feat: supports synchronizing queue between devices

ios/Runner.xcodeproj/project.pbxproj

@@ -380,6 +380,7 @@
 				PRODUCT_BUNDLE_IDENTIFIER = dev.koel.koel;
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				PROVISIONING_PROFILE_SPECIFIER = "";
+				SUPPORTED_PLATFORMS = "iphonesimulator iphoneos";
 				SWIFT_OBJC_BRIDGING_HEADER = "Runner/Runner-Bridging-Header.h";
 				SWIFT_VERSION = 5.0;
 				TARGETED_DEVICE_FAMILY = 1;
@@ -556,6 +557,7 @@
 				PRODUCT_BUNDLE_IDENTIFIER = dev.koel.koel;
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				PROVISIONING_PROFILE_SPECIFIER = "";
+				SUPPORTED_PLATFORMS = "iphonesimulator iphoneos";
 				SWIFT_OBJC_BRIDGING_HEADER = "Runner/Runner-Bridging-Header.h";
 				SWIFT_VERSION = 5.0;
 				TARGETED_DEVICE_FAMILY = 1;

lib/audio_handler.dart

@@ -1,10 +1,16 @@
 import 'dart:io';
 
+import 'package:app/app_state.dart';
 import 'package:app/models/models.dart';
 import 'package:app/providers/providers.dart';
+import 'package:app/utils/api_request.dart';
+import 'package:app/values/queue_state.dart';
 import 'package:audio_service/audio_service.dart';
 import 'package:just_audio/just_audio.dart';
 import 'package:app/utils/preferences.dart' as preferences;
+import 'package:collection/collection.dart';
+import 'package:version/version.dart';
+import 'package:app/extensions/extensions.dart';
 
 class KoelAudioHandler extends BaseAudioHandler with QueueHandler, SeekHandler {
   static const MAX_ERROR_COUNT = 10;
@@ -13,9 +19,11 @@ class KoelAudioHandler extends BaseAudioHandler with QueueHandler, SeekHandler {
   late final SongProvider songProvider;
   late AudioServiceRepeatMode repeatMode;
 
+  var _supportsQueueStateSync = false;
   var _errorCount = 0;
   var _initialized = false;
   var _currentMediaItem = MediaItem(id: '', title: '');
+
   final _player = AudioPlayer();
 
   AudioPlayer get player => _player;
@@ -41,6 +49,17 @@ class KoelAudioHandler extends BaseAudioHandler with QueueHandler, SeekHandler {
 
     await this.setVolume(preferences.volume);
 
+    try {
+      _supportsQueueStateSync = AppState.get<Version>(['app', 'apiVersion'])! >
+          Version.parse('6.11.5');
+    } catch (e) {
+      print(e);
+    }
+
+    if (_supportsQueueStateSync) {
+      _trySetUpQueue();
+    }
+
     _initialized = true;
   }
 
@@ -97,8 +116,55 @@ class KoelAudioHandler extends BaseAudioHandler with QueueHandler, SeekHandler {
     });
   }
 
+  void _trySetUpQueue() async {
+    final state = AppState.get<QueueState>(['app', 'queueState'])!;
+
+    if (state.songs.isEmpty) return;
+
+    try {
+      final songs = songProvider.syncWithVault(state.songs);
+      await replaceQueue(songs, shuffle: false, autoPlay: false);
+
+      if (state.currentSong != null) {
+        var currentSong = songProvider.syncWithVault(state.currentSong).first;
+
+        var queuedMediaItem = queue.value.firstWhereOrNull(
+          (item) => item.id == currentSong.id,
+        );
+
+        if (queuedMediaItem != null) {
+          _setPlayerSource(queuedMediaItem);
+          player.seek(Duration(seconds: state.playbackPosition));
+        }
+      }
+
+      queue.stream.listen((mediaItems) {
+        var songIds = mediaItems.map((item) => item.id).toList();
+        if (songIds.isEmpty) return;
+
+        put('queue/state', data: {
+          'songs': songIds,
+          'song': _currentMediaItem.id,
+        });
+      });
+
+      _player.positionStream.throttle(Duration(seconds: 1)).listen((position) {
+        if (mediaItem.value == null || position.inSeconds % 5 != 0) return;
+
+        put('queue/playback-status', data: {
+          'song': _currentMediaItem.id,
+          'position': position.inSeconds,
+        });
+      });
+    } catch (e) {
+      print(e);
+    }
+  }
+
   _setPlayerSource(MediaItem mediaItem) async {
     _currentMediaItem = mediaItem;
+    this.mediaItem.add(_currentMediaItem);
+
     final song = songProvider.byId(mediaItem.id)!;
     final download = downloadProvider.getForSong(song);
 
@@ -173,12 +239,16 @@ class KoelAudioHandler extends BaseAudioHandler with QueueHandler, SeekHandler {
     if (queue.value.length <= index) return;
 
     final mediaItem = queue.value[index];
-    this.mediaItem.add(mediaItem);
 
     try {
       await _setPlayerSource(mediaItem);
       await play();
 
