playback: Fix subtitle visibility leakage and filter missing episodes

lib/di/modules/playback_module.dart

@@ -23,6 +23,7 @@ import '../../preference/preference_constants.dart';
 import '../../preference/user_preferences.dart';
 import '../../syncplay/syncplay_manager.dart';
 import '../../util/platform_detection.dart';
+import '../../util/episode_playability.dart';
 
 final _getIt = GetIt.instance;
 
@@ -316,11 +317,14 @@ Future<List<dynamic>> _nextSeasonItemsProvider(
       seriesId: seriesId,
       seasonId: nextSeasonId,
     );
-    if (nextSeasonEpisodes.isEmpty ||
-        nextSeasonEpisodes.first.mediaSources.isEmpty) {
+    final playableEpisodes = nextSeasonEpisodes
+        .where(isEligibleNextEpisodeCandidate)
+        .toList();
+    if (playableEpisodes.isEmpty ||
+        playableEpisodes.first.mediaSources.isEmpty) {
       return const <dynamic>[];
     }
-    return nextSeasonEpisodes;
+    return playableEpisodes;
   } catch (_) {
     return const <dynamic>[];
   }

lib/playback/html_video_backend_stub.dart

@@ -6,7 +6,7 @@ import 'package:playback_core/playback_core.dart';
 import '../preference/user_preferences.dart';
 import 'html_video_backend_profile.dart';
 
-class HtmlVideoBackend implements PlayerBackend {
+class HtmlVideoBackend extends PlayerBackend {
   HtmlVideoBackend(this._prefs);
 
   final UserPreferences _prefs;
@@ -85,6 +85,7 @@ class HtmlVideoBackend implements PlayerBackend {
   @override
   Future<void> setAudioTrack(int index) async {}
 
+
   @override
   Future<void> setSubtitleTrack(
     int index, {

lib/playback/html_video_backend_web.dart

@@ -27,7 +27,7 @@ extension type _MoonfinHlsBridge._(JSObject _) implements JSObject {
   external void destroy(JSAny? controller);
 }
 
-class HtmlVideoBackend implements PlayerBackend {
+class HtmlVideoBackend extends PlayerBackend {
   HtmlVideoBackend(this._prefs)
     : _viewType = 'moonfin-html-video-${_nextViewId++}' {
     _videoElement = _createVideoElement();
@@ -440,6 +440,7 @@ class HtmlVideoBackend implements PlayerBackend {
   Future<void> setAudioTrack(int index) async {
   }
 
+
   @override
   Future<void> setSubtitleTrack(
     int index, {

lib/playback/media3_player_backend.dart

@@ -10,7 +10,7 @@ import 'audio_capability_profile.dart';
 import 'device_profile_builder.dart';
 import 'known_defects.dart';
 
-class Media3PlayerBackend implements PlayerBackend {
+class Media3PlayerBackend extends PlayerBackend {
   static const _discontinuityWindowMs = 15000;
   static const _discontinuityThreshold = 3;
 
@@ -543,6 +543,7 @@ class Media3PlayerBackend implements PlayerBackend {
     await _invoke<void>('setAudioTrack', {'index': index});
   }
 
+
   @override
   Future<void> setSubtitleTrack(
     int index, {

lib/playback/media_kit_player_backend.dart

@@ -168,7 +168,7 @@ class _MediaKitDeviceProfileCapabilities {
   }
 }
 
-class MediaKitPlayerBackend implements PlayerBackend {
+class MediaKitPlayerBackend extends PlayerBackend {
   static const Duration _linuxHwdecFirstFrameTimeout = Duration(
     milliseconds: 1500,
   );
@@ -543,6 +543,17 @@ class MediaKitPlayerBackend implements PlayerBackend {
     await _applyAudioPassthroughOptions();
     await _applyCustomMpvConfIfEnabled();
     await _applyAssOverrideMode();
+
+    if (_player.platform is NativePlayer) {
+      final native = _player.platform as NativePlayer;
+      await _nativeSetProperty(native, 'sid', 'auto');
+      await _nativeSetProperty(native, 'secondary-sid', 'no');
+      await _nativeSetProperty(native, 'sub-visibility', 'yes');
+      if (_useLibass) {
+        await _nativeSetProperty(native, 'sub-ass', 'yes');
+      }
+    }
+
     final media = Media(url);
     final openPaused = startPosition > Duration.zero;
     await _player.open(media, play: !openPaused);
@@ -1226,6 +1237,35 @@ class MediaKitPlayerBackend implements PlayerBackend {
     }
   }
 
