Initial mediaplayer implementation

Notable changes:
- Added dart_mpd package as a dependency.
- Added MPD client class and associated provider.
- Added MPD client configuration to the configuration file for
  potential usecases where MPD may not be available locally.
- Added playlist, play state, art, etc. providers for use in the
  mediaplayer front end UI.
- Reworked MediaPlayer classes to wire up MPD client backend.
- Removed volume slider from the bottom of the media pages to
  make more room for playlist / preset tables, as only being
  able to show 3 entries in each was not usable in practice.
- Reworked media player mocked up position indicator into an
  actual slider control, and reworked the radio slider styling
  to match for better UI consistency.
- Reworked media player and radio playlist / preset tables to
  attempt to have them layout at the same location and add an
  always visible scroll bar.  The scroll bars currently have a
  layout issue with respect to scroll track size that does not
  seem to have an obvious fix.  They are usable for now, and
  further investigation will be done when time permits.
- Wired up play/pause button on the side volume control via a
  new set of play state and controller providers.

Bug-AGL: SPEC-5028, SPEC-5029

Change-Id: I87efecc58b4e185443942eb32ff8148ebcd675c3
Signed-off-by: Scott Murray <scott.murray@konsulko.com>

1 files changed, 378 insertions, 0 deletions

diff --git a/lib/data/data_providers/mpd_client.dart b/lib/data/data_providers/mpd_client.dart
new file mode 100644
index 0000000..98d8918
--- /dev/null
+++ b/lib/data/data_providers/mpd_client.dart
@@ -0,0 +1,378 @@
+import 'package:dart_mpd/dart_mpd.dart' as api;
+import 'package:flutter_ics_homescreen/export.dart';
+import 'playlist_notifier.dart';
+
+class ArtStateEntry {
+  bool reading = false;
+  bool read = false;
+
+  ArtStateEntry({required this.reading, required this.read});
+}
+
+class MpdClient {
+  final MpdConfig config;
+  final Ref ref;
+  late api.MpdClient eventClient;
+  late api.MpdClient client;
+  Map<int, ArtStateEntry> artState = {};
+
+  MpdClient({required this.config, required this.ref}) {
+    debugPrint("Connecting to MPD at ${config.hostname}:${config.port}");
+    client = api.MpdClient(
+        connectionDetails: api.MpdConnectionDetails(
+            host: config.hostname,
+            port: config.port,
+            timeout: const Duration(minutes: 2)),
+        onConnect: () => handleConnect(),
+        onDone: () => handleDone(),
+        onError: (e, st) => handleError(e, st));
+
+    // Second client instance to keep running in idle state to receive
+    // events
+    eventClient = api.MpdClient(
+        connectionDetails: api.MpdConnectionDetails(
+            host: config.hostname,
+            port: config.port,
+            timeout: const Duration(minutes: 2)),
+        onConnect: () => handleConnect(),
+        onDone: () => handleDone(),
+        onError: (e, st) => handleError(e, st));
+  }
+
+  void run() async {
+    var idleEvents = <api.MpdSubsystem>{
+      api.MpdSubsystem.database,
+      api.MpdSubsystem.playlist,
+      api.MpdSubsystem.player
+    };
+    bool done = false;
+    while (!done) {
+      //debugPrint("Calling MPD idle!");
+      var events = await eventClient.idle(idleEvents);
+      for (var event in events) {
+        switch (event) {
+          case api.MpdSubsystem.database:
+            //debugPrint("Got MPD database event");
+            await handleDatabaseEvent();
+            break;
+          case api.MpdSubsystem.playlist:
+            //debugPrint("Got MPD queue event");
+            await handleQueueEvent();
+            break;
+          case api.MpdSubsystem.player:
+            //debugPrint("Got MPD player event");
+            await handlePlayerEvent();
+            break;
+          default:
+            break;
+        }
+      }
+    }
+  }
+
+  void handleConnect() {
+    debugPrint("Connected to MPD!");
+  }
+
+  void handleResponse(api.MpdResponse response) {
+    debugPrint('Got MPD response $response');
+  }
+
+  void handleDone() {
+    debugPrint('Got MPD done!');
+  }
+
+  void handleError(Object e, StackTrace st) {
+    debugPrint('ERROR:\n$st');
+  }
+
+  // Idle state event handlers
+
+  Future handleDatabaseEvent() async {
+    eventClient.clear();
