SpotiFLAC-Mobile/lib/screens/queue_tab.dart

import 'dart:async';
import 'dart:io';
import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:cached_network_image/cached_network_image.dart';
import 'package:share_plus/share_plus.dart';
import 'package:path_provider/path_provider.dart';
import 'package:spotiflac_android/services/cover_cache_manager.dart';
import 'package:spotiflac_android/services/ffmpeg_service.dart';
import 'package:spotiflac_android/services/platform_bridge.dart';
import 'package:spotiflac_android/l10n/l10n.dart';
import 'package:spotiflac_android/utils/app_bar_layout.dart';
import 'package:spotiflac_android/utils/file_access.dart';
import 'package:spotiflac_android/utils/lyrics_metadata_helper.dart';
import 'package:spotiflac_android/models/download_item.dart';
import 'package:spotiflac_android/models/track.dart';
import 'package:spotiflac_android/providers/download_queue_provider.dart';
import 'package:spotiflac_android/providers/extension_provider.dart';
import 'package:spotiflac_android/providers/library_collections_provider.dart';
import 'package:spotiflac_android/providers/settings_provider.dart';
import 'package:spotiflac_android/providers/local_library_provider.dart';
import 'package:spotiflac_android/providers/playback_provider.dart';
import 'package:spotiflac_android/services/library_database.dart';
import 'package:spotiflac_android/services/local_track_redownload_service.dart';
import 'package:spotiflac_android/services/history_database.dart';
import 'package:spotiflac_android/services/downloaded_embedded_cover_resolver.dart';
import 'package:spotiflac_android/screens/track_metadata_screen.dart';
import 'package:spotiflac_android/screens/downloaded_album_screen.dart';
import 'package:spotiflac_android/screens/library_tracks_folder_screen.dart';
import 'package:spotiflac_android/screens/local_album_screen.dart';
import 'package:spotiflac_android/utils/clickable_metadata.dart';
import 'package:spotiflac_android/utils/path_match_keys.dart';
import 'package:spotiflac_android/utils/string_utils.dart';
import 'package:spotiflac_android/widgets/download_service_picker.dart';
import 'package:spotiflac_android/widgets/animation_utils.dart';

enum LibraryItemSource { downloaded, local }

class UnifiedLibraryItem {
  final String id;
  final String trackName;
  final String artistName;
  final String albumName;
  final String? coverUrl;
  final String? localCoverPath;
  final String filePath;
  final String? quality;
  final DateTime addedAt;
  final LibraryItemSource source;

  final DownloadHistoryItem? historyItem;
  final LocalLibraryItem? localItem;

  UnifiedLibraryItem({
    required this.id,
    required this.trackName,
    required this.artistName,
    required this.albumName,
    this.coverUrl,
    this.localCoverPath,
    required this.filePath,
    this.quality,
    required this.addedAt,
    required this.source,
    this.historyItem,
    this.localItem,
  });

  factory UnifiedLibraryItem.fromDownloadHistory(DownloadHistoryItem item) {
    return UnifiedLibraryItem(
      id: 'dl_${item.id}',
      trackName: item.trackName,
      artistName: item.artistName,
      albumName: item.albumName,
      coverUrl: item.coverUrl,
      filePath: item.filePath,
      quality: buildDisplayAudioQuality(
        bitDepth: item.bitDepth,
        sampleRate: item.sampleRate,
        storedQuality: item.quality,
      ),
      addedAt: item.downloadedAt,
      source: LibraryItemSource.downloaded,
      historyItem: item,
    );
  }

  factory UnifiedLibraryItem.fromLocalLibrary(LocalLibraryItem item) {
    String? quality;
    if (item.bitrate != null && item.bitrate! > 0) {
      quality = buildDisplayAudioQuality(
        bitrateKbps: item.bitrate,
        format: item.format,
      );
    } else if (item.bitDepth != null &&
        item.bitDepth! > 0 &&
        item.sampleRate != null) {
      quality = buildDisplayAudioQuality(
        bitDepth: item.bitDepth,
        sampleRate: item.sampleRate,
      );
    }
    return UnifiedLibraryItem(
      id: 'local_${item.id}',
      trackName: item.trackName,
      artistName: item.artistName,
      albumName: item.albumName,
      coverUrl: null,
      localCoverPath: item.coverPath,
      filePath: item.filePath,
      quality: quality,
      addedAt: item.fileModTime != null
          ? DateTime.fromMillisecondsSinceEpoch(item.fileModTime!)
          : item.scannedAt,
      source: LibraryItemSource.local,
      localItem: item,
    );
  }

  bool get hasCover =>
      coverUrl != null ||
      (localCoverPath != null && localCoverPath!.isNotEmpty);

  String get searchKey =>
      '${trackName.toLowerCase()}|${artistName.toLowerCase()}|${albumName.toLowerCase()}';
  String get albumKey =>
      '${albumName.toLowerCase()}|${artistName.toLowerCase()}';

  /// Returns the collection key used to match this item against playlist
  /// entries. Uses the same logic as [trackCollectionKey] from the collections
  /// provider: prefer ISRC, fall back to source:id.
  String get collectionKey {
    if (historyItem != null) {
      final isrc = historyItem!.isrc?.trim();
      if (isrc != null && isrc.isNotEmpty) return 'isrc:${isrc.toUpperCase()}';
      final source = historyItem!.service.trim().isNotEmpty
          ? historyItem!.service.trim()
          : 'builtin';
      return '$source:${historyItem!.id}';
    }
    if (localItem != null) {
      final isrc = localItem!.isrc?.trim();
      if (isrc != null && isrc.isNotEmpty) return 'isrc:${isrc.toUpperCase()}';
      return 'local:${localItem!.id}';
    }
    return 'builtin:$id';
  }

  /// Convert to a [Track] for adding to collections/playlists.
  Track toTrack() {
    if (historyItem != null) {
      final h = historyItem!;
      return Track(
        id: h.id,
        name: h.trackName,
        artistName: h.artistName,
        albumName: h.albumName,
        albumArtist: h.albumArtist,
        coverUrl: h.coverUrl,
        isrc: h.isrc,
        duration: h.duration ?? 0,
        trackNumber: h.trackNumber,
        discNumber: h.discNumber,
        releaseDate: h.releaseDate,
        source: h.service,
      );
    }
    if (localItem != null) {
      final l = localItem!;
      return Track(
        id: l.id,
        name: l.trackName,
        artistName: l.artistName,
        albumName: l.albumName,
        albumArtist: l.albumArtist,
        coverUrl: l.coverPath,
        isrc: l.isrc,
        duration: l.duration ?? 0,
        trackNumber: l.trackNumber,
        discNumber: l.discNumber,
        releaseDate: l.releaseDate,
        source: 'local',
      );
    }
    return Track(
      id: id,
      name: trackName,
      artistName: artistName,
      albumName: albumName,
      coverUrl: coverUrl,
      duration: 0,
    );
  }
}

class _GroupedAlbum {
  final String albumName;
  final String artistName;
  final String? coverUrl;
  final String sampleFilePath;
  final List<DownloadHistoryItem> tracks;
  final DateTime latestDownload;
  final String searchKey;

  _GroupedAlbum({
    required this.albumName,
    required this.artistName,
    this.coverUrl,
    required this.sampleFilePath,
    required this.tracks,
    required this.latestDownload,
  }) : searchKey = '${albumName.toLowerCase()}|${artistName.toLowerCase()}';

  String get key => '$albumName|$artistName';
}

class _GroupedLocalAlbum {
  final String albumName;
  final String artistName;
  final String? coverPath;
  final List<LocalLibraryItem> tracks;
  final DateTime latestScanned;
  final String searchKey;

  _GroupedLocalAlbum({
    required this.albumName,
    required this.artistName,
    this.coverPath,
    required this.tracks,
    required this.latestScanned,
  }) : searchKey = '${albumName.toLowerCase()}|${artistName.toLowerCase()}';

  String get key => '$albumName|$artistName';
}

class _HistoryStats {
  final Map<String, int> albumCounts;
  final Map<String, int> localAlbumCounts;
  final List<_GroupedAlbum> groupedAlbums;
  final List<_GroupedLocalAlbum> groupedLocalAlbums;
  final int albumCount;
  final int singleTracks;
  final int localAlbumCount;
  final int localSingleTracks;

  const _HistoryStats({
    required this.albumCounts,
    this.localAlbumCounts = const {},
    required this.groupedAlbums,
    this.groupedLocalAlbums = const [],
    required this.albumCount,
    required this.singleTracks,
    this.localAlbumCount = 0,
    this.localSingleTracks = 0,
  });

  int get totalAlbumCount => albumCount + localAlbumCount;

  int get totalSingleTracks => singleTracks + localSingleTracks;
}

class _FilterContentData {
  final List<DownloadHistoryItem> historyItems;
  final List<UnifiedLibraryItem> unifiedItems;
  final List<UnifiedLibraryItem> filteredUnifiedItems;
  final List<_GroupedAlbum> filteredGroupedAlbums;
  final List<_GroupedLocalAlbum> filteredGroupedLocalAlbums;
  final bool showFilteringIndicator;

  const _FilterContentData({
    required this.historyItems,
    required this.unifiedItems,
    required this.filteredUnifiedItems,
    required this.filteredGroupedAlbums,
    required this.filteredGroupedLocalAlbums,
    required this.showFilteringIndicator,
  });

  int get totalTrackCount => filteredUnifiedItems.length;
  int get totalAlbumCount =>
      filteredGroupedAlbums.length + filteredGroupedLocalAlbums.length;
}

class _UnifiedCacheEntry {
  final List<DownloadHistoryItem> historyItems;
  final List<LocalLibraryItem> localItems;
  final Map<String, int> localAlbumCounts;
  final String query;
  final List<UnifiedLibraryItem> items;

  const _UnifiedCacheEntry({
    required this.historyItems,
    required this.localItems,
    required this.localAlbumCounts,
    required this.query,
    required this.items,
  });
}

class _QueueItemIdsSnapshot {
  final List<String> ids;

  const _QueueItemIdsSnapshot(this.ids);

  @override
  bool operator ==(Object other) =>
      identical(this, other) ||
      other is _QueueItemIdsSnapshot && listEquals(ids, other.ids);

  @override
  int get hashCode => Object.hashAll(ids);
}

class _QueueGroupedAlbumFilterRequest {
  final String searchQuery;
  final String? filterSource;
  final String? filterQuality;
  final String? filterFormat;
  final String sortMode;

  const _QueueGroupedAlbumFilterRequest({
    required this.searchQuery,
    required this.filterSource,
    required this.filterQuality,
    required this.filterFormat,
    required this.sortMode,
  });

  @override
  bool operator ==(Object other) =>
      identical(this, other) ||
      other is _QueueGroupedAlbumFilterRequest &&
          searchQuery == other.searchQuery &&
          filterSource == other.filterSource &&
          filterQuality == other.filterQuality &&
          filterFormat == other.filterFormat &&
          sortMode == other.sortMode;

  @override
  int get hashCode => Object.hash(
    searchQuery,
    filterSource,
    filterQuality,
    filterFormat,
    sortMode,
  );
}

String _queueFileExtLower(String filePath) {
  final slashIndex = filePath.lastIndexOf('/');
  final dotIndex = filePath.lastIndexOf('.');
  if (dotIndex == -1 || dotIndex < slashIndex + 1) {
    return '';
  }
  return filePath.substring(dotIndex + 1).toLowerCase();
}

String? _queueLocalQualityLabel(LocalLibraryItem item) {
  if (item.bitrate != null && item.bitrate! > 0) {
    return '${item.bitrate}kbps';
  }
  if (item.bitDepth == null || item.bitDepth == 0 || item.sampleRate == null) {
    return null;
  }
  return '${item.bitDepth}bit/${(item.sampleRate! / 1000).toStringAsFixed(1)}kHz';
}

bool _queuePassesQualityFilter(String? filterQuality, String? quality) {
  if (filterQuality == null) return true;
  if (quality == null) return filterQuality == 'lossy';
  final normalized = quality.toLowerCase();
  switch (filterQuality) {
    case 'hires':
      return normalized.startsWith('24');
    case 'cd':
      return normalized.startsWith('16');
    case 'lossy':
      return !normalized.startsWith('24') && !normalized.startsWith('16');
    default:
      return true;
  }
}

bool _queuePassesFormatFilter(String? filterFormat, String filePath) {
  if (filterFormat == null) return true;
  return _queueFileExtLower(filePath) == filterFormat;
}

_HistoryStats _buildQueueHistoryStats(
  List<DownloadHistoryItem> items, [
  List<LocalLibraryItem> localItems = const [],
]) {
  final albumCounts = <String, int>{};
  final albumMap = <String, List<DownloadHistoryItem>>{};
  for (final item in items) {
    final key =
        '${item.albumName.toLowerCase()}|${(item.albumArtist ?? item.artistName).toLowerCase()}';
    albumCounts[key] = (albumCounts[key] ?? 0) + 1;
    albumMap.putIfAbsent(key, () => []).add(item);
  }

  var singleTracks = 0;
  for (final item in items) {
    final key =
        '${item.albumName.toLowerCase()}|${(item.albumArtist ?? item.artistName).toLowerCase()}';
    if ((albumCounts[key] ?? 0) <= 1) {
      singleTracks++;
    }
  }

  final groupedAlbums = <_GroupedAlbum>[];
  albumMap.forEach((_, tracks) {
    if (tracks.length <= 1) return;
    tracks.sort((a, b) {
      final aNum = a.trackNumber ?? 999;
      final bNum = b.trackNumber ?? 999;
      return aNum.compareTo(bNum);
    });

    groupedAlbums.add(
      _GroupedAlbum(
        albumName: tracks.first.albumName,
        artistName: tracks.first.albumArtist ?? tracks.first.artistName,
        coverUrl: tracks.first.coverUrl,
        sampleFilePath: tracks.first.filePath,
        tracks: tracks,
        latestDownload: tracks
            .map((t) => t.downloadedAt)
            .reduce((a, b) => a.isAfter(b) ? a : b),
      ),
    );
  });
  groupedAlbums.sort((a, b) => b.latestDownload.compareTo(a.latestDownload));

  var albumCount = 0;
  for (final count in albumCounts.values) {
    if (count > 1) albumCount++;
  }

  final downloadedPathKeys = <String>{};
  for (final item in items) {
    downloadedPathKeys.addAll(buildPathMatchKeys(item.filePath));
  }

  final dedupedLocalItems = localItems
      .where((item) {
        final localPathKeys = buildPathMatchKeys(item.filePath);
        return !localPathKeys.any(downloadedPathKeys.contains);
      })
      .toList(growable: false);

  final localAlbumCounts = <String, int>{};
  final localAlbumMap = <String, List<LocalLibraryItem>>{};
  for (final item in dedupedLocalItems) {
    final key =
        '${item.albumName.toLowerCase()}|${(item.albumArtist ?? item.artistName).toLowerCase()}';
    localAlbumCounts[key] = (localAlbumCounts[key] ?? 0) + 1;
    localAlbumMap.putIfAbsent(key, () => []).add(item);
  }

  var localAlbumCount = 0;
  var localSingleTracks = 0;
  for (final count in localAlbumCounts.values) {
    if (count > 1) {
      localAlbumCount++;
    } else {
      localSingleTracks++;
    }
  }

  final groupedLocalAlbums = <_GroupedLocalAlbum>[];
  localAlbumMap.forEach((_, tracks) {
    if (tracks.length <= 1) return;
    tracks.sort((a, b) {
      final aNum = a.trackNumber ?? 999;
      final bNum = b.trackNumber ?? 999;
      return aNum.compareTo(bNum);
    });

    groupedLocalAlbums.add(
      _GroupedLocalAlbum(
        albumName: tracks.first.albumName,
        artistName: tracks.first.albumArtist ?? tracks.first.artistName,
        coverPath: tracks
            .firstWhere(
              (t) => t.coverPath != null && t.coverPath!.isNotEmpty,
              orElse: () => tracks.first,
            )
            .coverPath,
        tracks: tracks,
        latestScanned: tracks
            .map((t) => t.scannedAt)
            .reduce((a, b) => a.isAfter(b) ? a : b),
      ),
    );
  });
  groupedLocalAlbums.sort((a, b) => b.latestScanned.compareTo(a.latestScanned));

  return _HistoryStats(
    albumCounts: albumCounts,
    localAlbumCounts: localAlbumCounts,
    groupedAlbums: groupedAlbums,
    groupedLocalAlbums: groupedLocalAlbums,
    albumCount: albumCount,
    singleTracks: singleTracks,
    localAlbumCount: localAlbumCount,
    localSingleTracks: localSingleTracks,
  );
}

List<_GroupedAlbum> _queueFilterGroupedAlbums(
  List<_GroupedAlbum> albums,
  _QueueGroupedAlbumFilterRequest request,
) {
  if (request.filterSource == 'local') return const [];
  if (request.filterSource == null &&
      request.filterQuality == null &&
      request.filterFormat == null &&
      request.searchQuery.isEmpty &&
      request.sortMode == 'latest') {
    return albums;
  }

  final result = <_GroupedAlbum>[];
  for (final album in albums) {
    if (request.searchQuery.isNotEmpty &&
        !album.searchKey.contains(request.searchQuery)) {
      continue;
    }

    if (request.filterQuality != null || request.filterFormat != null) {
      var hasMatchingTrack = false;
      for (final track in album.tracks) {
        if (!_queuePassesQualityFilter(request.filterQuality, track.quality)) {
          continue;
        }
        if (!_queuePassesFormatFilter(request.filterFormat, track.filePath)) {
          continue;
        }
        hasMatchingTrack = true;
        break;
      }
      if (!hasMatchingTrack) continue;
    }

    result.add(album);
  }

  switch (request.sortMode) {
    case 'oldest':
      result.sort((a, b) => a.latestDownload.compareTo(b.latestDownload));
    case 'a-z':
      result.sort(
        (a, b) =>
            a.albumName.toLowerCase().compareTo(b.albumName.toLowerCase()),
      );
    case 'z-a':
      result.sort(
        (a, b) =>
            b.albumName.toLowerCase().compareTo(a.albumName.toLowerCase()),
      );
    default:
      break;
  }
  return result;
}

List<_GroupedLocalAlbum> _queueFilterGroupedLocalAlbums(
  List<_GroupedLocalAlbum> albums,
  _QueueGroupedAlbumFilterRequest request,
) {
  if (request.filterSource == 'downloaded') return const [];
  if (request.filterSource == null &&
      request.filterQuality == null &&
      request.filterFormat == null &&
      request.searchQuery.isEmpty &&
      request.sortMode == 'latest') {
    return albums;
  }

  final result = <_GroupedLocalAlbum>[];
  for (final album in albums) {
    if (request.searchQuery.isNotEmpty &&
        !album.searchKey.contains(request.searchQuery)) {
      continue;
    }

    if (request.filterQuality != null || request.filterFormat != null) {
      var hasMatchingTrack = false;
      for (final track in album.tracks) {
        if (!_queuePassesQualityFilter(
          request.filterQuality,
          _queueLocalQualityLabel(track),
        )) {
          continue;
        }
        if (!_queuePassesFormatFilter(request.filterFormat, track.filePath)) {
          continue;
        }
        hasMatchingTrack = true;
        break;
      }
      if (!hasMatchingTrack) continue;
    }

    result.add(album);
  }

  switch (request.sortMode) {
    case 'oldest':
      result.sort((a, b) => a.latestScanned.compareTo(b.latestScanned));
    case 'a-z':
      result.sort(
        (a, b) =>
            a.albumName.toLowerCase().compareTo(b.albumName.toLowerCase()),
      );
    case 'z-a':
      result.sort(
        (a, b) =>
            b.albumName.toLowerCase().compareTo(a.albumName.toLowerCase()),
      );
    default:
      break;
  }
  return result;
}

final _queueHistoryStatsProvider = Provider<_HistoryStats>((ref) {
  final historyItems = ref.watch(
    downloadHistoryProvider.select((s) => s.items),
  );
  final localLibraryEnabled = ref.watch(
    settingsProvider.select((s) => s.localLibraryEnabled),
  );
  final localItems = localLibraryEnabled
      ? ref.watch(localLibraryProvider.select((s) => s.items))
      : const <LocalLibraryItem>[];
  return _buildQueueHistoryStats(historyItems, localItems);
});

final _queueFilteredAlbumsProvider =
    Provider.family<
      ({List<_GroupedAlbum> albums, List<_GroupedLocalAlbum> localAlbums}),
      _QueueGroupedAlbumFilterRequest
    >((ref, request) {
      final historyStats = ref.watch(_queueHistoryStatsProvider);
      return (
        albums: _queueFilterGroupedAlbums(historyStats.groupedAlbums, request),
        localAlbums: _queueFilterGroupedLocalAlbums(
          historyStats.groupedLocalAlbums,
          request,
        ),
      );
    });

Map<String, List<String>> _filterHistoryInIsolate(Map<String, Object> payload) {
  final entries = (payload['entries'] as List).cast<List>();
  final albumCounts = (payload['albumCounts'] as Map).cast<String, int>();
  final query = (payload['query'] as String?) ?? '';
  final hasQuery = query.isNotEmpty;

  final allIds = <String>[];
  final albumIds = <String>[];
  final singleIds = <String>[];

  for (final entry in entries) {
    final id = entry[0] as String;
    final albumKey = entry[1] as String;
    if (hasQuery) {
      final searchKey = entry[2] as String;
      if (!searchKey.contains(query)) {
        continue;
      }
    }

    allIds.add(id);
    final count = albumCounts[albumKey] ?? 0;
    if (count > 1) {
      albumIds.add(id);
    } else if (count == 1) {
      singleIds.add(id);
    }
  }

  return {'all': allIds, 'albums': albumIds, 'singles': singleIds};
}

class QueueTab extends ConsumerStatefulWidget {
  final PageController? parentPageController;
  final int parentPageIndex;
  final int? nextPageIndex;

  const QueueTab({
    super.key,
    this.parentPageController,
    this.parentPageIndex = 1,
    this.nextPageIndex,
  });

  @override
  ConsumerState<QueueTab> createState() => _QueueTabState();
}

class _QueueTabState extends ConsumerState<QueueTab> {
  final Map<String, bool> _fileExistsCache = {};
  final Map<String, ValueNotifier<bool>> _fileExistsNotifiers = {};
  final ValueNotifier<bool> _alwaysMissingFileNotifier = ValueNotifier(false);
  final Set<String> _pendingChecks = {};
  static const int _maxCacheSize = 500;
  static const int _maxSearchIndexCacheSize = 4000;
  bool _embeddedCoverRefreshScheduled = false;
  // Version counter to trigger targeted cover image rebuilds
  // without rebuilding the entire widget tree via setState.
  final ValueNotifier<int> _embeddedCoverVersion = ValueNotifier<int>(0);

  bool _isSelectionMode = false;
  final Set<String> _selectedIds = {};
  OverlayEntry? _selectionOverlayEntry;
  List<UnifiedLibraryItem> _selectionOverlayItems = const [];
  double _selectionOverlayBottomPadding = 0;

  bool _isPlaylistSelectionMode = false;
  final Set<String> _selectedPlaylistIds = {};
  OverlayEntry? _playlistSelectionOverlayEntry;
  List<UserPlaylistCollection> _playlistSelectionOverlayItems = const [];
  double _playlistSelectionOverlayBottomPadding = 0;

