streaming edits

lib/playback/playback_engine.dart

@@ -32,6 +32,7 @@ class PlaybackState {
     this.queue = const [],
     this.currentIndex,
     this.playing = false,
+    this.buffering = false,
     this.position = Duration.zero,
     this.duration = Duration.zero,
     this.shuffle = false,
@@ -43,6 +44,13 @@ class PlaybackState {
   final List<Song> queue;
   final int? currentIndex;
   final bool playing;
+
+  /// True while the player is loading/buffering a source (not yet `ready`). A
+  /// streamed source that is buffering legitimately reports position 0; this
+  /// lets the UI show a spinner instead of a frozen 0:00 bar. Transient — never
+  /// persisted.
+  final bool buffering;
+
   final Duration position;
   final Duration duration;
   final bool shuffle;
@@ -83,6 +91,7 @@ class PlaybackState {
     List<Song>? queue,
     int? currentIndex,
     bool? playing,
+    bool? buffering,
     Duration? position,
     Duration? duration,
     bool? shuffle,
@@ -95,6 +104,7 @@ class PlaybackState {
       queue: queue ?? this.queue,
       currentIndex: currentIndex ?? this.currentIndex,
       playing: playing ?? this.playing,
+      buffering: buffering ?? this.buffering,
       position: position ?? this.position,
       duration: duration ?? this.duration,
       shuffle: shuffle ?? this.shuffle,
@@ -215,7 +225,12 @@ class PlaybackController extends StateNotifier<PlaybackState>
       _maybeSlideWindow();
     });
     player.playerStateStream.listen((s) {
-      state = state.copyWith(playing: s.playing);
+      final ps = s.processingState;
+      state = state.copyWith(
+        playing: s.playing,
+        buffering: ps == ProcessingState.loading ||
+            ps == ProcessingState.buffering,
+      );
     });
     player.positionStream.listen((p) {
       state = state.copyWith(position: p);
@@ -306,11 +321,10 @@ class PlaybackController extends StateNotifier<PlaybackState>
 
   AudioSource _sourceFor(Song song) {
     final uri = _streamUriFor(song)!;
-    if (!uri.isScheme('file')) _remoteSourceIds.add(song.id);
+    final isRemote = !uri.isScheme('file');
+    if (isRemote) _remoteSourceIds.add(song.id);
     final art = _coverArtUriFor(song);
-    return AudioSource.uri(
+    final tag = MediaItem(
-      uri,
-      tag: MediaItem(
       id: '${song.id}#${_tagSeq++}',
       title: song.title ?? 'Unknown',
       album: song.album,
@@ -318,8 +332,21 @@ class PlaybackController extends StateNotifier<PlaybackState>
       duration:
           song.duration != null ? Duration(seconds: song.duration!) : null,
       artUri: art,
-      ),
     );
+    // Wrap remote streams in a caching source on mobile: it fetches bytes to an
+    // OS-evictable temp file, giving the native player a genuinely seekable
+    // source with a known length — robust against chunked transcodes that omit
+    // Content-Length and against brief network drops. Downloads (file://) are
+    // already seekable, and the media_kit desktop backend uses just_audio's
+    // localhost proxy path we don't rely on, so both stay on the plain source.
+    if (isRemote && (Platform.isAndroid || Platform.isIOS)) {
+      // LockCachingAudioSource is marked experimental in just_audio but is
+      // stable in practice; the streaming reliability it provides is the whole
+      // point of this path.
+      // ignore: experimental_member_use
+      return LockCachingAudioSource(uri, tag: tag);
+    }
+    return AudioSource.uri(uri, tag: tag);
   }
 
   /// Replace the queue with [songs] and start at [startIndex].

lib/state/providers.dart

@@ -549,9 +549,15 @@ final playbackProvider =
     if (local != null) return Uri.file(local);
     final client = ref.read(subsonicClientProvider);
     if (client == null) return null;
+    final rate = ref.read(settingsProvider).streamMaxBitRate;
+    // When transcoding, ask the server to advertise a Content-Length so the
+    // native player can derive a duration and hold position (otherwise the
+    // playhead freezes at 0:00 and the track restarts). Harmless to omit for
+    // original streams, which already carry a real length.
     return client.streamUri(
       s.id,
-      maxBitRate: ref.read(settingsProvider).streamMaxBitRate,
+      maxBitRate: rate,
+      estimateContentLength: rate > 0,
     );
   }
 

lib/subsonic/subsonic_client.dart

@@ -302,11 +302,25 @@ class SubsonicClient {
   /// manager, which fetches these bytes to disk). `maxBitRate == 0` means
   /// original / no transcode; [format] requests a specific transcode container
   /// (e.g. `mp3`, `opus`), or null for the server default / original.
-  Uri streamUri(String id, {int maxBitRate = 0, String? format}) =>
+  ///
+  /// [estimateContentLength] asks the server to send an (estimated)
+  /// `Content-Length` header even for on-the-fly transcodes. Transcoded
+  /// responses are otherwise chunked with no length and no byte ranges, so the
+  /// native player reports `duration == null`, never reaches `ready`, and the
+  /// playhead freezes at 0:00 (then restarts). Only meaningful when transcoding
+  /// (`maxBitRate > 0` or a [format]); original streams already carry a real
+  /// length.
+  Uri streamUri(
+    String id, {
+    int maxBitRate = 0,
+    String? format,
+    bool estimateContentLength = false,
+  }) =>
       _uri('stream', {
         'id': id,
         if (maxBitRate > 0) 'maxBitRate': '$maxBitRate',
         if (format != null && format.isNotEmpty) 'format': format,
+        if (estimateContentLength) 'estimateContentLength': 'true',
       });
 
   /// Signed cover-art URL. [size] is clamped to Subsonic's 32–2048 range.