✨ Endless playback

lib/main.dart

@@ -7,6 +7,7 @@ import 'package:rhythm_box/providers/audio_player.dart';
 import 'package:rhythm_box/providers/audio_player_stream.dart';
 import 'package:rhythm_box/providers/auth.dart';
 import 'package:rhythm_box/providers/database.dart';
+import 'package:rhythm_box/providers/endless_playback.dart';
 import 'package:rhythm_box/providers/history.dart';
 import 'package:rhythm_box/providers/palette.dart';
 import 'package:rhythm_box/providers/scrobbler.dart';
@@ -92,6 +93,7 @@ class MyApp extends StatelessWidget {
     Get.put(AudioPlayerProvider());
     Get.put(ActiveSourcedTrackProvider());
     Get.put(AudioPlayerStreamProvider());
+    Get.put(EndlessPlaybackProvider());
 
     Get.put(PlaybackHistoryProvider());
     Get.put(SegmentsProvider());

lib/providers/endless_playback.dart

@@ -0,0 +1,103 @@
+import 'dart:async';
+import 'dart:developer';
+
+import 'package:get/get.dart';
+import 'package:rhythm_box/providers/audio_player.dart';
+import 'package:rhythm_box/providers/auth.dart';
+import 'package:rhythm_box/providers/spotify.dart';
+import 'package:rhythm_box/providers/user_preferences.dart';
+import 'package:rhythm_box/services/audio_player/audio_player.dart';
+import 'package:spotify/spotify.dart';
+
+class EndlessPlaybackProvider extends GetxController {
+  late final _auth = Get.find<AuthenticationProvider>();
+  late final _playback = Get.find<AudioPlayerProvider>();
+  late final _spotify = Get.find<SpotifyProvider>().api;
+  late final _preferences = Get.find<UserPreferencesProvider>();
+
+  bool get isEndlessPlayback => _preferences.state.value.endlessPlayback;
+
+  late final StreamSubscription _subscription;
+
+  StreamSubscription? _idxSubscription;
+
+  @override
+  void onInit() {
+    super.onInit();
+
+    _initPlayback();
+
+    _subscription = _preferences.state.listen((value) {
+      if (value.endlessPlayback && _idxSubscription == null) {
+        _initPlayback();
+      } else if (!value.endlessPlayback && _idxSubscription != null) {
+        _idxSubscription!.cancel();
+        _idxSubscription = null;
+      }
+    });
+  }
+
+  @override
+  void dispose() {
+    _subscription.cancel();
+    super.dispose();
+  }
+
+  void _initPlayback() {
+    if (!isEndlessPlayback || _auth.auth.value == null) return;
+
+    void listener(int index) async {
+      try {
+        final playState = _playback.state.value;
+        if (index != playState.tracks.length - 1) return;
+
+        final track = playState.tracks.last;
+
+        final query = '${track.name} Radio';
+        final pages = await _spotify.search
+            .get(query, types: [SearchType.playlist]).first();
+
+        final radios = pages
+            .expand((e) => e.items?.toList() ?? <PlaylistSimple>[])
+            .toList()
+            .cast<PlaylistSimple>();
+
+        final artists = track.artists!.map((e) => e.name);
+
+        final radio = radios.firstWhere(
+          (e) {
+            final validPlaylists =
+                artists.where((a) => e.description!.contains(a!));
+            return e.name == '${track.name} Radio' &&
+                (validPlaylists.length >= 2 ||
+                    validPlaylists.length == artists.length) &&
+                e.owner?.displayName != 'Spotify';
+          },
+          orElse: () => radios.first,
+        );
+
+        final tracks =
+            await _spotify.playlists.getTracksByPlaylistId(radio.id!).all();
+
+        await _playback.addTracks(
+          tracks.toList()
+            ..removeWhere((e) {
+              final isDuplicate =
+                  _playback.state.value.tracks.any((t) => t.id == e.id);
+              return e.id == track.id || isDuplicate;
+            }),
+        );
+      } catch (e, stack) {
+        log('[EndlessPlayback] Error: $e; Trace:\n$stack');
+      }
+    }
+
+    if (_playback.state.value.playlist.index ==
+            _playback.state.value.playlist.medias.length - 1 &&
+        _playback.isPlaying.value) {
+      listener(_playback.state.value.playlist.index);
+    }
+
+    _idxSubscription = audioPlayer.currentIndexChangedStream.listen(listener);
+  }
+}

lib/screens/settings.dart

@@ -100,6 +100,17 @@ class _SettingsScreenState extends State<SettingsScreen> {
                 );
               }),
               const Divider(thickness: 0.3, height: 1),
+              Obx(
+                () => SwitchListTile(
+                  contentPadding: const EdgeInsets.symmetric(horizontal: 24),
+                  secondary: const Icon(Icons.all_inclusive),
+                  title: const Text('Endless Playback'),
+                  subtitle: const Text(
+                      'Automatically get more recommendation for you after your queue finish playing'),
+                  value: _preferences.state.value.endlessPlayback,
+                  onChanged: _preferences.setEndlessPlayback,
+                ),
+              ),
               Obx(
                 () => SwitchListTile(
                   contentPadding: const EdgeInsets.symmetric(horizontal: 24),

lib/widgets/lyrics/synced_lyrics.dart

@@ -63,8 +63,16 @@ class _SyncedLyricsState extends State<SyncedLyrics> {
           idx,
           preferPosition: AutoScrollPosition.middle,
         );
+        return;
       }
     }
+
+    if (_lyric!.lyrics.isNotEmpty) {
+      _autoScrollController.scrollToIndex(
+        0,
+        preferPosition: AutoScrollPosition.begin,
+      );
+    }
   }
 
   @override
@@ -77,7 +85,9 @@ class _SyncedLyricsState extends State<SyncedLyrics> {
       _playback.state.listen((value) {
         if (value.activeTrack == null) return;
         if (value.activeTrack!.id != _activeTrackId) {
-          _pullLyrics();
+          _pullLyrics().then((_) {
+            _syncLyricsProgress();
+          });
         }
       }),
     ];