  PageController? _filterPageController;
  final List<String> _filterModes = ['all', 'albums', 'singles'];
  bool _isPageControllerInitialized = false;
  static const List<String> _months = [
    'Jan',
    'Feb',
    'Mar',
    'Apr',
    'May',
    'Jun',
    'Jul',
    'Aug',
    'Sep',
    'Oct',
    'Nov',
    'Dec',
  ];

  final TextEditingController _searchController = TextEditingController();
  final FocusNode _searchFocusNode = FocusNode();
  String _searchQuery = '';
  Timer? _searchDebounce;
  List<DownloadHistoryItem>? _historyItemsCache;
  List<LocalLibraryItem>? _localLibraryItemsCache;
  _HistoryStats? _historyStatsCache;
  final Map<String, String> _searchIndexCache = {};
  final Map<String, String> _localSearchIndexCache = {};
  Map<String, List<DownloadHistoryItem>> _filteredHistoryCache = const {};
  List<DownloadHistoryItem>? _filterItemsCache;
  String _filterQueryCache = '';
  bool _filterRefreshScheduled = false;
  bool _isFilteringHistory = false;
  int _filterRequestId = 0;
  static const int _filterIsolateThreshold = 800;
  List<LocalLibraryItem>? _localFilterItemsCache;
  String _localFilterQueryCache = '';
  List<LocalLibraryItem> _filteredLocalItemsCache = const [];
  final Map<String, _UnifiedCacheEntry> _unifiedItemsCache = {};
  List<DownloadHistoryItem>? _cachedUnifiedDownloadedSource;
  List<UnifiedLibraryItem> _cachedUnifiedDownloaded = const [];
  List<LocalLibraryItem>? _cachedUnifiedLocalSource;
  List<UnifiedLibraryItem> _cachedUnifiedLocal = const [];
  List<DownloadHistoryItem>? _cachedDownloadedPathKeysSource;
  Set<String> _cachedDownloadedPathKeys = const <String>{};
  final Map<String, _FilterContentData> _filterContentDataCache = {};
  List<DownloadHistoryItem>? _filterCacheAllHistoryItems;
  _HistoryStats? _filterCacheHistoryStats;
  List<LocalLibraryItem>? _filterCacheLocalLibraryItems;
  LibraryCollectionsState? _filterCacheCollectionState;
  String _filterCacheSearchQuery = '';
  String? _filterCacheSource;
  String? _filterCacheQuality;
  String? _filterCacheFormat;
  String _filterCacheSortMode = 'latest';
  String? _filterSource; // null = all, 'downloaded', 'local'
  String? _filterQuality; // null = all, 'hires', 'cd', 'lossy'
  String? _filterFormat; // null = all, 'flac', 'mp3', 'm4a', 'opus', 'ogg'
  String _sortMode = 'latest'; // 'latest', 'oldest', 'a-z', 'z-a'

  double _effectiveTextScale() {
    final textScale = MediaQuery.textScalerOf(context).scale(1.0);
    if (textScale < 1.0) return 1.0;
    if (textScale > 1.4) return 1.4;
    return textScale;
  }

  double _queueCoverSize() {
    final shortestSide = MediaQuery.sizeOf(context).shortestSide;
    final scale = (shortestSide / 390).clamp(0.82, 1.0);
    final textScale = _effectiveTextScale();
    return (56 * scale * (1 + ((textScale - 1) * 0.12))).clamp(46.0, 56.0);
  }

  @override
  void initState() {
    super.initState();
  }

  void _initializePageController() {
    if (_isPageControllerInitialized) return;
    _isPageControllerInitialized = true;
    final currentFilter = ref.read(settingsProvider).historyFilterMode;
    final initialPage = _filterModes.indexOf(currentFilter).clamp(0, 2);
    _filterPageController = PageController(initialPage: initialPage);
  }

  @override
  void dispose() {
    _hideSelectionOverlay();
    _hidePlaylistSelectionOverlay();
    for (final notifier in _fileExistsNotifiers.values) {
      notifier.dispose();
    }
    _fileExistsNotifiers.clear();
    _alwaysMissingFileNotifier.dispose();
    _embeddedCoverVersion.dispose();
    _filterPageController?.dispose();
    _searchController.dispose();
    _searchFocusNode.dispose();
    _searchDebounce?.cancel();
    super.dispose();
  }

  void _onSearchChanged(String value) {
    _searchDebounce?.cancel();
    final normalized = value.trim().toLowerCase();
    _searchDebounce = Timer(const Duration(milliseconds: 180), () {
      if (!mounted || _searchQuery == normalized) return;
      setState(() => _searchQuery = normalized);
      _requestFilterRefresh();
    });
  }

  void _clearSearch() {
    _searchDebounce?.cancel();
    if (_searchQuery.isEmpty) return;
    setState(() => _searchQuery = '');
    _requestFilterRefresh();
  }

  void _invalidateFilterContentCache() {
    _filterContentDataCache.clear();
    _filterCacheAllHistoryItems = null;
    _filterCacheHistoryStats = null;
    _filterCacheLocalLibraryItems = null;
    _filterCacheCollectionState = null;
  }

  void _prepareFilterContentCache({
    required List<DownloadHistoryItem> allHistoryItems,
    required _HistoryStats historyStats,
    required List<LocalLibraryItem> localLibraryItems,
    required LibraryCollectionsState collectionState,
  }) {
    final isCacheValid =
        identical(_filterCacheAllHistoryItems, allHistoryItems) &&
        identical(_filterCacheHistoryStats, historyStats) &&
        identical(_filterCacheLocalLibraryItems, localLibraryItems) &&
        identical(_filterCacheCollectionState, collectionState) &&
        _filterCacheSearchQuery == _searchQuery &&
        _filterCacheSource == _filterSource &&
        _filterCacheQuality == _filterQuality &&
        _filterCacheFormat == _filterFormat &&
        _filterCacheSortMode == _sortMode;

    if (isCacheValid) {
      return;
    }

    _filterContentDataCache.clear();
    _filterCacheAllHistoryItems = allHistoryItems;
    _filterCacheHistoryStats = historyStats;
    _filterCacheLocalLibraryItems = localLibraryItems;
    _filterCacheCollectionState = collectionState;
    _filterCacheSearchQuery = _searchQuery;
    _filterCacheSource = _filterSource;
    _filterCacheQuality = _filterQuality;
    _filterCacheFormat = _filterFormat;
    _filterCacheSortMode = _sortMode;
  }

  void _ensureHistoryCaches(
    List<DownloadHistoryItem> items,
    List<LocalLibraryItem> localItems,
    _HistoryStats historyStats,
  ) {
    final historyChanged = !identical(items, _historyItemsCache);
    final localChanged = !identical(localItems, _localLibraryItemsCache);

    if (!historyChanged && !localChanged) return;

    _historyItemsCache = items;
    _localLibraryItemsCache = localItems;
    _historyStatsCache = historyStats;
    if (historyChanged) {
      _searchIndexCache.clear();
      _cachedUnifiedDownloadedSource = null;
      _cachedUnifiedDownloaded = const [];
      _cachedDownloadedPathKeysSource = null;
      _cachedDownloadedPathKeys = const <String>{};
    }
    if (localChanged) {
      _localSearchIndexCache.clear();
      _localFilterItemsCache = null;
      _localFilterQueryCache = '';
      _filteredLocalItemsCache = const [];
      _cachedUnifiedLocalSource = null;
      _cachedUnifiedLocal = const [];
    }
    _unifiedItemsCache.clear();
    _invalidateFilterContentCache();

    if (historyChanged) {
      final validPaths = items
          .map((item) => _cleanFilePath(item.filePath))
          .where((path) => path.isNotEmpty)
          .toSet();
      DownloadedEmbeddedCoverResolver.invalidatePathsNotIn(validPaths);
    }
    _requestFilterRefresh();
  }

  String _buildSearchKey(DownloadHistoryItem item) {
    return '${item.trackName} ${item.artistName} ${item.albumName}'
        .toLowerCase();
  }

  String _buildLocalSearchKey(LocalLibraryItem item) {
    return '${item.trackName} ${item.artistName} ${item.albumName}'
        .toLowerCase();
  }

  String _historySearchKeyForItem(DownloadHistoryItem item) {
    final cached = _searchIndexCache[item.id];
    if (cached != null) return cached;

    final searchKey = _buildSearchKey(item);
    _searchIndexCache[item.id] = searchKey;
    while (_searchIndexCache.length > _maxSearchIndexCacheSize) {
      _searchIndexCache.remove(_searchIndexCache.keys.first);
    }
    return searchKey;
  }

  String _localSearchKeyForItem(LocalLibraryItem item) {
    final cached = _localSearchIndexCache[item.id];
    if (cached != null) return cached;

    final searchKey = _buildLocalSearchKey(item);
    _localSearchIndexCache[item.id] = searchKey;
    while (_localSearchIndexCache.length > _maxSearchIndexCacheSize) {
      _localSearchIndexCache.remove(_localSearchIndexCache.keys.first);
    }
    return searchKey;
  }

  List<UnifiedLibraryItem> _unifiedDownloadedItems(
    List<DownloadHistoryItem> items,
  ) {
    if (identical(items, _cachedUnifiedDownloadedSource)) {
      return _cachedUnifiedDownloaded;
    }
    final unified = items
        .map(UnifiedLibraryItem.fromDownloadHistory)
        .toList(growable: false);
    _cachedUnifiedDownloadedSource = items;
    _cachedUnifiedDownloaded = unified;
    return unified;
  }

  List<UnifiedLibraryItem> _unifiedLocalItems(List<LocalLibraryItem> items) {
    if (identical(items, _cachedUnifiedLocalSource)) {
      return _cachedUnifiedLocal;
    }
    final unified = items
        .map(UnifiedLibraryItem.fromLocalLibrary)
        .toList(growable: false);
    _cachedUnifiedLocalSource = items;
    _cachedUnifiedLocal = unified;
    return unified;
  }

  Set<String> _downloadedPathKeys(List<DownloadHistoryItem> historyItems) {
    if (identical(historyItems, _cachedDownloadedPathKeysSource)) {
      return _cachedDownloadedPathKeys;
    }
    final keys = <String>{};
    for (final item in historyItems) {
      keys.addAll(buildPathMatchKeys(item.filePath));
    }
    _cachedDownloadedPathKeysSource = historyItems;
    _cachedDownloadedPathKeys = Set<String>.unmodifiable(keys);
    return _cachedDownloadedPathKeys;
  }

  List<LocalLibraryItem> _filterLocalItems(
    List<LocalLibraryItem> items,
    String query,
  ) {
    if (query.isEmpty) return items;
    if (identical(items, _localFilterItemsCache) &&
        query == _localFilterQueryCache) {
      return _filteredLocalItemsCache;
    }

    final filtered = items
        .where((item) {
          final searchKey = _localSearchKeyForItem(item);
          return searchKey.contains(query);
        })
        .toList(growable: false);

    _localFilterItemsCache = items;
    _localFilterQueryCache = query;
    _filteredLocalItemsCache = filtered;
    return filtered;
  }

  bool _isFilterCacheValid(List<DownloadHistoryItem> items, String query) {
    return identical(items, _filterItemsCache) && query == _filterQueryCache;
  }

  void _requestFilterRefresh() {
    if (_filterRefreshScheduled) return;
    _filterRefreshScheduled = true;
    WidgetsBinding.instance.addPostFrameCallback((_) {
      _filterRefreshScheduled = false;
      if (!mounted) return;
      _scheduleHistoryFilterUpdate();
    });
  }

  void _scheduleHistoryFilterUpdate() {
    final items = _historyItemsCache;
    if (items == null) return;
    final query = _searchQuery;
    if (_isFilterCacheValid(items, query)) return;

    final albumCounts =
        _historyStatsCache?.albumCounts ?? const <String, int>{};
    if (items.isEmpty) {
      setState(() {
        _filteredHistoryCache = const {};
        _filterItemsCache = items;
        _filterQueryCache = query;
        _isFilteringHistory = false;
      });
      return;
    }

    if (items.length <= _filterIsolateThreshold) {
      final filteredAll = _applyHistorySearchFilter(items, query);
      final filteredAlbums = _filterHistoryByAlbumCount(
        filteredAll,
        albumCounts,
        2,
      );
      final filteredSingles = _filterHistoryByAlbumCount(
        filteredAll,
        albumCounts,
        1,
      );
      setState(() {
        _filteredHistoryCache = {
          'all': filteredAll,
          'albums': filteredAlbums,
          'singles': filteredSingles,
        };
        _filterItemsCache = items;
        _filterQueryCache = query;
        _isFilteringHistory = false;
      });
      return;
    }

    if (!_isFilteringHistory) {
      setState(() => _isFilteringHistory = true);
    }

    final requestId = ++_filterRequestId;
    final includeSearchKey = query.isNotEmpty;
    final entries = List<List<String>>.generate(items.length, (index) {
      final item = items[index];
      final albumKey =
          '${item.albumName.toLowerCase()}|${(item.albumArtist ?? item.artistName).toLowerCase()}';
      if (!includeSearchKey) {
        return [item.id, albumKey];
      }
      final searchKey = _historySearchKeyForItem(item);
      return [item.id, albumKey, searchKey];
    }, growable: false);
    final payload = <String, Object>{
      'entries': entries,
      'albumCounts': albumCounts,
      'query': query,
    };

    compute(_filterHistoryInIsolate, payload).then((result) {
      if (!mounted || requestId != _filterRequestId) return;
      final itemsById = {for (final item in items) item.id: item};
      final filtered = <String, List<DownloadHistoryItem>>{};
      for (final entry in result.entries) {
        filtered[entry.key] = entry.value
            .map((id) => itemsById[id])
            .whereType<DownloadHistoryItem>()
            .toList(growable: false);
      }
      setState(() {
        _filteredHistoryCache = filtered;
        _filterItemsCache = items;
        _filterQueryCache = query;
        _isFilteringHistory = false;
      });
    });
  }

  List<DownloadHistoryItem> _resolveHistoryItems({
    required String filterMode,
    required List<DownloadHistoryItem> allHistoryItems,
    required Map<String, int> albumCounts,
  }) {
    final query = _searchQuery;
    if (_isFilterCacheValid(allHistoryItems, query)) {
      final cached = _filteredHistoryCache[filterMode];
      if (cached != null) return cached;
    }
    if (allHistoryItems.isEmpty) return const [];
    if (query.isEmpty && filterMode == 'all') return allHistoryItems;
    if (allHistoryItems.length <= _filterIsolateThreshold) {
      return _filterHistoryItems(
        allHistoryItems,
        filterMode,
        albumCounts,
        query,
      );
    }
    return const [];
  }

  List<DownloadHistoryItem> _applyHistorySearchFilter(
    List<DownloadHistoryItem> items,
    String searchQuery,
  ) {
    if (searchQuery.isEmpty) return items;
    final query = searchQuery;
    return items
        .where((item) {
          final searchKey = _historySearchKeyForItem(item);
          return searchKey.contains(query);
        })
        .toList(growable: false);
  }

  List<DownloadHistoryItem> _filterHistoryByAlbumCount(
    List<DownloadHistoryItem> items,
    Map<String, int> albumCounts,
    int targetCount,
  ) {
    return items
        .where((item) {
          final key =
              '${item.albumName.toLowerCase()}|${(item.albumArtist ?? item.artistName).toLowerCase()}';
          final count = albumCounts[key] ?? 0;
          return targetCount == 1 ? count == 1 : count >= targetCount;
        })
        .toList(growable: false);
  }

  bool _shouldShowFilteringIndicator({
    required List<DownloadHistoryItem> allHistoryItems,
    required String filterMode,
  }) {
    if (allHistoryItems.isEmpty) return false;
    if (_searchQuery.isEmpty && filterMode == 'all') return false;
    if (allHistoryItems.length <= _filterIsolateThreshold) return false;
    return !_isFilterCacheValid(allHistoryItems, _searchQuery) ||
        _isFilteringHistory;
  }

  void _onFilterPageChanged(int index) {
    final filterMode = _filterModes[index];
    ref.read(settingsProvider.notifier).setHistoryFilterMode(filterMode);
  }

  void _animateToFilterPage(int index) {
    _filterPageController?.animateToPage(
      index,
      duration: const Duration(milliseconds: 300),
      curve: Curves.easeOutCubic,
    );
  }

  void _enterSelectionMode(String itemId) {
    HapticFeedback.mediumImpact();
    setState(() {
      _isPlaylistSelectionMode = false;
      _selectedPlaylistIds.clear();
      _isSelectionMode = true;
      _selectedIds.add(itemId);
    });
    _hidePlaylistSelectionOverlay();
  }

  void _exitSelectionMode() {
    setState(() {
      _isSelectionMode = false;
      _selectedIds.clear();
    });
    _hideSelectionOverlay();
  }

  void _toggleSelection(String itemId) {
    setState(() {
      if (_selectedIds.contains(itemId)) {
        _selectedIds.remove(itemId);
        if (_selectedIds.isEmpty) {
          _isSelectionMode = false;
        }
      } else {
        _selectedIds.add(itemId);
      }
    });
  }

  void _selectAll(List<UnifiedLibraryItem> items) {
    setState(() {
      _selectedIds.addAll(items.map((e) => e.id));
    });
  }

  void _hideSelectionOverlay() {
    _selectionOverlayEntry?.remove();
    _selectionOverlayEntry = null;
  }

  void _syncSelectionOverlay({
    required List<UnifiedLibraryItem> items,
    required double bottomPadding,
  }) {
    if (!mounted) return;
    if (!_isSelectionMode || _isPlaylistSelectionMode) {
      _hideSelectionOverlay();
      return;
    }

    _selectionOverlayItems = items;
    _selectionOverlayBottomPadding = bottomPadding;

    if (_selectionOverlayEntry != null) {
      _selectionOverlayEntry!.markNeedsBuild();
      return;
    }

    final overlay = Overlay.of(context, rootOverlay: true);
    _selectionOverlayEntry = OverlayEntry(
      builder: (overlayContext) {
        final colorScheme = Theme.of(context).colorScheme;
        return Positioned(
          left: 0,
          right: 0,
          bottom: 0,
          child: Material(
            color: Colors.transparent,
            child: _buildSelectionBottomBar(
              context,
              colorScheme,
              _selectionOverlayItems,
              _selectionOverlayBottomPadding,
            ),
          ),
        );
      },
    );
    overlay.insert(_selectionOverlayEntry!);
  }

  void _hidePlaylistSelectionOverlay() {
    _playlistSelectionOverlayEntry?.remove();
    _playlistSelectionOverlayEntry = null;
  }

  void _syncPlaylistSelectionOverlay({
    required List<UserPlaylistCollection> playlists,
    required double bottomPadding,
  }) {
    if (!mounted) return;
    if (!_isPlaylistSelectionMode || _isSelectionMode) {
      _hidePlaylistSelectionOverlay();
      return;
    }

    _playlistSelectionOverlayItems = playlists;
    _playlistSelectionOverlayBottomPadding = bottomPadding;

    if (_playlistSelectionOverlayEntry != null) {
      _playlistSelectionOverlayEntry!.markNeedsBuild();
      return;
    }

    final overlay = Overlay.of(context, rootOverlay: true);
    _playlistSelectionOverlayEntry = OverlayEntry(
      builder: (overlayContext) {
        final colorScheme = Theme.of(context).colorScheme;
        return Positioned(
          left: 0,
          right: 0,
          bottom: 0,
          child: Material(
            color: Colors.transparent,
            child: _buildPlaylistSelectionBottomBar(
              context,
              colorScheme,
              _playlistSelectionOverlayItems,
              _playlistSelectionOverlayBottomPadding,
            ),
          ),
        );
      },
    );
    overlay.insert(_playlistSelectionOverlayEntry!);
  }

  void _enterPlaylistSelectionMode(String playlistId) {
    HapticFeedback.mediumImpact();
    setState(() {
      _isSelectionMode = false;
      _selectedIds.clear();
      _isPlaylistSelectionMode = true;
      _selectedPlaylistIds.add(playlistId);
    });
    _hideSelectionOverlay();
  }

  void _exitPlaylistSelectionMode() {
    setState(() {
      _isPlaylistSelectionMode = false;
      _selectedPlaylistIds.clear();
    });
    _hidePlaylistSelectionOverlay();
  }

  void _togglePlaylistSelection(String playlistId) {
    setState(() {
      if (_selectedPlaylistIds.contains(playlistId)) {
        _selectedPlaylistIds.remove(playlistId);
        if (_selectedPlaylistIds.isEmpty) {
          _isPlaylistSelectionMode = false;
        }
      } else {
        _selectedPlaylistIds.add(playlistId);
      }
    });
  }

  void _selectAllPlaylists(List<UserPlaylistCollection> playlists) {
    setState(() {
      _selectedPlaylistIds.addAll(playlists.map((e) => e.id));
    });
  }

  Future<void> _downloadAllSelectedPlaylists(BuildContext context) async {
    final collectionsState = ref.read(libraryCollectionsProvider);
    final selectedPlaylists = collectionsState.playlists
        .where((p) => _selectedPlaylistIds.contains(p.id))
        .toList();

    final totalTracks = selectedPlaylists.fold<int>(
      0,
      (sum, p) => sum + p.tracks.length,
    );

    if (totalTracks == 0) {
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text(context.l10n.snackbarSelectedPlaylistsEmpty)),
      );
      return;
    }

    final confirmed = await showDialog<bool>(
      context: context,
      builder: (ctx) => AlertDialog(
        title: Text(ctx.l10n.dialogDownloadAllTitle),
        content: Text(
          ctx.l10n.dialogDownloadPlaylistsMessage(
            totalTracks,
            selectedPlaylists.length,
          ),
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(ctx, false),
            child: Text(ctx.l10n.dialogCancel),
          ),
          FilledButton(
            onPressed: () => Navigator.pop(ctx, true),
            child: Text(ctx.l10n.dialogDownload),
          ),
        ],
      ),
    );

    if (confirmed != true || !context.mounted) return;

    final settings = ref.read(settingsProvider);
    final queueNotifier = ref.read(downloadQueueProvider.notifier);

    void enqueueAll({String? qualityOverride, String? service}) {
      final svc = service ?? settings.defaultService;
      for (final playlist in selectedPlaylists) {
        final tracks = playlist.tracks.map((e) => e.track).toList();
        queueNotifier.addMultipleToQueue(
          tracks,
          svc,
          qualityOverride: qualityOverride,
          playlistName: playlist.name,
        );
      }
    }

    if (settings.askQualityBeforeDownload) {
      DownloadServicePicker.show(
        context,
        trackName: context.l10n.tracksCount(totalTracks),
        artistName: context.l10n.playlistsCount(selectedPlaylists.length),
        onSelect: (quality, service) {
          enqueueAll(qualityOverride: quality, service: service);
          if (!mounted) return;
          _exitPlaylistSelectionMode();
          ScaffoldMessenger.of(context).showSnackBar(
            SnackBar(
              content: Text(
                context.l10n.snackbarAddedTracksToQueue(totalTracks),
              ),
            ),
          );
        },
      );
    } else {
      enqueueAll();
      _exitPlaylistSelectionMode();
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(
          content: Text(context.l10n.snackbarAddedTracksToQueue(totalTracks)),
        ),
      );
    }
  }

  Future<void> _deleteSelectedPlaylists(BuildContext context) async {
    final count = _selectedPlaylistIds.length;
    final confirmed = await showDialog<bool>(
      context: context,
      builder: (ctx) => AlertDialog(
        title: Text(ctx.l10n.collectionDeletePlaylist),
        content: Text(
          'Delete $count ${count == 1 ? 'playlist' : 'playlists'}?',
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(ctx, false),
            child: Text(ctx.l10n.dialogCancel),
          ),
          FilledButton(
            onPressed: () => Navigator.pop(ctx, true),
            style: FilledButton.styleFrom(
              backgroundColor: Theme.of(context).colorScheme.error,
            ),
            child: Text(ctx.l10n.dialogDelete),
          ),
        ],
      ),
    );

    if (confirmed != true || !context.mounted) return;

    final notifier = ref.read(libraryCollectionsProvider.notifier);
    for (final id in _selectedPlaylistIds.toList()) {
      await notifier.deletePlaylist(id);
    }

    if (!context.mounted) return;
    _exitPlaylistSelectionMode();
    ScaffoldMessenger.of(context).showSnackBar(
      SnackBar(
        content: Text(
          '$count ${count == 1 ? 'playlist' : 'playlists'} deleted',
        ),
      ),
    );
  }

  Widget _buildPlaylistSelectionBottomBar(
    BuildContext context,
    ColorScheme colorScheme,
    List<UserPlaylistCollection> playlists,
    double bottomPadding,
  ) {
    final selectedCount = _selectedPlaylistIds.length;
    final allSelected =
        selectedCount == playlists.length && playlists.isNotEmpty;

    return Container(
      decoration: BoxDecoration(
        color: colorScheme.surfaceContainerHigh,
        borderRadius: const BorderRadius.vertical(top: Radius.circular(28)),
        boxShadow: [
          BoxShadow(
            color: Colors.black.withValues(alpha: 0.15),
            blurRadius: 12,
            offset: const Offset(0, -4),
          ),
        ],
      ),
      child: SafeArea(
        top: false,
        child: Padding(
          padding: EdgeInsets.fromLTRB(16, 16, 16, bottomPadding > 0 ? 8 : 16),
          child: Column(
            mainAxisSize: MainAxisSize.min,
            children: [
              Container(
                width: 32,
                height: 4,
                margin: const EdgeInsets.only(bottom: 16),
                decoration: BoxDecoration(
                  color: colorScheme.outlineVariant,
                  borderRadius: BorderRadius.circular(2),
                ),
              ),