+      put('queue/playback-status', data: {
+        'song': mediaItem.id,
+        'position': _player.position.inSeconds,
+      });
+
       // Reset the error count if the song is successfully loaded.
       _errorCount = 0;
     } catch (e) {
@@ -236,13 +306,19 @@ class KoelAudioHandler extends BaseAudioHandler with QueueHandler, SeekHandler {
 
   Future<void> setVolume(double value) async => await _player.setVolume(value);
 
-  Future<void> replaceQueue(List<Song> songs, {bool shuffle = false}) async {
+  Future<void> replaceQueue(
+    List<Song> songs, {
+    bool shuffle = false,
+    bool autoPlay = true,
+  }) async {
     final items = await Future.wait(songs.map((song) => song.asMediaItem()));
     if (shuffle) items.shuffle();
 
     await updateQueue(items);
 
-    await _playAtIndex(0);
+    if (autoPlay) {
+      await _playAtIndex(0);
+    }
   }
 
   Future<AudioServiceRepeatMode> rotateRepeatMode() async {

lib/extensions/extensions.dart

@@ -1,3 +1,4 @@
 export 'duration.dart';
 export 'song_list.dart';
 export 'string.dart';
+export 'stream.dart';

lib/extensions/stream.dart

@@ -0,0 +1,17 @@
+import 'dart:async';
+
+extension StreamExtensions<T> on Stream<T> {
+  Stream<T> throttle(Duration duration) {
+    Timer? throttleTimer;
+    StreamController<T> resultStreamController = StreamController<T>();
+
+    listen((event) {
+      if (throttleTimer == null || !throttleTimer!.isActive) {
+        throttleTimer = Timer(duration, () {});
+        resultStreamController.add(event);
+      }
+    });
+
+    return resultStreamController.stream;
+  }
+}

lib/providers/data_provider.dart

@@ -1,7 +1,9 @@
 import 'package:app/app_state.dart';
 import 'package:app/providers/providers.dart';
 import 'package:app/utils/api_request.dart';
+import 'package:app/values/values.dart';
 import 'package:flutter/widgets.dart';
+import 'package:version/version.dart';
 
 class DataProvider with ChangeNotifier {
   final PlaylistProvider _playlistProvider;
@@ -17,6 +19,21 @@ class DataProvider with ChangeNotifier {
     AppState.set(['app', 'cdnUrl'], data['cdn_url']);
     AppState.set(['app', 'transcoding'], data['transcoding']);
 
+    // Since the API version starts with v, we need to remove it before parsing
+    AppState.set(
+      ['app', 'apiVersion'],
+      Version.parse(data['current_version'].toString().substring(1)),
+    );
+
+    if (data.containsKey('queue_state')) {
+      AppState.set(
+        ['app', 'queueState'],
+        QueueState.parse(data['queue_state']),
+      );
+    } else {
+      AppState.set(['app', 'queueState'], QueueState.empty());
+    }
+
     await _playlistProvider.init(data['playlists']);
   }
 }

lib/values/queue_state.dart

@@ -0,0 +1,33 @@
+import 'package:app/models/models.dart';
+
+class QueueState {
+  List<Song> songs;
+  Song? currentSong;
+  int playbackPosition;
+
+  QueueState({
+    required this.songs,
+    this.currentSong,
+    this.playbackPosition = 0,
+  });
+
+  static parse(Map<String, dynamic> json) {
+    return QueueState(
+      songs: (json['songs'] as List<dynamic>)
+          .map<Song>((song) => Song.fromJson(song))
+          .toList(),
+      currentSong: json['current_song'] != null
+          ? Song.fromJson(json['current_song'])
+          : null,
+      playbackPosition: json['playback_position'],
+    );
+  }
+
+  static empty() {
+    return QueueState(
+      songs: [],
+      currentSong: null,
+      playbackPosition: 0,
+    );
+  }
+}

lib/values/values.dart

@@ -1,3 +1,3 @@
 export 'pagination_result.dart';
-export 'parse_result.dart';
 export 'song_sort_config.dart';
+export 'queue_state.dart';

pubspec.lock

@@ -997,6 +997,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.1.4"
+  version:
+    dependency: "direct main"
+    description:
+      name: version
+      sha256: "3d4140128e6ea10d83da32fef2fa4003fccbf6852217bb854845802f04191f94"
+      url: "https://pub.dev"
+    source: hosted
+    version: "3.0.2"
   video_player:
     dependency: transitive
     description:

pubspec.yaml

@@ -47,6 +47,7 @@ dependencies:
   path_provider: ^2.0.14
   scrolls_to_top: ^2.1.0
   fading_edge_scrollview: ^3.0.0
+  version: ^3.0.2
 
 dev_dependencies:
   golden_toolkit: ^0.12.0