+  @override
+  int? get activeSubtitleTrackIndex {
+    if (_player.platform is! NativePlayer) {
+      return null;
+    }
+    try {
+      final active = _player.state.track.subtitle;
+      if (active.id == 'no') {
+        return -1;
+      }
+      if (active.id == 'auto') {
+        return null;
+      }
+      final subtitleTracks = _player.state.tracks.subtitle;
+      final playableSubtitleTracks = subtitleTracks
+          .where((t) => t.id != 'auto' && t.id != 'no')
+          .toList();
+      final idx = playableSubtitleTracks.indexWhere((t) => t.id == active.id);
+      if (idx >= 0) {
+        return idx + 1;
+      }
+    } catch (_) {}
+    return null;
+  }
+
+  @override
+  Future<int?> getActiveSubtitleTrackIndexAsync() async => activeSubtitleTrackIndex;
+
+
   @override
   Future<void> setSubtitleTrack(
     int mpvTrackId, {

lib/playback/tizen_player_backend.dart

@@ -3,7 +3,6 @@ import 'dart:async';
 import 'package:video_player/video_player.dart';
 import 'package:playback_core/playback_core.dart';
 
-import '../preference/preference_constants.dart';
 import '../preference/user_preferences.dart';
 import 'audio_capability_profile.dart';
 import 'device_profile_builder.dart';
@@ -22,7 +21,7 @@ import 'known_defects.dart';
 ///     is false) — the `video_player` API does not expose track lists.
 ///   * No bitmap (PGS/VOBSUB) subtitle rendering, no ASS styling, no audio/
 ///     subtitle delay, and no external subtitle sideloading.
-class TizenPlayerBackend implements PlayerBackend {
+class TizenPlayerBackend extends PlayerBackend {
   TizenPlayerBackend(this._prefs);
 
   final UserPreferences _prefs;
@@ -279,6 +278,7 @@ class TizenPlayerBackend implements PlayerBackend {
     await _controller?.setPlaybackSpeed(speed);
   }
 
+
   // The standard video_player API exposes no runtime track selection; tracks are
   // selected server-side via the device profile / transcoding instead.
   @override

lib/ui/screens/detail/item_detail_screen.dart

@@ -5883,7 +5883,7 @@ class _ActionButtonsState extends State<_ActionButtons> {
             );
 
           case 'Season':
-            final episodes = viewModel.episodes;
+            final episodes = viewModel.episodes.where(isEligibleNextEpisodeCandidate).toList();
             if (episodes.isEmpty) return;
             final startIndex = resume
                 ? episodes.indexWhere(
@@ -5939,11 +5939,12 @@ class _ActionButtonsState extends State<_ActionButtons> {
             if (!context.mounted) return;
 
             if (episodes.length > 1) {
-              final startIndex = episodes.indexWhere((e) => e.id == item.id);
+              final playableEpisodes = episodes.where((e) => e.id == item.id || isEligibleNextEpisodeCandidate(e)).toList();
+              final startIndex = playableEpisodes.indexWhere((e) => e.id == item.id);
               final idx = startIndex >= 0 ? startIndex : 0;
-              final selectedEpisode = episodes[idx];
+              final selectedEpisode = playableEpisodes[idx];
               final episodeQueue = _truncateQueueIfImmediateNextUnplayable(
-                episodes,
+                playableEpisodes,
                 startIndex: idx,
               );
 
@@ -6102,10 +6103,11 @@ class _ActionButtonsState extends State<_ActionButtons> {
   ) async {
     final manager = GetIt.instance<PlaybackManager>();
     final queue = await _shuffleQueueForItem(item);
-    if (queue.length < 2) return;
+    final playableQueue = queue.where((e) => isEligibleNextEpisodeCandidate(e) || e.id == item.id).toList();
+    if (playableQueue.length < 2) return;
     if (!context.mounted) return;
 
-    final shuffled = List<AggregatedItem>.from(queue)..shuffle();
+    final shuffled = List<AggregatedItem>.from(playableQueue)..shuffle();
     final isAudio = shuffled.every((queuedItem) {
       final mediaType = queuedItem.rawData['MediaType'] as String?;
       return queuedItem.type == 'Audio' || mediaType == 'Audio';

lib/ui/screens/playback/video_player_screen.dart

@@ -5837,88 +5837,90 @@ class _VideoPlayerScreenState extends State<VideoPlayerScreen>
     final canDownloadRemote =
         !audio && item is AggregatedItem && _canDownloadRemoteSubtitles(item);
 