              Row(
                children: [
                  IconButton.filledTonal(
                    onPressed: _exitPlaylistSelectionMode,
                    tooltip: MaterialLocalizations.of(
                      context,
                    ).closeButtonTooltip,
                    icon: const Icon(Icons.close),
                    style: IconButton.styleFrom(
                      backgroundColor: colorScheme.surfaceContainerHighest,
                    ),
                  ),
                  const SizedBox(width: 12),

                  Expanded(
                    child: Column(
                      crossAxisAlignment: CrossAxisAlignment.start,
                      children: [
                        Text(
                          context.l10n.selectionSelected(selectedCount),
                          style: Theme.of(context).textTheme.titleMedium
                              ?.copyWith(fontWeight: FontWeight.bold),
                        ),
                        Text(
                          allSelected
                              ? context.l10n.selectionAllPlaylistsSelected
                              : context.l10n.selectionTapPlaylistsToSelect,
                          style: Theme.of(context).textTheme.bodySmall
                              ?.copyWith(color: colorScheme.onSurfaceVariant),
                        ),
                      ],
                    ),
                  ),

                  TextButton.icon(
                    onPressed: () {
                      if (allSelected) {
                        _exitPlaylistSelectionMode();
                      } else {
                        _selectAllPlaylists(playlists);
                      }
                    },
                    icon: Icon(
                      allSelected ? Icons.deselect : Icons.select_all,
                      size: 20,
                    ),
                    label: Text(
                      allSelected
                          ? context.l10n.actionDeselect
                          : context.l10n.actionSelectAll,
                    ),
                    style: TextButton.styleFrom(
                      foregroundColor: colorScheme.primary,
                    ),
                  ),
                ],
              ),

              const SizedBox(height: 12),

              SizedBox(
                width: double.infinity,
                child: FilledButton.icon(
                  onPressed: selectedCount > 0
                      ? () => _downloadAllSelectedPlaylists(context)
                      : null,
                  icon: const Icon(Icons.download_rounded),
                  label: Text(
                    selectedCount > 0
                        ? context.l10n.bulkDownloadPlaylistsButton(
                            selectedCount,
                          )
                        : context.l10n.bulkDownloadSelectPlaylists,
                  ),
                  style: FilledButton.styleFrom(
                    backgroundColor: selectedCount > 0
                        ? colorScheme.primary
                        : colorScheme.surfaceContainerHighest,
                    foregroundColor: selectedCount > 0
                        ? colorScheme.onPrimary
                        : colorScheme.onSurfaceVariant,
                    padding: const EdgeInsets.symmetric(vertical: 16),
                    shape: RoundedRectangleBorder(
                      borderRadius: BorderRadius.circular(16),
                    ),
                  ),
                ),
              ),

              const SizedBox(height: 8),

              SizedBox(
                width: double.infinity,
                child: FilledButton.icon(
                  onPressed: selectedCount > 0
                      ? () => _deleteSelectedPlaylists(context)
                      : null,
                  icon: const Icon(Icons.delete_outline),
                  label: Text(
                    selectedCount > 0
                        ? 'Delete $selectedCount ${selectedCount == 1 ? 'playlist' : 'playlists'}'
                        : context.l10n.selectionSelectPlaylistsToDelete,
                  ),
                  style: FilledButton.styleFrom(
                    backgroundColor: selectedCount > 0
                        ? colorScheme.error
                        : colorScheme.surfaceContainerHighest,
                    foregroundColor: selectedCount > 0
                        ? colorScheme.onError
                        : colorScheme.onSurfaceVariant,
                    padding: const EdgeInsets.symmetric(vertical: 16),
                    shape: RoundedRectangleBorder(
                      borderRadius: BorderRadius.circular(16),
                    ),
                  ),
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }

  String _getQualityBadgeText(String quality) {
    final q = quality.trim().toLowerCase();
    if (q.contains('bit')) {
      return quality.split('/').first;
    }

    // Supports "MP3 320k", "Opus 256kbps", etc.
    final bitrateTextMatch = RegExp(
      r'(\d+)\s*k(?:bps)?',
      caseSensitive: false,
    ).firstMatch(quality);
    if (bitrateTextMatch != null) {
      return '${bitrateTextMatch.group(1)}k';
    }

    // Supports legacy quality IDs like "opus_256" / "mp3_320".
    final bitrateIdMatch = RegExp(r'_(\d+)$').firstMatch(q);
    if (bitrateIdMatch != null) {
      return '${bitrateIdMatch.group(1)}k';
    }

    return quality.split(' ').first;
  }

  Future<void> _deleteSelected(List<UnifiedLibraryItem> allItems) async {
    final count = _selectedIds.length;
    final confirmed = await showDialog<bool>(
      context: context,
      builder: (ctx) => AlertDialog(
        title: Text(context.l10n.dialogDeleteSelectedTitle),
        content: Text(context.l10n.dialogDeleteSelectedMessage(count)),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(ctx, false),
            child: Text(context.l10n.dialogCancel),
          ),
          FilledButton(
            onPressed: () => Navigator.pop(ctx, true),
            style: FilledButton.styleFrom(
              backgroundColor: Theme.of(context).colorScheme.error,
            ),
            child: Text(context.l10n.dialogDelete),
          ),
        ],
      ),
    );

    if (confirmed == true && mounted) {
      final historyNotifier = ref.read(downloadHistoryProvider.notifier);
      final localLibraryDb = LibraryDatabase.instance;
      final itemsById = {for (final item in allItems) item.id: item};

      int deletedCount = 0;
      for (final id in _selectedIds) {
        final item = itemsById[id];
        if (item != null) {
          try {
            final cleanPath = _cleanFilePath(item.filePath);
            await deleteFile(cleanPath);
          } catch (_) {}

          if (item.source == LibraryItemSource.downloaded) {
            historyNotifier.removeFromHistory(item.historyItem!.id);
          } else {
            await localLibraryDb.deleteByPath(item.filePath);
          }
          deletedCount++;
        }
      }

      // Reload local library if we deleted any local items
      if (allItems.any(
        (i) =>
            _selectedIds.contains(i.id) && i.source == LibraryItemSource.local,
      )) {
        ref.read(localLibraryProvider.notifier).reloadFromStorage();
      }

      _exitSelectionMode();

      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(
            content: Text(context.l10n.snackbarDeletedTracks(deletedCount)),
          ),
        );
      }
    }
  }

  /// Strip EXISTS: prefix from file path (legacy history items)
  String _cleanFilePath(String? filePath) {
    return DownloadedEmbeddedCoverResolver.cleanFilePath(filePath);
  }

  Future<int?> _readFileModTimeMillis(String? filePath) async {
    return DownloadedEmbeddedCoverResolver.readFileModTimeMillis(filePath);
  }

  void _onEmbeddedCoverChanged() {
    if (!mounted || _embeddedCoverRefreshScheduled) return;
    _embeddedCoverRefreshScheduled = true;
    WidgetsBinding.instance.addPostFrameCallback((_) {
      _embeddedCoverRefreshScheduled = false;
      if (mounted) {
        // Increment version to trigger ValueListenableBuilder rebuilds
        // on cover images only, instead of rebuilding the entire widget tree.
        _embeddedCoverVersion.value++;
      }
    });
  }

  Future<void> _scheduleDownloadedEmbeddedCoverRefreshForPath(
    String? filePath, {
    int? beforeModTime,
    bool force = false,
  }) async {
    await DownloadedEmbeddedCoverResolver.scheduleRefreshForPath(
      filePath,
      beforeModTime: beforeModTime,
      force: force,
      onChanged: _onEmbeddedCoverChanged,
    );
  }

  String? _resolveDownloadedEmbeddedCoverPath(String? filePath) {
    return DownloadedEmbeddedCoverResolver.resolve(
      filePath,
      onChanged: _onEmbeddedCoverChanged,
    );
  }

  ValueListenable<bool> _fileExistsListenable(String? filePath) {
    if (filePath == null) return _alwaysMissingFileNotifier;
    final cleanPath = _cleanFilePath(filePath);
    if (cleanPath.isEmpty) return _alwaysMissingFileNotifier;

    final existingNotifier = _fileExistsNotifiers[cleanPath];
    if (existingNotifier != null) {
      final cached = _fileExistsCache[cleanPath];
      if (cached != null && existingNotifier.value != cached) {
        existingNotifier.value = cached;
      } else if (cached == null) {
        _startFileExistsCheck(cleanPath);
      }
      return existingNotifier;
    }

    if (_fileExistsNotifiers.length >= _maxCacheSize) {
      final oldestKey = _fileExistsNotifiers.keys.first;
      _fileExistsNotifiers.remove(oldestKey)?.dispose();
      _fileExistsCache.remove(oldestKey);
    }

    final notifier = ValueNotifier<bool>(_fileExistsCache[cleanPath] ?? true);
    _fileExistsNotifiers[cleanPath] = notifier;
    _startFileExistsCheck(cleanPath);
    return notifier;
  }

  void _startFileExistsCheck(String cleanPath) {
    if (_pendingChecks.contains(cleanPath)) {
      return;
    }

    final cached = _fileExistsCache[cleanPath];
    if (cached != null) {
      final notifier = _fileExistsNotifiers[cleanPath];
      if (notifier != null && notifier.value != cached) {
        notifier.value = cached;
      }
      return;
    }

    _pendingChecks.add(cleanPath);
    Future.microtask(() async {
      final exists = await fileExists(cleanPath);
      _pendingChecks.remove(cleanPath);
      _fileExistsCache[cleanPath] = exists;
      final notifier = _fileExistsNotifiers[cleanPath];
      if (notifier != null && notifier.value != exists) {
        notifier.value = exists;
      }
    });
  }

  int get _activeFilterCount {
    int count = 0;
    if (_filterSource != null) count++;
    if (_filterQuality != null) count++;
    if (_filterFormat != null) count++;
    return count;
  }

  void _resetFilters() {
    setState(() {
      _filterSource = null;
      _filterQuality = null;
      _filterFormat = null;
      _sortMode = 'latest';
      _unifiedItemsCache.clear();
      _invalidateFilterContentCache();
    });
  }

  String _fileExtLower(String filePath) {
    final dotIndex = filePath.lastIndexOf('.');
    if (dotIndex < 0 || dotIndex == filePath.length - 1) {
      return '';
    }
    return filePath.substring(dotIndex + 1).toLowerCase();
  }

  List<UnifiedLibraryItem> _applyAdvancedFilters(
    List<UnifiedLibraryItem> items,
  ) {
    List<UnifiedLibraryItem> filtered;
    if (_activeFilterCount == 0) {
      filtered = items;
    } else {
      filtered = items
          .where((item) {
            if (_filterSource != null) {
              if (_filterSource == 'downloaded' &&
                  item.source != LibraryItemSource.downloaded) {
                return false;
              }
              if (_filterSource == 'local' &&
                  item.source != LibraryItemSource.local) {
                return false;
              }
            }

            if (_filterQuality != null && item.quality != null) {
              final quality = item.quality!.toLowerCase();
              switch (_filterQuality) {
                case 'hires':
                  if (!quality.startsWith('24')) return false;
                case 'cd':
                  if (!quality.startsWith('16')) return false;
                case 'lossy':
                  if (quality.startsWith('24') || quality.startsWith('16')) {
                    return false;
                  }
              }
            } else if (_filterQuality != null && item.quality == null) {
              if (_filterQuality != 'lossy') return false;
            }

            if (_filterFormat != null) {
              final ext = _fileExtLower(item.filePath);
              if (ext != _filterFormat) return false;
            }

            return true;
          })
          .toList(growable: false);
    }

    return _applySorting(filtered);
  }

  List<UnifiedLibraryItem> _applySorting(List<UnifiedLibraryItem> items) {
    if (_sortMode == 'latest') {
      return items; // Already sorted newest first from _getUnifiedItems
    }
    final sorted = List<UnifiedLibraryItem>.of(items);
    switch (_sortMode) {
      case 'oldest':
        sorted.sort((a, b) => a.addedAt.compareTo(b.addedAt));
      case 'a-z':
        sorted.sort(
          (a, b) =>
              a.trackName.toLowerCase().compareTo(b.trackName.toLowerCase()),
        );
      case 'z-a':
        sorted.sort(
          (a, b) =>
              b.trackName.toLowerCase().compareTo(a.trackName.toLowerCase()),
        );
    }
    return sorted;
  }

  Set<String> _getAvailableFormats(List<UnifiedLibraryItem> items) {
    final formats = <String>{};
    for (final item in items) {
      final ext = _fileExtLower(item.filePath);
      if (['flac', 'mp3', 'm4a', 'opus', 'ogg', 'wav', 'aiff'].contains(ext)) {
        formats.add(ext);
      }
    }
    return formats;
  }

  void _showFilterSheet(
    BuildContext context,
    List<UnifiedLibraryItem> allItems,
  ) {
    final colorScheme = Theme.of(context).colorScheme;
    final availableFormats = _getAvailableFormats(allItems);

    String? tempSource = _filterSource;
    String? tempQuality = _filterQuality;
    String? tempFormat = _filterFormat;
    String tempSortMode = _sortMode;

    showModalBottomSheet(
      context: context,
      useRootNavigator: true,
      isScrollControlled: true,
      backgroundColor: colorScheme.surfaceContainerLow,
      shape: const RoundedRectangleBorder(
        borderRadius: BorderRadius.vertical(top: Radius.circular(28)),
      ),
      builder: (context) => StatefulBuilder(
        builder: (context, setSheetState) {
          return SafeArea(
            child: LayoutBuilder(
              builder: (context, constraints) {
                final maxSheetHeight = constraints.maxHeight * 0.9;
                return ConstrainedBox(
                  constraints: BoxConstraints(maxHeight: maxSheetHeight),
                  child: Padding(
                    padding: const EdgeInsets.fromLTRB(16, 8, 16, 16),
                    child: SingleChildScrollView(
                      physics: const ClampingScrollPhysics(),
                      child: Column(
                        mainAxisSize: MainAxisSize.min,
                        crossAxisAlignment: CrossAxisAlignment.start,
                        children: [
                          Center(
                            child: Container(
                              width: 32,
                              height: 4,
                              margin: const EdgeInsets.only(bottom: 16),
                              decoration: BoxDecoration(
                                color: colorScheme.outlineVariant,
                                borderRadius: BorderRadius.circular(2),
                              ),
                            ),
                          ),

                          Row(
                            children: [
                              Text(
                                context.l10n.libraryFilterTitle,
                                style: Theme.of(context).textTheme.titleLarge
                                    ?.copyWith(fontWeight: FontWeight.bold),
                              ),
                              const Spacer(),
                              TextButton(
                                onPressed: () {
                                  setSheetState(() {
                                    tempSource = null;
                                    tempQuality = null;
                                    tempFormat = null;
                                    tempSortMode = 'latest';
                                  });
                                },
                                child: Text(context.l10n.libraryFilterReset),
                              ),
                            ],
                          ),
                          const SizedBox(height: 16),

                          Text(
                            context.l10n.libraryFilterSource,
                            style: Theme.of(context).textTheme.titleSmall
                                ?.copyWith(fontWeight: FontWeight.w600),
                          ),
                          const SizedBox(height: 8),
                          Wrap(
                            spacing: 8,
                            children: [
                              FilterChip(
                                label: Text(context.l10n.libraryFilterAll),
                                selected: tempSource == null,
                                onSelected: (_) =>
                                    setSheetState(() => tempSource = null),
                              ),
                              FilterChip(
                                label: Text(
                                  context.l10n.libraryFilterDownloaded,
                                ),
                                selected: tempSource == 'downloaded',
                                onSelected: (_) => setSheetState(
                                  () => tempSource = 'downloaded',
                                ),
                              ),
                              FilterChip(
                                label: Text(context.l10n.libraryFilterLocal),
                                selected: tempSource == 'local',
                                onSelected: (_) =>
                                    setSheetState(() => tempSource = 'local'),
                              ),
                            ],
                          ),
                          const SizedBox(height: 16),

                          Text(
                            context.l10n.libraryFilterQuality,
                            style: Theme.of(context).textTheme.titleSmall
                                ?.copyWith(fontWeight: FontWeight.w600),
                          ),
                          const SizedBox(height: 8),
                          Wrap(
                            spacing: 8,
                            children: [
                              FilterChip(
                                label: Text(context.l10n.libraryFilterAll),
                                selected: tempQuality == null,
                                onSelected: (_) =>
                                    setSheetState(() => tempQuality = null),
                              ),
                              FilterChip(
                                label: Text(
                                  context.l10n.libraryFilterQualityHiRes,
                                ),
                                selected: tempQuality == 'hires',
                                onSelected: (_) =>
                                    setSheetState(() => tempQuality = 'hires'),
                              ),
                              FilterChip(
                                label: Text(
                                  context.l10n.libraryFilterQualityCD,
                                ),
                                selected: tempQuality == 'cd',
                                onSelected: (_) =>
                                    setSheetState(() => tempQuality = 'cd'),
                              ),
                              FilterChip(
                                label: Text(
                                  context.l10n.libraryFilterQualityLossy,
                                ),
                                selected: tempQuality == 'lossy',
                                onSelected: (_) =>
                                    setSheetState(() => tempQuality = 'lossy'),
                              ),
                            ],
                          ),
                          const SizedBox(height: 16),

                          Text(
                            context.l10n.libraryFilterFormat,
                            style: Theme.of(context).textTheme.titleSmall
                                ?.copyWith(fontWeight: FontWeight.w600),
                          ),
                          const SizedBox(height: 8),
                          Wrap(
                            spacing: 8,
                            children: [
                              FilterChip(
                                label: Text(context.l10n.libraryFilterAll),
                                selected: tempFormat == null,
                                onSelected: (_) =>
                                    setSheetState(() => tempFormat = null),
                              ),
                              for (final format
                                  in availableFormats.toList()..sort())
                                FilterChip(
                                  label: Text(format.toUpperCase()),
                                  selected: tempFormat == format,
                                  onSelected: (_) =>
                                      setSheetState(() => tempFormat = format),
                                ),
                            ],
                          ),
                          const SizedBox(height: 16),

                          Text(
                            context.l10n.libraryFilterSort,
                            style: Theme.of(context).textTheme.titleSmall
                                ?.copyWith(fontWeight: FontWeight.w600),
                          ),
                          const SizedBox(height: 8),
                          Wrap(
                            spacing: 8,
                            children: [
                              FilterChip(
                                label: Text(
                                  context.l10n.libraryFilterSortLatest,
                                ),
                                selected: tempSortMode == 'latest',
                                onSelected: (_) => setSheetState(
                                  () => tempSortMode = 'latest',
                                ),
                              ),
                              FilterChip(
                                label: Text(
                                  context.l10n.libraryFilterSortOldest,
                                ),
                                selected: tempSortMode == 'oldest',
                                onSelected: (_) => setSheetState(
                                  () => tempSortMode = 'oldest',
                                ),
                              ),
                              FilterChip(
                                label: const Text('A-Z'),
                                selected: tempSortMode == 'a-z',
                                onSelected: (_) =>
                                    setSheetState(() => tempSortMode = 'a-z'),
                              ),
                              FilterChip(
                                label: const Text('Z-A'),
                                selected: tempSortMode == 'z-a',
                                onSelected: (_) =>
                                    setSheetState(() => tempSortMode = 'z-a'),
                              ),
                            ],
                          ),
                          const SizedBox(height: 24),

                          SizedBox(
                            width: double.infinity,
                            child: FilledButton(
                              onPressed: () {
                                setState(() {
                                  _filterSource = tempSource;
                                  _filterQuality = tempQuality;
                                  _filterFormat = tempFormat;
                                  _sortMode = tempSortMode;
                                  _unifiedItemsCache.clear();
                                  _invalidateFilterContentCache();
                                });
                                Navigator.pop(context);
                              },
                              child: Text(context.l10n.libraryFilterApply),
                            ),
                          ),
                        ],
                      ),
                    ),
                  ),
                );
              },
            ),
          );
        },
      ),
    );
  }

  Future<void> _openFile(
    String filePath, {
    String title = '',
    String artist = '',
    String album = '',
    String coverUrl = '',
  }) async {
    final cleanPath = _cleanFilePath(filePath);
    try {
      final fallbackTitle = cleanPath.split('/').last.split('\\').last;
      await ref
          .read(playbackProvider.notifier)
          .playLocalPath(
            path: cleanPath,
            title: title.isNotEmpty ? title : fallbackTitle,
            artist: artist,
            album: album,
            coverUrl: coverUrl,
          );
    } catch (e) {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(
            content: Text(context.l10n.snackbarCannotOpenFile(e.toString())),
          ),
        );
      }
    }
  }

  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,
    );
  }

  Future<void> _navigateToMetadataScreen(DownloadItem item) async {
    final historyItem = ref
        .read(downloadHistoryProvider)
        .items
        .firstWhere(
          (h) => h.filePath == item.filePath,
          orElse: () => DownloadHistoryItem(
            id: item.id,
            trackName: item.track.name,
            artistName: item.track.artistName,
            albumName: item.track.albumName,
            coverUrl: item.track.coverUrl,
            filePath: item.filePath ?? '',
            downloadedAt: DateTime.now(),
            service: item.service,
          ),
        );

    final navigator = Navigator.of(context);
    _precacheCover(historyItem.coverUrl);
    _searchFocusNode.unfocus();
    final beforeModTime = await _readFileModTimeMillis(historyItem.filePath);
    if (!mounted) return;
    final result = await navigator.push(
      slidePageRoute(page: TrackMetadataScreen(item: historyItem)),
    );
    _searchFocusNode.unfocus();
    if (result == true) {
      await _scheduleDownloadedEmbeddedCoverRefreshForPath(
        historyItem.filePath,
        beforeModTime: beforeModTime,
        force: true,
      );
      return;
    }
    await _scheduleDownloadedEmbeddedCoverRefreshForPath(
      historyItem.filePath,
      beforeModTime: beforeModTime,
    );
  }

  Future<void> _navigateToHistoryMetadataScreen(
    DownloadHistoryItem item,
  ) async {
    final navigator = Navigator.of(context);
    _precacheCover(item.coverUrl);
    _searchFocusNode.unfocus();
    final beforeModTime = await _readFileModTimeMillis(item.filePath);
    if (!mounted) return;
    final result = await navigator.push(
      slidePageRoute(page: TrackMetadataScreen(item: item)),
    );
    _searchFocusNode.unfocus();
    if (result == true) {
      await _scheduleDownloadedEmbeddedCoverRefreshForPath(
        item.filePath,
        beforeModTime: beforeModTime,
        force: true,
      );
      return;
    }
    await _scheduleDownloadedEmbeddedCoverRefreshForPath(
      item.filePath,
      beforeModTime: beforeModTime,
    );
  }

  void _navigateToLocalMetadataScreen(LocalLibraryItem item) {
    _searchFocusNode.unfocus();
    Navigator.push(
      context,
      slidePageRoute(page: TrackMetadataScreen(localItem: item)),
    ).then((_) => _searchFocusNode.unfocus());
  }

  List<DownloadHistoryItem> _filterHistoryItems(
    List<DownloadHistoryItem> items,
    String filterMode,
    Map<String, int> albumCounts, [
    String searchQuery = '',
  ]) {
    var filteredItems = items;
    if (searchQuery.isNotEmpty) {
      final query = searchQuery;
      filteredItems = items.where((item) {
        final searchKey = _historySearchKeyForItem(item);
        return searchKey.contains(query);
      }).toList();
    }

    if (filterMode == 'all') return filteredItems;

    switch (filterMode) {
      case 'albums':
        return filteredItems.where((item) {
          final key =
              '${item.albumName.toLowerCase()}|${(item.albumArtist ?? item.artistName).toLowerCase()}';
          return (albumCounts[key] ?? 0) > 1;
        }).toList();
      case 'singles':
        return filteredItems.where((item) {
          final key =
              '${item.albumName.toLowerCase()}|${(item.albumArtist ?? item.artistName).toLowerCase()}';
          return (albumCounts[key] ?? 0) == 1;
        }).toList();
      default:
        return filteredItems;
    }
  }

