feat: add source change support and re-add prefetching tracks

lib/components/player/player_queue.dart

@@ -161,7 +161,7 @@ class PlayerQueue extends HookConsumerWidget {
                         snap: false,
                         backgroundColor: Colors.transparent,
                         elevation: 0,
-                        automaticallyImplyLeading: !isSearching.value,
+                        automaticallyImplyLeading: false,
                         title: BackdropFilter(
                           filter: ImageFilter.blur(
                             sigmaX: 10,

lib/provider/proxy_playlist/player_listeners.dart

@@ -6,6 +6,7 @@ import 'package:catcher_2/catcher_2.dart';
 import 'package:spotube/models/local_track.dart';
 import 'package:spotube/provider/proxy_playlist/proxy_playlist_provider.dart';
 import 'package:spotube/provider/proxy_playlist/skip_segments.dart';
+import 'package:spotube/provider/server/sourced_track.dart';
 import 'package:spotube/services/audio_player/audio_player.dart';
 
 extension ProxyPlaylistListeners on ProxyPlaylistNotifier {
@@ -63,6 +64,21 @@ extension ProxyPlaylistListeners on ProxyPlaylistNotifier {
     });
   }
 
+  StreamSubscription subscribeToPosition() {
+    String lastTrack = ""; // used to prevent multiple calls to the same track
+    return audioPlayer.positionStream.listen((event) async {
+      if (event < const Duration(seconds: 3) ||
+          state.active == null ||
+          state.active == state.tracks.length - 1) return;
+      final nextTrack = state.tracks.elementAt(state.active! + 1);
+
+      if (lastTrack == nextTrack.id) return;
+
+      await ref.read(sourcedTrackProvider(nextTrack).future);
+      lastTrack = nextTrack.id!;
+    });
+  }
+
   StreamSubscription subscribeToPlayerError() {
     return audioPlayer.errorStream.listen((event) {});
   }

lib/provider/proxy_playlist/proxy_playlist_provider.dart

@@ -51,6 +51,7 @@ class ProxyPlaylistNotifier extends PersistedStateNotifier<ProxyPlaylist> {
       // These are subscription methods from player_listeners.dart
       subscribeToPlaylist(),
       subscribeToSkipSponsor(),
+      subscribeToPosition(),
       subscribeToScrobbleChanged(),
     ];
   }

lib/provider/server/server.dart

@@ -13,9 +13,9 @@ import 'package:spotube/models/logger.dart';
 import 'package:spotube/provider/proxy_playlist/proxy_playlist.dart';
 import 'package:spotube/provider/proxy_playlist/proxy_playlist_provider.dart';
 import 'package:spotube/provider/server/active_sourced_track.dart';
+import 'package:spotube/provider/server/sourced_track.dart';
 import 'package:spotube/provider/user_preferences/user_preferences_provider.dart';
 import 'package:spotube/provider/user_preferences/user_preferences_state.dart';
-import 'package:spotube/services/sourced_track/sourced_track.dart';
 
 class PlaybackServer {
   final Ref ref;
@@ -38,7 +38,6 @@ class PlaybackServer {
 
     if (kDebugMode) {
       pipeline.addMiddleware(logRequests());
-      dio.interceptors.add(LogInterceptor());
     }
 
     serve(pipeline.addHandler(router.call), InternetAddress.loopbackIPv4, port)
@@ -58,13 +57,15 @@ class PlaybackServer {
     try {
       final track =
           playlist.tracks.firstWhere((element) => element.id == trackId);
-      final sourcedTrack =
-          await SourcedTrack.fetchFromTrack(track: track, ref: ref);
+      final activeSourcedTrack = ref.read(activeSourcedTrackProvider);
+      final sourcedTrack = activeSourcedTrack?.id == track.id
+          ? activeSourcedTrack
+          : await ref.read(sourcedTrackProvider(track).future);
 
       ref.read(activeSourcedTrackProvider.notifier).update(sourcedTrack);
 
       final res = await dio.get(
-        sourcedTrack.url,
+        sourcedTrack!.url,
         options: Options(
           headers: {
             ...request.headers,
@@ -75,13 +76,14 @@ class PlaybackServer {
             "Connection": "keep-alive",
           },
           responseType: ResponseType.stream,
+          validateStatus: (status) => status! < 500,
         ),
       );
 
       final audioStream = res.data?.stream as Stream<Uint8List>?;
 
       return Response(
-        200,
+        res.statusCode!,
         body: audioStream,
         context: {
           "shelf.io.buffer_output": false,

lib/provider/server/sourced_track.dart

@@ -0,0 +1,27 @@
+import 'package:collection/collection.dart';
+import 'package:hooks_riverpod/hooks_riverpod.dart';
+import 'package:spotify/spotify.dart';
+import 'package:spotube/provider/proxy_playlist/proxy_playlist_provider.dart';
+import 'package:spotube/services/sourced_track/sourced_track.dart';
+
+final sourcedTrackProvider =
+    FutureProvider.family<SourcedTrack?, Track?>((ref, track) async {
+  if (track == null) {
+    return null;
+  }
+
+  ref.listen(
+    ProxyPlaylistNotifier.provider,
+    (old, next) {
+      if (next.tracks.isEmpty ||
+          next.tracks.none((element) => element.id == track.id)) {
+        ref.invalidateSelf();
+      }
+    },
+  );
+
+  final sourcedTrack =
+      await SourcedTrack.fetchFromTrack(track: track, ref: ref);
+
+  return sourcedTrack;
+});