort(_compareLibraryItems);
 
         final now = DateTime.now();
         try {
@@ -388,8 +382,11 @@ class LocalLibraryNotifier extends Notifier<LocalLibraryState> {
           _log.w('Failed to save lastScannedAt: $e');
         }
 
+        await _refreshSummaryFromStorage(
+          lastScannedAt: now,
+          excludedDownloadedCount: skippedDownloads,
+        );
         state = state.copyWith(
-          items: persistedItems,
           isScanning: false,
           scanIsFinalizing: false,
           scanProgress: 100,
@@ -397,14 +394,14 @@ class LocalLibraryNotifier extends Notifier<LocalLibraryState> {
           scanWasCancelled: false,
           excludedDownloadedCount: skippedDownloads,
         );
-        await _pruneLibraryCoverCache(persistedItems);
+        await _pruneLibraryCoverCache();
 
         _log.i(
-          'Full scan complete: ${persistedItems.length} tracks found, '
+          'Full scan complete: ${state.totalCount} tracks found, '
           '$skippedDownloads already in downloads',
         );
         await _showScanCompleteNotification(
-          totalTracks: persistedItems.length,
+          totalTracks: state.totalCount,
           excludedDownloadedCount: skippedDownloads,
           errorCount: state.scanErrorCount,
         );
@@ -497,17 +494,13 @@ class LocalLibraryNotifier extends Notifier<LocalLibraryState> {
           '$skippedCount skipped, ${deletedPaths.length} deleted, $totalFiles total',
         );
 
-        final currentByPath = await _currentItemsByPathForIncrementalScan(
-          existingFiles,
-        );
+        final existingPaths = existingFiles.keys.toList(growable: false);
         final existingDownloadedPaths = <String>[];
-        currentByPath.removeWhere((path, _) {
-          final shouldExclude = _isDownloadedPath(path, downloadedPathKeys);
-          if (shouldExclude) {
+        for (final path in existingPaths) {
+          if (_isDownloadedPath(path, downloadedPathKeys)) {
             existingDownloadedPaths.add(path);
           }
-          return shouldExclude;
-        });
+        }
         if (existingDownloadedPaths.isNotEmpty) {
           final removed = await _db.deleteByPaths(existingDownloadedPaths);
           _log.i(
@@ -527,7 +520,6 @@ class LocalLibraryNotifier extends Notifier<LocalLibraryState> {
             }
             final item = LocalLibraryItem.fromJson(map);
             updatedItems.add(item);
-            currentByPath[item.filePath] = item;
           }
           if (updatedItems.isNotEmpty) {
             await _db.upsertBatch(updatedItems.map((e) => e.toJson()).toList());
@@ -542,15 +534,9 @@ class LocalLibraryNotifier extends Notifier<LocalLibraryState> {
 
         if (deletedPaths.isNotEmpty) {
           final deleteCount = await _db.deleteByPaths(deletedPaths);
-          for (final path in deletedPaths) {
-            currentByPath.remove(path);
-          }
           _log.i('Deleted $deleteCount items from database');
         }
 
-        final items = currentByPath.values.toList(growable: false)
-          ..sort(_compareLibraryItems);
-
         final now = DateTime.now();
         try {
           final prefs = await SharedPreferences.getInstance();
@@ -561,8 +547,11 @@ class LocalLibraryNotifier extends Notifier<LocalLibraryState> {
           _log.w('Failed to save lastScannedAt: $e');
         }
 
+        await _refreshSummaryFromStorage(
+          lastScannedAt: now,
+          excludedDownloadedCount: skippedDownloads,
+        );
         state = state.copyWith(
-          items: items,
           isScanning: false,
           scanIsFinalizing: false,
           scanProgress: 100,
@@ -572,12 +561,12 @@ class LocalLibraryNotifier extends Notifier<LocalLibraryState> {
         );
 
         _log.i(
-          'Incremental scan complete: ${items.length} total tracks '
+          'Incremental scan complete: ${state.totalCount} total tracks '
           '(${scannedList.length} new/updated, $skippedCount unchanged, '
           '${deletedPaths.length} removed, $skippedDownloads already in downloads)',
         );
         await _showScanCompleteNotification(
-          totalTracks: items.length,
+          totalTracks: state.totalCount,
           excludedDownloadedCount: skippedDownloads,
           errorCount: state.scanErrorCount,
         );
@@ -893,7 +882,7 @@ class LocalLibraryNotifier extends Notifier<LocalLibraryState> {
     try {
       final removed = await _db.cleanupMissingFiles();
       if (removed > 0) {
-        await reloadFromStorage();
+        await _refreshSummaryFromStorage();
       }
       return removed;
     } finally {
@@ -914,11 +903,11 @@ class LocalLibraryNotifier extends Notifier<LocalLibraryState> {
       _log.w('Failed to clear lastScannedAt: $e');
     }
 
-    state = LocalLibraryState();
+    state = LocalLibraryState(loadedIndexVersion: state.loadedIndexVersion + 1);
     _log.i('Library cleared');
   }
 
-  Future<void> _pruneLibraryCoverCache(Iterable<LocalLibraryItem> items) async {
+  Future<void> _pruneLibraryCoverCache() async {
     try {
       final appSupportDir = await getApplicationSupportDirectory();
       final libraryCoverDir = Directory('${appSupportDir.path}/library_covers');
@@ -926,11 +915,16 @@ class LocalLibraryNotifier extends Notifier<LocalLibraryState> {
         return;
       }
 
-      final referencedCoverPaths = items
-          .map((item) => item.coverPath)
-          .whereType<String>()
-          .where((path) => path.isNotEmpty)
-          .toSet();
+      final referencedCoverPaths = <String>{};
+      var offset = 0;
+      const pageSize = 500;
+      while (true) {
+        final page = await _db.getCoverPaths(limit: pageSize, offset: offset);
+        if (page.isEmpty) break;
+        referencedCoverPaths.addAll(page);
+        if (page.length < pageSize) break;
+        offset += pageSize;
+      }
 
       var deletedCount = 0;
       await for (final entity in libraryCoverDir.list(
@@ -960,9 +954,7 @@ class LocalLibraryNotifier extends Notifier<LocalLibraryState> {
 
   Future<void> removeItem(String id) async {
     await _db.delete(id);
-    state = state.copyWith(
-      items: state.items.where((item) => item.id != id).toList(),
-    );
+    await _refreshSummaryFromStorage();
   }
 
   bool existsInLibrary({String? isrc, String? trackName, String? artistName}) {
@@ -973,21 +965,40 @@ class LocalLibraryNotifier extends Notifier<LocalLibraryState> {
     );
   }
 
-  LocalLibraryItem? getByIsrc(String isrc) {
-    return state.getByIsrc(isrc);
+  Future<LocalLibraryItem?> getById(String id) async {
+    final json = await _db.getById(id);
+    return json == null ? null : LocalLibraryItem.fromJson(json);
   }
 
-  LocalLibraryItem? findExisting({
+  Future<LocalLibraryItem?> getByIsrcAsync(String isrc) async {
+    final json = await _db.getByIsrc(isrc);
+    return json == null ? null : LocalLibraryItem.fromJson(json);
+  }
+
+  Future<LocalLibraryItem?> findByTrackAndArtistAsync(
+    String trackName,
+    String artistName,
+  ) async {
+    final json = await _db.findFirstByTrackAndArtist(trackName, artistName);
+    return json == null ? null : LocalLibraryItem.fromJson(json);
+  }
+
+  Future<LocalLibraryItem?> findExistingAsync({
+    String? id,
     String? isrc,
     String? trackName,
     String? artistName,
-  }) {
+  }) async {
+    if (id != null && id.isNotEmpty) {
+      final byId = await getById(id);
+      if (byId != null) return byId;
+    }
     if (isrc != null && isrc.isNotEmpty) {
-      final byIsrc = state.getByIsrc(isrc);
+      final byIsrc = await getByIsrcAsync(isrc);
       if (byIsrc != null) return byIsrc;
     }
     if (trackName != null && artistName != null) {
-      return state.findByTrackAndArtist(trackName, artistName);
+      return findByTrackAndArtistAsync(trackName, artistName);
     }
     return null;
   }
@@ -1003,23 +1014,6 @@ class LocalLibraryNotifier extends Notifier<LocalLibraryState> {
     return await _db.getCount();
   }
 