  /// Navigate with unfocus pattern — unfocuses search before and after navigation.
  void _navigateWithUnfocus(Route<dynamic> route) {
    _searchFocusNode.unfocus();
    Navigator.of(context).push(route).then((_) => _searchFocusNode.unfocus());
  }

  void _navigateToDownloadedAlbum(_GroupedAlbum album) {
    _navigateWithUnfocus(
      slidePageRoute(
        page: DownloadedAlbumScreen(
          albumName: album.albumName,
          artistName: album.artistName,
          coverUrl: album.coverUrl,
        ),
      ),
    );
  }

  void _navigateToLocalAlbum(_GroupedLocalAlbum album) {
    _navigateWithUnfocus(
      slidePageRoute(
        page: LocalAlbumScreen(
          albumName: album.albumName,
          artistName: album.artistName,
          coverPath: album.coverPath,
          tracks: album.tracks,
        ),
      ),
    );
  }

  void _openWishlistFolder() {
    _navigateWithUnfocus(
      MaterialPageRoute(
        builder: (_) => const LibraryTracksFolderScreen(
          mode: LibraryTracksFolderMode.wishlist,
        ),
      ),
    );
  }

  void _openLovedFolder() {
    _navigateWithUnfocus(
      MaterialPageRoute(
        builder: (_) => const LibraryTracksFolderScreen(
          mode: LibraryTracksFolderMode.loved,
        ),
      ),
    );
  }

  void _openPlaylistById(String playlistId) {
    _navigateWithUnfocus(
      MaterialPageRoute(
        builder: (_) => LibraryTracksFolderScreen(
          mode: LibraryTracksFolderMode.playlist,
          playlistId: playlistId,
        ),
      ),
    );
  }

  Future<void> _showCreatePlaylistDialog(BuildContext context) async {
    final controller = TextEditingController();
    final formKey = GlobalKey<FormState>();

    final playlistName = await showDialog<String>(
      context: context,
      builder: (dialogContext) {
        return AlertDialog(
          title: Text(dialogContext.l10n.collectionCreatePlaylist),
          content: Form(
            key: formKey,
            child: TextFormField(
              controller: controller,
              autofocus: true,
              decoration: InputDecoration(
                hintText: dialogContext.l10n.collectionPlaylistNameHint,
              ),
              validator: (value) {
                final trimmed = value?.trim() ?? '';
                if (trimmed.isEmpty) {
                  return dialogContext.l10n.collectionPlaylistNameRequired;
                }
                return null;
              },
              onFieldSubmitted: (_) {
                if (formKey.currentState?.validate() != true) return;
                Navigator.of(dialogContext).pop(controller.text.trim());
              },
            ),
          ),
          actions: [
            TextButton(
              onPressed: () => Navigator.of(dialogContext).pop(),
              child: Text(dialogContext.l10n.dialogCancel),
            ),
            FilledButton(
              onPressed: () {
                if (formKey.currentState?.validate() != true) return;
                Navigator.of(dialogContext).pop(controller.text.trim());
              },
              child: Text(dialogContext.l10n.actionCreate),
            ),
          ],
        );
      },
    );

    if (playlistName == null || playlistName.isEmpty) return;
    await ref
        .read(libraryCollectionsProvider.notifier)
        .createPlaylist(playlistName);
  }

  /// Build a playlist cover thumbnail (custom cover > first track cover > icon fallback).
  /// Pass a finite [size] (e.g. 56) for list view, or `null` for grid view
  /// where the widget should expand to fill its parent.
  Widget _buildPlaylistCover(
    BuildContext context,
    UserPlaylistCollection playlist,
    ColorScheme colorScheme, [
    double? size,
  ]) {
    final borderRadius = BorderRadius.circular(8);
    final dpr = MediaQuery.devicePixelRatioOf(context);
    final cacheExtent = size != null
        ? (size * dpr).round().clamp(64, 1024)
        : 420;
    final placeholder = _playlistIconFallback(colorScheme, size);

    final customCoverPath = playlist.coverImagePath;
    if (customCoverPath != null && customCoverPath.isNotEmpty) {
      return ClipRRect(
        borderRadius: borderRadius,
        child: Image.file(
          File(customCoverPath),
          width: size,
          height: size,
          fit: BoxFit.cover,
          cacheWidth: cacheExtent,
          gaplessPlayback: true,
          filterQuality: FilterQuality.low,
          frameBuilder: (_, child, frame, wasSynchronouslyLoaded) {
            if (wasSynchronouslyLoaded || frame != null) return child;
            return placeholder;
          },
          errorBuilder: (_, _, _) => placeholder,
        ),
      );
    }

    final firstCoverUrl = playlist.tracks
        .where((e) => e.track.coverUrl != null && e.track.coverUrl!.isNotEmpty)
        .map((e) => e.track.coverUrl!)
        .firstOrNull;

    if (firstCoverUrl != null) {
      // Guard against local file paths that may have been stored as coverUrl
      final isLocalPath =
          !firstCoverUrl.startsWith('http://') &&
          !firstCoverUrl.startsWith('https://');
      if (isLocalPath) {
        return ClipRRect(
          borderRadius: borderRadius,
          child: Image.file(
            File(firstCoverUrl),
            width: size,
            height: size,
            fit: BoxFit.cover,
            cacheWidth: cacheExtent,
            gaplessPlayback: true,
            filterQuality: FilterQuality.low,
            frameBuilder: (_, child, frame, wasSynchronouslyLoaded) {
              if (wasSynchronouslyLoaded || frame != null) return child;
              return placeholder;
            },
            errorBuilder: (_, _, _) => placeholder,
          ),
        );
      }
      return ClipRRect(
        borderRadius: borderRadius,
        child: CachedNetworkImage(
          imageUrl: firstCoverUrl,
          width: size,
          height: size,
          fit: BoxFit.cover,
          memCacheWidth: cacheExtent,
          cacheManager: CoverCacheManager.instance,
          placeholder: (_, _) => placeholder,
          errorWidget: (_, _, _) => placeholder,
        ),
      );
    }

    return placeholder;
  }

  /// Icon fallback for playlists with no cover.
  /// When [size] is null the container expands to fill its parent (grid view)
  /// and uses a fixed icon size.
  Widget _playlistIconFallback(ColorScheme colorScheme, [double? size]) {
    return Container(
      width: size,
      height: size,
      decoration: BoxDecoration(
        color: const Color(0xFF5085A5),
        borderRadius: BorderRadius.circular(8),
      ),
      child: Icon(
        Icons.queue_music,
        color: Colors.white,
        size: size != null ? size * 0.5 : 40,
      ),
    );
  }

  /// Handle a track being dropped onto a playlist.
  /// When selection mode is active and the dragged item is among the selected,
  /// all selected tracks are added to the playlist.
  Future<void> _onTrackDroppedOnPlaylist(
    BuildContext context,
    UnifiedLibraryItem item,
    String playlistId,
    String playlistName, {
    List<UnifiedLibraryItem> allItems = const [],
  }) async {
    final notifier = ref.read(libraryCollectionsProvider.notifier);

    // If in selection mode and the dragged item is selected, add ALL selected
    if (_isSelectionMode &&
        _selectedIds.isNotEmpty &&
        _selectedIds.contains(item.id)) {
      final selectedItems = allItems
          .where((e) => _selectedIds.contains(e.id))
          .toList();
      // Fallback: if allItems is empty or no match, at least add the dragged item
      if (selectedItems.isEmpty) {
        selectedItems.add(item);
      }

      final batchResult = await notifier.addTracksToPlaylist(
        playlistId,
        selectedItems.map((selected) => selected.toTrack()),
      );
      final addedCount = batchResult.addedCount;
      final alreadyCount = batchResult.alreadyInPlaylistCount;

      if (!context.mounted) return;
      final message = addedCount > 0
          ? 'Added $addedCount ${addedCount == 1 ? 'track' : 'tracks'} to $playlistName'
                '${alreadyCount > 0 ? ' ($alreadyCount already in playlist)' : ''}'
          : context.l10n.collectionAlreadyInPlaylist(playlistName);
      ScaffoldMessenger.of(
        context,
      ).showSnackBar(SnackBar(content: Text(message)));
      _exitSelectionMode();
      return;
    }

    final track = item.toTrack();
    final added = await notifier.addTrackToPlaylist(playlistId, track);

    if (!context.mounted) return;
    ScaffoldMessenger.of(context).showSnackBar(
      SnackBar(
        content: Text(
          added
              ? context.l10n.collectionAddedToPlaylist(playlistName)
              : context.l10n.collectionAlreadyInPlaylist(playlistName),
        ),
      ),
    );
  }

  /// Build a compact floating feedback widget shown while dragging a track.
  /// Shows the count when multiple tracks are selected and being dragged.
  Widget _buildDragFeedback(
    BuildContext context,
    UnifiedLibraryItem item,
    ColorScheme colorScheme,
  ) {
    final isDraggingMultiple =
        _isSelectionMode &&
        _selectedIds.contains(item.id) &&
        _selectedIds.length > 1;
    final count = isDraggingMultiple ? _selectedIds.length : 1;

    return Material(
      elevation: 6,
      borderRadius: BorderRadius.circular(12),
      color: colorScheme.surfaceContainerHighest,
      child: Padding(
        padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 8),
        child: Row(
          mainAxisSize: MainAxisSize.min,
          children: [
            Icon(Icons.playlist_add, size: 18, color: colorScheme.primary),
            const SizedBox(width: 8),
            ConstrainedBox(
              constraints: const BoxConstraints(maxWidth: 180),
              child: Text(
                isDraggingMultiple ? '$count tracks' : item.trackName,
                maxLines: 1,
                overflow: TextOverflow.ellipsis,
                style: Theme.of(
                  context,
                ).textTheme.bodySmall?.copyWith(fontWeight: FontWeight.w600),
              ),
            ),
          ],
        ),
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    _initializePageController();

    final hasQueueItems = ref.watch(
      downloadQueueLookupProvider.select((lookup) => lookup.itemIds.isNotEmpty),
    );
    final allHistoryItems = ref.watch(
      downloadHistoryProvider.select((s) => s.items),
    );
    final localLibraryEnabled = ref.watch(
      settingsProvider.select((s) => s.localLibraryEnabled),
    );
    final localLibraryItems = localLibraryEnabled
        ? ref.watch(localLibraryProvider.select((s) => s.items))
        : const <LocalLibraryItem>[];
    // Watch with selector on key fields to reduce unnecessary rebuilds.
    // LibraryCollectionsState doesn't implement == so watching without
    // selector rebuilds on every provider notification.
    ref.watch(
      libraryCollectionsProvider.select(
        (s) => (
          s.wishlistCount,
          s.lovedCount,
          s.playlistCount,
          s.hasPlaylistTracks,
          s.isLoaded,
        ),
      ),
    );
    final collectionState = ref.read(libraryCollectionsProvider);
    final historyStats = ref.watch(_queueHistoryStatsProvider);
    final filteredGrouped = ref.watch(
      _queueFilteredAlbumsProvider(
        _QueueGroupedAlbumFilterRequest(
          searchQuery: _searchQuery,
          filterSource: _filterSource,
          filterQuality: _filterQuality,
          filterFormat: _filterFormat,
          sortMode: _sortMode,
        ),
      ),
    );
    _ensureHistoryCaches(allHistoryItems, localLibraryItems, historyStats);
    final historyViewMode = ref.watch(
      settingsProvider.select((s) => s.historyViewMode),
    );
    final historyFilterMode = ref.watch(
      settingsProvider.select((s) => s.historyFilterMode),
    );
    final colorScheme = Theme.of(context).colorScheme;
    final topPadding = normalizedHeaderTopPadding(context);
    final filteredGroupedAlbums = filteredGrouped.albums;
    final filteredGroupedLocalAlbums = filteredGrouped.localAlbums;
    final albumCount = historyStats.totalAlbumCount;
    final singleCount = historyStats.totalSingleTracks;
    _prepareFilterContentCache(
      allHistoryItems: allHistoryItems,
      historyStats: historyStats,
      localLibraryItems: localLibraryItems,
      collectionState: collectionState,
    );

    _FilterContentData getFilterData(String filterMode) {
      return _filterContentDataCache.putIfAbsent(
        filterMode,
        () => _computeFilterContentData(
          filterMode: filterMode,
          allHistoryItems: allHistoryItems,
          filteredGroupedAlbums: filteredGroupedAlbums,
          filteredGroupedLocalAlbums: filteredGroupedLocalAlbums,
          albumCounts: historyStats.albumCounts,
          localAlbumCounts: historyStats.localAlbumCounts,
          localLibraryItems: localLibraryItems,
          collectionState: collectionState,
        ),
      );
    }

    final bottomPadding = MediaQuery.paddingOf(context).bottom;
    final selectionItems = getFilterData(
      historyFilterMode,
    ).filteredUnifiedItems;
    // Only sync overlays when selection mode is active
    if (_isSelectionMode || _isPlaylistSelectionMode) {
      WidgetsBinding.instance.addPostFrameCallback((_) {
        if (_isSelectionMode) {
          _syncSelectionOverlay(
            items: selectionItems,
            bottomPadding: bottomPadding,
          );
        }
        if (_isPlaylistSelectionMode) {
          _syncPlaylistSelectionOverlay(
            playlists: collectionState.playlists,
            bottomPadding: bottomPadding,
          );
        }
      });
    }

    return PopScope(
      canPop: !_isSelectionMode && !_isPlaylistSelectionMode,
      onPopInvokedWithResult: (didPop, result) {
        if (!didPop) {
          if (_isPlaylistSelectionMode) {
            _exitPlaylistSelectionMode();
          } else if (_isSelectionMode) {
            _exitSelectionMode();
          }
        }
      },
      child: Stack(
        children: [
          // ScrollConfiguration disables stretch overscroll to fix _StretchController exception
          // This is a known Flutter issue with NestedScrollView + Material 3 stretch indicator
          ScrollConfiguration(
            behavior: ScrollConfiguration.of(
              context,
            ).copyWith(overscroll: false),
            child: NestedScrollView(
              headerSliverBuilder: (context, innerBoxIsScrolled) => [
                SliverAppBar(
                  expandedHeight: 120 + topPadding,
                  collapsedHeight: kToolbarHeight,
                  floating: false,
                  pinned: true,
                  backgroundColor: colorScheme.surface,
                  surfaceTintColor: Colors.transparent,
                  automaticallyImplyLeading: false,
                  flexibleSpace: LayoutBuilder(
                    builder: (context, constraints) {
                      final maxHeight = 120 + topPadding;
                      final minHeight = kToolbarHeight + topPadding;
                      final expandRatio =
                          ((constraints.maxHeight - minHeight) /
                                  (maxHeight - minHeight))
                              .clamp(0.0, 1.0);

                      return FlexibleSpaceBar(
                        expandedTitleScale: 1.0,
                        titlePadding: const EdgeInsets.only(
                          left: 24,
                          bottom: 16,
                        ),
                        title: Text(
                          context.l10n.navLibrary,
                          style: TextStyle(
                            fontSize: 20 + (14 * expandRatio),
                            fontWeight: FontWeight.bold,
                            color: colorScheme.onSurface,
                          ),
                        ),
                      );
                    },
                  ),
                ),

                if (allHistoryItems.isNotEmpty ||
                    hasQueueItems ||
                    localLibraryItems.isNotEmpty)
                  SliverToBoxAdapter(
                    child: Padding(
                      padding: const EdgeInsets.fromLTRB(16, 8, 16, 0),
                      child: GestureDetector(
                        onTap: () {},
                        child: TextField(
                          controller: _searchController,
                          focusNode: _searchFocusNode,
                          autofocus: false,
                          canRequestFocus: true,
                          decoration: InputDecoration(
                            hintText: context.l10n.historySearchHint,
                            prefixIcon: const Icon(Icons.search),
                            suffixIcon: _searchQuery.isNotEmpty
                                ? IconButton(
                                    tooltip: 'Clear',
                                    icon: const Icon(Icons.clear),
                                    onPressed: () {
                                      _searchController.clear();
                                      _clearSearch();
                                      FocusScope.of(context).unfocus();
                                    },
                                  )
                                : null,
                            filled: true,
                            fillColor: colorScheme.surfaceContainerHighest,
                            border: OutlineInputBorder(
                              borderRadius: BorderRadius.circular(28),
                              borderSide: BorderSide(
                                color: colorScheme.outlineVariant,
                              ),
                            ),
                            enabledBorder: OutlineInputBorder(
                              borderRadius: BorderRadius.circular(28),
                              borderSide: BorderSide(
                                color: colorScheme.outlineVariant,
                              ),
                            ),
                            focusedBorder: OutlineInputBorder(
                              borderRadius: BorderRadius.circular(28),
                              borderSide: BorderSide(
                                color: colorScheme.primary,
                                width: 2,
                              ),
                            ),
                            contentPadding: const EdgeInsets.symmetric(
                              horizontal: 20,
                              vertical: 16,
                            ),
                          ),
                          onChanged: _onSearchChanged,
                          onTapOutside: (_) {
                            FocusScope.of(context).unfocus();
                          },
                        ),
                      ),
                    ),
                  ),

                if (hasQueueItems)
                  _buildQueueHeaderSliver(context, colorScheme),

                if (hasQueueItems) _buildQueueItemsSliver(context, colorScheme),

                if (allHistoryItems.isNotEmpty || localLibraryItems.isNotEmpty)
                  SliverToBoxAdapter(
                    child: Padding(
                      padding: const EdgeInsets.fromLTRB(16, 12, 16, 4),
                      child: Builder(
                        builder: (context) {
                          int filteredAllCount;
                          int filteredAlbumCount;
                          int filteredSingleCount;

                          if (_activeFilterCount == 0 && _searchQuery.isEmpty) {
                            filteredAllCount =
                                allHistoryItems.length +
                                localLibraryItems.length;
                            filteredAlbumCount = albumCount;
                            filteredSingleCount = singleCount;
                          } else {
                            final allData = getFilterData('all');
                            final albumsData = getFilterData('albums');
                            final singlesData = getFilterData('singles');
                            filteredAllCount = allData.totalTrackCount;
                            filteredAlbumCount = albumsData.totalAlbumCount;
                            filteredSingleCount = singlesData.totalTrackCount;
                          }

                          return SingleChildScrollView(
                            scrollDirection: Axis.horizontal,
                            child: Row(
                              children: [
                                _FilterChip(
                                  label: context.l10n.historyFilterAll,
                                  count: filteredAllCount,
                                  isSelected: historyFilterMode == 'all',
                                  onTap: () {
                                    _animateToFilterPage(0);
                                  },
                                ),
                                const SizedBox(width: 8),
                                _FilterChip(
                                  label: context.l10n.historyFilterAlbums,
                                  count: filteredAlbumCount,
                                  isSelected: historyFilterMode == 'albums',
                                  onTap: () {
                                    _animateToFilterPage(1);
                                  },
                                ),
                                const SizedBox(width: 8),
                                _FilterChip(
                                  label: context.l10n.historyFilterSingles,
                                  count: filteredSingleCount,
                                  isSelected: historyFilterMode == 'singles',
                                  onTap: () {
                                    _animateToFilterPage(2);
                                  },
                                ),
                              ],
                            ),
                          );
                        },
                      ),
                    ),
                  ),
              ],
              body: PageView.builder(
                controller: _filterPageController!,
                physics: const ClampingScrollPhysics(),
                onPageChanged: _onFilterPageChanged,
                itemCount: _filterModes.length,
                itemBuilder: (context, index) {
                  final filterMode = _filterModes[index];
                  final filterData = getFilterData(filterMode);
                  return _buildFilterContent(
                    context: context,
                    colorScheme: colorScheme,
                    filterMode: filterMode,
                    historyViewMode: historyViewMode,
                    hasQueueItems: hasQueueItems,
                    filterData: filterData,
                    localLibraryItems: localLibraryItems,
                    collectionState: collectionState,
                  );
                },
              ),
            ),
          ), // ScrollConfiguration
        ],
      ),
    );
  }

  List<UnifiedLibraryItem> _getUnifiedItems({
    required String filterMode,
    required List<DownloadHistoryItem> historyItems,
    required List<LocalLibraryItem> localLibraryItems,
    required Map<String, int> localAlbumCounts,
  }) {
    if (filterMode == 'albums') return const [];

    final query = _searchQuery;
    final cached = _unifiedItemsCache[filterMode];
    if (cached != null &&
        identical(cached.historyItems, historyItems) &&
        identical(cached.localItems, localLibraryItems) &&
        identical(cached.localAlbumCounts, localAlbumCounts) &&
        cached.query == query) {
      return cached.items;
    }

    final unifiedDownloaded = _unifiedDownloadedItems(historyItems);

    List<LocalLibraryItem> localItemsForMerge;
    if (filterMode == 'all') {
      localItemsForMerge = _filterLocalItems(localLibraryItems, query);
    } else {
      final localSingles = localLibraryItems
          .where((item) {
            final count = localAlbumCounts[item.albumKey] ?? 0;
            return count == 1;
          })
          .toList(growable: false);
      localItemsForMerge = _filterLocalItems(localSingles, query);
    }

    final unifiedLocal = _unifiedLocalItems(localItemsForMerge);
    final downloadedPathKeys = _downloadedPathKeys(historyItems);

    final dedupedUnifiedLocal = <UnifiedLibraryItem>[];
    for (final item in unifiedLocal) {
      final localPathKeys = buildPathMatchKeys(item.filePath);
      final overlapsDownloaded = localPathKeys.any(downloadedPathKeys.contains);
      if (!overlapsDownloaded) {
        dedupedUnifiedLocal.add(item);
      }
    }

    final merged = <UnifiedLibraryItem>[
      ...unifiedDownloaded,
      ...dedupedUnifiedLocal,
    ]..sort((a, b) => b.addedAt.compareTo(a.addedAt));

    _unifiedItemsCache[filterMode] = _UnifiedCacheEntry(
      historyItems: historyItems,
      localItems: localLibraryItems,
      localAlbumCounts: localAlbumCounts,
      query: query,
      items: merged,
    );

    return merged;
  }

  _FilterContentData _computeFilterContentData({
    required String filterMode,
    required List<DownloadHistoryItem> allHistoryItems,
    required List<_GroupedAlbum> filteredGroupedAlbums,
    required List<_GroupedLocalAlbum> filteredGroupedLocalAlbums,
    required Map<String, int> albumCounts,
    required Map<String, int> localAlbumCounts,
    required List<LocalLibraryItem> localLibraryItems,
    required LibraryCollectionsState collectionState,
  }) {
    final historyItems = _resolveHistoryItems(
      filterMode: filterMode,
      allHistoryItems: allHistoryItems,
      albumCounts: albumCounts,
    );
    final showFilteringIndicator = _shouldShowFilteringIndicator(
      allHistoryItems: allHistoryItems,
      filterMode: filterMode,
    );

    final unifiedItems = _getUnifiedItems(
      filterMode: filterMode,
      historyItems: historyItems,
      localLibraryItems: localLibraryItems,
      localAlbumCounts: localAlbumCounts,
    );
    final filtered = _applyAdvancedFilters(unifiedItems);

    // Remove tracks that are already in any playlist so they don't appear
    // in the main tracks list.  When a track is removed from a playlist (or
    // the playlist is deleted) it will automatically reappear here because it
    // will no longer be in the set.
    final filteredUnifiedItems = !collectionState.hasPlaylistTracks
        ? filtered
        : filtered
              .where(
                (item) =>
                    !collectionState.isTrackInAnyPlaylist(item.collectionKey),
              )
              .toList(growable: false);

    return _FilterContentData(
      historyItems: historyItems,
      unifiedItems: unifiedItems,
      filteredUnifiedItems: filteredUnifiedItems,
      filteredGroupedAlbums: filteredGroupedAlbums,
      filteredGroupedLocalAlbums: filteredGroupedLocalAlbums,
      showFilteringIndicator: showFilteringIndicator,
    );
  }

  Widget _buildQueueHeaderSliver(
    BuildContext context,
    ColorScheme colorScheme,
  ) {
    return Consumer(
      builder: (context, ref, child) {
        final queueCount = ref.watch(
          downloadQueueLookupProvider.select((lookup) => lookup.itemIds.length),
        );
        if (queueCount == 0) {
          return const SliverToBoxAdapter(child: SizedBox.shrink());
        }
        return SliverToBoxAdapter(
          child: Padding(
            padding: const EdgeInsets.fromLTRB(16, 12, 16, 8),
            child: Row(
              children: [
                Text(
                  context.l10n.queueDownloadingCount(queueCount),
                  style: Theme.of(context).textTheme.titleMedium?.copyWith(
                    fontWeight: FontWeight.bold,
                  ),
                ),
                const Spacer(),
                _buildPauseResumeButton(context, ref, colorScheme),
                const SizedBox(width: 4),
                _buildClearAllButton(context, ref, colorScheme),
              ],
            ),
          ),
        );
      },
    );
  }

