implemented current position

lib/domain/repositories/audio_repository.dart

@@ -7,6 +7,7 @@ import '../entities/song.dart';
 abstract class AudioRepository {
   Stream<Song> get currentSongStream;
   Stream<PlaybackState> get playbackStateStream;
+  Stream<int> get currentPositionStream;
 
   Future<Either<Failure, void>> playSong(int index, List<Song> songList);
   Future<Either<Failure, void>> play();

lib/presentation/pages/currently_playing.dart

@@ -90,7 +90,7 @@ class CurrentlyPlayingPage extends StatelessWidget {
                         const Spacer(
                           flex: 3,
                         ),
-                        TimeProgressIndicator(),
+                        const TimeProgressIndicator(),
                         const Spacer(
                           flex: 3,
                         ),

lib/presentation/state/audio_store.dart

@@ -32,12 +32,18 @@ abstract class _AudioStore with Store {
   @observable
   ObservableStream<PlaybackState> playbackStateStream;
 
+  @observable
+  ObservableStream<int> currentPositionStream;
+
   @action
   Future<void> init() async {
     if (!_initialized) {
       print('AudioStore.init');
       currentSong = _audioRepository.currentSongStream.asObservable();
 
+      currentPositionStream =
+          _audioRepository.currentPositionStream.asObservable(initialValue: 0);
+
       _disposers.add(autorun((_) {
         updateSong(currentSong.value);
       }));

lib/presentation/state/audio_store.g.dart

@@ -63,6 +63,26 @@ mixin _$AudioStore on _AudioStore, Store {
         name: '${_$playbackStateStreamAtom.name}_set');
   }
 
+  final _$currentPositionStreamAtom =
+      Atom(name: '_AudioStore.currentPositionStream');
+
+  @override
+  ObservableStream<int> get currentPositionStream {
+    _$currentPositionStreamAtom.context
+        .enforceReadPolicy(_$currentPositionStreamAtom);
+    _$currentPositionStreamAtom.reportObserved();
+    return super.currentPositionStream;
+  }
+
+  @override
+  set currentPositionStream(ObservableStream<int> value) {
+    _$currentPositionStreamAtom.context.conditionallyRunInAction(() {
+      super.currentPositionStream = value;
+      _$currentPositionStreamAtom.reportChanged();
+    }, _$currentPositionStreamAtom,
+        name: '${_$currentPositionStreamAtom.name}_set');
+  }
+
   final _$initAsyncAction = AsyncAction('init');
 
   @override
@@ -101,7 +121,7 @@ mixin _$AudioStore on _AudioStore, Store {
   @override
   String toString() {
     final string =
-        'currentSong: ${currentSong.toString()},song: ${song.toString()},playbackStateStream: ${playbackStateStream.toString()}';
+        'currentSong: ${currentSong.toString()},song: ${song.toString()},playbackStateStream: ${playbackStateStream.toString()},currentPositionStream: ${currentPositionStream.toString()}';
     return '{$string}';
   }
 }

lib/presentation/utils.dart

@@ -10,3 +10,25 @@ ImageProvider getAlbumImage(String albumArtPath) {
   }
   return FileImage(File(albumArtPath));
 }
+
+String msToTimeString(int milliseconds) {
+  String twoDigits(num n) {
+    if (n >= 10) {
+      return '$n';
+    }
+    return '0$n';
+  }
+
+  final Duration duration = Duration(seconds: (milliseconds / 1000).round());
+
+  final int hours = duration.inHours;
+  final int minutes = duration.inMinutes.remainder(60) as int;
+  
+  final String twoDigitMinutes = twoDigits(minutes);
+  final String twoDigitSeconds = twoDigits(duration.inSeconds.remainder(60));
+
+  if (hours > 0) {
+    return '$hours:$twoDigitMinutes:$twoDigitSeconds';
+  }
+  return '$minutes:$twoDigitSeconds';
+}

lib/presentation/widgets/currently_playing_bar.dart

@@ -23,8 +23,8 @@ class CurrentlyPlayingBar extends StatelessWidget {
           return Column(
             children: <Widget>[
               Container(
-                child: const LinearProgressIndicator(
+                child: LinearProgressIndicator(
-                  value: 0.42,
+                  value: audioStore.currentPositionStream.value / audioStore.currentSong.value.duration,
                 ),
                 height: 2,
               ),

lib/presentation/widgets/time_progress_indicator.dart

@@ -1,35 +1,42 @@
 import 'package:flutter/material.dart';
+import 'package:flutter_mobx/flutter_mobx.dart';
+import 'package:provider/provider.dart';
 
-class TimeProgressIndicator extends StatefulWidget {
+import '../state/audio_store.dart';
-  TimeProgressIndicator({Key key}) : super(key: key);
+import '../utils.dart';
 