+    eventClient.add("/");
+  }
+
+  Future handleQueueEvent() async {
+    ref.read(playlistProvider.notifier).clear();
+    artState.clear();
+    ref.read(playlistArtProvider.notifier).clear();
+    ref.read(mediaPlayerStateProvider.notifier).reset();
+
+    var songs = await eventClient.playlistinfo();
+    for (var song in songs) {
+      //debugPrint("Got song ${song.title} - ${song.artist} at pos ${song.pos}");
+      int position = 0;
+      if (song.pos != null) {
+        position = song.pos!;
+      } else {
+        //debugPrint("WARNING: song has no position in queue, ignoring");
+        continue;
+      }
+      String title = "";
+      if (song.title != null) {
+        title = song.title!.join(" ");
+      } else {
+        // Just use filename
+        title = song.file;
+      }
+      String album = "";
+      if (song.album != null) {
+        album = song.album!.join(" ");
+      }
+      String artist = "";
+      if (song.artist != null) {
+        artist = song.artist!.join(" ");
+      }
+      Duration duration = Duration.zero;
+      if (song.duration != null) {
+        duration = song.duration!;
+      }
+      //debugPrint(
+      //    "Got playlist entry \"$title\" - \"$album\" - \"$artist\" at $position");
+
+      if (position == 0) {
+        ref.read(mediaPlayerStateProvider.notifier).updateCurrent(PlaylistEntry(
+            title: title,
+            album: album,
+            artist: artist,
+            file: song.file,
+            duration: duration,
+            position: position));
+
+        if (song.file.isNotEmpty) {
+          readSongArt(position, song.file);
+        }
+      }
+      ref.read(playlistProvider.notifier).add(PlaylistEntry(
+          title: title,
+          album: album,
+          artist: artist,
+          file: song.file,
+          duration: duration,
+          position: position));
+    }
+  }
+
+  Future handlePlayerEvent() async {
+    String songFile = "";
+    int songPosition = -1;
+    var song = await eventClient.currentsong();
+    if (song != null) {
+      //debugPrint(
+      //    "Player event: song ${song.title} - ${song.artist} at pos ${song.pos}");
+      if (song.pos != null) {
+        songPosition = song.pos!;
+      }
+      if (songPosition < 0) {
+        debugPrint("WARNING: song has no position in queue, ignoring");
+        return;
+      }
+      String title = "";
+      if (song.title != null) {
+        title = song.title!.first;
+      } else {
+        // Just use filename
+        title = song.file;
+      }
+      String album = "";
+      if (song.album != null) {
+        album = song.album!.first;
+      }
+      String artist = "";
+      if (song.artist != null) {
+        artist = song.artist!.first;
+      }
+      Duration duration = Duration.zero;
+      if (song.duration != null) {
+        duration = song.duration!;
+      }
+      songFile = song.file;
+      //debugPrint(
+      //    "Got song \"$title\" - \"$album\" - \"$artist\" at $songPosition, file \"$songFile\"");
+      ref.read(mediaPlayerStateProvider.notifier).updateCurrent(PlaylistEntry(
+          title: title,
+          album: album,
+          artist: artist,
+          file: songFile,
+          duration: duration,
+          position: songPosition));
+    }
+
+    var status = await eventClient.status();
+    if (status.elapsed != null) {
+      //debugPrint("Using elapsed time ${status.elapsed} s");
+      ref
+          .read(mediaPlayerPositionProvider.notifier)
+          .set(Duration(milliseconds: (status.elapsed! * 1000.0).toInt()));
+    }
+    PlayState playState = PlayState.stopped;
+    if (status.state != null) {
+      switch (status.state!) {
+        case api.MpdState.stop:
+          //debugPrint("status.state = stop");
+          playState = PlayState.stopped;
+          ref.read(mediaPlayerPositionProvider.notifier).pause();
+          break;
+        case api.MpdState.play:
+          //debugPrint("status.state = play");
+          playState = PlayState.playing;
+          ref.read(mediaPlayerPositionProvider.notifier).play();
+          break;
+        case api.MpdState.pause:
+          //debugPrint("status.state = paused");
+          playState = PlayState.paused;
+          ref.read(mediaPlayerPositionProvider.notifier).pause();
+          break;