  Widget _buildQueueItemsSliver(BuildContext context, ColorScheme colorScheme) {
    return Consumer(
      builder: (context, ref, child) {
        final queueIdsSnapshot = ref.watch(
          downloadQueueLookupProvider.select(
            (lookup) => _QueueItemIdsSnapshot(lookup.itemIds),
          ),
        );
        if (queueIdsSnapshot.ids.isEmpty) {
          return const SliverToBoxAdapter(child: SizedBox.shrink());
        }
        return SliverList(
          delegate: SliverChildBuilderDelegate((context, index) {
            final itemId = queueIdsSnapshot.ids[index];
            return _QueueItemSliverRow(
              key: ValueKey(itemId),
              itemId: itemId,
              colorScheme: colorScheme,
              itemBuilder: _buildQueueItem,
            );
          }, childCount: queueIdsSnapshot.ids.length),
        );
      },
    );
  }

  /// Build a Spotify-style collection list item (Wishlist, Loved, Playlists)
  Widget _buildCollectionListItem({
    required BuildContext context,
    required ColorScheme colorScheme,
    IconData? icon,
    Color? iconColor,
    Color? iconBgColor,
    Widget? coverWidget,
    required String title,
    required String subtitle,
    required VoidCallback onTap,
    VoidCallback? onLongPress,
  }) {
    final cover =
        coverWidget ??
        Container(
          width: 56,
          height: 56,
          decoration: BoxDecoration(
            color: iconBgColor ?? colorScheme.surfaceContainerHighest,
            borderRadius: BorderRadius.circular(8),
          ),
          child: Icon(
            icon ?? Icons.folder,
            color: iconColor ?? Colors.white,
            size: 28,
          ),
        );

    return Card(
      margin: const EdgeInsets.symmetric(horizontal: 16, vertical: 4),
      child: InkWell(
        onTap: onTap,
        onLongPress: onLongPress,
        borderRadius: BorderRadius.circular(12),
        child: Padding(
          padding: const EdgeInsets.all(12),
          child: Row(
            children: [
              SizedBox(width: 56, height: 56, child: cover),
              const SizedBox(width: 12),
              Expanded(
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    Text(
                      title,
                      maxLines: 1,
                      overflow: TextOverflow.ellipsis,
                      style: Theme.of(context).textTheme.titleSmall?.copyWith(
                        fontWeight: FontWeight.w600,
                      ),
                    ),
                    const SizedBox(height: 2),
                    Text(
                      subtitle,
                      maxLines: 1,
                      overflow: TextOverflow.ellipsis,
                      style: Theme.of(context).textTheme.bodySmall?.copyWith(
                        color: colorScheme.onSurfaceVariant,
                      ),
                    ),
                  ],
                ),
              ),
              Icon(
                Icons.chevron_right,
                color: colorScheme.onSurfaceVariant,
                size: 20,
              ),
            ],
          ),
        ),
      ),
    );
  }

  /// Build a collection grid item for grid view mode
  Widget _buildCollectionGridItem({
    required BuildContext context,
    required ColorScheme colorScheme,
    IconData? icon,
    Color? iconColor,
    Color? iconBgColor,
    Widget? coverWidget,
    required String title,
    required int count,
    required VoidCallback onTap,
    VoidCallback? onLongPress,
  }) {
    final cover =
        coverWidget ??
        Container(
          decoration: BoxDecoration(
            color: iconBgColor ?? colorScheme.surfaceContainerHighest,
            borderRadius: BorderRadius.circular(8),
          ),
          child: Icon(
            icon ?? Icons.folder,
            color: iconColor ?? Colors.white,
            size: 40,
          ),
        );

    return Semantics(
      button: true,
      label: 'Open $title, $count ${count == 1 ? 'item' : 'items'}',
      child: GestureDetector(
        onTap: onTap,
        onLongPress: onLongPress,
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            AspectRatio(
              aspectRatio: 1,
              child: ClipRRect(
                borderRadius: BorderRadius.circular(8),
                child: cover,
              ),
            ),
            const SizedBox(height: 6),
            Text(
              title,
              maxLines: 1,
              overflow: TextOverflow.ellipsis,
              style: Theme.of(
                context,
              ).textTheme.bodySmall?.copyWith(fontWeight: FontWeight.w500),
            ),
            Text(
              '$count ${count == 1 ? 'item' : 'items'}',
              maxLines: 1,
              overflow: TextOverflow.ellipsis,
              style: Theme.of(context).textTheme.labelSmall?.copyWith(
                color: colorScheme.onSurfaceVariant,
              ),
            ),
          ],
        ),
      ),
    );
  }

  /// Returns the visible collection entries, hiding Wishlist/Loved when empty.
  List<_CollectionEntry> _getVisibleCollectionEntries(
    LibraryCollectionsState collectionState,
  ) {
    final entries = <_CollectionEntry>[];
    if (collectionState.wishlistCount > 0) {
      entries.add(_CollectionEntry.wishlist);
    }
    if (collectionState.lovedCount > 0) {
      entries.add(_CollectionEntry.loved);
    }
    for (var i = 0; i < collectionState.playlists.length; i++) {
      entries.add(_CollectionEntry.playlist(i));
    }
    return entries;
  }

  /// Build a collection item for the unified "All" tab grid view.
  Widget _buildAllTabGridCollectionItem({
    required BuildContext context,
    required ColorScheme colorScheme,
    required _CollectionEntry entry,
    required LibraryCollectionsState collectionState,
    List<UnifiedLibraryItem> filteredUnifiedItems = const [],
  }) {
    switch (entry.type) {
      case _CollectionEntryType.wishlist:
        return _buildCollectionGridItem(
          context: context,
          colorScheme: colorScheme,
          icon: Icons.add_circle_outline,
          iconColor: Colors.white,
          iconBgColor: const Color(0xFF1DB954),
          title: context.l10n.collectionWishlist,
          count: collectionState.wishlistCount,
          onTap: _openWishlistFolder,
        );
      case _CollectionEntryType.loved:
        return _buildCollectionGridItem(
          context: context,
          colorScheme: colorScheme,
          icon: Icons.favorite,
          iconColor: Colors.white,
          iconBgColor: const Color(0xFF8C67AC),
          title: context.l10n.collectionLoved,
          count: collectionState.lovedCount,
          onTap: _openLovedFolder,
        );
      case _CollectionEntryType.playlist:
        final playlist = collectionState.playlists[entry.playlistIndex];
        final isSelected = _selectedPlaylistIds.contains(playlist.id);
        return DragTarget<UnifiedLibraryItem>(
          onWillAcceptWithDetails: (_) => !_isPlaylistSelectionMode,
          onAcceptWithDetails: (details) {
            _onTrackDroppedOnPlaylist(
              context,
              details.data,
              playlist.id,
              playlist.name,
              allItems: filteredUnifiedItems,
            );
          },
          builder: (context, candidateData, rejectedData) {
            final isHovering = candidateData.isNotEmpty;
            return AnimatedContainer(
              duration: const Duration(milliseconds: 150),
              decoration: isHovering
                  ? BoxDecoration(
                      borderRadius: BorderRadius.circular(12),
                      border: Border.all(color: colorScheme.primary, width: 2),
                      color: colorScheme.primary.withValues(alpha: 0.1),
                    )
                  : null,
              child: Stack(
                children: [
                  _buildCollectionGridItem(
                    context: context,
                    colorScheme: colorScheme,
                    coverWidget: _buildPlaylistCover(
                      context,
                      playlist,
                      colorScheme,
                    ),
                    title: playlist.name,
                    count: playlist.tracks.length,
                    onTap: _isPlaylistSelectionMode
                        ? () => _togglePlaylistSelection(playlist.id)
                        : () => _openPlaylistById(playlist.id),
                    onLongPress: _isPlaylistSelectionMode
                        ? () => _togglePlaylistSelection(playlist.id)
                        : () => _enterPlaylistSelectionMode(playlist.id),
                  ),
                  if (_isPlaylistSelectionMode)
                    Positioned(
                      left: 0,
                      top: 0,
                      right: 0,
                      child: IgnorePointer(
                        child: AspectRatio(
                          aspectRatio: 1,
                          child: Container(
                            decoration: BoxDecoration(
                              color: isSelected
                                  ? colorScheme.primary.withValues(alpha: 0.3)
                                  : Colors.transparent,
                              borderRadius: BorderRadius.circular(8),
                            ),
                          ),
                        ),
                      ),
                    ),
                  if (_isPlaylistSelectionMode)
                    Positioned(
                      top: 4,
                      right: 4,
                      child: IgnorePointer(
                        child: AnimatedSelectionCheckbox(
                          visible: true,
                          selected: isSelected,
                          colorScheme: colorScheme,
                          size: 20,
                          unselectedColor: colorScheme.surface.withValues(
                            alpha: 0.85,
                          ),
                        ),
                      ),
                    ),
                ],
              ),
            );
          },
        );
    }
  }

  /// Build a collection item for the unified "All" tab list view.
  Widget _buildAllTabListCollectionItem({
    required BuildContext context,
    required ColorScheme colorScheme,
    required _CollectionEntry entry,
    required LibraryCollectionsState collectionState,
    List<UnifiedLibraryItem> filteredUnifiedItems = const [],
  }) {
    switch (entry.type) {
      case _CollectionEntryType.wishlist:
        return _buildCollectionListItem(
          context: context,
          colorScheme: colorScheme,
          icon: Icons.add_circle_outline,
          iconColor: Colors.white,
          iconBgColor: const Color(0xFF1DB954),
          title: context.l10n.collectionWishlist,
          subtitle:
              '${context.l10n.collectionFoldersTitle} • ${collectionState.wishlistCount} ${collectionState.wishlistCount == 1 ? 'track' : 'tracks'}',
          onTap: _openWishlistFolder,
        );
      case _CollectionEntryType.loved:
        return _buildCollectionListItem(
          context: context,
          colorScheme: colorScheme,
          icon: Icons.favorite,
          iconColor: Colors.white,
          iconBgColor: const Color(0xFF8C67AC),
          title: context.l10n.collectionLoved,
          subtitle:
              '${context.l10n.collectionFoldersTitle} • ${collectionState.lovedCount} ${collectionState.lovedCount == 1 ? 'track' : 'tracks'}',
          onTap: _openLovedFolder,
        );
      case _CollectionEntryType.playlist:
        final playlist = collectionState.playlists[entry.playlistIndex];
        final isSelected = _selectedPlaylistIds.contains(playlist.id);
        return DragTarget<UnifiedLibraryItem>(
          onWillAcceptWithDetails: (_) => !_isPlaylistSelectionMode,
          onAcceptWithDetails: (details) {
            _onTrackDroppedOnPlaylist(
              context,
              details.data,
              playlist.id,
              playlist.name,
              allItems: filteredUnifiedItems,
            );
          },
          builder: (context, candidateData, rejectedData) {
            final isHovering = candidateData.isNotEmpty;
            return AnimatedContainer(
              duration: const Duration(milliseconds: 150),
              decoration: isHovering
                  ? BoxDecoration(
                      borderRadius: BorderRadius.circular(12),
                      border: Border.all(color: colorScheme.primary, width: 2),
                      color: colorScheme.primary.withValues(alpha: 0.1),
                    )
                  : null,
              child: Row(
                children: [
                  if (_isPlaylistSelectionMode)
                    GestureDetector(
                      onTap: () => _togglePlaylistSelection(playlist.id),
                      behavior: HitTestBehavior.opaque,
                      child: Padding(
                        padding: const EdgeInsets.only(left: 8),
                        child: AnimatedSelectionCheckbox(
                          visible: true,
                          selected: isSelected,
                          colorScheme: colorScheme,
                          size: 24,
                        ),
                      ),
                    ),
                  Expanded(
                    child: _buildCollectionListItem(
                      context: context,
                      colorScheme: colorScheme,
                      coverWidget: _buildPlaylistCover(
                        context,
                        playlist,
                        colorScheme,
                        56,
                      ),
                      title: playlist.name,
                      subtitle:
                          '${playlist.tracks.length} ${playlist.tracks.length == 1 ? 'track' : 'tracks'}',
                      onTap: _isPlaylistSelectionMode
                          ? () => _togglePlaylistSelection(playlist.id)
                          : () => _openPlaylistById(playlist.id),
                      onLongPress: _isPlaylistSelectionMode
                          ? () => _togglePlaylistSelection(playlist.id)
                          : () => _enterPlaylistSelectionMode(playlist.id),
                    ),
                  ),
                ],
              ),
            );
          },
        );
    }
  }

  Widget _buildFilterContent({
    required BuildContext context,
    required ColorScheme colorScheme,
    required String filterMode,
    required String historyViewMode,
    required bool hasQueueItems,
    required _FilterContentData filterData,
    required List<LocalLibraryItem> localLibraryItems,
    required LibraryCollectionsState collectionState,
  }) {
    final historyItems = filterData.historyItems;
    final showFilteringIndicator = filterData.showFilteringIndicator;
    final filteredGroupedAlbums = filterData.filteredGroupedAlbums;
    final filteredGroupedLocalAlbums = filterData.filteredGroupedLocalAlbums;
    final unifiedItems = filterData.unifiedItems;
    final filteredUnifiedItems = filterData.filteredUnifiedItems;
    final totalTrackCount = filterData.totalTrackCount;
    final totalAlbumCount = filterData.totalAlbumCount;

    return CustomScrollView(
      slivers: [
        if (totalTrackCount > 0 && filterMode == 'all')
          SliverToBoxAdapter(
            child: Padding(
              padding: const EdgeInsets.fromLTRB(16, 8, 16, 8),
              child: Row(
                children: [
                  Text(
                    context.l10n.queueTrackCount(totalTrackCount),
                    style: Theme.of(context).textTheme.bodyMedium?.copyWith(
                      color: colorScheme.onSurfaceVariant,
                    ),
                  ),
                  const Spacer(),
                  if (!_isSelectionMode)
                    _buildFilterButton(context, unifiedItems),
                  if (!_isSelectionMode && filteredUnifiedItems.isNotEmpty)
                    TextButton.icon(
                      onPressed: () => _showCreatePlaylistDialog(context),
                      icon: const Icon(Icons.add, size: 20),
                      label: Text(context.l10n.collectionCreatePlaylist),
                      style: TextButton.styleFrom(
                        visualDensity: VisualDensity.compact,
                      ),
                    ),
                ],
              ),
            ),
          ),

        // Collection folders as list items (Spotify-style) in "All" tab
        // are now rendered inline with tracks below (unified sliver)
        if ((filteredGroupedAlbums.isNotEmpty ||
                filteredGroupedLocalAlbums.isNotEmpty) &&
            filterMode == 'albums')
          SliverToBoxAdapter(
            child: Padding(
              padding: const EdgeInsets.fromLTRB(16, 8, 16, 8),
              child: Row(
                children: [
                  Text(
                    context.l10n.queueAlbumCount(totalAlbumCount),
                    style: Theme.of(context).textTheme.bodyMedium?.copyWith(
                      color: colorScheme.onSurfaceVariant,
                    ),
                  ),
                  const Spacer(),
                  _buildFilterButton(context, unifiedItems),
                ],
              ),
            ),
          ),

        if (filteredGroupedAlbums.isEmpty &&
            filteredGroupedLocalAlbums.isEmpty &&
            filterMode == 'albums' &&
            (historyItems.isNotEmpty || localLibraryItems.isNotEmpty))
          SliverToBoxAdapter(
            child: Padding(
              padding: const EdgeInsets.fromLTRB(16, 8, 16, 8),
              child: Row(
                children: [
                  const Spacer(),
                  _buildFilterButton(context, unifiedItems),
                ],
              ),
            ),
          ),

        if (historyItems.isNotEmpty && hasQueueItems)
          SliverToBoxAdapter(
            child: Padding(
              padding: const EdgeInsets.fromLTRB(16, 16, 16, 8),
              child: Text(
                context.l10n.queueDownloadedHeader,
                style: Theme.of(
                  context,
                ).textTheme.titleMedium?.copyWith(fontWeight: FontWeight.bold),
              ),
            ),
          ),

        if (showFilteringIndicator)
          SliverToBoxAdapter(
            child: Padding(
              padding: const EdgeInsets.fromLTRB(16, 12, 16, 8),
              child: Row(
                children: [
                  SizedBox(
                    width: 18,
                    height: 18,
                    child: CircularProgressIndicator(
                      strokeWidth: 2,
                      color: colorScheme.primary,
                    ),
                  ),
                  const SizedBox(width: 12),
                  Text(
                    context.l10n.queueFilteringIndicator,
                    style: Theme.of(context).textTheme.bodyMedium?.copyWith(
                      color: colorScheme.onSurfaceVariant,
                    ),
                  ),
                ],
              ),
            ),
          ),

        if (filterMode == 'albums' &&
            (filteredGroupedAlbums.isNotEmpty ||
                filteredGroupedLocalAlbums.isNotEmpty))
          SliverPadding(
            padding: const EdgeInsets.symmetric(horizontal: 16),
            sliver: SliverGrid(
              gridDelegate: const SliverGridDelegateWithFixedCrossAxisCount(
                crossAxisCount: 2,
                mainAxisSpacing: 12,
                crossAxisSpacing: 12,
                childAspectRatio: 0.75,
              ),
              delegate: SliverChildBuilderDelegate(
                (context, index) {
                  if (index < filteredGroupedAlbums.length) {
                    final album = filteredGroupedAlbums[index];
                    return KeyedSubtree(
                      key: ValueKey(album.key),
                      child: _buildAlbumGridItem(context, album, colorScheme),
                    );
                  } else {
                    final localIndex = index - filteredGroupedAlbums.length;
                    final album = filteredGroupedLocalAlbums[localIndex];
                    return KeyedSubtree(
                      key: ValueKey('local_${album.key}'),
                      child: _buildLocalAlbumGridItem(
                        context,
                        album,
                        colorScheme,
                      ),
                    );
                  }
                },
                childCount:
                    filteredGroupedAlbums.length +
                    filteredGroupedLocalAlbums.length,
              ),
            ),
          ),

        if (filterMode == 'all') ...[
          if (historyViewMode == 'grid')
            SliverPadding(
              padding: const EdgeInsets.symmetric(horizontal: 16),
              sliver: SliverGrid(
                gridDelegate: const SliverGridDelegateWithFixedCrossAxisCount(
                  crossAxisCount: 3,
                  mainAxisSpacing: 8,
                  crossAxisSpacing: 8,
                  childAspectRatio: 0.75,
                ),
                delegate: SliverChildBuilderDelegate(
                  (context, index) {
                    final collectionEntries = _getVisibleCollectionEntries(
                      collectionState,
                    );
                    final collectionCount = collectionEntries.length;
                    if (index < collectionCount) {
                      return _buildAllTabGridCollectionItem(
                        context: context,
                        colorScheme: colorScheme,
                        entry: collectionEntries[index],
                        collectionState: collectionState,
                        filteredUnifiedItems: filteredUnifiedItems,
                      );
                    }
                    final trackIndex = index - collectionCount;
                    if (trackIndex < filteredUnifiedItems.length) {
                      final item = filteredUnifiedItems[trackIndex];
                      return KeyedSubtree(
                        key: ValueKey(item.id),
                        child: LongPressDraggable<UnifiedLibraryItem>(
                          data: item,
                          feedback: _buildDragFeedback(
                            context,
                            item,
                            colorScheme,
                          ),
                          childWhenDragging: Opacity(
                            opacity: 0.4,
                            child: _buildUnifiedGridItem(
                              context,
                              item,
                              colorScheme,
                            ),
                          ),
                          child: _buildUnifiedGridItem(
                            context,
                            item,
                            colorScheme,
                          ),
                        ),
                      );
                    }
                    return const SizedBox.shrink();
                  },
                  childCount:
                      _getVisibleCollectionEntries(collectionState).length +
                      filteredUnifiedItems.length,
                ),
              ),
            )
          else
            SliverList(
              delegate: SliverChildBuilderDelegate(
                (context, index) {
                  final collectionEntries = _getVisibleCollectionEntries(
                    collectionState,
                  );
                  final collectionCount = collectionEntries.length;
                  if (index < collectionCount) {
                    return _buildAllTabListCollectionItem(
                      context: context,
                      colorScheme: colorScheme,
                      entry: collectionEntries[index],
                      collectionState: collectionState,
                      filteredUnifiedItems: filteredUnifiedItems,
                    );
                  }
                  final trackIndex = index - collectionCount;
                  if (trackIndex < filteredUnifiedItems.length) {
                    final item = filteredUnifiedItems[trackIndex];
                    return KeyedSubtree(
                      key: ValueKey(item.id),
                      child: LongPressDraggable<UnifiedLibraryItem>(
                        data: item,
                        feedback: _buildDragFeedback(
                          context,
                          item,
                          colorScheme,
                        ),
                        childWhenDragging: Opacity(
                          opacity: 0.4,
                          child: _buildUnifiedLibraryItem(
                            context,
                            item,
                            colorScheme,
                          ),
                        ),
                        child: _buildUnifiedLibraryItem(
                          context,
                          item,
                          colorScheme,
                        ),
                      ),
                    );
                  }
                  return const SizedBox.shrink();
                },
                childCount:
                    _getVisibleCollectionEntries(collectionState).length +
                    filteredUnifiedItems.length,
              ),
            ),
        ],

        if (filterMode == 'singles')
          SliverToBoxAdapter(
            child: Padding(
              padding: const EdgeInsets.fromLTRB(16, 8, 16, 8),
              child: Row(
                children: [
                  Text(
                    context.l10n.queueTrackCount(totalTrackCount),
                    style: Theme.of(context).textTheme.bodyMedium?.copyWith(
                      color: colorScheme.onSurfaceVariant,
                    ),
                  ),
                  const Spacer(),
                  if (!_isSelectionMode)
                    _buildFilterButton(context, unifiedItems),
                  if (!_isSelectionMode && filteredUnifiedItems.isNotEmpty)
                    TextButton.icon(
                      onPressed: () => _showCreatePlaylistDialog(context),
                      icon: const Icon(Icons.add, size: 20),
                      label: Text(context.l10n.collectionCreatePlaylist),
                      style: TextButton.styleFrom(
                        visualDensity: VisualDensity.compact,
                      ),
                    ),
                ],
              ),
            ),
          ),

        if (filteredUnifiedItems.isNotEmpty && filterMode == 'singles')
          historyViewMode == 'grid'
              ? SliverPadding(
                  padding: const EdgeInsets.symmetric(horizontal: 16),
                  sliver: SliverGrid(
                    gridDelegate:
                        const SliverGridDelegateWithFixedCrossAxisCount(
                          crossAxisCount: 3,
                          mainAxisSpacing: 8,
                          crossAxisSpacing: 8,
                          childAspectRatio: 0.75,
                        ),
                    delegate: SliverChildBuilderDelegate((context, index) {
                      final item = filteredUnifiedItems[index];
                      return KeyedSubtree(
                        key: ValueKey(item.id),
                        child: _buildUnifiedGridItem(
                          context,
                          item,
                          colorScheme,
                        ),
                      );
                    }, childCount: filteredUnifiedItems.length),
                  ),
                )
              : SliverList(
                  delegate: SliverChildBuilderDelegate((context, index) {
                    final item = filteredUnifiedItems[index];
                    return KeyedSubtree(
                      key: ValueKey(item.id),
                      child: _buildUnifiedLibraryItem(
                        context,
                        item,
                        colorScheme,
                      ),
                    );
                  }, childCount: filteredUnifiedItems.length),
                ),

        if (!hasQueueItems &&
            totalTrackCount == 0 &&
            (filterMode != 'albums' ||
                (filteredGroupedAlbums.isEmpty &&
                    filteredGroupedLocalAlbums.isEmpty)) &&
            !showFilteringIndicator)
          SliverFillRemaining(
            hasScrollBody: false,
            child: _buildEmptyState(context, colorScheme, filterMode),
          )
        else
          SliverToBoxAdapter(
            child: SizedBox(height: _isSelectionMode ? 100 : 16),
          ),
      ],
    );
  }

  Widget _buildPauseResumeButton(
    BuildContext context,
    WidgetRef ref,
    ColorScheme colorScheme,
  ) {
    final isPaused = ref.watch(downloadQueueProvider.select((s) => s.isPaused));

    return TextButton.icon(
      onPressed: () {
        ref.read(downloadQueueProvider.notifier).togglePause();
      },
      icon: Icon(isPaused ? Icons.play_arrow : Icons.pause, size: 18),
      label: Text(
        isPaused ? context.l10n.actionResume : context.l10n.actionPause,
      ),
      style: TextButton.styleFrom(
        visualDensity: VisualDensity.compact,
        foregroundColor: isPaused
            ? colorScheme.primary
            : colorScheme.onSurfaceVariant,
      ),
    );
  }