-    final int? currentStreamIndex;
-    if (audio) {
-      currentStreamIndex =
-          _manager.audioStreamIndex ??
-          streams.where((s) => s['IsDefault'] == true).firstOrNull?['Index']
-              as int?;
-    } else {
-      final subIdx = _manager.subtitleStreamIndex;
-      currentStreamIndex =
-          subIdx ??
-          streams.where((s) => s['IsDefault'] == true).firstOrNull?['Index']
-              as int?;
-    }
-    final isSubsOff = !audio && _manager.subtitleStreamIndex == -1;
-
-    final options = <TrackOption>[
-      if (!audio) TrackOption(label: l10n.off),
-      ...optionStreams.asMap().entries.map((entry) {
-        final index = entry.key;
-        final trackNumber = index + 1;
-        final s = entry.value;
-        final displayTitle = s['DisplayTitle'] as String?;
-        final title = s['Title'] as String?;
-        final language = s['Language'] as String?;
-        final codec = s['Codec'] as String?;
-        final label =
-            displayTitle ??
-            title ??
-            language ??
-            l10n.streamTypeFallback(streamType, index + 1);
-        final subtitle = audio
-            ? [
-                if (language != null && displayTitle != null) language,
-                if (codec != null) codec.toUpperCase(),
-                if (s['Channels'] != null) '${s['Channels']}ch',
-              ].join(' · ')
-            : (() {
-                final subtitleType =
-                    ((codec == null || codec.isEmpty) ? 'Unknown' : codec)
-                        .toUpperCase();
-                final deliveryMethod = (s['DeliveryMethod'] as String?)
-                    ?.trim()
-                    .toLowerCase();
-                final location = s['IsExternal'] == true
-                    ? 'External'
-                    : (deliveryMethod == 'embed' ? 'Embedded' : 'Internal');
-                return '$subtitleType · $location';
-              })();
-        return TrackOption(
-          label: '$trackNumber - $label',
-          subtitle: subtitle.isNotEmpty ? subtitle : null,
-          scrollLabel: true,
-          scrollSubtitle: true,
-        );
-      }),
-      if (canDownloadRemote)
-        TrackOption(
-          label: l10n.downloadSubtitlesLabel,
-          subtitle: l10n.searchOpenSubtitlesPlugin,
-        ),
-    ];
+    unawaited(() async {
+      final int? currentStreamIndex;
+      if (audio) {
+        currentStreamIndex =
+            _manager.audioStreamIndex ??
+            streams.where((s) => s['IsDefault'] == true).firstOrNull?['Index']
+                as int?;
+      } else {
+        final subIdx = await _manager.getSubtitleStreamIndexAsync();
+        currentStreamIndex =
+            subIdx ??
+            streams.where((s) => s['IsDefault'] == true).firstOrNull?['Index']
+                as int?;
+      }
+      final isSubsOff = !audio && currentStreamIndex == -1;
+
+      final options = <TrackOption>[
+        if (!audio) TrackOption(label: l10n.off),
+        ...optionStreams.asMap().entries.map((entry) {
+          final index = entry.key;
+          final trackNumber = index + 1;
+          final s = entry.value;
+          final displayTitle = s['DisplayTitle'] as String?;
+          final title = s['Title'] as String?;
+          final language = s['Language'] as String?;
+          final codec = s['Codec'] as String?;
+          final label =
+              displayTitle ??
+              title ??
+              language ??
+              l10n.streamTypeFallback(streamType, index + 1);
+          final subtitle = audio
+              ? [
+                  if (language != null && displayTitle != null) language,
+                  if (codec != null) codec.toUpperCase(),
+                  if (s['Channels'] != null) '${s['Channels']}ch',
+                ].join(' · ')
+              : (() {
+                  final subtitleType =
+                      ((codec == null || codec.isEmpty) ? 'Unknown' : codec)
+                          .toUpperCase();
+                  final deliveryMethod = (s['DeliveryMethod'] as String?)
+                      ?.trim()
+                      .toLowerCase();
+                  final location = s['IsExternal'] == true
+                      ? 'External'
+                      : (deliveryMethod == 'embed' ? 'Embedded' : 'Internal');
+                  return '$subtitleType · $location';
+                })();
+          return TrackOption(
+            label: '$trackNumber - $label',
+            subtitle: subtitle.isNotEmpty ? subtitle : null,
+            scrollLabel: true,
+            scrollSubtitle: true,
+          );
+        }),
+        if (canDownloadRemote)
+          TrackOption(
+            label: l10n.downloadSubtitlesLabel,
+            subtitle: l10n.searchOpenSubtitlesPlugin,
+          ),
+      ];
 
-    final int? selectedIndex;
-    if (audio) {
-      final idx = currentStreamIndex != null
-          ? streams.indexWhere((s) => s['Index'] == currentStreamIndex)
-          : -1;
-      selectedIndex = idx >= 0 ? idx : null;
-    } else {
-      if (isSubsOff || (currentStreamIndex == null && streams.isNotEmpty)) {
-        selectedIndex = 0;
-      } else if (currentStreamIndex != null) {
-        final idx = optionStreams.indexWhere(
-          (s) => s['Index'] == currentStreamIndex,
-        );
-        selectedIndex = idx >= 0 ? idx + 1 : null;
+      final int? selectedIndex;
+      if (audio) {
+        final idx = currentStreamIndex != null
+            ? streams.indexWhere((s) => s['Index'] == currentStreamIndex)
+            : -1;
+        selectedIndex = idx >= 0 ? idx : null;
       } else {
-        selectedIndex = null;
+        if (isSubsOff || (currentStreamIndex == null && streams.isNotEmpty)) {
+          selectedIndex = 0;
+        } else if (currentStreamIndex != null) {
+          final idx = optionStreams.indexWhere(
+            (s) => s['Index'] == currentStreamIndex,
+          );
+          selectedIndex = idx >= 0 ? idx + 1 : null;
+        } else {
+          selectedIndex = null;
+        }
       }
-    }
 
-    unawaited(() async {
+      if (!mounted) return;
+
       final result = await TrackSelectorDialog.show(
         context,
         title: audio ? l10n.audioTrack : l10n.subtitleTrack,