-  @override
+class TimeProgressIndicator extends StatelessWidget {
-  _TimeProgressIndicatorState createState() => _TimeProgressIndicatorState();
+  const TimeProgressIndicator({Key key}) : super(key: key);
-}
 
-class _TimeProgressIndicatorState extends State<TimeProgressIndicator> {
   @override
   Widget build(BuildContext context) {
-    return Padding(
+    final AudioStore audioStore = Provider.of<AudioStore>(context);
-      padding: const EdgeInsets.symmetric(horizontal: 16.0),
+
-      child: Row(
+    return Observer(
-        children: [
+      builder: (BuildContext context) {
-          Text("0:42"),
+        return Padding(
-          Container(
+          padding: const EdgeInsets.symmetric(horizontal: 16.0),
-            width: 10,
+          child: Row(
+            children: [
+              Text(msToTimeString(audioStore.currentPositionStream.value)),
+              Container(
+                width: 10,
+              ),
+              Expanded(
+                child: Container(
+                  child: LinearProgressIndicator(value: audioStore.currentPositionStream.value / audioStore.currentSong.value.duration),
+                  height: 3.0,
+                ),
+              ),
+              Container(
+                width: 10,
+              ),
+              Text(msToTimeString(audioStore.currentSong.value.duration)),
+            ],
+            mainAxisAlignment: MainAxisAlignment.spaceEvenly,
           ),
-          Expanded(
+        );
-              child: Container(
+      },
-            child: LinearProgressIndicator(value: 0.42),
-            height: 3.0,
-          )),
-          Container(
-            width: 10,
-          ),
-          Text("3:42"),
-        ],
-        mainAxisAlignment: MainAxisAlignment.spaceEvenly,
-      ),
     );
   }
 }

lib/system/datasources/audio_manager.dart

@@ -1,12 +1,12 @@
 import 'dart:async';
 
 import 'package:audio_service/audio_service.dart';
-import 'package:just_audio/just_audio.dart';
 
 import '../../domain/entities/playback_state.dart' as entity;
 import '../models/playback_state_model.dart';
 import '../models/song_model.dart';
 import 'audio_manager_contract.dart';
+import 'audio_player_task.dart';
 
 typedef Conversion<S, T> = T Function(S);
 
@@ -29,6 +29,9 @@ class AudioManagerImpl implements AudioManager {
         (PlaybackState ps) => PlaybackStateModel.fromASPlaybackState(ps),
       );
 
+  @override
+  Stream<int> get currentPositionStream => _position().distinct();
+
   @override
   Future<void> playSong(int index, List<SongModel> songList) async {
     await _startAudioService();
@@ -68,80 +71,35 @@ class AudioManagerImpl implements AudioManager {
       }
     }
   }
+
+  Stream<int> _position() async* {
+    BasicPlaybackState state;
+    int updateTime;
+    int statePosition;
+
+    // should this class get an init method for this?
+    _sourcePlaybackStateStream.listen((currentState) {
+      state = currentState?.basicState;
+      updateTime = currentState?.updateTime;
+      statePosition = currentState?.position;
+    });
+
+    while (true) {
+      if (statePosition != null && updateTime != null && state != null) {
+        if (state == BasicPlaybackState.playing) {
+          yield statePosition +
+              (DateTime.now().millisecondsSinceEpoch - updateTime);
+        } else {
+          yield statePosition;
+        }
+      } else {
+        yield 0;
+      }
+      await Future.delayed(const Duration(milliseconds: 200));
+    }
+  }
 }
 
 void _backgroundTaskEntrypoint() {
   AudioServiceBackground.run(() => AudioPlayerTask());
 }
-
-class AudioPlayerTask extends BackgroundAudioTask {
-  final _audioPlayer = AudioPlayer();
-  final _completer = Completer();
-
-  final _mediaItems = <String, MediaItem>{};
-
-  @override
-  Future<void> onStart() async {
-    // AudioServiceBackground.setState(
-    //   controls: [],
-    //   basicState: BasicPlaybackState.none,
-    // );
-    await _completer.future;
-  }
-
-  @override
-  void onStop() {
-    _audioPlayer.stop();
-    _completer.complete();
-  }
-
-  @override
-  void onAddQueueItem(MediaItem mediaItem) {
-    _mediaItems[mediaItem.id] = mediaItem;
-  }
-
-  @override
-  Future<void> onPlayFromMediaId(String mediaId) async {
-    AudioServiceBackground.setState(
-      controls: [pauseControl, stopControl],
-      basicState: BasicPlaybackState.playing,
-    );
-
-    await AudioServiceBackground.setMediaItem(_mediaItems[mediaId]);
-    await _audioPlayer.setFilePath(mediaId);
-
-    _audioPlayer.play();
-  }
-
-  @override
-  Future<void> onPlay() async {
-    AudioServiceBackground.setState(
-        controls: [pauseControl, stopControl],
-        basicState: BasicPlaybackState.playing);
-    _audioPlayer.play();
-  }
-
-  @override
-  Future<void> onPause() async {
-    AudioServiceBackground.setState(
-        controls: [playControl, stopControl],
-        basicState: BasicPlaybackState.paused);
-    await _audioPlayer.pause();
-  }
-}
-
-MediaControl playControl = const MediaControl(
-  androidIcon: 'drawable/ic_action_play_arrow',
-  label: 'Play',
-  action: MediaAction.play,
-);
-MediaControl pauseControl = const MediaControl(
-  androidIcon: 'drawable/ic_action_pause',
-  label: 'Pause',
-  action: MediaAction.pause,
-);
-MediaControl stopControl = const MediaControl(
-  androidIcon: 'drawable/ic_action_stop',
-  label: 'Stop',
-  action: MediaAction.stop,
-);