-  int _compareLibraryItems(LocalLibraryItem a, LocalLibraryItem b) {
-    final artistA = (a.albumArtist ?? a.artistName).toLowerCase();
-    final artistB = (b.albumArtist ?? b.artistName).toLowerCase();
-    final artistCompare = artistA.compareTo(artistB);
-    if (artistCompare != 0) return artistCompare;
-
-    final albumCompare = a.albumName.toLowerCase().compareTo(
-      b.albumName.toLowerCase(),
-    );
-    if (albumCompare != 0) return albumCompare;
-
-    final discCompare = (a.discNumber ?? 0).compareTo(b.discNumber ?? 0);
-    if (discCompare != 0) return discCompare;
-
-    return (a.trackNumber ?? 0).compareTo(b.trackNumber ?? 0);
-  }
-
   Future<Map<String, int>> _backfillLegacyFileModTimes({
     required bool isSaf,
     required Map<String, int> existingFiles,
@@ -1097,3 +1091,239 @@ final localLibraryProvider =
     NotifierProvider<LocalLibraryNotifier, LocalLibraryState>(
       LocalLibraryNotifier.new,
     );
+
+final localLibrarySummaryProvider = Provider<LocalLibraryState>((ref) {
+  return ref.watch(localLibraryProvider);
+});
+
+class LocalLibraryLookup {
+  final LibraryDatabase _db;
+
+  const LocalLibraryLookup(this._db);
+
+  Future<LocalLibraryItem?> byId(String id) async {
+    final json = await _db.getById(id);
+    return json == null ? null : LocalLibraryItem.fromJson(json);
+  }
+
+  Future<LocalLibraryItem?> byIsrc(String isrc) async {
+    final json = await _db.getByIsrc(isrc);
+    return json == null ? null : LocalLibraryItem.fromJson(json);
+  }
+
+  Future<LocalLibraryItem?> byTrackAndArtist(
+    String trackName,
+    String artistName,
+  ) async {
+    final json = await _db.findFirstByTrackAndArtist(trackName, artistName);
+    return json == null ? null : LocalLibraryItem.fromJson(json);
+  }
+
+  Future<LocalLibraryItem?> existing({
+    String? id,
+    String? isrc,
+    String? trackName,
+    String? artistName,
+  }) async {
+    if (id != null && id.isNotEmpty) {
+      final item = await byId(id);
+      if (item != null) return item;
+    }
+    if (isrc != null && isrc.isNotEmpty) {
+      final item = await byIsrc(isrc);
+      if (item != null) return item;
+    }
+    if (trackName != null && artistName != null) {
+      return byTrackAndArtist(trackName, artistName);
+    }
+    return null;
+  }
+}
+
+final localLibraryLookupProvider = Provider<LocalLibraryLookup>((ref) {
+  ref.watch(localLibraryProvider.select((state) => state.loadedIndexVersion));
+  return LocalLibraryLookup(LibraryDatabase.instance);
+});
+
+class LocalLibraryCoverRequest {
+  final String? isrc;
+  final String trackName;
+  final String artistName;
+
+  const LocalLibraryCoverRequest({
+    this.isrc,
+    required this.trackName,
+    required this.artistName,
+  });
+
+  @override
+  bool operator ==(Object other) {
+    return other is LocalLibraryCoverRequest &&
+        other.isrc == isrc &&
+        other.trackName == trackName &&
+        other.artistName == artistName;
+  }
+
+  @override
+  int get hashCode => Object.hash(isrc, trackName, artistName);
+}
+
+class LocalLibraryCoverBatchRequest {
+  final List<LocalLibraryCoverRequest> tracks;
+
+  const LocalLibraryCoverBatchRequest(this.tracks);
+
+  @override
+  bool operator ==(Object other) {
+    if (other is! LocalLibraryCoverBatchRequest) return false;
+    if (other.tracks.length != tracks.length) return false;
+    for (var i = 0; i < tracks.length; i++) {
+      if (other.tracks[i] != tracks[i]) return false;
+    }
+    return true;
+  }
+
+  @override
+  int get hashCode => Object.hashAll(tracks);
+}
+
+String? _nonEmptyCoverPath(Map<String, dynamic>? json) {
+  final coverPath = json?['coverPath'] as String?;
+  final trimmed = coverPath?.trim();
+  return trimmed == null || trimmed.isEmpty ? null : trimmed;
+}
+
+final localLibraryCoverProvider =
+    FutureProvider.family<String?, LocalLibraryCoverRequest>((ref, request) {
+      ref.watch(
+        localLibraryProvider.select((state) => state.loadedIndexVersion),
+      );
+      return LibraryDatabase.instance
+          .findExisting(
+            isrc: request.isrc,
+            trackName: request.trackName,
+            artistName: request.artistName,
+          )
+          .then(_nonEmptyCoverPath);
+    });
+
+final localLibraryFirstCoverProvider =
+    FutureProvider.family<String?, LocalLibraryCoverBatchRequest>((
+      ref,
+      request,
+    ) async {
+      ref.watch(
+        localLibraryProvider.select((state) => state.loadedIndexVersion),
+      );
+      for (final track in request.tracks) {
+        final cover = _nonEmptyCoverPath(
+          await LibraryDatabase.instance.findExisting(
+            isrc: track.isrc,
+            trackName: track.trackName,
+            artistName: track.artistName,
+          ),
+        );
+        if (cover != null) return cover;
+      }
+      return null;
+    });
+
+final localLibraryPageProvider =
+    FutureProvider.family<List<LocalLibraryItem>, LocalLibraryPageRequest>((
+      ref,
+      request,
+    ) async {
+      ref.watch(
+        localLibraryProvider.select((state) => state.loadedIndexVersion),
+      );
+      final rows = await LibraryDatabase.instance.getPage(request);
+      return rows.map(LocalLibraryItem.fromJson).toList(growable: false);
+    });
+
+final localLibraryPageCountProvider =
+    FutureProvider.family<int, LocalLibraryPageRequest>((ref, request) async {
+      ref.watch(
+        localLibraryProvider.select((state) => state.loadedIndexVersion),
+      );
+      return LibraryDatabase.instance.getPageCount(request);
+    });
+
+class LocalLibraryAlbumPageRequest {
+  final int limit;
+  final int offset;
+  final LocalLibraryFilterMode filterMode;
+  final LocalLibrarySortMode sortMode;
+  final String? searchQuery;
+
+  const LocalLibraryAlbumPageRequest({
+    this.limit = 100,
+    this.offset = 0,
+    this.filterMode = LocalLibraryFilterMode.albums,
+    this.sortMode = LocalLibrarySortMode.album,
+    this.searchQuery,
+  });
+
+  @override
+  bool operator ==(Object other) {
+    return other is LocalLibraryAlbumPageRequest &&
+        other.limit == limit &&
+        other.offset == offset &&
+        other.filterMode == filterMode &&
+        other.sortMode == sortMode &&
+        other.searchQuery == searchQuery;
+  }
+
+  @override
+  int get hashCode =>
+      Object.hash(limit, offset, filterMode, sortMode, searchQuery);
+}
+
+final localLibraryAlbumPageProvider =
+    FutureProvider.family<
+      List<LocalLibraryAlbumGroup>,
+      LocalLibraryAlbumPageRequest
+    >((ref, request) async {
+      ref.watch(
+        localLibraryProvider.select((state) => state.loadedIndexVersion),
+      );
+      return LibraryDatabase.instance.getAlbumPage(
+        limit: request.limit,
+        offset: request.offset,
+        filterMode: request.filterMode,
+        sortMode: request.sortMode,
+        searchQuery: request.searchQuery,
+      );
+    });
+
+final localLibraryAlbumCountProvider =
+    FutureProvider.family<int, LocalLibraryAlbumPageRequest>((
+      ref,
+      request,
+    ) async {
+      ref.watch(
+        localLibraryProvider.select((state) => state.loadedIndexVersion),
+      );
+      return LibraryDatabase.instance.getAlbumCount(
+        filterMode: request.filterMode,
+        searchQuery: request.searchQuery,
+      );
+    });
+
+final localLibraryAllItemsProvider = FutureProvider<List<LocalLibraryItem>>((
+  ref,
+) async {
+  ref.watch(localLibraryProvider.select((state) => state.loadedIndexVersion));
+  const pageSize = 500;
+  final items = <LocalLibraryItem>[];
+  var offset = 0;
+  while (true) {
+    final rows = await LibraryDatabase.instance.getPage(
+      const LocalLibraryPageRequest(limit: pageSize).copyWithOffset(offset),
+    );
+    if (rows.isEmpty) break;
+    items.addAll(rows.map(LocalLibraryItem.fromJson));
+    if (rows.length < pageSize) break;
+    offset += pageSize;
+  }
+  return items;
+});

lib/providers/playback_provider.dart

@@ -76,11 +76,10 @@ class PlaybackController extends Notifier<PlaybackState> {
   }
 
   Future<String?> _resolveTrackPath(Track track) async {
-    final localState = ref.read(localLibraryProvider);
     final historyState = ref.read(downloadHistoryProvider);
     final historyNotifier = ref.read(downloadHistoryProvider.notifier);
 
-    final localItem = _findLocalLibraryItemForTrack(track, localState);
+    final localItem = await _findLocalLibraryItemForTrack(track);
     if (localItem != null && await fileExists(localItem.filePath)) {
       return localItem.filePath;
     }
@@ -96,28 +95,23 @@ class PlaybackController extends Notifier<PlaybackState> {
     return null;
   }
 
-  LocalLibraryItem? _findLocalLibraryItemForTrack(
-    Track track,
-    LocalLibraryState localState,
-  ) {
+  Future<LocalLibraryItem?> _findLocalLibraryItemForTrack(Track track) async {
     final isLocalSource = (track.source ?? '').toLowerCase() == 'local';
     if (isLocalSource) {
-      for (final item in localState.items) {
-        if (item.id == track.id) {
-          return item;
-        }
-      }
+      final byId = await ref
+          .read(localLibraryProvider.notifier)
+          .getById(track.id);
+      if (byId != null) return byId;
     }
 
     final isrc = track.isrc?.trim();
-    if (isrc != null && isrc.isNotEmpty) {
-      final byIsrc = localState.getByIsrc(isrc);
-      if (byIsrc != null) {
-        return byIsrc;
-      }
-    }
-
-    return localState.findByTrackAndArtist(track.name, track.artistName);
+    return ref
+        .read(localLibraryProvider.notifier)
+        .findExistingAsync(
+          isrc: isrc,
+          trackName: track.name,
+          artistName: track.artistName,
+        );
   }
 