  Widget _buildClearAllButton(
    BuildContext context,
    WidgetRef ref,
    ColorScheme colorScheme,
  ) {
    return TextButton.icon(
      onPressed: () => _showClearAllDialog(context, ref, colorScheme),
      icon: const Icon(Icons.clear_all, size: 18),
      label: Text(context.l10n.queueClearAll),
      style: TextButton.styleFrom(
        visualDensity: VisualDensity.compact,
        foregroundColor: colorScheme.error,
      ),
    );
  }

  Future<void> _showClearAllDialog(
    BuildContext context,
    WidgetRef ref,
    ColorScheme colorScheme,
  ) async {
    final confirmed = await showDialog<bool>(
      context: context,
      builder: (ctx) => AlertDialog(
        title: Text(context.l10n.queueClearAll),
        content: Text(context.l10n.queueClearAllMessage),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(ctx, false),
            child: Text(context.l10n.dialogCancel),
          ),
          FilledButton(
            onPressed: () => Navigator.pop(ctx, true),
            style: FilledButton.styleFrom(backgroundColor: colorScheme.error),
            child: Text(context.l10n.dialogClear),
          ),
        ],
      ),
    );

    if (confirmed == true && context.mounted) {
      ref.read(downloadQueueProvider.notifier).clearAll();
    }
  }

  Widget _buildEmptyState(
    BuildContext context,
    ColorScheme colorScheme,
    String filterMode,
  ) {
    String message;
    String subtitle;
    IconData icon;

    switch (filterMode) {
      case 'albums':
        message = context.l10n.queueEmptyAlbums;
        subtitle = context.l10n.queueEmptyAlbumsSubtitle;
        icon = Icons.album;
        break;
      case 'singles':
        message = context.l10n.queueEmptySingles;
        subtitle = context.l10n.queueEmptySinglesSubtitle;
        icon = Icons.music_note;
        break;
      default:
        message = context.l10n.queueEmptyHistory;
        subtitle = context.l10n.queueEmptyHistorySubtitle;
        icon = Icons.history;
    }

    return Center(
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          Icon(icon, size: 64, color: colorScheme.onSurfaceVariant),
          const SizedBox(height: 16),
          Text(
            message,
            style: Theme.of(context).textTheme.bodyLarge?.copyWith(
              color: colorScheme.onSurfaceVariant,
            ),
          ),
          const SizedBox(height: 8),
          Text(
            subtitle,
            style: Theme.of(context).textTheme.bodyMedium?.copyWith(
              color: colorScheme.onSurfaceVariant.withValues(alpha: 0.7),
            ),
          ),
        ],
      ),
    );
  }

  Widget _buildAlbumGridItem(
    BuildContext context,
    _GroupedAlbum album,
    ColorScheme colorScheme,
  ) {
    return ValueListenableBuilder<int>(
      valueListenable: _embeddedCoverVersion,
      builder: (context, _, child) {
        final embeddedCoverPath = _resolveDownloadedEmbeddedCoverPath(
          album.sampleFilePath,
        );
        return _buildAlbumGridItemCore(
          context: context,
          albumName: album.albumName,
          artistName: album.artistName,
          trackCount: album.tracks.length,
          colorScheme: colorScheme,
          coverWidget: embeddedCoverPath != null
              ? Image.file(
                  File(embeddedCoverPath),
                  fit: BoxFit.cover,
                  width: double.infinity,
                  height: double.infinity,
                  cacheWidth: 300,
                  cacheHeight: 300,
                  errorBuilder: (context, error, stackTrace) =>
                      _albumPlaceholder(colorScheme),
                )
              : album.coverUrl != null
              ? CachedNetworkImage(
                  imageUrl: album.coverUrl!,
                  fit: BoxFit.cover,
                  width: double.infinity,
                  height: double.infinity,
                  memCacheWidth: 300,
                  memCacheHeight: 300,
                  cacheManager: CoverCacheManager.instance,
                )
              : null,
          badgeColor: colorScheme.primaryContainer,
          badgeTextColor: colorScheme.onPrimaryContainer,
          badgeIcon: Icons.music_note,
          coverUrl: album.coverUrl,
          onTap: () => _navigateToDownloadedAlbum(album),
        );
      },
    );
  }

  /// Album grid item for local library albums
  Widget _buildLocalAlbumGridItem(
    BuildContext context,
    _GroupedLocalAlbum album,
    ColorScheme colorScheme,
  ) {
    return _buildAlbumGridItemCore(
      context: context,
      albumName: album.albumName,
      artistName: album.artistName,
      trackCount: album.tracks.length,
      colorScheme: colorScheme,
      coverWidget: album.coverPath != null
          ? Image.file(
              File(album.coverPath!),
              fit: BoxFit.cover,
              width: double.infinity,
              height: double.infinity,
              cacheWidth: 300,
              cacheHeight: 300,
              errorBuilder: (context, error, stackTrace) =>
                  _albumPlaceholder(colorScheme),
            )
          : null,
      badgeColor: colorScheme.tertiaryContainer,
      badgeTextColor: colorScheme.onTertiaryContainer,
      badgeIcon: Icons.folder,
      onTap: () => _navigateToLocalAlbum(album),
    );
  }

  Widget _albumPlaceholder(ColorScheme colorScheme) {
    return Container(
      color: colorScheme.surfaceContainerHighest,
      child: Center(
        child: Icon(Icons.album, color: colorScheme.onSurfaceVariant, size: 48),
      ),
    );
  }

  Widget _buildAlbumGridItemCore({
    required BuildContext context,
    required String albumName,
    required String artistName,
    required int trackCount,
    required ColorScheme colorScheme,
    required Widget? coverWidget,
    required Color badgeColor,
    required Color badgeTextColor,
    required IconData badgeIcon,
    required VoidCallback onTap,
    String? coverUrl,
  }) {
    return Semantics(
      button: true,
      label: 'Open album $albumName by $artistName, $trackCount tracks',
      child: GestureDetector(
        onTap: onTap,
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Expanded(
              child: Stack(
                children: [
                  ClipRRect(
                    borderRadius: BorderRadius.circular(12),
                    child: coverWidget ?? _albumPlaceholder(colorScheme),
                  ),
                  Positioned(
                    right: 8,
                    bottom: 8,
                    child: Container(
                      padding: const EdgeInsets.symmetric(
                        horizontal: 8,
                        vertical: 4,
                      ),
                      decoration: BoxDecoration(
                        color: badgeColor,
                        borderRadius: BorderRadius.circular(12),
                      ),
                      child: Row(
                        mainAxisSize: MainAxisSize.min,
                        children: [
                          Icon(badgeIcon, size: 12, color: badgeTextColor),
                          const SizedBox(width: 4),
                          Text(
                            '$trackCount',
                            style: TextStyle(
                              color: badgeTextColor,
                              fontSize: 12,
                              fontWeight: FontWeight.bold,
                            ),
                          ),
                        ],
                      ),
                    ),
                  ),
                ],
              ),
            ),
            const SizedBox(height: 8),
            Text(
              albumName,
              maxLines: 1,
              overflow: TextOverflow.ellipsis,
              style: Theme.of(
                context,
              ).textTheme.bodyMedium?.copyWith(fontWeight: FontWeight.w600),
            ),
            ClickableArtistName(
              artistName: artistName,
              coverUrl: coverUrl,
              maxLines: 1,
              overflow: TextOverflow.ellipsis,
              style: Theme.of(context).textTheme.bodySmall?.copyWith(
                color: colorScheme.onSurfaceVariant,
              ),
            ),
          ],
        ),
      ),
    );
  }

  bool _hasTextValue(String? value) => value != null && value.trim().isNotEmpty;

  List<UnifiedLibraryItem> _selectedItemsFromAll(
    List<UnifiedLibraryItem> allItems,
  ) {
    final itemsById = {for (final item in allItems) item.id: item};
    return _selectedIds
        .map((id) => itemsById[id])
        .whereType<UnifiedLibraryItem>()
        .toList(growable: false);
  }

  bool _isLocalOnlySelection(List<UnifiedLibraryItem> allItems) {
    final selectedItems = _selectedItemsFromAll(allItems);
    return selectedItems.isNotEmpty &&
        selectedItems.every((item) => item.localItem != null);
  }

  Future<void> _safeDeleteTempFile(String path) async {
    try {
      final file = File(path);
      if (await file.exists()) {
        await file.delete();
      }
    } catch (_) {}
  }

  Future<void> _cleanupTempFileAndParentDir(String path) async {
    await _safeDeleteTempFile(path);
    try {
      final parent = File(path).parent;
      if (await parent.exists()) {
        await parent.delete();
      }
    } catch (_) {}
  }

  Future<bool> _applyQueueFfmpegReEnrichResult(
    LocalLibraryItem item,
    Map<String, dynamic> result,
  ) async {
    final tempPath = result['temp_path'] as String?;
    final safUri = result['saf_uri'] as String?;
    final ffmpegTarget = _hasTextValue(tempPath) ? tempPath! : item.filePath;
    final downloadedCoverPath = result['cover_path'] as String?;
    String? effectiveCoverPath = downloadedCoverPath;
    String? extractedCoverPath;

    if (!_hasTextValue(effectiveCoverPath)) {
      try {
        final tempDir = await Directory.systemTemp.createTemp(
          'reenrich_cover_',
        );
        final coverOutput = '${tempDir.path}${Platform.pathSeparator}cover.jpg';
        final extracted = await PlatformBridge.extractCoverToFile(
          ffmpegTarget,
          coverOutput,
        );
        if (extracted['error'] == null) {
          effectiveCoverPath = coverOutput;
          extractedCoverPath = coverOutput;
        } else {
          try {
            await tempDir.delete(recursive: true);
          } catch (_) {}
        }
      } catch (_) {}
    }

    final metadata = (result['metadata'] as Map<String, dynamic>?)?.map(
      (k, v) => MapEntry(k, v.toString()),
    );

    final format = item.format?.toLowerCase();
    final lowerPath = item.filePath.toLowerCase();
    final isMp3 = format == 'mp3' || lowerPath.endsWith('.mp3');
    final isM4A =
        format == 'm4a' ||
        format == 'aac' ||
        lowerPath.endsWith('.m4a') ||
        lowerPath.endsWith('.aac');
    final isOpus =
        format == 'opus' ||
        format == 'ogg' ||
        lowerPath.endsWith('.opus') ||
        lowerPath.endsWith('.ogg');

    String? ffmpegResult;
    if (isMp3) {
      ffmpegResult = await FFmpegService.embedMetadataToMp3(
        mp3Path: ffmpegTarget,
        coverPath: effectiveCoverPath,
        metadata: metadata,
      );
    } else if (isM4A) {
      ffmpegResult = await FFmpegService.embedMetadataToM4a(
        m4aPath: ffmpegTarget,
        coverPath: effectiveCoverPath,
        metadata: metadata,
      );
    } else if (isOpus) {
      ffmpegResult = await FFmpegService.embedMetadataToOpus(
        opusPath: ffmpegTarget,
        coverPath: effectiveCoverPath,
        metadata: metadata,
      );
    }

    if (ffmpegResult != null &&
        _hasTextValue(tempPath) &&
        _hasTextValue(safUri)) {
      final ok = await PlatformBridge.writeTempToSaf(ffmpegResult, safUri!);
      if (!ok) {
        if (_hasTextValue(downloadedCoverPath)) {
          await _safeDeleteTempFile(downloadedCoverPath!);
        }
        if (_hasTextValue(extractedCoverPath)) {
          await _cleanupTempFileAndParentDir(extractedCoverPath!);
        }
        await _safeDeleteTempFile(tempPath!);
        return false;
      }
    }

    if (_hasTextValue(downloadedCoverPath)) {
      await _safeDeleteTempFile(downloadedCoverPath!);
    }
    if (_hasTextValue(extractedCoverPath)) {
      await _cleanupTempFileAndParentDir(extractedCoverPath!);
    }
    if (_hasTextValue(tempPath)) {
      await _safeDeleteTempFile(tempPath!);
    }

    return ffmpegResult != null;
  }

  Future<bool> _reEnrichQueueLocalTrack(LocalLibraryItem item) async {
    final durationMs = (item.duration ?? 0) * 1000;
    final request = <String, dynamic>{
      'file_path': item.filePath,
      'cover_url': '',
      'max_quality': true,
      'embed_lyrics': true,
      'spotify_id': '',
      'track_name': item.trackName,
      'artist_name': item.artistName,
      'album_name': item.albumName,
      'album_artist': item.albumArtist ?? item.artistName,
      'track_number': item.trackNumber ?? 0,
      'disc_number': item.discNumber ?? 0,
      'release_date': item.releaseDate ?? '',
      'isrc': item.isrc ?? '',
      'genre': item.genre ?? '',
      'label': '',
      'copyright': '',
      'duration_ms': durationMs,
      'search_online': true,
    };

    final result = await PlatformBridge.reEnrichFile(request);
    final method = result['method'] as String?;
    if (method == 'native') {
      return true;
    }
    if (method == 'ffmpeg') {
      return _applyQueueFfmpegReEnrichResult(item, result);
    }
    return false;
  }

  List<LocalLibraryItem> _selectedFlacEligibleLocalItems(
    List<UnifiedLibraryItem> allItems,
  ) {
    final selectedItems = _selectedItemsFromAll(allItems);
    return selectedItems
        .map((item) => item.localItem)
        .whereType<LocalLibraryItem>()
        .where(LocalTrackRedownloadService.isFlacUpgradeEligible)
        .toList(growable: false);
  }

  Future<void> _queueSelectedLocalAsFlac(
    List<UnifiedLibraryItem> allItems,
  ) async {
    final selectedLocalItems = _selectedFlacEligibleLocalItems(allItems);

    if (selectedLocalItems.isEmpty) {
      return;
    }

    final confirmed = await showDialog<bool>(
      context: context,
      builder: (ctx) => AlertDialog(
        title: Text(context.l10n.queueFlacAction),
        content: Text(
          context.l10n.queueFlacConfirmMessage(selectedLocalItems.length),
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(ctx, false),
            child: Text(context.l10n.dialogCancel),
          ),
          FilledButton(
            onPressed: () => Navigator.pop(ctx, true),
            child: Text(context.l10n.queueFlacAction),
          ),
        ],
      ),
    );

    if (confirmed != true || !mounted) {
      return;
    }

    final settings = ref.read(settingsProvider);
    final extensionState = ref.read(extensionProvider);
    final includeExtensions =
        settings.useExtensionProviders &&
        extensionState.extensions.any(
          (ext) => ext.enabled && ext.hasMetadataProvider,
        );
    final targetService = LocalTrackRedownloadService.preferredFlacService(
      settings,
    );
    final targetQuality =
        LocalTrackRedownloadService.preferredFlacQualityForService(
          targetService,
        );

    final matchedTracks = <Track>[];
    var skippedCount = 0;
    final total = selectedLocalItems.length;

    for (var i = 0; i < total; i++) {
      if (!mounted) break;

      ScaffoldMessenger.of(context).clearSnackBars();
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(
          content: Text(context.l10n.queueFlacFindingProgress(i + 1, total)),
          duration: const Duration(seconds: 30),
        ),
      );

      try {
        final resolution = await LocalTrackRedownloadService.resolveBestMatch(
          selectedLocalItems[i],
          includeExtensions: includeExtensions,
        );
        if (resolution.canQueue && resolution.match != null) {
          matchedTracks.add(resolution.match!);
        } else {
          skippedCount++;
        }
      } catch (_) {
        skippedCount++;
      }
    }

    if (!mounted) {
      return;
    }

    ScaffoldMessenger.of(context).clearSnackBars();

    if (matchedTracks.isEmpty) {
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text(context.l10n.queueFlacNoReliableMatches)),
      );
      return;
    }

    ref
        .read(downloadQueueProvider.notifier)
        .addMultipleToQueue(
          matchedTracks,
          targetService,
          qualityOverride: targetQuality,
        );

    final summary = skippedCount == 0
        ? context.l10n.snackbarAddedTracksToQueue(matchedTracks.length)
        : context.l10n.queueFlacQueuedWithSkipped(
            matchedTracks.length,
            skippedCount,
          );

    ScaffoldMessenger.of(
      context,
    ).showSnackBar(SnackBar(content: Text(summary)));
    setState(() {
      _selectedIds.clear();
      _isSelectionMode = false;
    });
  }

  Future<void> _reEnrichSelectedLocalFromQueue(
    List<UnifiedLibraryItem> allItems,
  ) async {
    final selectedItems = _selectedItemsFromAll(allItems);
    final selectedLocalItems = selectedItems
        .map((item) => item.localItem)
        .whereType<LocalLibraryItem>()
        .toList(growable: false);

    if (selectedLocalItems.isEmpty) {
      return;
    }

    final confirmed = await showDialog<bool>(
      context: context,
      builder: (ctx) => AlertDialog(
        title: Text(context.l10n.trackReEnrich),
        content: Text(
          '${context.l10n.trackReEnrichOnlineSubtitle}\n\n'
          '${context.l10n.downloadedAlbumSelectedCount(selectedLocalItems.length)}',
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(ctx, false),
            child: Text(context.l10n.dialogCancel),
          ),
          FilledButton(
            onPressed: () => Navigator.pop(ctx, true),
            child: Text(context.l10n.trackReEnrich),
          ),
        ],
      ),
    );

    if (confirmed != true || !mounted) {
      return;
    }

    var successCount = 0;
    final total = selectedLocalItems.length;

    for (var i = 0; i < total; i++) {
      if (!mounted) break;
      final item = selectedLocalItems[i];

      ScaffoldMessenger.of(context).clearSnackBars();
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(
          content: Text(
            '${context.l10n.trackReEnrichProgress} (${i + 1}/$total)',
          ),
          duration: const Duration(seconds: 30),
        ),
      );

      try {
        final ok = await _reEnrichQueueLocalTrack(item);
        if (ok) {
          successCount++;
        }
      } catch (_) {}
    }

    if (!mounted) {
      return;
    }

    final settings = ref.read(settingsProvider);
    final localLibraryPath = settings.localLibraryPath.trim();
    final iosBookmark = settings.localLibraryBookmark;
    try {
      if (localLibraryPath.isNotEmpty &&
          !ref.read(localLibraryProvider).isScanning) {
        await ref
            .read(localLibraryProvider.notifier)
            .startScan(
              localLibraryPath,
              iosBookmark: iosBookmark.isNotEmpty ? iosBookmark : null,
            );
      } else {
        await ref.read(localLibraryProvider.notifier).reloadFromStorage();
      }
    } catch (_) {
      await ref.read(localLibraryProvider.notifier).reloadFromStorage();
    }

    _exitSelectionMode();

    if (!mounted) {
      return;
    }

    ScaffoldMessenger.of(context).clearSnackBars();
    final failedCount = total - successCount;
    final summary = failedCount <= 0
        ? '${context.l10n.trackReEnrichSuccess} ($successCount/$total)'
        : '${context.l10n.trackReEnrichSuccess} ($successCount/$total) • Failed: $failedCount';
    ScaffoldMessenger.of(
      context,
    ).showSnackBar(SnackBar(content: Text(summary)));
  }

  /// Share selected tracks via system share sheet
  Future<void> _shareSelected(List<UnifiedLibraryItem> allItems) async {
    final itemsById = {for (final item in allItems) item.id: item};
    final safUris = <String>[];
    final filesToShare = <XFile>[];

    for (final id in _selectedIds) {
      final item = itemsById[id];
      if (item == null) continue;
      final path = item.filePath;
      if (isContentUri(path)) {
        if (await fileExists(path)) safUris.add(path);
      } else if (await fileExists(path)) {
        filesToShare.add(XFile(path));
      }
    }

    if (safUris.isEmpty && filesToShare.isEmpty) {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text(context.l10n.selectionShareNoFiles)),
        );
      }
      return;
    }

    // Share SAF content URIs via native intent
    if (safUris.isNotEmpty) {
      try {
        if (safUris.length == 1) {
          await PlatformBridge.shareContentUri(safUris.first);
        } else {
          await PlatformBridge.shareMultipleContentUris(safUris);
        }
      } catch (_) {}
    }

    // Share regular files via SharePlus
    if (filesToShare.isNotEmpty) {
      await SharePlus.instance.share(ShareParams(files: filesToShare));
    }
  }

  /// Show batch convert bottom sheet for selected tracks
  Future<void> _showBatchConvertSheet(
    BuildContext context,
    List<UnifiedLibraryItem> allItems,
  ) async {
    final itemsById = {for (final item in allItems) item.id: item};
    final sourceFormats = <String>{};
    for (final id in _selectedIds) {
      final item = itemsById[id];
      if (item == null) continue;
      String nameToCheck;
      if (item.historyItem?.safFileName != null &&
          item.historyItem!.safFileName!.isNotEmpty) {
        nameToCheck = item.historyItem!.safFileName!.toLowerCase();
      } else if (item.localItem?.format != null &&
          item.localItem!.format!.isNotEmpty) {
        nameToCheck = '.${item.localItem!.format!.toLowerCase()}';
      } else {
        nameToCheck = item.filePath.toLowerCase();
      }
      final ext = nameToCheck.endsWith('.flac')
          ? 'FLAC'
          : nameToCheck.endsWith('.m4a')
          ? 'M4A'
          : nameToCheck.endsWith('.mp3')
          ? 'MP3'
          : (nameToCheck.endsWith('.opus') || nameToCheck.endsWith('.ogg'))
          ? 'Opus'
          : null;
      if (ext != null) sourceFormats.add(ext);
    }

    final formats = ['ALAC', 'FLAC', 'MP3', 'Opus'].where((target) {
      return sourceFormats.any((src) {
        if (src == target) return false;
        final isLosslessTarget = target == 'ALAC' || target == 'FLAC';
        final isLosslessSource = src == 'FLAC' || src == 'M4A';
        if (isLosslessTarget && !isLosslessSource) return false;
        return true;
      });
    }).toList();

    if (formats.isEmpty) return;

    String selectedFormat = formats.first;
    bool isLosslessTarget =
        selectedFormat == 'ALAC' || selectedFormat == 'FLAC';
    String selectedBitrate = isLosslessTarget
        ? '320k'
        : (selectedFormat == 'Opus' ? '128k' : '320k');
    var didStartConversion = false;

    _hideSelectionOverlay();
    _hidePlaylistSelectionOverlay();

    await showModalBottomSheet(
      context: context,
      useRootNavigator: true,
      shape: const RoundedRectangleBorder(
        borderRadius: BorderRadius.vertical(top: Radius.circular(20)),
      ),
      builder: (sheetContext) {
        return StatefulBuilder(
          builder: (context, setSheetState) {
            final colorScheme = Theme.of(context).colorScheme;
            final bitrates = ['128k', '192k', '256k', '320k'];

            return SafeArea(
              child: Padding(
                padding: const EdgeInsets.all(24),
                child: Column(
                  mainAxisSize: MainAxisSize.min,
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    Center(
                      child: Container(
                        width: 40,
                        height: 4,
                        decoration: BoxDecoration(
                          color: colorScheme.onSurfaceVariant.withValues(
                            alpha: 0.4,
                          ),
                          borderRadius: BorderRadius.circular(2),
                        ),
                      ),
                    ),
                    const SizedBox(height: 16),
                    Text(
                      context.l10n.selectionBatchConvertConfirmTitle,
                      style: Theme.of(context).textTheme.titleLarge?.copyWith(
                        fontWeight: FontWeight.bold,
                      ),
                    ),
                    const SizedBox(height: 20),
                    Text(
                      context.l10n.trackConvertTargetFormat,
                      style: Theme.of(context).textTheme.titleSmall?.copyWith(
                        color: colorScheme.onSurfaceVariant,
                      ),
                    ),
                    const SizedBox(height: 8),
                    Wrap(
                      spacing: 8,
                      children: formats.map((format) {
                        final isSelected = format == selectedFormat;
                        return ChoiceChip(
                          label: Text(format),
                          selected: isSelected,
                          onSelected: (selected) {
                            if (selected) {
                              setSheetState(() {
                                selectedFormat = format;
                                isLosslessTarget =
                                    format == 'ALAC' || format == 'FLAC';
                                if (!isLosslessTarget) {
                                  selectedBitrate = format == 'Opus'
                                      ? '128k'
                                      : '320k';
                                }
                              });
                            }
                          },
                        );
                      }).toList(),
                    ),
                    if (!isLosslessTarget) ...[
                      const SizedBox(height: 16),
                      Text(
                        context.l10n.trackConvertBitrate,
                        style: Theme.of(context).textTheme.titleSmall?.copyWith(
                          color: colorScheme.onSurfaceVariant,
                        ),
                      ),
                      const SizedBox(height: 8),
                      Wrap(
                        spacing: 8,
                        children: bitrates.map((br) {
                          final isSelected = br == selectedBitrate;
                          return ChoiceChip(
                            label: Text(br),
                            selected: isSelected,
                            onSelected: (selected) {
                              if (selected) {
                                setSheetState(() => selectedBitrate = br);
                              }
                            },
                          );
                        }).toList(),
                      ),
                    ],
                    if (isLosslessTarget) ...[
                      const SizedBox(height: 16),
                      Row(
                        children: [
                          Icon(
                            Icons.verified,
                            size: 16,
                            color: colorScheme.primary,
                          ),
                          const SizedBox(width: 6),
                          Text(
                            context.l10n.trackConvertLosslessHint,
                            style: Theme.of(context).textTheme.bodySmall
                                ?.copyWith(color: colorScheme.primary),
                          ),
                        ],
                      ),
                    ],
                    const SizedBox(height: 24),
                    SizedBox(
                      width: double.infinity,
                      child: FilledButton(
                        onPressed: () {
                          didStartConversion = true;
                          Navigator.pop(context);
                          _performBatchConversion(
                            allItems: allItems,
                            targetFormat: selectedFormat,
                            bitrate: selectedBitrate,
                          );
                        },
                        style: FilledButton.styleFrom(
                          padding: const EdgeInsets.symmetric(vertical: 16),
                          shape: RoundedRectangleBorder(
                            borderRadius: BorderRadius.circular(16),
                          ),
                        ),
                        child: Text(
                          context.l10n.selectionConvertCount(
                            _selectedIds.length,
                          ),
                        ),
                      ),
                    ),
                  ],
                ),
              ),
            );
          },
        );
      },
    );

    if (!mounted || didStartConversion) return;
    if (_isSelectionMode) {
      _syncSelectionOverlay(
        items: allItems,
        bottomPadding: MediaQuery.of(this.context).padding.bottom,
      );
    } else if (_isPlaylistSelectionMode) {
      _syncPlaylistSelectionOverlay(
        playlists: ref.read(libraryCollectionsProvider).playlists,
        bottomPadding: MediaQuery.of(this.context).padding.bottom,
      );
    }
  }