+        default:
+          break;
+      }
+      ref.read(mediaPlayerStateProvider.notifier).updatePlayState(playState);
+    }
+
+    if (playState != PlayState.playing) {
+      // No need to attempt to load art, exit
+      return;
+    }
+
+    if (!artState.containsKey(songPosition) ||
+        !(artState[songPosition]!.read || artState[songPosition]!.reading)) {
+      if (songFile.isNotEmpty) {
+        readSongArt(songPosition, songFile);
+      } else {
+        // Do not attempt any fallback for providing the art for now
+        debugPrint("No file for position $songPosition, no art");
+        artState[songPosition] = ArtStateEntry(reading: false, read: true);
+        ref
+            .read(playlistArtProvider.notifier)
+            .update(songPosition, Uint8List(0));
+      }
+    }
+  }
+
+  void readSongArt(int position, String file) async {
+    int offset = 0;
+    int size = 0;
+    List<int> bytes = [];
+
+    if (artState.containsKey(position)) {
+      if (artState[position]!.reading) {
+        return;
+      } else {
+        //debugPrint("Reading art for position $position");
+        artState[position]!.reading = true;
+      }
+    } else {
+      artState[position] = ArtStateEntry(reading: true, read: false);
+    }
+    debugPrint("Reading art for \"$file\"");
+    // Work around dart_mpd not escaping spaced strings itself
+    String escapedFile = file.replaceAll(RegExp(r" "), "\\ ");
+    escapedFile = "\"$file\"";
+
+    bool first = true;
+    do {
+      //debugPrint("Reading, offset = $offset, size = $size");
+      var chunk = await client.readpicture(escapedFile, offset);
+      if (chunk != null) {
+        if (chunk.size != null) {
+          if (chunk.size == 0) {
+            if (first) {
+              // No art, exit
+              break;
+            }
+          }
+          size = chunk.size!;
+        }
+        // else unexpected error
+
+        if (chunk.bytes.isNotEmpty) {
+          //debugPrint("Got ${chunk.bytes.length} bytes of album art");
+          bytes = bytes + chunk.bytes;
+          offset += chunk.bytes.length;
+        } else {
+          break;
+        }
+      }
+    } while (offset < size);
+    //debugPrint("Done, offset = $offset, size = $size");
+
+    if (offset == size) {
+      debugPrint("Read $size bytes of album art for $file");
+    } else {
+      // else error, leave art empty
+      bytes.clear();
+    }
+
+    artState[position]!.read = true;
+    artState[position]!.reading = false;
+    ref
+        .read(playlistArtProvider.notifier)
+        .update(position, Uint8List.fromList(bytes));
+  }
+
+  // Player commands
+
+  void play() async {
+    var playState = ref.read(mediaPlayerStateProvider
+        .select((mediaplayer) => mediaplayer.playState));
+    if (playState == PlayState.stopped) {
+      int position = ref.read(mediaPlayerStateProvider
+          .select((mediaplayer) => mediaplayer.playlistPosition));
+      //debugPrint("Calling MPD play, position = $position");
+      if (position >= 0) {
+        client.play(position);
+      }
+    } else if (playState == PlayState.paused) {
+      client.pause(false);
+    }
+  }
+
+  void pause() async {
+    if (ref.read(mediaPlayerStateProvider
+            .select((mediaplayer) => mediaplayer.playState)) ==
+        PlayState.playing) {
+      client.pause(true);
+    }
+  }
+
+  void next() async {
+    if (ref.read(mediaPlayerStateProvider
+            .select((mediaplayer) => mediaplayer.playState)) ==
+        PlayState.playing) {
+      client.next();
+    }
+  }
+
+  void previous() async {
+    if (ref.read(mediaPlayerStateProvider
+            .select((mediaplayer) => mediaplayer.playState)) ==
+        PlayState.playing) {
+      client.previous();
+    }
+  }
+
+  void seek(int milliseconds) async {
+    client.seekcur((milliseconds / 1000.0).toString());
+  }
+
+  void fastForward(int milliseconds) async {
+    if (milliseconds > 0) {
+      client.seekcur("+${(milliseconds / 1000.0).toString()}");
+    }
+  }
+
+  void rewind(int milliseconds) async {
+    if (milliseconds > 0) {
+      client.seekcur("-${(milliseconds / 1000.0).toString()}");
+    }
+  }
+
+  void pickTrack(int position) async {
+    if (position >= 0) {
+      client.play(position);
+    }
+  }
+
+  void loopPlaylist(bool loop) async {}
+}