   DownloadHistoryItem? _findDownloadHistoryItemForTrack(

lib/screens/album_screen.dart

@@ -1085,7 +1085,6 @@ class _AlbumTrackItem extends ConsumerWidget {
     BuildContext context,
     WidgetRef ref,
   ) async {
-    final localState = ref.read(localLibraryProvider);
     final historyState = ref.read(downloadHistoryProvider);
     final historyNotifier = ref.read(downloadHistoryProvider.notifier);
 
@@ -1119,13 +1118,13 @@ class _AlbumTrackItem extends ConsumerWidget {
         historyNotifier.removeFromHistory(historyItem.id);
       }
 
-      var localItem = (isrc != null && isrc.isNotEmpty)
-          ? localState.getByIsrc(isrc)
-          : null;
-      localItem ??= localState.findByTrackAndArtist(
-        track.name,
-        track.artistName,
-      );
+      final localItem = await ref
+          .read(localLibraryProvider.notifier)
+          .findExistingAsync(
+            isrc: isrc,
+            trackName: track.name,
+            artistName: track.artistName,
+          );
 
       if (localItem != null && await fileExists(localItem.filePath)) {
         await ref

lib/screens/artist_screen.dart

@@ -1600,7 +1600,6 @@ class _ArtistScreenState extends ConsumerState<ArtistScreen> {
   }
 
   Future<bool> _playLocalIfAvailable(Track track) async {
-    final localState = ref.read(localLibraryProvider);
     final historyState = ref.read(downloadHistoryProvider);
     final historyNotifier = ref.read(downloadHistoryProvider.notifier);
 
@@ -1634,13 +1633,13 @@ class _ArtistScreenState extends ConsumerState<ArtistScreen> {
         historyNotifier.removeFromHistory(historyItem.id);
       }
 
-      var localItem = (isrc != null && isrc.isNotEmpty)
-          ? localState.getByIsrc(isrc)
-          : null;
-      localItem ??= localState.findByTrackAndArtist(
-        track.name,
-        track.artistName,
-      );
+      final localItem = await ref
+          .read(localLibraryProvider.notifier)
+          .findExistingAsync(
+            isrc: isrc,
+            trackName: track.name,
+            artistName: track.artistName,
+          );
 
       if (localItem != null && await fileExists(localItem.filePath)) {
         await ref

lib/screens/library_tracks_folder_screen.dart

@@ -12,7 +12,6 @@ import 'package:spotiflac_android/providers/extension_provider.dart';
 import 'package:spotiflac_android/providers/library_collections_provider.dart';
 import 'package:spotiflac_android/providers/playback_provider.dart';
 import 'package:spotiflac_android/providers/local_library_provider.dart';
-import 'package:spotiflac_android/services/library_database.dart';
 import 'package:spotiflac_android/providers/settings_provider.dart';
 import 'package:spotiflac_android/services/cover_cache_manager.dart';
 import 'package:spotiflac_android/screens/track_metadata_screen.dart';
@@ -79,45 +78,20 @@ class _LibraryTracksFolderScreenState
     };
   }
 
-  String? _resolveEntryCoverUrl(
-    CollectionTrackEntry entry,
-    LocalLibraryState localState,
-  ) {
+  String? _resolveRawEntryCoverUrl(CollectionTrackEntry entry) {
     final rawCover = entry.track.coverUrl?.trim();
     if (rawCover != null &&
         rawCover.isNotEmpty &&
         !rawCover.startsWith('content://')) {
       return rawCover;
     }
-
-    final isrc = entry.track.isrc?.trim();
-    if (isrc != null && isrc.isNotEmpty) {
-      final byIsrc = localState.getByIsrc(isrc);
-      final localCover = byIsrc?.coverPath?.trim();
-      if (localCover != null && localCover.isNotEmpty) {
-        return localCover;
-      }
-    }
-
-    final byTrack = localState.findByTrackAndArtist(
-      entry.track.name,
-      entry.track.artistName,
-    );
-    final localCover = byTrack?.coverPath?.trim();
-    if (localCover != null && localCover.isNotEmpty) {
-      return localCover;
-    }
-
     return null;
   }
 
   /// Find the first available cover URL from entries.
-  String? _firstCoverUrl(
-    List<CollectionTrackEntry> entries,
-    LocalLibraryState localState,
-  ) {
+  String? _firstRawCoverUrl(List<CollectionTrackEntry> entries) {
     for (final entry in entries) {
-      final cover = _resolveEntryCoverUrl(entry, localState);
+      final cover = _resolveRawEntryCoverUrl(entry);
       if (cover != null && cover.isNotEmpty) {
         return cover;
       }
@@ -212,6 +186,22 @@ class _LibraryTracksFolderScreenState
     );
   }
 
+  LocalLibraryCoverBatchRequest _coverBatchRequest(
+    List<CollectionTrackEntry> entries,
+  ) {
+    return LocalLibraryCoverBatchRequest(
+      entries
+          .map(
+            (entry) => LocalLibraryCoverRequest(
+              isrc: entry.track.isrc?.trim(),
+              trackName: entry.track.name,
+              artistName: entry.track.artistName,
+            ),
+          )
+          .toList(growable: false),
+    );
+  }
+
   void _downloadSelected(List<CollectionTrackEntry> entries) {
     final settings = ref.read(settingsProvider);
     final extensionState = ref.read(extensionProvider);
@@ -255,8 +245,7 @@ class _LibraryTracksFolderScreenState
   @override
   Widget build(BuildContext context) {
     final colorScheme = Theme.of(context).colorScheme;
-    ref.watch(localLibraryProvider.select((s) => s.items));
-    final localState = ref.read(localLibraryProvider);
+    ref.watch(localLibraryProvider.select((s) => s.loadedIndexVersion));
     final List<CollectionTrackEntry> entries;
 
     switch (widget.mode) {
@@ -337,14 +326,7 @@ class _LibraryTracksFolderScreenState
             CustomScrollView(
               controller: _scrollController,
               slivers: [
-                _buildAppBar(
-                  context,
-                  colorScheme,
-                  title,
-                  entries,
-                  playlist,
-                  localState,
-                ),
+                _buildAppBar(context, colorScheme, title, entries, playlist),
                 if (entries.isEmpty)
                   SliverFillRemaining(
                     hasScrollBody: false,
@@ -366,7 +348,6 @@ class _LibraryTracksFolderScreenState
                             entry: entry,
                             mode: widget.mode,
                             playlistId: widget.playlistId,
-                            localLibraryState: localState,
                             folderTracks: folderTracks,
                             isSelectionMode: _isSelectionMode,
                             isSelected: isSelected,
@@ -602,13 +583,21 @@ class _LibraryTracksFolderScreenState
     String title,
     List<CollectionTrackEntry> entries,
     UserPlaylistCollection? playlist,
-    LocalLibraryState localState,
   ) {
     final expandedHeight = _calculateExpandedHeight(context);
     final customCoverPath = playlist?.coverImagePath;
     final isLovedMode = widget.mode == LibraryTracksFolderMode.loved;
     final isPlaylistMode = widget.mode == LibraryTracksFolderMode.playlist;
-    final coverUrl = isLovedMode ? null : _firstCoverUrl(entries, localState);
+    final rawCoverUrl = isLovedMode ? null : _firstRawCoverUrl(entries);
+    final localCoverUrl =
+        rawCoverUrl == null && !isLovedMode && entries.isNotEmpty
+        ? ref
+              .watch(
+                localLibraryFirstCoverProvider(_coverBatchRequest(entries)),
+              )
+              .maybeWhen(data: (cover) => cover, orElse: () => null)
+        : null;
+    final coverUrl = rawCoverUrl ?? localCoverUrl;
     final hasCustomCover =
         customCoverPath != null && customCoverPath.isNotEmpty;
     final hasCoverUrl = coverUrl != null;
@@ -1069,7 +1058,6 @@ class _CollectionTrackTile extends ConsumerWidget {
   final CollectionTrackEntry entry;
   final LibraryTracksFolderMode mode;
   final String? playlistId;
-  final LocalLibraryState localLibraryState;
   final List<Track> folderTracks;
   final bool isSelectionMode;
   final bool isSelected;
@@ -1080,7 +1068,6 @@ class _CollectionTrackTile extends ConsumerWidget {
     required this.entry,
     required this.mode,
     required this.playlistId,
-    required this.localLibraryState,
     required this.folderTracks,
     this.isSelectionMode = false,
     this.isSelected = false,
@@ -1092,7 +1079,21 @@ class _CollectionTrackTile extends ConsumerWidget {
   Widget build(BuildContext context, WidgetRef ref) {
     final track = entry.track;
     final colorScheme = Theme.of(context).colorScheme;
-    final effectiveCoverUrl = _resolveCoverUrl(track);
+    final rawCoverUrl = _resolveRawCoverUrl(track);
+    final localCoverUrl = rawCoverUrl == null
+        ? ref
+              .watch(
+                localLibraryCoverProvider(
+                  LocalLibraryCoverRequest(
+                    isrc: track.isrc?.trim(),
+                    trackName: track.name,
+                    artistName: track.artistName,
+                  ),
+                ),
+              )
+              .maybeWhen(data: (cover) => cover, orElse: () => null)
+        : null;
+    final effectiveCoverUrl = rawCoverUrl ?? localCoverUrl;
 