  /// Perform batch conversion on selected tracks
  Future<void> _performBatchConversion({
    required List<UnifiedLibraryItem> allItems,
    required String targetFormat,
    required String bitrate,
  }) async {
    final itemsById = {for (final item in allItems) item.id: item};
    final selectedItems = <UnifiedLibraryItem>[];
    for (final id in _selectedIds) {
      final item = itemsById[id];
      if (item == null) continue;
      String nameToCheck;
      if (item.historyItem?.safFileName != null &&
          item.historyItem!.safFileName!.isNotEmpty) {
        nameToCheck = item.historyItem!.safFileName!.toLowerCase();
      } else if (item.localItem?.format != null &&
          item.localItem!.format!.isNotEmpty) {
        nameToCheck = '.${item.localItem!.format!.toLowerCase()}';
      } else {
        nameToCheck = item.filePath.toLowerCase();
      }
      final ext = nameToCheck.endsWith('.flac')
          ? 'FLAC'
          : nameToCheck.endsWith('.m4a')
          ? 'M4A'
          : nameToCheck.endsWith('.mp3')
          ? 'MP3'
          : (nameToCheck.endsWith('.opus') || nameToCheck.endsWith('.ogg'))
          ? 'Opus'
          : null;
      if (ext == null || ext == targetFormat) continue;
      final isLosslessTarget = targetFormat == 'ALAC' || targetFormat == 'FLAC';
      final isLosslessSource = ext == 'FLAC' || ext == 'M4A';
      if (isLosslessTarget && !isLosslessSource) continue;
      selectedItems.add(item);
    }

    if (selectedItems.isEmpty) {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text(context.l10n.selectionConvertNoConvertible)),
        );
      }
      return;
    }

    final isLossless = targetFormat == 'ALAC' || targetFormat == 'FLAC';
    final confirmed = await showDialog<bool>(
      context: context,
      builder: (ctx) => AlertDialog(
        title: Text(context.l10n.selectionBatchConvertConfirmTitle),
        content: Text(
          isLossless
              ? context.l10n.selectionBatchConvertConfirmMessageLossless(
                  selectedItems.length,
                  targetFormat,
                )
              : context.l10n.selectionBatchConvertConfirmMessage(
                  selectedItems.length,
                  targetFormat,
                  bitrate,
                ),
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(ctx, false),
            child: Text(context.l10n.dialogCancel),
          ),
          FilledButton(
            onPressed: () => Navigator.pop(ctx, true),
            child: Text(context.l10n.trackConvertFormat),
          ),
        ],
      ),
    );

    if (confirmed != true || !mounted) return;

    int successCount = 0;
    final total = selectedItems.length;
    final historyDb = HistoryDatabase.instance;
    final newQuality =
        (targetFormat.toUpperCase() == 'ALAC' ||
            targetFormat.toUpperCase() == 'FLAC')
        ? '${targetFormat.toUpperCase()} Lossless'
        : '${targetFormat.toUpperCase()} ${bitrate.trim().toLowerCase()}';
    final settings = ref.read(settingsProvider);
    final shouldEmbedLyrics =
        settings.embedLyrics && settings.lyricsMode != 'external';

    for (int i = 0; i < total; i++) {
      if (!mounted) break;
      final item = selectedItems[i];

      ScaffoldMessenger.of(context).clearSnackBars();
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(
          content: Text(
            context.l10n.selectionBatchConvertProgress(i + 1, total),
          ),
          duration: const Duration(seconds: 30),
        ),
      );

      try {
        final metadata = <String, String>{
          'TITLE': item.trackName,
          'ARTIST': item.artistName,
          'ALBUM': item.albumName,
        };
        try {
          final result = await PlatformBridge.readFileMetadata(item.filePath);
          if (result['error'] == null) {
            mergePlatformMetadataForTagEmbed(target: metadata, source: result);
          }
        } catch (_) {}
        await ensureLyricsMetadataForConversion(
          metadata: metadata,
          sourcePath: item.filePath,
          shouldEmbedLyrics: shouldEmbedLyrics,
          trackName: item.trackName,
          artistName: item.artistName,
          spotifyId: item.historyItem?.spotifyId ?? '',
          durationMs:
              ((item.historyItem?.duration ?? item.localItem?.duration) ?? 0) *
              1000,
        );

        String? coverPath;
        try {
          final tempDir = await getTemporaryDirectory();
          final coverOutput =
              '${tempDir.path}${Platform.pathSeparator}batch_cover_${DateTime.now().millisecondsSinceEpoch}.jpg';
          final coverResult = await PlatformBridge.extractCoverToFile(
            item.filePath,
            coverOutput,
          );
          if (coverResult['error'] == null) {
            coverPath = coverOutput;
          }
        } catch (_) {}

        String workingPath = item.filePath;
        final isSaf = isContentUri(item.filePath);
        String? safTempPath;

        if (isSaf) {
          safTempPath = await PlatformBridge.copyContentUriToTemp(
            item.filePath,
          );
          if (safTempPath == null) continue;
          workingPath = safTempPath;
        }

        final newPath = await FFmpegService.convertAudioFormat(
          inputPath: workingPath,
          targetFormat: targetFormat.toLowerCase(),
          bitrate: bitrate,
          metadata: metadata,
          coverPath: coverPath,
          deleteOriginal: !isSaf,
        );

        if (coverPath != null) {
          try {
            await File(coverPath).delete();
          } catch (_) {}
        }

        if (newPath == null) {
          if (safTempPath != null) {
            try {
              await File(safTempPath).delete();
            } catch (_) {}
          }
          continue;
        }

        if (isSaf && item.historyItem != null) {
          final hi = item.historyItem!;
          final treeUri = hi.downloadTreeUri;
          final relativeDir = hi.safRelativeDir ?? '';
          if (treeUri != null && treeUri.isNotEmpty) {
            final oldFileName = hi.safFileName ?? '';
            final dotIdx = oldFileName.lastIndexOf('.');
            final baseName = dotIdx > 0
                ? oldFileName.substring(0, dotIdx)
                : oldFileName;
            String newExt;
            String mimeType;
            switch (targetFormat.toLowerCase()) {
              case 'opus':
                newExt = '.opus';
                mimeType = 'audio/opus';
                break;
              case 'alac':
                newExt = '.m4a';
                mimeType = 'audio/mp4';
                break;
              case 'flac':
                newExt = '.flac';
                mimeType = 'audio/flac';
                break;
              default:
                newExt = '.mp3';
                mimeType = 'audio/mpeg';
                break;
            }
            final newFileName = '$baseName$newExt';

            final safUri = await PlatformBridge.createSafFileFromPath(
              treeUri: treeUri,
              relativeDir: relativeDir,
              fileName: newFileName,
              mimeType: mimeType,
              srcPath: newPath,
            );

            if (safUri == null || safUri.isEmpty) {
              try {
                await File(newPath).delete();
              } catch (_) {}
              if (safTempPath != null) {
                try {
                  await File(safTempPath).delete();
                } catch (_) {}
              }
              continue;
            }

            try {
              await PlatformBridge.safDelete(item.filePath);
            } catch (_) {}

            await historyDb.updateFilePath(
              hi.id,
              safUri,
              newSafFileName: newFileName,
              newQuality: newQuality,
              clearAudioSpecs: true,
            );
          }
          try {
            await File(newPath).delete();
          } catch (_) {}
          if (safTempPath != null) {
            try {
              await File(safTempPath).delete();
            } catch (_) {}
          }
        } else if (isSaf && item.localItem != null) {
          final uri = Uri.parse(item.filePath);
          final pathSegments = uri.pathSegments;

          String? treeUri;
          String relativeDir = '';
          String oldFileName = '';

          final treeIdx = pathSegments.indexOf('tree');
          final docIdx = pathSegments.indexOf('document');
          if (treeIdx >= 0 && treeIdx + 1 < pathSegments.length) {
            final treeId = pathSegments[treeIdx + 1];
            treeUri =
                'content://${uri.authority}/tree/${Uri.encodeComponent(treeId)}';
          }
          if (docIdx >= 0 && docIdx + 1 < pathSegments.length) {
            final docPath = Uri.decodeFull(pathSegments[docIdx + 1]);
            final slashIdx = docPath.lastIndexOf('/');
            if (slashIdx >= 0) {
              oldFileName = docPath.substring(slashIdx + 1);
              final treeId = treeIdx >= 0 && treeIdx + 1 < pathSegments.length
                  ? Uri.decodeFull(pathSegments[treeIdx + 1])
                  : '';
              if (treeId.isNotEmpty && docPath.startsWith(treeId)) {
                final afterTree = docPath.substring(treeId.length);
                final trimmed = afterTree.startsWith('/')
                    ? afterTree.substring(1)
                    : afterTree;
                final lastSlash = trimmed.lastIndexOf('/');
                relativeDir = lastSlash >= 0
                    ? trimmed.substring(0, lastSlash)
                    : '';
              }
            } else {
              oldFileName = docPath;
            }
          }

          if (treeUri != null && oldFileName.isNotEmpty) {
            final dotIdx = oldFileName.lastIndexOf('.');
            final baseName = dotIdx > 0
                ? oldFileName.substring(0, dotIdx)
                : oldFileName;
            final newExt = targetFormat.toLowerCase() == 'opus'
                ? '.opus'
                : '.mp3';
            final newFileName = '$baseName$newExt';
            final mimeType = targetFormat.toLowerCase() == 'opus'
                ? 'audio/opus'
                : 'audio/mpeg';

            final safUri = await PlatformBridge.createSafFileFromPath(
              treeUri: treeUri,
              relativeDir: relativeDir,
              fileName: newFileName,
              mimeType: mimeType,
              srcPath: newPath,
            );

            if (safUri == null || safUri.isEmpty) {
              try {
                await File(newPath).delete();
              } catch (_) {}
              if (safTempPath != null) {
                try {
                  await File(safTempPath).delete();
                } catch (_) {}
              }
              continue;
            }

            try {
              await PlatformBridge.safDelete(item.filePath);
            } catch (_) {}
            await LibraryDatabase.instance.deleteByPath(item.filePath);
          }

          try {
            await File(newPath).delete();
          } catch (_) {}
          if (safTempPath != null) {
            try {
              await File(safTempPath).delete();
            } catch (_) {}
          }
        } else if (item.historyItem != null) {
          await historyDb.updateFilePath(
            item.historyItem!.id,
            newPath,
            newQuality: newQuality,
            clearAudioSpecs: true,
          );
        } else if (item.localItem != null) {
          await LibraryDatabase.instance.deleteByPath(item.filePath);
        }

        successCount++;
      } catch (_) {}
    }

    ref.read(downloadHistoryProvider.notifier).reloadFromStorage();
    ref.read(localLibraryProvider.notifier).reloadFromStorage();

    _exitSelectionMode();

    if (mounted) {
      ScaffoldMessenger.of(context).clearSnackBars();
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(
          content: Text(
            context.l10n.selectionBatchConvertSuccess(
              successCount,
              total,
              targetFormat,
            ),
          ),
        ),
      );
    }
  }

  Widget _buildSelectionBottomBar(
    BuildContext context,
    ColorScheme colorScheme,
    List<UnifiedLibraryItem> unifiedItems,
    double bottomPadding,
  ) {
    final selectedCount = _selectedIds.length;
    final allSelected =
        selectedCount == unifiedItems.length && unifiedItems.isNotEmpty;
    final localOnlySelection = _isLocalOnlySelection(unifiedItems);
    final flacEligibleCount = _selectedFlacEligibleLocalItems(
      unifiedItems,
    ).length;

    return Container(
      decoration: BoxDecoration(
        color: colorScheme.surfaceContainerHigh,
        borderRadius: const BorderRadius.vertical(top: Radius.circular(28)),
        boxShadow: [
          BoxShadow(
            color: Colors.black.withValues(alpha: 0.15),
            blurRadius: 12,
            offset: const Offset(0, -4),
          ),
        ],
      ),
      child: SafeArea(
        top: false,
        child: Padding(
          padding: EdgeInsets.fromLTRB(16, 16, 16, bottomPadding > 0 ? 8 : 16),
          child: Column(
            mainAxisSize: MainAxisSize.min,
            children: [
              Container(
                width: 32,
                height: 4,
                margin: const EdgeInsets.only(bottom: 16),
                decoration: BoxDecoration(
                  color: colorScheme.outlineVariant,
                  borderRadius: BorderRadius.circular(2),
                ),
              ),

              Row(
                children: [
                  IconButton.filledTonal(
                    onPressed: _exitSelectionMode,
                    tooltip: MaterialLocalizations.of(
                      context,
                    ).closeButtonTooltip,
                    icon: const Icon(Icons.close),
                    style: IconButton.styleFrom(
                      backgroundColor: colorScheme.surfaceContainerHighest,
                    ),
                  ),
                  const SizedBox(width: 12),

                  Expanded(
                    child: Column(
                      crossAxisAlignment: CrossAxisAlignment.start,
                      children: [
                        Text(
                          context.l10n.selectionSelected(selectedCount),
                          style: Theme.of(context).textTheme.titleMedium
                              ?.copyWith(fontWeight: FontWeight.bold),
                        ),
                        Text(
                          allSelected
                              ? context.l10n.selectionAllSelected
                              : context.l10n.downloadedAlbumTapToSelect,
                          style: Theme.of(context).textTheme.bodySmall
                              ?.copyWith(color: colorScheme.onSurfaceVariant),
                        ),
                      ],
                    ),
                  ),

                  TextButton.icon(
                    onPressed: () {
                      if (allSelected) {
                        _exitSelectionMode();
                      } else {
                        _selectAll(unifiedItems);
                      }
                    },
                    icon: Icon(
                      allSelected ? Icons.deselect : Icons.select_all,
                      size: 20,
                    ),
                    label: Text(
                      allSelected
                          ? context.l10n.actionDeselect
                          : context.l10n.actionSelectAll,
                    ),
                    style: TextButton.styleFrom(
                      foregroundColor: colorScheme.primary,
                    ),
                  ),
                ],
              ),

              const SizedBox(height: 12),

              Row(
                children: [
                  if (localOnlySelection && flacEligibleCount > 0) ...[
                    Expanded(
                      child: _SelectionActionButton(
                        icon: Icons.download_for_offline_outlined,
                        label:
                            '${context.l10n.queueFlacAction} ($flacEligibleCount)',
                        onPressed: () =>
                            _queueSelectedLocalAsFlac(unifiedItems),
                        colorScheme: colorScheme,
                      ),
                    ),
                    const SizedBox(width: 8),
                  ],
                  Expanded(
                    child: _SelectionActionButton(
                      icon: localOnlySelection
                          ? Icons.auto_fix_high_outlined
                          : Icons.share_outlined,
                      label: localOnlySelection
                          ? '${context.l10n.trackReEnrich} ($selectedCount)'
                          : context.l10n.selectionShareCount(selectedCount),
                      onPressed: selectedCount > 0
                          ? () => localOnlySelection
                                ? _reEnrichSelectedLocalFromQueue(unifiedItems)
                                : _shareSelected(unifiedItems)
                          : null,
                      colorScheme: colorScheme,
                    ),
                  ),
                  const SizedBox(width: 8),
                  Expanded(
                    child: _SelectionActionButton(
                      icon: Icons.swap_horiz,
                      label: context.l10n.selectionConvertCount(selectedCount),
                      onPressed: selectedCount > 0
                          ? () => _showBatchConvertSheet(context, unifiedItems)
                          : null,
                      colorScheme: colorScheme,
                    ),
                  ),
                ],
              ),

              const SizedBox(height: 8),

              SizedBox(
                width: double.infinity,
                child: FilledButton.icon(
                  onPressed: selectedCount > 0
                      ? () => _deleteSelected(unifiedItems)
                      : null,
                  icon: const Icon(Icons.delete_outline),
                  label: Text(
                    selectedCount > 0
                        ? 'Delete $selectedCount ${selectedCount == 1 ? 'track' : 'tracks'}'
                        : context.l10n.selectionSelectToDelete,
                  ),
                  style: FilledButton.styleFrom(
                    backgroundColor: selectedCount > 0
                        ? colorScheme.error
                        : colorScheme.surfaceContainerHighest,
                    foregroundColor: selectedCount > 0
                        ? colorScheme.onError
                        : colorScheme.onSurfaceVariant,
                    padding: const EdgeInsets.symmetric(vertical: 16),
                    shape: RoundedRectangleBorder(
                      borderRadius: BorderRadius.circular(16),
                    ),
                  ),
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }

  Widget _buildQueueItem(
    BuildContext context,
    DownloadItem item,
    ColorScheme colorScheme,
  ) {
    final isCompleted = item.status == DownloadStatus.completed;
    final isActive =
        item.status == DownloadStatus.queued ||
        item.status == DownloadStatus.downloading ||
        item.status == DownloadStatus.finalizing;

    return Dismissible(
      key: ValueKey('dismiss_${item.id}'),
      direction: DismissDirection.endToStart,
      confirmDismiss: isActive
          ? (_) async {
              return await showDialog<bool>(
                    context: context,
                    builder: (ctx) => AlertDialog(
                      title: const Text('Cancel download?'),
                      content: Text(
                        'This will cancel the active download for "${item.track.name}".',
                      ),
                      actions: [
                        TextButton(
                          onPressed: () => Navigator.of(ctx).pop(false),
                          child: const Text('Keep'),
                        ),
                        TextButton(
                          onPressed: () => Navigator.of(ctx).pop(true),
                          child: const Text('Cancel'),
                        ),
                      ],
                    ),
                  ) ??
                  false;
            }
          : null,
      onDismissed: (_) {
        ref.read(downloadQueueProvider.notifier).dismissItem(item.id);
      },
      background: Container(
        margin: const EdgeInsets.symmetric(horizontal: 16, vertical: 4),
        decoration: BoxDecoration(
          color: colorScheme.errorContainer,
          borderRadius: BorderRadius.circular(12),
        ),
        alignment: Alignment.centerRight,
        padding: const EdgeInsets.only(right: 20),
        child: Icon(Icons.delete_outline, color: colorScheme.onErrorContainer),
      ),
      child: DownloadSuccessOverlay(
        showSuccess: isCompleted,
        child: Card(
          margin: const EdgeInsets.symmetric(horizontal: 16, vertical: 4),
          child: InkWell(
            onTap: isCompleted ? () => _navigateToMetadataScreen(item) : null,
            borderRadius: BorderRadius.circular(12),
            child: Padding(
              padding: const EdgeInsets.all(12),
              child: Row(
                children: [
                  isCompleted
                      ? Hero(
                          tag: 'cover_${item.id}',
                          child: _buildCoverArt(item, colorScheme),
                        )
                      : _buildCoverArt(item, colorScheme),
                  const SizedBox(width: 12),
                  Expanded(
                    child: Column(
                      crossAxisAlignment: CrossAxisAlignment.start,
                      children: [
                        Text(
                          item.track.name,
                          maxLines: 1,
                          overflow: TextOverflow.ellipsis,
                          style: Theme.of(context).textTheme.titleSmall
                              ?.copyWith(fontWeight: FontWeight.w600),
                        ),
                        const SizedBox(height: 2),
                        ClickableArtistName(
                          artistName: item.track.artistName,
                          artistId: item.track.artistId,
                          coverUrl: item.track.coverUrl,
                          maxLines: 1,
                          overflow: TextOverflow.ellipsis,
                          style: Theme.of(context).textTheme.bodySmall
                              ?.copyWith(color: colorScheme.onSurfaceVariant),
                        ),
                        if (item.status == DownloadStatus.downloading) ...[
                          const SizedBox(height: 8),
                          Row(
                            children: [
                              Expanded(
                                child: ClipRRect(
                                  borderRadius: BorderRadius.circular(4),
                                  child: LinearProgressIndicator(
                                    value: item.progress > 0
                                        ? item.progress
                                        : null,
                                    backgroundColor:
                                        colorScheme.surfaceContainerHighest,
                                    color: colorScheme.primary,
                                    minHeight: 6,
                                  ),
                                ),
                              ),
                              const SizedBox(width: 8),
                              Text(
                                // When progress is 0 (unknown size, e.g. YouTube tunnel mode),
                                // show bytes downloaded instead of percentage
                                item.progress > 0
                                    ? (item.speedMBps > 0
                                          ? '${(item.progress * 100).toStringAsFixed(0)}% • ${item.speedMBps.toStringAsFixed(1)} MB/s'
                                          : '${(item.progress * 100).toStringAsFixed(0)}%')
                                    : (item.bytesReceived > 0
                                          ? '${(item.bytesReceived / (1024 * 1024)).toStringAsFixed(1)} MB • ${item.speedMBps.toStringAsFixed(1)} MB/s'
                                          : (item.speedMBps > 0
                                                ? 'Downloading • ${item.speedMBps.toStringAsFixed(1)} MB/s'
                                                : 'Starting...')),
                                style: Theme.of(context).textTheme.labelSmall
                                    ?.copyWith(
                                      color: colorScheme.primary,
                                      fontWeight: FontWeight.bold,
                                    ),
                              ),
                            ],
                          ),
                        ],
                        if (item.status == DownloadStatus.failed) ...[
                          const SizedBox(height: 4),
                          Text(
                            item.errorMessage,
                            maxLines: 1,
                            overflow: TextOverflow.ellipsis,
                            style: Theme.of(context).textTheme.labelSmall
                                ?.copyWith(color: colorScheme.error),
                          ),
                        ],
                      ],
                    ),
                  ),
                  const SizedBox(width: 8),
                  _buildActionButtons(context, item, colorScheme),
                ],
              ),
            ),
          ),
        ),
      ),
    );
  }

  Widget _buildCoverArt(DownloadItem item, ColorScheme colorScheme) {
    final coverSize = _queueCoverSize();
    final memCacheSize = (coverSize * 2).round();

    return item.track.coverUrl != null
        ? ClipRRect(
            borderRadius: BorderRadius.circular(8),
            child: CachedNetworkImage(
              imageUrl: item.track.coverUrl!,
              width: coverSize,
              height: coverSize,
              fit: BoxFit.cover,
              memCacheWidth: memCacheSize,
              memCacheHeight: memCacheSize,
              cacheManager: CoverCacheManager.instance,
            ),
          )
        : Container(
            width: coverSize,
            height: coverSize,
            decoration: BoxDecoration(
              color: colorScheme.surfaceContainerHighest,
              borderRadius: BorderRadius.circular(8),
            ),
            child: Icon(Icons.music_note, color: colorScheme.onSurfaceVariant),
          );
  }