lib/system/datasources/audio_manager_contract.dart

@@ -4,6 +4,8 @@ import '../models/song_model.dart';
 abstract class AudioManager {
   Stream<SongModel> get currentSongStream;
   Stream<PlaybackState> get playbackStateStream;
+  /// Current position in the song in milliseconds.
+  Stream<int> get currentPositionStream;
 
   Future<void> playSong(int index, List<SongModel> songList);
   Future<void> play();

lib/system/datasources/audio_player_task.dart

@@ -0,0 +1,87 @@
+import 'dart:async';
+
+import 'package:audio_service/audio_service.dart';
+import 'package:just_audio/just_audio.dart';
+
+class AudioPlayerTask extends BackgroundAudioTask {
+  final _audioPlayer = AudioPlayer();
+  final _completer = Completer();
+
+  final _mediaItems = <String, MediaItem>{};
+
+  Duration _position;
+
+  @override
+  Future<void> onStart() async {
+    _audioPlayer.getPositionStream().listen((duration) => _position = duration);
+
+    // AudioServiceBackground.setState(
+    //   controls: [],
+    //   basicState: BasicPlaybackState.none,
+    // );
+    await _completer.future;
+  }
+
+  @override
+  void onStop() {
+    _audioPlayer.stop();
+    _completer.complete();
+  }
+
+  @override
+  void onAddQueueItem(MediaItem mediaItem) {
+    _mediaItems[mediaItem.id] = mediaItem;
+  }
+
+  @override
+  Future<void> onPlayFromMediaId(String mediaId) async {
+    AudioServiceBackground.setState(
+      controls: [pauseControl, stopControl],
+      basicState: BasicPlaybackState.playing,
+      updateTime: DateTime.now().millisecondsSinceEpoch,
+    );
+
+    await AudioServiceBackground.setMediaItem(_mediaItems[mediaId]);
+    await _audioPlayer.setFilePath(mediaId);
+
+    _audioPlayer.play();
+  }
+
+  @override
+  Future<void> onPlay() async {
+    AudioServiceBackground.setState(
+      controls: [pauseControl, stopControl],
+      basicState: BasicPlaybackState.playing,
+      updateTime: DateTime.now().millisecondsSinceEpoch,
+      position: _position.inMilliseconds,
+    );
+    _audioPlayer.play();
+  }
+
+  @override
+  Future<void> onPause() async {
+    AudioServiceBackground.setState(
+      controls: [playControl, stopControl],
+      basicState: BasicPlaybackState.paused,
+      updateTime: DateTime.now().millisecondsSinceEpoch,
+      position: _position.inMilliseconds,
+    );
+    await _audioPlayer.pause();
+  }
+}
+
+MediaControl playControl = const MediaControl(
+  androidIcon: 'drawable/ic_action_play_arrow',
+  label: 'Play',
+  action: MediaAction.play,
+);
+MediaControl pauseControl = const MediaControl(
+  androidIcon: 'drawable/ic_action_pause',
+  label: 'Pause',
+  action: MediaAction.pause,
+);
+MediaControl stopControl = const MediaControl(
+  androidIcon: 'drawable/ic_action_stop',
+  label: 'Stop',
+  action: MediaAction.stop,
+);

lib/system/repositories/audio_repository_impl.dart

@@ -19,6 +19,11 @@ class AudioRepositoryImpl implements AudioRepository {
   Stream<PlaybackState> get playbackStateStream =>
       _audioManager.playbackStateStream;
 
+  @override
+  Stream<int> get currentPositionStream {
+    return _audioManager.currentPositionStream;
+  }
+
   @override
   Future<Either<Failure, void>> playSong(int index, List<Song> songList) async {
     final List<SongModel> songModelList =