     // Fine-grained provider watches – only this tile rebuilds when its own
     // history / local-library entry changes.
@@ -1113,26 +1114,21 @@ class _CollectionTrackTile extends ConsumerWidget {
         (s) => s.localLibraryEnabled && s.localLibraryShowDuplicates,
       ),
     );
-    final localItem = showLocalLibraryIndicator
+    final isInLocalLibrary = showLocalLibraryIndicator
         ? ref.watch(
             localLibraryProvider.select((state) {
               final isrc = track.isrc?.trim();
-              if (isrc != null && isrc.isNotEmpty) {
-                final byIsrc = state.getByIsrc(isrc);
-                if (byIsrc != null) return byIsrc;
-              }
-              return state.findByTrackAndArtist(track.name, track.artistName);
+              return state.existsInLibrary(
+                isrc: isrc,
+                trackName: track.name,
+                artistName: track.artistName,
+              );
             }),
           )
-        : null;
+        : false;
 
     final isInHistory = historyItem != null;
-    final isInLocalLibrary = localItem != null;
-    final heroTag = historyItem != null
-        ? 'cover_${historyItem.id}'
-        : localItem != null
-        ? 'cover_lib_${localItem.id}'
-        : null;
+    final heroTag = historyItem != null ? 'cover_${historyItem.id}' : null;
 
     return Padding(
       padding: const EdgeInsets.symmetric(horizontal: 8),
@@ -1245,7 +1241,7 @@ class _CollectionTrackTile extends ConsumerWidget {
           ),
           trailing: isSelectionMode
               ? null
-              : historyItem != null || localItem != null
+              : historyItem != null || isInLocalLibrary
               ? IconButton(
                   tooltip: context.l10n.tooltipPlay,
                   onPressed: () {
@@ -1275,28 +1271,13 @@ class _CollectionTrackTile extends ConsumerWidget {
     );
   }
 
-  String? _resolveCoverUrl(Track track) {
+  String? _resolveRawCoverUrl(Track track) {
     final rawCover = track.coverUrl?.trim();
     if (rawCover != null &&
         rawCover.isNotEmpty &&
         !rawCover.startsWith('content://')) {
       return rawCover;
     }
-
-    final isrc = track.isrc?.trim();
-    if (isrc != null && isrc.isNotEmpty) {
-      final byIsrc = localLibraryState.getByIsrc(isrc);
-      final localCover = byIsrc?.coverPath?.trim();
-      if (localCover != null && localCover.isNotEmpty) return localCover;
-    }
-
-    final byTrack = localLibraryState.findByTrackAndArtist(
-      track.name,
-      track.artistName,
-    );
-    final localCover = byTrack?.coverPath?.trim();
-    if (localCover != null && localCover.isNotEmpty) return localCover;
-
     return null;
   }
 
@@ -1418,13 +1399,14 @@ class _CollectionTrackTile extends ConsumerWidget {
       return;
     }
 
-    final localState = ref.read(localLibraryProvider);
-    LocalLibraryItem? localItem;
-    if (track.isrc != null && track.isrc!.isNotEmpty) {
-      localItem = localState.getByIsrc(track.isrc!);
-    }
-
-    localItem ??= localState.findByTrackAndArtist(track.name, track.artistName);
+    final localItem = await ref
+        .read(localLibraryProvider.notifier)
+        .findExistingAsync(
+          isrc: track.isrc,
+          trackName: track.name,
+          artistName: track.artistName,
+        );
+    if (!context.mounted) return;
 
     if (localItem != null) {
       await Navigator.of(context).push(

lib/screens/playlist_screen.dart

@@ -942,7 +942,6 @@ class _PlaylistTrackItem extends ConsumerWidget {
     BuildContext context,
     WidgetRef ref,
   ) async {
-    final localState = ref.read(localLibraryProvider);
     final historyState = ref.read(downloadHistoryProvider);
     final historyNotifier = ref.read(downloadHistoryProvider.notifier);
 
@@ -976,13 +975,13 @@ class _PlaylistTrackItem extends ConsumerWidget {
         historyNotifier.removeFromHistory(historyItem.id);
       }
 
-      var localItem = (isrc != null && isrc.isNotEmpty)
-          ? localState.getByIsrc(isrc)
-          : null;
-      localItem ??= localState.findByTrackAndArtist(
-        track.name,
-        track.artistName,
-      );
+      final localItem = await ref
+          .read(localLibraryProvider.notifier)
+          .findExistingAsync(
+            isrc: isrc,
+            trackName: track.name,
+            artistName: track.artistName,
+          );
 
       if (localItem != null && await fileExists(localItem.filePath)) {
         await ref

lib/screens/queue_tab.dart

@@ -2369,7 +2369,12 @@ class _QueueTabState extends ConsumerState<QueueTab> {
       settingsProvider.select((s) => s.localLibraryEnabled),
     );
     final localLibraryItems = localLibraryEnabled
-        ? ref.watch(localLibraryProvider.select((s) => s.items))
+        ? ref
+              .watch(localLibraryAllItemsProvider)
+              .maybeWhen(
+                data: (items) => items,
+                orElse: () => const <LocalLibraryItem>[],
+              )
         : const <LocalLibraryItem>[];
     // Watch with selector on key fields to reduce unnecessary rebuilds.
     // LibraryCollectionsState doesn't implement == so watching without

lib/screens/queue_tab_helpers.dart

@@ -1106,7 +1106,12 @@ final _queueHistoryStatsProvider = Provider<_HistoryStats>((ref) {
     settingsProvider.select((s) => s.localLibraryEnabled),
   );
   final localItems = localLibraryEnabled
-      ? ref.watch(localLibraryProvider.select((s) => s.items))
+      ? ref
+            .watch(localLibraryAllItemsProvider)
+            .maybeWhen(
+              data: (items) => items,
+              orElse: () => const <LocalLibraryItem>[],
+            )
       : const <LocalLibraryItem>[];
   return _buildQueueHistoryStats(historyItems, localItems);
 });

lib/screens/settings/library_settings_page.dart

@@ -374,7 +374,7 @@ class _LibrarySettingsPageState extends ConsumerState<LibrarySettingsPage> {
 
           SliverToBoxAdapter(
             child: _LibraryHeroCard(
-              itemCount: libraryState.items.length,
+              itemCount: libraryState.totalCount,
               excludedDownloadedCount: libraryState.excludedDownloadedCount,
               isScanning: libraryState.isScanning,
               scanIsFinalizing: libraryState.scanIsFinalizing,
@@ -547,25 +547,23 @@ class _LibrarySettingsPageState extends ConsumerState<LibrarySettingsPage> {
                     ),
                   ],
                   Opacity(
-                    opacity: libraryState.items.isNotEmpty ? 1.0 : 0.5,
+                    opacity: libraryState.totalCount > 0 ? 1.0 : 0.5,
                     child: SettingsItem(
                       icon: Icons.cleaning_services_outlined,
                       title: context.l10n.libraryCleanupMissingFiles,
                       subtitle: context.l10n.libraryCleanupMissingFilesSubtitle,
-                      onTap: libraryState.items.isNotEmpty
+                      onTap: libraryState.totalCount > 0
                           ? _cleanupMissingFiles
                           : null,
                     ),
                   ),
                   Opacity(
-                    opacity: libraryState.items.isNotEmpty ? 1.0 : 0.5,
+                    opacity: libraryState.totalCount > 0 ? 1.0 : 0.5,
                     child: SettingsItem(
                       icon: Icons.delete_outline,
                       title: context.l10n.libraryClear,
                       subtitle: context.l10n.libraryClearSubtitle,
-                      onTap: libraryState.items.isNotEmpty
-                          ? _clearLibrary
-                          : null,
+                      onTap: libraryState.totalCount > 0 ? _clearLibrary : null,
                       showDivider: false,
                     ),
                   ),

lib/screens/track_metadata_screen.dart

@@ -24,7 +24,6 @@ import 'package:spotiflac_android/utils/lyrics_metadata_helper.dart';
 import 'package:spotiflac_android/utils/mime_utils.dart';
 import 'package:spotiflac_android/utils/image_cache_utils.dart';
 import 'package:spotiflac_android/utils/string_utils.dart';
-import 'package:spotiflac_android/widgets/animation_utils.dart';
 import 'package:spotiflac_android/widgets/audio_analysis_widget.dart';
 
 part 'track_metadata_edit_sheet.dart';
@@ -101,6 +100,11 @@ class _TrackMetadataScreenState extends ConsumerState<TrackMetadataScreen> {
   bool _hasMetadataChanges = false;
   bool _hasLoadedResolvedAudioMetadata = false;
   bool _isTrackSwipeNavigationInFlight = false;
+  int _metadataLoadGeneration = 0;
+  int _metadataTransitionDirection = 0;
+  late DownloadHistoryItem? _currentDownloadItem;
+  late LocalLibraryItem? _currentLocalLibraryItem;
+  late int? _currentNavigationIndex;
   Map<String, dynamic>? _editedMetadata;
   String? _embeddedCoverPreviewPath;
   final ScrollController _scrollController = ScrollController();
@@ -226,6 +230,9 @@ class _TrackMetadataScreenState extends ConsumerState<TrackMetadataScreen> {
   @override
   void initState() {
     super.initState();
+    _currentDownloadItem = widget.item;
+    _currentLocalLibraryItem = widget.localItem;
+    _currentNavigationIndex = widget.navigationIndex;
     _scrollController.addListener(_onScroll);
     _checkFile();
   }
@@ -253,6 +260,7 @@ class _TrackMetadataScreenState extends ConsumerState<TrackMetadataScreen> {
   }
 