  Widget _buildActionButtons(
    BuildContext context,
    DownloadItem item,
    ColorScheme colorScheme,
  ) {
    switch (item.status) {
      case DownloadStatus.queued:
        return IconButton(
          onPressed: () =>
              ref.read(downloadQueueProvider.notifier).cancelItem(item.id),
          icon: Icon(Icons.close, color: colorScheme.error),
          tooltip: 'Cancel',
          style: IconButton.styleFrom(
            backgroundColor: colorScheme.errorContainer.withValues(alpha: 0.3),
          ),
        );
      case DownloadStatus.downloading:
        return IconButton(
          onPressed: () =>
              ref.read(downloadQueueProvider.notifier).cancelItem(item.id),
          icon: Icon(Icons.stop, color: colorScheme.error),
          tooltip: 'Stop',
          style: IconButton.styleFrom(
            backgroundColor: colorScheme.errorContainer.withValues(alpha: 0.3),
          ),
        );
      case DownloadStatus.finalizing:
        return Semantics(
          label: 'Finalizing download',
          child: SizedBox(
            width: 40,
            height: 40,
            child: Stack(
              alignment: Alignment.center,
              children: [
                CircularProgressIndicator(
                  strokeWidth: 3,
                  color: colorScheme.tertiary,
                ),
                ExcludeSemantics(
                  child: Icon(
                    Icons.edit_note,
                    color: colorScheme.tertiary,
                    size: 16,
                  ),
                ),
              ],
            ),
          ),
        );
      case DownloadStatus.completed:
        return ValueListenableBuilder<bool>(
          valueListenable: _fileExistsListenable(item.filePath),
          builder: (context, fileExists, child) {
            return Row(
              mainAxisSize: MainAxisSize.min,
              children: [
                if (fileExists)
                  IconButton(
                    onPressed: () => _openFile(
                      item.filePath!,
                      title: item.track.name,
                      artist: item.track.artistName,
                      album: item.track.albumName,
                      coverUrl: item.track.coverUrl ?? '',
                    ),
                    icon: Icon(Icons.play_arrow, color: colorScheme.primary),
                    tooltip: 'Play',
                    style: IconButton.styleFrom(
                      backgroundColor: colorScheme.primaryContainer.withValues(
                        alpha: 0.3,
                      ),
                    ),
                  )
                else
                  Semantics(
                    label: 'Downloaded file missing',
                    child: ExcludeSemantics(
                      child: Icon(
                        Icons.error_outline,
                        color: colorScheme.error,
                        size: 20,
                      ),
                    ),
                  ),
                const SizedBox(width: 4),
                Semantics(
                  label: 'Download completed',
                  child: ExcludeSemantics(
                    child: Container(
                      padding: const EdgeInsets.all(8),
                      decoration: BoxDecoration(
                        color: colorScheme.primaryContainer,
                        shape: BoxShape.circle,
                      ),
                      child: Icon(
                        Icons.check,
                        color: colorScheme.onPrimaryContainer,
                        size: 20,
                      ),
                    ),
                  ),
                ),
              ],
            );
          },
        );
      case DownloadStatus.failed:
      case DownloadStatus.skipped:
        return Row(
          mainAxisSize: MainAxisSize.min,
          children: [
            IconButton(
              onPressed: () =>
                  ref.read(downloadQueueProvider.notifier).retryItem(item.id),
              icon: Icon(Icons.refresh, color: colorScheme.primary),
              tooltip: 'Retry',
              style: IconButton.styleFrom(
                backgroundColor: colorScheme.primaryContainer.withValues(
                  alpha: 0.3,
                ),
              ),
            ),
            const SizedBox(width: 4),
            IconButton(
              onPressed: () =>
                  ref.read(downloadQueueProvider.notifier).removeItem(item.id),
              icon: Icon(
                Icons.close,
                color: item.status == DownloadStatus.failed
                    ? colorScheme.error
                    : colorScheme.onSurfaceVariant,
              ),
              tooltip: 'Remove',
              style: item.status == DownloadStatus.failed
                  ? IconButton.styleFrom(
                      backgroundColor: colorScheme.errorContainer.withValues(
                        alpha: 0.3,
                      ),
                    )
                  : null,
            ),
          ],
        );
    }
  }

  /// Reusable filter button with badge showing active filter count.
  Widget _buildFilterButton(
    BuildContext context,
    List<UnifiedLibraryItem> unifiedItems,
  ) {
    return GestureDetector(
      onLongPress: _activeFilterCount > 0 ? _resetFilters : null,
      child: TextButton.icon(
        onPressed: () => _showFilterSheet(context, unifiedItems),
        icon: Badge(
          isLabelVisible: _activeFilterCount > 0,
          label: Text('$_activeFilterCount'),
          child: const Icon(Icons.filter_list, size: 18),
        ),
        label: Text(context.l10n.libraryFilterTitle),
        style: TextButton.styleFrom(visualDensity: VisualDensity.compact),
      ),
    );
  }

  /// Build cover image widget for unified library item.
  /// When [size] is provided, renders at fixed dimensions (list mode).
  /// When [size] is null, fills the parent container (grid mode).
  Widget _buildUnifiedCoverImage(
    UnifiedLibraryItem item,
    ColorScheme colorScheme, [
    double? size,
  ]) {
    final isDownloaded = item.source == LibraryItemSource.downloaded;

    // For downloaded items, listen to embedded cover version so the cover
    // updates after async extraction completes.
    if (isDownloaded) {
      return ValueListenableBuilder<int>(
        valueListenable: _embeddedCoverVersion,
        builder: (context, _, child) =>
            _buildUnifiedCoverImageInner(item, colorScheme, isDownloaded, size),
      );
    }

    return _buildUnifiedCoverImageInner(item, colorScheme, isDownloaded, size);
  }

  Widget _buildUnifiedCoverImageInner(
    UnifiedLibraryItem item,
    ColorScheme colorScheme,
    bool isDownloaded, [
    double? size,
  ]) {
    final cacheSize = size != null ? (size * 2).toInt() : 200;
    final iconSize = size != null ? size * 0.4 : 32.0;

    Widget buildPlaceholder({bool isLocal = false}) {
      final bgColor = (isDownloaded && !isLocal)
          ? colorScheme.surfaceContainerHighest
          : colorScheme.secondaryContainer;
      final fgColor = (isDownloaded && !isLocal)
          ? colorScheme.onSurfaceVariant
          : colorScheme.onSecondaryContainer;
      return Container(
        width: size,
        height: size,
        decoration: size != null
            ? BoxDecoration(
                color: bgColor,
                borderRadius: BorderRadius.circular(8),
              )
            : null,
        color: size != null ? null : bgColor,
        child: Center(
          child: Icon(Icons.music_note, color: fgColor, size: iconSize),
        ),
      );
    }

    if (isDownloaded) {
      final embeddedCoverPath = _resolveDownloadedEmbeddedCoverPath(
        item.filePath,
      );
      if (embeddedCoverPath != null) {
        return ClipRRect(
          borderRadius: BorderRadius.circular(8),
          child: Image.file(
            File(embeddedCoverPath),
            width: size,
            height: size,
            fit: BoxFit.cover,
            cacheWidth: cacheSize,
            cacheHeight: cacheSize,
            errorBuilder: (context, error, stackTrace) => buildPlaceholder(),
          ),
        );
      }
    }

    // Network URL cover (downloaded items)
    if (item.coverUrl != null) {
      return ClipRRect(
        borderRadius: BorderRadius.circular(8),
        child: CachedNetworkImage(
          imageUrl: item.coverUrl!,
          width: size,
          height: size,
          fit: BoxFit.cover,
          memCacheWidth: cacheSize,
          memCacheHeight: cacheSize,
          cacheManager: CoverCacheManager.instance,
          placeholder: (context, url) => buildPlaceholder(),
          errorWidget: (context, url, error) => buildPlaceholder(),
        ),
      );
    }

    // Local file cover (from library scan)
    if (item.localCoverPath != null && item.localCoverPath!.isNotEmpty) {
      return ClipRRect(
        borderRadius: BorderRadius.circular(8),
        child: Image.file(
          File(item.localCoverPath!),
          width: size,
          height: size,
          fit: BoxFit.cover,
          cacheWidth: cacheSize,
          cacheHeight: cacheSize,
          errorBuilder: (context, error, stackTrace) =>
              buildPlaceholder(isLocal: true),
        ),
      );
    }

    // Placeholder (no cover)
    if (size != null) {
      return buildPlaceholder();
    }
    return ClipRRect(
      borderRadius: BorderRadius.circular(8),
      child: buildPlaceholder(),
    );
  }

  /// Build a unified library item (merged downloaded + local)
  Widget _buildUnifiedLibraryItem(
    BuildContext context,
    UnifiedLibraryItem item,
    ColorScheme colorScheme,
  ) {
    final fileExistsListenable = _fileExistsListenable(item.filePath);
    final isSelected = _selectedIds.contains(item.id);
    final date = item.addedAt;
    final dateStr =
        '${_months[date.month - 1]} ${date.day}, ${date.hour.toString().padLeft(2, '0')}:${date.minute.toString().padLeft(2, '0')}';

    final isDownloaded = item.source == LibraryItemSource.downloaded;
    final sourceLabel = isDownloaded
        ? context.l10n.librarySourceDownloaded
        : context.l10n.librarySourceLocal;
    final sourceColor = isDownloaded
        ? colorScheme.primaryContainer
        : colorScheme.secondaryContainer;
    final sourceTextColor = isDownloaded
        ? colorScheme.onPrimaryContainer
        : colorScheme.onSecondaryContainer;

    return Semantics(
      label: '${item.trackName} by ${item.artistName}',
      selected: isSelected,
      child: Card(
        margin: const EdgeInsets.symmetric(horizontal: 16, vertical: 4),
        color: isSelected
            ? colorScheme.primaryContainer.withValues(alpha: 0.3)
            : null,
        child: InkWell(
          onTap: _isSelectionMode
              ? () => _toggleSelection(item.id)
              : isDownloaded
              ? () => _navigateToHistoryMetadataScreen(item.historyItem!)
              : item.localItem != null
              ? () => _navigateToLocalMetadataScreen(item.localItem!)
              : () => _openFile(
                  item.filePath,
                  title: item.trackName,
                  artist: item.artistName,
                  album: item.albumName,
                  coverUrl: item.coverUrl ?? item.localCoverPath ?? '',
                ),
          onLongPress: _isSelectionMode
              ? null
              : () => _enterSelectionMode(item.id),
          borderRadius: BorderRadius.circular(12),
          child: Padding(
            padding: const EdgeInsets.all(12),
            child: Row(
              children: [
                if (_isSelectionMode) ...[
                  Semantics(
                    checked: isSelected,
                    label: isSelected ? 'Deselect track' : 'Select track',
                    child: AnimatedSelectionCheckbox(
                      visible: true,
                      selected: isSelected,
                      colorScheme: colorScheme,
                      size: 24,
                    ),
                  ),
                  const SizedBox(width: 12),
                ],
                Hero(
                  tag: 'cover_lib_${item.id}',
                  child: _buildUnifiedCoverImage(item, colorScheme, 56),
                ),
                const SizedBox(width: 12),

                Expanded(
                  child: Column(
                    crossAxisAlignment: CrossAxisAlignment.start,
                    children: [
                      Text(
                        item.trackName,
                        maxLines: 1,
                        overflow: TextOverflow.ellipsis,
                        style: Theme.of(context).textTheme.titleSmall?.copyWith(
                          fontWeight: FontWeight.w600,
                        ),
                      ),
                      const SizedBox(height: 2),
                      ClickableArtistName(
                        artistName: item.artistName,
                        coverUrl: item.coverUrl,
                        maxLines: 1,
                        overflow: TextOverflow.ellipsis,
                        style: Theme.of(context).textTheme.bodySmall?.copyWith(
                          color: colorScheme.onSurfaceVariant,
                        ),
                      ),
                      const SizedBox(height: 2),
                      Row(
                        children: [
                          Container(
                            padding: const EdgeInsets.symmetric(
                              horizontal: 6,
                              vertical: 2,
                            ),
                            decoration: BoxDecoration(
                              color: sourceColor,
                              borderRadius: BorderRadius.circular(4),
                            ),
                            child: Text(
                              sourceLabel,
                              style: Theme.of(context).textTheme.labelSmall
                                  ?.copyWith(
                                    color: sourceTextColor,
                                    fontSize: 10,
                                    fontWeight: FontWeight.w500,
                                  ),
                            ),
                          ),
                          const SizedBox(width: 8),
                          Flexible(
                            child: Text(
                              dateStr,
                              maxLines: 1,
                              overflow: TextOverflow.ellipsis,
                              style: Theme.of(context).textTheme.labelSmall
                                  ?.copyWith(
                                    color: colorScheme.onSurfaceVariant
                                        .withValues(alpha: 0.7),
                                  ),
                            ),
                          ),
                          if (item.quality != null &&
                              item.quality!.isNotEmpty) ...[
                            const SizedBox(width: 8),
                            Container(
                              padding: const EdgeInsets.symmetric(
                                horizontal: 6,
                                vertical: 2,
                              ),
                              decoration: BoxDecoration(
                                color: item.quality!.startsWith('24')
                                    ? colorScheme.tertiaryContainer
                                    : colorScheme.surfaceContainerHighest,
                                borderRadius: BorderRadius.circular(4),
                              ),
                              child: Text(
                                item.quality!,
                                style: Theme.of(context).textTheme.labelSmall
                                    ?.copyWith(
                                      color: item.quality!.startsWith('24')
                                          ? colorScheme.onTertiaryContainer
                                          : colorScheme.onSurfaceVariant,
                                      fontSize: 10,
                                      fontWeight: FontWeight.w500,
                                    ),
                              ),
                            ),
                          ],
                        ],
                      ),
                    ],
                  ),
                ),
                const SizedBox(width: 8),

                if (!_isSelectionMode)
                  ValueListenableBuilder<bool>(
                    valueListenable: fileExistsListenable,
                    builder: (context, fileExists, child) {
                      return Row(
                        mainAxisSize: MainAxisSize.min,
                        children: [
                          if (fileExists)
                            IconButton(
                              onPressed: () => _openFile(
                                item.filePath,
                                title: item.trackName,
                                artist: item.artistName,
                                album: item.albumName,
                                coverUrl:
                                    item.coverUrl ?? item.localCoverPath ?? '',
                              ),
                              icon: Icon(
                                Icons.play_arrow,
                                color: colorScheme.primary,
                              ),
                              tooltip: context.l10n.tooltipPlay,
                              style: IconButton.styleFrom(
                                backgroundColor: colorScheme.primaryContainer
                                    .withValues(alpha: 0.3),
                              ),
                            )
                          else
                            Icon(
                              Icons.error_outline,
                              color: colorScheme.error,
                              size: 20,
                            ),
                        ],
                      );
                    },
                  ),
              ],
            ),
          ),
        ),
      ),
    );
  }

  /// Build unified grid item for grid view mode
  Widget _buildUnifiedGridItem(
    BuildContext context,
    UnifiedLibraryItem item,
    ColorScheme colorScheme,
  ) {
    final fileExistsListenable = _fileExistsListenable(item.filePath);
    final isSelected = _selectedIds.contains(item.id);
    final isDownloaded = item.source == LibraryItemSource.downloaded;

    return GestureDetector(
      onTap: _isSelectionMode
          ? () => _toggleSelection(item.id)
          : isDownloaded
          ? () => _navigateToHistoryMetadataScreen(item.historyItem!)
          : item.localItem != null
          ? () => _navigateToLocalMetadataScreen(item.localItem!)
          : () => _openFile(
              item.filePath,
              title: item.trackName,
              artist: item.artistName,
              album: item.albumName,
              coverUrl: item.coverUrl ?? item.localCoverPath ?? '',
            ),
      onLongPress: _isSelectionMode ? null : () => _enterSelectionMode(item.id),
      child: Stack(
        children: [
          Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Stack(
                children: [
                  AspectRatio(
                    aspectRatio: 1,
                    child: _buildUnifiedCoverImage(item, colorScheme),
                  ),
                  Positioned(
                    right: 4,
                    top: 4,
                    child: Container(
                      padding: const EdgeInsets.symmetric(
                        horizontal: 4,
                        vertical: 2,
                      ),
                      decoration: BoxDecoration(
                        color: isDownloaded
                            ? colorScheme.primaryContainer
                            : colorScheme.secondaryContainer,
                        borderRadius: BorderRadius.circular(4),
                      ),
                      child: Icon(
                        isDownloaded ? Icons.download_done : Icons.folder,
                        size: 12,
                        color: isDownloaded
                            ? colorScheme.onPrimaryContainer
                            : colorScheme.onSecondaryContainer,
                      ),
                    ),
                  ),
                  if (item.quality != null && item.quality!.isNotEmpty)
                    Positioned(
                      left: 4,
                      top: 4,
                      child: Container(
                        padding: const EdgeInsets.symmetric(
                          horizontal: 4,
                          vertical: 2,
                        ),
                        decoration: BoxDecoration(
                          color: item.quality!.startsWith('24')
                              ? colorScheme.tertiary
                              : colorScheme.surfaceContainerHighest,
                          borderRadius: BorderRadius.circular(4),
                        ),
                        child: Text(
                          _getQualityBadgeText(item.quality!),
                          style: Theme.of(context).textTheme.labelSmall
                              ?.copyWith(
                                color: item.quality!.startsWith('24')
                                    ? colorScheme.onTertiary
                                    : colorScheme.onSurfaceVariant,
                                fontSize: 9,
                                fontWeight: FontWeight.w600,
                              ),
                        ),
                      ),
                    ),
                  if (!_isSelectionMode)
                    Positioned(
                      right: 4,
                      bottom: 4,
                      child: ValueListenableBuilder<bool>(
                        valueListenable: fileExistsListenable,
                        builder: (context, fileExists, child) {
                          return fileExists
                              ? Semantics(
                                  button: true,
                                  label:
                                      'Play ${item.trackName} by ${item.artistName}',
                                  child: GestureDetector(
                                    onTap: () => _openFile(
                                      item.filePath,
                                      title: item.trackName,
                                      artist: item.artistName,
                                      album: item.albumName,
                                      coverUrl:
                                          item.coverUrl ??
                                          item.localCoverPath ??
                                          '',
                                    ),
                                    child: Container(
                                      padding: const EdgeInsets.all(6),
                                      decoration: BoxDecoration(
                                        color: colorScheme.primary,
                                        shape: BoxShape.circle,
                                      ),
                                      child: ExcludeSemantics(
                                        child: Icon(
                                          Icons.play_arrow,
                                          color: colorScheme.onPrimary,
                                          size: 16,
                                        ),
                                      ),
                                    ),
                                  ),
                                )
                              : Container(
                                  padding: const EdgeInsets.all(4),
                                  decoration: BoxDecoration(
                                    color: colorScheme.errorContainer,
                                    shape: BoxShape.circle,
                                  ),
                                  child: Icon(
                                    Icons.error_outline,
                                    color: colorScheme.error,
                                    size: 14,
                                  ),
                                );
                        },
                      ),
                    ),
                  if (_isSelectionMode)
                    Positioned.fill(
                      child: Container(
                        decoration: BoxDecoration(
                          color: isSelected
                              ? colorScheme.primary.withValues(alpha: 0.3)
                              : Colors.transparent,
                          borderRadius: BorderRadius.circular(8),
                        ),
                      ),
                    ),
                ],
              ),
              const SizedBox(height: 6),
              Text(
                item.trackName,
                maxLines: 1,
                overflow: TextOverflow.ellipsis,
                style: Theme.of(
                  context,
                ).textTheme.bodySmall?.copyWith(fontWeight: FontWeight.w500),
              ),
              ClickableArtistName(
                artistName: item.artistName,
                coverUrl: item.coverUrl,
                maxLines: 1,
                overflow: TextOverflow.ellipsis,
                style: Theme.of(context).textTheme.labelSmall?.copyWith(
                  color: colorScheme.onSurfaceVariant,
                ),
              ),
            ],
          ),
          if (_isSelectionMode)
            Positioned(
              right: 4,
              top: 4,
              child: Container(
                decoration: BoxDecoration(
                  color: isSelected ? colorScheme.primary : colorScheme.surface,
                  shape: BoxShape.circle,
                  border: Border.all(
                    color: isSelected
                        ? colorScheme.primary
                        : colorScheme.outline,
                    width: 2,
                  ),
                ),
                child: isSelected
                    ? Icon(Icons.check, color: colorScheme.onPrimary, size: 16)
                    : const SizedBox(width: 16, height: 16),
              ),
            ),
        ],
      ),
    );
  }
}

class _QueueItemSliverRow extends ConsumerWidget {
  final String itemId;
  final ColorScheme colorScheme;
  final Widget Function(BuildContext, DownloadItem, ColorScheme) itemBuilder;

  const _QueueItemSliverRow({
    super.key,
    required this.itemId,
    required this.colorScheme,
    required this.itemBuilder,
  });

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final item = ref.watch(
      downloadQueueLookupProvider.select((lookup) => lookup.byItemId[itemId]),
    );
    if (item == null) {
      return const SizedBox.shrink();
    }

    return RepaintBoundary(child: itemBuilder(context, item, colorScheme));
  }
}

enum _CollectionEntryType { wishlist, loved, playlist }

class _CollectionEntry {
  final _CollectionEntryType type;
  final int playlistIndex;

  const _CollectionEntry._(this.type, [this.playlistIndex = -1]);

  static const wishlist = _CollectionEntry._(_CollectionEntryType.wishlist);
  static const loved = _CollectionEntry._(_CollectionEntryType.loved);
  static _CollectionEntry playlist(int index) =>
      _CollectionEntry._(_CollectionEntryType.playlist, index);
}

class _FilterChip extends StatelessWidget {
  final String label;
  final int count;
  final bool isSelected;
  final VoidCallback onTap;

  const _FilterChip({
    required this.label,
    required this.count,
    required this.isSelected,
    required this.onTap,
  });

  @override
  Widget build(BuildContext context) {
    final colorScheme = Theme.of(context).colorScheme;

    return FilterChip(
      label: Row(
        mainAxisSize: MainAxisSize.min,
        children: [
          Text(label),
          const SizedBox(width: 6),
          Container(
            padding: const EdgeInsets.symmetric(horizontal: 6, vertical: 2),
            decoration: BoxDecoration(
              color: isSelected
                  ? colorScheme.primary.withValues(alpha: 0.2)
                  : colorScheme.outline.withValues(alpha: 0.2),
              borderRadius: BorderRadius.circular(10),
            ),
            child: Text(
              count.toString(),
              style: TextStyle(
                fontSize: 11,
                color: isSelected
                    ? colorScheme.onPrimaryContainer
                    : colorScheme.onSurfaceVariant,
                fontWeight: FontWeight.w500,
              ),
            ),
          ),
        ],
      ),
      selected: isSelected,
      onSelected: (_) => onTap(),
      showCheckmark: false,
    );
  }
}

/// Reusable action button for selection mode bottom bar
class _SelectionActionButton extends StatelessWidget {
  final IconData icon;
  final String label;
  final VoidCallback? onPressed;
  final ColorScheme colorScheme;

  const _SelectionActionButton({
    required this.icon,
    required this.label,
    required this.onPressed,
    required this.colorScheme,
  });

  @override
  Widget build(BuildContext context) {
    final isDisabled = onPressed == null;
    return Material(
      color: isDisabled
          ? colorScheme.surfaceContainerHighest.withValues(alpha: 0.5)
          : colorScheme.secondaryContainer,
      borderRadius: BorderRadius.circular(14),
      child: InkWell(
        onTap: onPressed,
        borderRadius: BorderRadius.circular(14),
        child: Padding(
          padding: const EdgeInsets.symmetric(vertical: 12, horizontal: 12),
          child: Row(
            mainAxisAlignment: MainAxisAlignment.center,
            children: [
              Icon(
                icon,
                size: 18,
                color: isDisabled
                    ? colorScheme.onSurfaceVariant.withValues(alpha: 0.5)
                    : colorScheme.onSecondaryContainer,
              ),
              const SizedBox(width: 6),
              Flexible(
                child: Text(
                  label,
                  maxLines: 1,
                  overflow: TextOverflow.ellipsis,
                  style: TextStyle(
                    fontSize: 13,
                    fontWeight: FontWeight.w600,
                    color: isDisabled
                        ? colorScheme.onSurfaceVariant.withValues(alpha: 0.5)
                        : colorScheme.onSecondaryContainer,
                  ),
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
}