   Future<void> _checkFile() async {
+    final generation = _metadataLoadGeneration;
     final filePath = cleanFilePath;
 
     bool exists = false;
@@ -266,6 +274,8 @@ class _TrackMetadataScreenState extends ConsumerState<TrackMetadataScreen> {
     } catch (_) {}
 
     if (mounted &&
+        generation == _metadataLoadGeneration &&
+        filePath == cleanFilePath &&
         (exists != _fileExists || size != _fileSize || !_hasCheckedFile)) {
       setState(() {
         _fileExists = exists;
@@ -274,21 +284,35 @@ class _TrackMetadataScreenState extends ConsumerState<TrackMetadataScreen> {
       });
     }
 
-    if (mounted && exists && _lyrics == null && !_lyricsLoading) {
+    if (mounted &&
+        generation == _metadataLoadGeneration &&
+        filePath == cleanFilePath &&
+        exists &&
+        _lyrics == null &&
+        !_lyricsLoading) {
       _checkEmbeddedLyrics();
     }
     if (mounted &&
+        generation == _metadataLoadGeneration &&
+        filePath == cleanFilePath &&
         exists &&
         !_isCueVirtualTrack &&
         !_hasLoadedResolvedAudioMetadata) {
       unawaited(_refreshResolvedAudioMetadataFromFile());
     }
-    if (mounted && exists && !_hasPath(_embeddedCoverPreviewPath)) {
+    if (mounted &&
+        generation == _metadataLoadGeneration &&
+        filePath == cleanFilePath &&
+        exists &&
+        !_hasPath(_embeddedCoverPreviewPath)) {
       final cachedPath = await _getCachedEmbeddedCoverPreviewPathIfValid(
         _coverCacheKey,
-        cleanFilePath,
+        filePath,
       );
-      if (_hasPath(cachedPath)) {
+      if (mounted &&
+          generation == _metadataLoadGeneration &&
+          filePath == cleanFilePath &&
+          _hasPath(cachedPath)) {
         setState(() => _embeddedCoverPreviewPath = cachedPath);
       }
     }
@@ -318,6 +342,8 @@ class _TrackMetadataScreenState extends ConsumerState<TrackMetadataScreen> {
   }
 
   Future<void> _refreshResolvedAudioMetadataFromFile() async {
+    final generation = _metadataLoadGeneration;
+    final sourcePath = cleanFilePath;
     if ((_isLocalItem && _localLibraryItem == null) ||
         (!_isLocalItem && _downloadItem == null) ||
         _isCueVirtualTrack ||
@@ -328,7 +354,12 @@ class _TrackMetadataScreenState extends ConsumerState<TrackMetadataScreen> {
     _hasLoadedResolvedAudioMetadata = true;
 
     try {
-      final metadata = await PlatformBridge.readFileMetadata(cleanFilePath);
+      final metadata = await PlatformBridge.readFileMetadata(sourcePath);
+      if (!mounted ||
+          generation != _metadataLoadGeneration ||
+          sourcePath != cleanFilePath) {
+        return;
+      }
       if (metadata['error'] != null) {
         return;
       }
@@ -463,6 +494,7 @@ class _TrackMetadataScreenState extends ConsumerState<TrackMetadataScreen> {
   }
 
   Future<void> _refreshEmbeddedCoverPreview({bool force = false}) async {
+    final generation = _metadataLoadGeneration;
     final cacheKey = _coverCacheKey;
     final sourcePath = cleanFilePath;
     if (!force) {
@@ -471,7 +503,10 @@ class _TrackMetadataScreenState extends ConsumerState<TrackMetadataScreen> {
         sourcePath,
       );
       if (_hasPath(cachedPath)) {
-        if (mounted && _embeddedCoverPreviewPath != cachedPath) {
+        if (mounted &&
+            generation == _metadataLoadGeneration &&
+            sourcePath == cleanFilePath &&
+            _embeddedCoverPreviewPath != cachedPath) {
           setState(() => _embeddedCoverPreviewPath = cachedPath);
         }
         return;
@@ -483,7 +518,9 @@ class _TrackMetadataScreenState extends ConsumerState<TrackMetadataScreen> {
       if (!_fileExists) {
         await _invalidateEmbeddedCoverPreviewCacheForPath(cacheKey);
         await _cleanupTempFileAndParentIfNotCached(_embeddedCoverPreviewPath);
-        if (mounted) {
+        if (mounted &&
+            generation == _metadataLoadGeneration &&
+            sourcePath == cleanFilePath) {
           setState(() => _embeddedCoverPreviewPath = null);
         }
         return;
@@ -511,7 +548,9 @@ class _TrackMetadataScreenState extends ConsumerState<TrackMetadataScreen> {
     } catch (_) {}
 
     final oldPreviewPath = _embeddedCoverPreviewPath;
-    if (!mounted) {
+    if (!mounted ||
+        generation != _metadataLoadGeneration ||
+        sourcePath != cleanFilePath) {
       if (newPreviewPath != null) {
         await _cleanupTempFileAndParentIfNotCached(newPreviewPath);
       }
@@ -524,16 +563,16 @@ class _TrackMetadataScreenState extends ConsumerState<TrackMetadataScreen> {
     }
   }
 
-  bool get _isLocalItem => widget.localItem != null;
-  DownloadHistoryItem? get _downloadItem => widget.item;
-  LocalLibraryItem? get _localLibraryItem => widget.localItem;
+  bool get _isLocalItem => _currentLocalLibraryItem != null;
+  DownloadHistoryItem? get _downloadItem => _currentDownloadItem;
+  LocalLibraryItem? get _localLibraryItem => _currentLocalLibraryItem;
   bool get _hasHistoryNavigation =>
       widget.historyNavigationItems != null && widget.navigationIndex != null;
   bool get _hasLocalNavigation =>
       widget.localNavigationItems != null && widget.navigationIndex != null;
   bool get _hasTrackSwipeNavigation =>
       _hasHistoryNavigation || _hasLocalNavigation;
-  int? get _navigationIndex => widget.navigationIndex;
+  int? get _navigationIndex => _currentNavigationIndex;
   int get _navigationLength =>
       widget.historyNavigationItems?.length ??
       widget.localNavigationItems?.length ??
@@ -869,28 +908,50 @@ class _TrackMetadataScreenState extends ConsumerState<TrackMetadataScreen> {
     if (targetIndex < 0 || targetIndex >= _navigationLength) return;
 
     _isTrackSwipeNavigationInFlight = true;
-    await Navigator.of(context).pushReplacement<bool, bool>(
-      adjacentHorizontalPageRoute<bool>(
-        page: _buildSiblingTrackScreen(targetIndex),
-        fromRight: offset > 0,
-      ),
-      result: _hasMetadataChanges ? true : null,
-    );
-  }
+    final oldPreviewPath = _embeddedCoverPreviewPath;
 
-  TrackMetadataScreen _buildSiblingTrackScreen(int targetIndex) {
-    if (_hasHistoryNavigation) {
-      return TrackMetadataScreen(
-        item: widget.historyNavigationItems![targetIndex],
-        historyNavigationItems: widget.historyNavigationItems,
-        navigationIndex: targetIndex,
-      );
+    try {
+      setState(() {
+        _metadataLoadGeneration++;
+        _metadataTransitionDirection = offset > 0 ? 1 : -1;
+        _currentNavigationIndex = targetIndex;
+        if (_hasHistoryNavigation) {
+          _currentDownloadItem = widget.historyNavigationItems![targetIndex];
+          _currentLocalLibraryItem = null;
+        } else {
+          _currentDownloadItem = null;
+          _currentLocalLibraryItem = widget.localNavigationItems![targetIndex];
+        }
+        _fileExists = false;
+        _hasCheckedFile = false;
+        _fileSize = null;
+        _lyrics = null;
+        _rawLyrics = null;
+        _lyricsLoading = false;
+        _lyricsError = null;
+        _lyricsSource = null;
+        _showTitleInAppBar = false;
+        _lyricsEmbedded = false;
+        _isInstrumental = false;
+        _embeddedLyricsChecked = false;
+        _hasLoadedResolvedAudioMetadata = false;
+        _editedMetadata = null;
+        _embeddedCoverPreviewPath = null;
+      });
+
+      if (_scrollController.hasClients) {
+        _scrollController.jumpTo(0);
+      }
+
+      if (oldPreviewPath != null) {
+        unawaited(_cleanupTempFileAndParentIfNotCached(oldPreviewPath));
+      }
+      await _checkFile();
+    } finally {
+      if (mounted) {
+        _isTrackSwipeNavigationInFlight = false;
+      }
     }
-    return TrackMetadataScreen(
-      localItem: widget.localNavigationItems![targetIndex],
-      localNavigationItems: widget.localNavigationItems,
-      navigationIndex: targetIndex,
-    );
   }
 
   @override
@@ -973,39 +1034,7 @@ class _TrackMetadataScreenState extends ConsumerState<TrackMetadataScreen> {
             ),
 
             SliverToBoxAdapter(
-              child: Padding(
-                padding: const EdgeInsets.all(16),
-                child: Column(
-                  crossAxisAlignment: CrossAxisAlignment.start,
-                  children: [
-                    _buildMetadataCard(context, colorScheme, _fileSize),
-
-                    const SizedBox(height: 16),
-
-                    _buildFileInfoCard(
-                      context,
-                      colorScheme,
-                      _fileExists,
-                      _fileSize,
-                    ),
-
-                    const SizedBox(height: 16),
-
-                    _buildLyricsCard(context, colorScheme),
-
-                    if (_fileExists) ...[
-                      const SizedBox(height: 16),
-                      AudioAnalysisCard(filePath: _filePath),
-                    ],
-
-                    const SizedBox(height: 24),
-
-                    _buildActionButtons(context, ref, colorScheme, _fileExists),
-
-                    const SizedBox(height: 32),
-                  ],
-                ),
-              ),
+              child: _buildAnimatedTrackContent(context, ref, colorScheme),
             ),
           ],
         ),
@@ -1013,6 +1042,80 @@ class _TrackMetadataScreenState extends ConsumerState<TrackMetadataScreen> {
     );
   }
 
+  Widget _buildAnimatedTrackContent(
+    BuildContext context,
+    WidgetRef ref,
+    ColorScheme colorScheme,
+  ) {
+    final currentKey = ValueKey<String>('metadata_content_$_itemId');
+    return AnimatedSwitcher(
+      duration: const Duration(milliseconds: 240),
+      reverseDuration: const Duration(milliseconds: 180),
+      switchInCurve: Curves.easeOutCubic,
+      switchOutCurve: Curves.easeInCubic,
+      layoutBuilder: (currentChild, previousChildren) {
+        return Stack(
+          alignment: Alignment.topCenter,
+          children: <Widget>[...previousChildren, ?currentChild],
+        );
+      },
+      transitionBuilder: (child, animation) {
+        if (_metadataTransitionDirection == 0) {
+          return child;
+        }
+        final isIncoming = child.key == currentKey;
+        final direction = _metadataTransitionDirection.toDouble();
+        final begin = Offset(
+          isIncoming ? 0.18 * direction : -0.18 * direction,
+          0,
+        );
+        final curved = CurvedAnimation(
+          parent: animation,
+          curve: Curves.easeOutCubic,
+          reverseCurve: Curves.easeInCubic,
+        );
+        return ClipRect(
+          child: SlideTransition(
+            position: Tween<Offset>(
+              begin: begin,
+              end: Offset.zero,
+            ).animate(curved),
+            child: FadeTransition(opacity: animation, child: child),
+          ),
+        );
+      },
+      child: Padding(
+        key: currentKey,
+        padding: const EdgeInsets.all(16),
+        child: Column(
+          crossAxisAlignment: CrossAxisAlignment.start,
+          children: [
+            _buildMetadataCard(context, colorScheme, _fileSize),
+
+            const SizedBox(height: 16),
+
+            _buildFileInfoCard(context, colorScheme, _fileExists, _fileSize),
+
+            const SizedBox(height: 16),
+
+            _buildLyricsCard(context, colorScheme),
+
+            if (_fileExists) ...[
+              const SizedBox(height: 16),
+              AudioAnalysisCard(filePath: _filePath),
+            ],
+
+            const SizedBox(height: 24),
+
+            _buildActionButtons(context, ref, colorScheme, _fileExists),
+
+            const SizedBox(height: 32),
+          ],
+        ),
+      ),
+    );
+  }
+
   Widget _buildHeaderBackground(
     BuildContext context,
     ColorScheme colorScheme,
@@ -1944,6 +2047,9 @@ class _TrackMetadataScreenState extends ConsumerState<TrackMetadataScreen> {
   /// Called automatically when the screen opens.
   Future<void> _checkEmbeddedLyrics() async {
     if (_lyricsLoading || !_fileExists) return;
+    final generation = _metadataLoadGeneration;
+    final sourcePath = cleanFilePath;
+    if (!mounted) return;
 
     setState(() {
       _lyricsLoading = true;
@@ -1958,7 +2064,7 @@ class _TrackMetadataScreenState extends ConsumerState<TrackMetadataScreen> {
             '',
             trackName,
             artistName,
-            filePath: cleanFilePath,
+            filePath: sourcePath,
             durationMs: 0,
           ).timeout(
             const Duration(seconds: 5),
@@ -1968,7 +2074,9 @@ class _TrackMetadataScreenState extends ConsumerState<TrackMetadataScreen> {
       final embeddedLyrics = embeddedResult['lyrics']?.toString() ?? '';
       final embeddedSource = embeddedResult['source']?.toString() ?? '';
 
-      if (mounted) {
+      if (mounted &&
+          generation == _metadataLoadGeneration &&
+          sourcePath == cleanFilePath) {
         if (embeddedLyrics.isNotEmpty) {
           final cleanLyrics = _cleanLrcForDisplay(embeddedLyrics);
           setState(() {
@@ -1989,7 +2097,9 @@ class _TrackMetadataScreenState extends ConsumerState<TrackMetadataScreen> {
         }
       }
     } catch (e) {
-      if (mounted) {
+      if (mounted &&
+          generation == _metadataLoadGeneration &&
+          sourcePath == cleanFilePath) {
         setState(() {
           _lyricsLoading = false;
           _embeddedLyricsChecked = true;

lib/services/library_database.dart

@@ -117,9 +117,113 @@ class LocalLibraryItem {
       );
 
   String get matchKey =>
-      '${trackName.toLowerCase()}|${artistName.toLowerCase()}';
+      '${LibraryDatabase.normalizeLookupText(trackName)}|${LibraryDatabase.normalizeLookupText(artistName)}';
   String get albumKey =>
-      '${albumName.toLowerCase()}|${(albumArtist ?? artistName).toLowerCase()}';
+      '${LibraryDatabase.normalizeLookupText(albumName)}|${LibraryDatabase.normalizeLookupText(albumArtist ?? artistName)}';
+}
+
+enum LocalLibrarySortMode { album, title, artist, latest, quality }
+
+enum LocalLibraryFilterMode { all, albums, singles }
+
+class LocalLibraryPageRequest {
+  final int limit;
+  final int offset;
+  final LocalLibrarySortMode sortMode;
+  final LocalLibraryFilterMode filterMode;
+  final String? searchQuery;
+  final String? format;
+
+  const LocalLibraryPageRequest({
+    this.limit = 100,
+    this.offset = 0,
+    this.sortMode = LocalLibrarySortMode.album,
+    this.filterMode = LocalLibraryFilterMode.all,
+    this.searchQuery,
+    this.format,
+  });
+
+  LocalLibraryPageRequest copyWithOffset(int nextOffset) {
+    return LocalLibraryPageRequest(
+      limit: limit,
+      offset: nextOffset,
+      sortMode: sortMode,
+      filterMode: filterMode,
+      searchQuery: searchQuery,
+      format: format,
+    );
+  }
+
+  @override
+  bool operator ==(Object other) {
+    return other is LocalLibraryPageRequest &&
+        other.limit == limit &&
+        other.offset == offset &&
+        other.sortMode == sortMode &&
+        other.filterMode == filterMode &&
+        other.searchQuery == searchQuery &&
+        other.format == format;
+  }
+
+  @override
+  int get hashCode =>
+      Object.hash(limit, offset, sortMode, filterMode, searchQuery, format);
+}
+
+class LocalLibraryAlbumGroup {
+  final String albumKey;
+  final String albumName;
+  final String artistName;
+  final String? coverPath;
+  final int trackCount;
+  final int? maxBitDepth;
+  final int? maxSampleRate;
+  final int? maxBitrate;
+  final String? format;
+  final String? releaseDate;
+  final String? genre;
+
+  const LocalLibraryAlbumGroup({
+    required this.albumKey,
+    required this.albumName,
+    required this.artistName,
+    this.coverPath,
+    required this.trackCount,
+    this.maxBitDepth,
+    this.maxSampleRate,
+    this.maxBitrate,
+    this.format,
+    this.releaseDate,
+    this.genre,
+  });
+
+  factory LocalLibraryAlbumGroup.fromDbRow(Map<String, dynamic> row) {
+    return LocalLibraryAlbumGroup(
+      albumKey: row['album_key'] as String,
+      albumName: row['album_name'] as String? ?? '',
+      artistName: row['artist_name'] as String? ?? '',
+      coverPath: row['cover_path'] as String?,
+      trackCount: (row['track_count'] as num?)?.toInt() ?? 0,
+      maxBitDepth: (row['max_bit_depth'] as num?)?.toInt(),
+      maxSampleRate: (row['max_sample_rate'] as num?)?.toInt(),
+      maxBitrate: (row['max_bitrate'] as num?)?.toInt(),
+      format: row['format'] as String?,
+      releaseDate: row['release_date'] as String?,
+      genre: row['genre'] as String?,
+    );
+  }
+}
+
+class LocalLibraryLookupIndex {
+  final Set<String> isrcs;
+  final Set<String> matchKeys;
+  final Map<String, String> filePathById;
+
+  const LocalLibraryLookupIndex({
+    this.isrcs = const <String>{},
+    this.matchKeys = const <String>{},
+    this.filePathById = const <String, String>{},
+  });
 }
 
 class LibraryDatabase {
@@ -142,7 +246,7 @@ class LibraryDatabase {
 
     return await openDatabase(
       path,
-      version: 6,
+      version: 7,
       onConfigure: (db) async {
         await db.rawQuery('PRAGMA journal_mode = WAL');
         await db.execute('PRAGMA synchronous = NORMAL');
@@ -180,7 +284,13 @@ class LibraryDatabase {
         composer TEXT,
         label TEXT,
         copyright TEXT,
-        format TEXT
+        format TEXT,
+        track_name_norm TEXT,
+        artist_name_norm TEXT,
+        album_name_norm TEXT,
+        album_artist_norm TEXT,
+        match_key TEXT,
+        album_key TEXT
       )
     ''');
 
@@ -194,6 +304,7 @@ class LibraryDatabase {
     await db.execute(
       'CREATE INDEX idx_library_file_path ON library(file_path)',
     );
+    await _createNormalizedIndexes(db);
 
     _log.i('Library database schema created with indexes');
   }
@@ -228,10 +339,124 @@ class LibraryDatabase {
       await db.execute('ALTER TABLE library ADD COLUMN composer TEXT');
       _log.i('Added total_tracks/total_discs/composer columns');
     }
+
+    if (oldVersion < 7) {
+      await _addColumnIfMissing(db, 'library', 'track_name_norm', 'TEXT');
+      await _addColumnIfMissing(db, 'library', 'artist_name_norm', 'TEXT');
+      await _addColumnIfMissing(db, 'library', 'album_name_norm', 'TEXT');
+      await _addColumnIfMissing(db, 'library', 'album_artist_norm', 'TEXT');
+      await _addColumnIfMissing(db, 'library', 'match_key', 'TEXT');
+      await _addColumnIfMissing(db, 'library', 'album_key', 'TEXT');
+      await _backfillNormalizedColumns(db);
+      await _createNormalizedIndexes(db);
+      _log.i('Added normalized local library lookup columns');
+    }
+  }
+
+  static String normalizeLookupText(String? value) {
+    return (value ?? '').trim().toLowerCase();
+  }
+
+  static String matchKeyFor(String trackName, String artistName) {
+    return '${normalizeLookupText(trackName)}|${normalizeLookupText(artistName)}';
+  }
+
+  static String albumKeyFor(
+    String albumName,
+    String? albumArtist,
+    String artistName,
+  ) {
+    return '${normalizeLookupText(albumName)}|${normalizeLookupText(albumArtist ?? artistName)}';
+  }
+
+  Future<void> _addColumnIfMissing(
+    Database db,
+    String table,
+    String column,
+    String type,
+  ) async {
+    final info = await db.rawQuery('PRAGMA table_info($table)');
+    final exists = info.any((row) => row['name'] == column);
+    if (!exists) {
+      await db.execute('ALTER TABLE $table ADD COLUMN $column $type');
+    }
+  }
+
+  Future<void> _createNormalizedIndexes(DatabaseExecutor db) async {
+    await db.execute(
+      'CREATE INDEX IF NOT EXISTS idx_library_match_key ON library(match_key)',
+    );
+    await db.execute(
+      'CREATE INDEX IF NOT EXISTS idx_library_album_key ON library(album_key)',
+    );
+    await db.execute(
+      'CREATE INDEX IF NOT EXISTS idx_library_track_norm ON library(track_name_norm)',
+    );
+    await db.execute(
+      'CREATE INDEX IF NOT EXISTS idx_library_artist_norm ON library(artist_name_norm)',
+    );
+    await db.execute(
+      'CREATE INDEX IF NOT EXISTS idx_library_album_norm ON library(album_name_norm)',
+    );
+    await db.execute(
+      'CREATE INDEX IF NOT EXISTS idx_library_scanned_at ON library(scanned_at)',
+    );
+  }
+
+  Future<void> _backfillNormalizedColumns(Database db) async {
+    final rows = await db.query(
+      'library',
+      columns: [
+        'id',
+        'track_name',
+        'artist_name',
+        'album_name',
+        'album_artist',
+      ],
+    );
+    final batch = db.batch();
+    for (final row in rows) {
+      final trackName = row['track_name'] as String? ?? '';
+      final artistName = row['artist_name'] as String? ?? '';
+      final albumName = row['album_name'] as String? ?? '';
+      final albumArtist = row['album_artist'] as String?;
+      batch.update(
+        'library',
+        _normalizedColumns(
+          trackName: trackName,
+          artistName: artistName,
+          albumName: albumName,
+          albumArtist: albumArtist,
+        ),
+        where: 'id = ?',
+        whereArgs: [row['id']],
+      );
+    }
+    await batch.commit(noResult: true);
+  }
+
+  Map<String, dynamic> _normalizedColumns({
+    required String trackName,
+    required String artistName,
+    required String albumName,
+    required String? albumArtist,
+  }) {
+    final trackNorm = normalizeLookupText(trackName);
+    final artistNorm = normalizeLookupText(artistName);
+    final albumNorm = normalizeLookupText(albumName);
+    final albumArtistNorm = normalizeLookupText(albumArtist ?? artistName);
+    return {
+      'track_name_norm': trackNorm,
+      'artist_name_norm': artistNorm,
+      'album_name_norm': albumNorm,
+      'album_artist_norm': albumArtistNorm,
+      'match_key': '$trackNorm|$artistNorm',
+      'album_key': '$albumNorm|$albumArtistNorm',
+    };
   }
 
   Map<String, dynamic> _jsonToDbRow(Map<String, dynamic> json) {
-    return {
+    final row = {
       'id': json['id'],
       'track_name': json['trackName'],
       'artist_name': json['artistName'],
@@ -257,6 +482,15 @@ class LibraryDatabase {
       'copyright': json['copyright'],
       'format': json['format'],
     };
+    row.addAll(
+      _normalizedColumns(
+        trackName: json['trackName'] as String? ?? '',
+        artistName: json['artistName'] as String? ?? '',
+        albumName: json['albumName'] as String? ?? '',
+        albumArtist: json['albumArtist'] as String?,
+      ),
+    );
+    return row;
   }
 
   Map<String, dynamic> _dbRowToJson(Map<String, dynamic> row) {
@@ -346,6 +580,173 @@ class LibraryDatabase {
     return rows.map(_dbRowToJson).toList();
   }
 
+  Future<List<Map<String, dynamic>>> getPage(
+    LocalLibraryPageRequest request,
+  ) async {
+    final db = await database;
+    final where = <String>[];
+    final whereArgs = <Object?>[];
+    _appendPageFilters(where, whereArgs, request);
+
+    final rows = await db.query(
+      'library',
+      where: where.isEmpty ? null : where.join(' AND '),
+      whereArgs: whereArgs,
+      orderBy: _orderByForSort(request.sortMode),
+      limit: request.limit,
+      offset: request.offset,
+    );
+    return rows.map(_dbRowToJson).toList(growable: false);
+  }
+
+  Future<int> getPageCount(LocalLibraryPageRequest request) async {
+    final db = await database;
+    final where = <String>[];
+    final whereArgs = <Object?>[];
+    _appendPageFilters(where, whereArgs, request);
+    final rows = await db.rawQuery(
+      'SELECT COUNT(*) AS count FROM library'
+      '${where.isEmpty ? '' : ' WHERE ${where.join(' AND ')}'}',
+      whereArgs,
+    );
+    return Sqflite.firstIntValue(rows) ?? 0;
+  }
+
+  Future<List<LocalLibraryAlbumGroup>> getAlbumPage({
+    int limit = 100,
+    int offset = 0,
+    LocalLibraryFilterMode filterMode = LocalLibraryFilterMode.albums,
+    LocalLibrarySortMode sortMode = LocalLibrarySortMode.album,
+    String? searchQuery,
+  }) async {
+    final db = await database;
+    final where = <String>[];
+    final whereArgs = <Object?>[];
+    _appendSearchFilter(where, whereArgs, searchQuery);
+    final having = switch (filterMode) {
+      LocalLibraryFilterMode.singles => 'COUNT(*) = 1',
+      LocalLibraryFilterMode.albums => 'COUNT(*) > 1',
+      LocalLibraryFilterMode.all => null,
+    };
+    final rows = await db.rawQuery(
+      '''
+      SELECT
+        album_key,
+        MIN(album_name) AS album_name,
+        COALESCE(NULLIF(MIN(album_artist), ''), MIN(artist_name)) AS artist_name,
+        MAX(CASE WHEN cover_path IS NOT NULL AND cover_path != '' THEN cover_path END) AS cover_path,
+        COUNT(*) AS track_count,
+        MAX(bit_depth) AS max_bit_depth,
+        MAX(sample_rate) AS max_sample_rate,
+        MAX(bitrate) AS max_bitrate,
+        MAX(format) AS format,
+        MAX(release_date) AS release_date,
+        MAX(genre) AS genre
+      FROM library
+      ${where.isEmpty ? '' : 'WHERE ${where.join(' AND ')}'}
+      GROUP BY album_key
+      ${having == null ? '' : 'HAVING $having'}
+      ORDER BY ${_albumOrderByForSort(sortMode)}
+      LIMIT ? OFFSET ?
+      ''',
+      [...whereArgs, limit, offset],
+    );
+    return rows.map(LocalLibraryAlbumGroup.fromDbRow).toList(growable: false);
+  }
+
+  Future<int> getAlbumCount({
+    LocalLibraryFilterMode filterMode = LocalLibraryFilterMode.albums,
+    String? searchQuery,
+  }) async {
+    final db = await database;
+    final where = <String>[];
+    final whereArgs = <Object?>[];
+    _appendSearchFilter(where, whereArgs, searchQuery);
+    final having = switch (filterMode) {
+      LocalLibraryFilterMode.singles => 'COUNT(*) = 1',
+      LocalLibraryFilterMode.albums => 'COUNT(*) > 1',
+      LocalLibraryFilterMode.all => null,
+    };
+    final rows = await db.rawQuery('''
+      SELECT COUNT(*) AS count FROM (
+        SELECT album_key
+        FROM library
+        ${where.isEmpty ? '' : 'WHERE ${where.join(' AND ')}'}
+        GROUP BY album_key
+        ${having == null ? '' : 'HAVING $having'}
+      )
+      ''', whereArgs);
+    return Sqflite.firstIntValue(rows) ?? 0;
+  }
+
+  void _appendPageFilters(
+    List<String> where,
+    List<Object?> whereArgs,
+    LocalLibraryPageRequest request,
+  ) {
+    _appendSearchFilter(where, whereArgs, request.searchQuery);
+    final normalizedFormat = request.format?.trim().toLowerCase();
+    if (normalizedFormat != null && normalizedFormat.isNotEmpty) {
+      where.add('LOWER(format) = ?');
+      whereArgs.add(normalizedFormat);
+    }
+    switch (request.filterMode) {
+      case LocalLibraryFilterMode.all:
+        break;
+      case LocalLibraryFilterMode.albums:
+        where.add(
+          'album_key IN (SELECT album_key FROM library GROUP BY album_key HAVING COUNT(*) > 1)',
+        );
+        break;
+      case LocalLibraryFilterMode.singles:
+        where.add(
+          'album_key IN (SELECT album_key FROM library GROUP BY album_key HAVING COUNT(*) = 1)',
+        );
+        break;
+    }
+  }
+
+  void _appendSearchFilter(
+    List<String> where,
+    List<Object?> whereArgs,
+    String? searchQuery,
+  ) {
+    final query = normalizeLookupText(searchQuery);
+    if (query.isEmpty) return;
+    final like = '%$query%';
+    where.add(
+      '(track_name_norm LIKE ? OR artist_name_norm LIKE ? OR album_name_norm LIKE ? OR album_artist_norm LIKE ?)',
+    );
+    whereArgs.addAll([like, like, like, like]);
+  }
+
+  String _orderByForSort(LocalLibrarySortMode sortMode) {
+    return switch (sortMode) {
+      LocalLibrarySortMode.title =>
+        'track_name_norm, artist_name_norm, album_name_norm, disc_number, track_number',
+      LocalLibrarySortMode.artist =>
+        'artist_name_norm, album_name_norm, disc_number, track_number, track_name_norm',
+      LocalLibrarySortMode.latest =>
+        'scanned_at DESC, album_artist_norm, album_name_norm, disc_number, track_number',
+      LocalLibrarySortMode.quality =>
+        'COALESCE(bit_depth, 0) DESC, COALESCE(sample_rate, 0) DESC, COALESCE(bitrate, 0) DESC, album_artist_norm, album_name_norm, disc_number, track_number',
+      LocalLibrarySortMode.album =>
+        'album_artist_norm, album_name_norm, COALESCE(disc_number, 0), COALESCE(track_number, 0), track_name_norm',
+    };
+  }
+
+  String _albumOrderByForSort(LocalLibrarySortMode sortMode) {
+    return switch (sortMode) {
+      LocalLibrarySortMode.latest =>
+        'MAX(scanned_at) DESC, artist_name, album_name',
+      LocalLibrarySortMode.quality =>
+        'MAX(COALESCE(bit_depth, 0)) DESC, MAX(COALESCE(sample_rate, 0)) DESC, MAX(COALESCE(bitrate, 0)) DESC, artist_name, album_name',
+      LocalLibrarySortMode.title => 'album_name, artist_name',
+      LocalLibrarySortMode.artist ||
+      LocalLibrarySortMode.album => 'artist_name, album_name',
+    };
+  }
+
   Future<Map<String, dynamic>?> getById(String id) async {
     final db = await database;
     final rows = await db.query(
@@ -370,6 +771,18 @@ class LibraryDatabase {
     return _dbRowToJson(rows.first);
   }
 
+  Future<Map<String, dynamic>?> getByFilePath(String filePath) async {
+    final db = await database;
+    final rows = await db.query(
+      'library',
+      where: 'file_path = ?',
+      whereArgs: [filePath],
+      limit: 1,
+    );
+    if (rows.isEmpty) return null;
+    return _dbRowToJson(rows.first);
+  }
+
   Future<bool> existsByIsrc(String isrc) async {
     final db = await database;
     final result = await db.rawQuery(
@@ -386,12 +799,28 @@ class LibraryDatabase {
     final db = await database;
     final rows = await db.query(
       'library',
-      where: 'LOWER(track_name) = ? AND LOWER(artist_name) = ?',
-      whereArgs: [trackName.toLowerCase(), artistName.toLowerCase()],
+      where: 'match_key = ?',
+      whereArgs: [matchKeyFor(trackName, artistName)],
     );
     return rows.map(_dbRowToJson).toList();
   }
 
+  Future<Map<String, dynamic>?> findFirstByTrackAndArtist(
+    String trackName,
+    String artistName,
+  ) async {
+    final db = await database;
+    final rows = await db.query(
+      'library',
+      where: 'match_key = ?',
+      whereArgs: [matchKeyFor(trackName, artistName)],
+      orderBy: _orderByForSort(LocalLibrarySortMode.album),
+      limit: 1,
+    );
+    if (rows.isEmpty) return null;
+    return _dbRowToJson(rows.first);
+  }
+
   Future<Map<String, dynamic>?> findExisting({
     String? isrc,
     String? trackName,
@@ -421,11 +850,56 @@ class LibraryDatabase {
   Future<Set<String>> getAllTrackKeys() async {
     final db = await database;
     final rows = await db.rawQuery(
-      'SELECT LOWER(track_name) || "|" || LOWER(artist_name) as match_key FROM library',
+      'SELECT match_key FROM library WHERE match_key IS NOT NULL AND match_key != ""',
     );
     return rows.map((r) => r['match_key'] as String).toSet();
   }
 
+  Future<LocalLibraryLookupIndex> getLookupIndex() async {
+    final db = await database;
+    final rows = await db.rawQuery(
+      'SELECT id, file_path, isrc, match_key FROM library',
+    );
+    final isrcs = <String>{};
+    final matchKeys = <String>{};
+    final filePathById = <String, String>{};
+    for (final row in rows) {
+      final id = row['id'] as String?;
+      final filePath = row['file_path'] as String?;
+      if (id != null && id.isNotEmpty && filePath != null) {
+        filePathById[id] = filePath;
+      }
+      final isrc = row['isrc'] as String?;
+      if (isrc != null && isrc.isNotEmpty) {
+        isrcs.add(isrc);
+      }
+      final matchKey = row['match_key'] as String?;
+      if (matchKey != null && matchKey.isNotEmpty) {
+        matchKeys.add(matchKey);
+      }
+    }
+    return LocalLibraryLookupIndex(
+      isrcs: Set<String>.unmodifiable(isrcs),
+      matchKeys: Set<String>.unmodifiable(matchKeys),
+      filePathById: Map<String, String>.unmodifiable(filePathById),
+    );
+  }
+
+  Future<List<String>> getCoverPaths({int? limit, int? offset}) async {
+    final db = await database;
+    final rows = await db.query(
+      'library',
+      columns: ['cover_path'],
+      where: 'cover_path IS NOT NULL AND cover_path != ""',
+      limit: limit,
+      offset: offset,
+    );
+    return rows
+        .map((row) => row['cover_path'] as String?)
+        .whereType<String>()
+        .toList(growable: false);
+  }
+
   Future<void> deleteByPath(String filePath) async {
     final db = await database;
     await db.delete('library', where: 'file_path = ?', whereArgs: [filePath]);