Add "Play mix" button in player

lib/api/deezer.dart

@@ -430,5 +430,13 @@ class DeezerAPI {
     });
     return data['results']['data'].map<Track>((t) => Track.fromPrivateJson(t)).toList();
   }
+
+  // Get similar tracks for track with id [trackId]
+  Future<List<Track>> playMix(String trackId) async {
+    Map data = await callApi('song.getContextualTrackMix', params: {
+      'sng_ids': [trackId]
+    });
+    return data['results']['data'].map<Track>((t) => Track.fromPrivateJson(t)).toList();
+  }
 }
 

lib/api/player.dart

@@ -150,35 +150,32 @@ class PlayerHelper {
     //Flow
     if (queueSource == null) return;
 
-    if (queueSource.id == 'flow') {
-      List<Track> tracks = await deezerAPI.flow();
-      List<MediaItem> mi = tracks.map<MediaItem>((t) => t.toMediaItem()).toList();
-      await AudioService.addQueueItems(mi);
-      AudioService.skipToNext();
-      return;
-    }
-
-    //SmartRadio/Artist radio
-    if (queueSource.source == 'smartradio') {
-      List<Track> tracks = await deezerAPI.smartRadio(queueSource.id);
-      List<MediaItem> mi = tracks.map<MediaItem>((t) => t.toMediaItem()).toList();
-      await AudioService.addQueueItems(mi);
-      AudioService.skipToNext();
-      return;
-    }
-
-    //Library shuffle
-    if (queueSource.source == 'libraryshuffle') {
-      List<Track> tracks = await deezerAPI.libraryShuffle(start: AudioService.queue.length);
-      List<MediaItem> mi = tracks.map<MediaItem>((t) => t.toMediaItem()).toList();
-      await AudioService.addQueueItems(mi);
-      AudioService.skipToNext();
-      return;
-    }
-
+    List<Track> tracks = [];
+    switch(queueSource.source) {
+      case 'flow':
+        tracks = await deezerAPI.flow();
+        break;
+      case 'smartradio':      //SmartRadio/Artist radio
+        tracks = await deezerAPI.smartRadio(queueSource.id);
+        break;
+      case 'libraryshuffle':  //Library shuffle
+        tracks = await deezerAPI.libraryShuffle(start: AudioService.queue.length);
+        break;
+      case 'mix':
+        tracks = await deezerAPI.playMix(queueSource.id);
+        // Deduplicate tracks with the same id
+        List<String> queueIds = AudioService.queue.map((e) => e.id).toList();
+        tracks.removeWhere((track) => queueIds.contains(track.id));
+        break;
+      default:
         print(queueSource.toJson());
     }
 
+    List<MediaItem> mi = tracks.map<MediaItem>((t) => t.toMediaItem()).toList();
+    await AudioService.addQueueItems(mi);
+    AudioService.skipToNext();
+  }
+
   //Play track from album
   Future playFromAlbum(Album album, String trackId) async {
     await playFromTrackList(album.tracks, trackId, QueueSource(
@@ -187,6 +184,16 @@ class PlayerHelper {
       source: 'album'
     ));
   }
+
+  //Play mix by track
+  Future playMix(String trackId, String trackTitle) async {
+    List<Track> tracks = await deezerAPI.playMix(trackId);
+    playFromTrackList(tracks, tracks[0].id, QueueSource(
+        id: trackId,
+        text: 'Mix based on'.i18n + ' $trackTitle',
+        source: 'mix'
+    ));
+  }
   //Play from artist top tracks
   Future playFromTopTracks(List<Track> tracks, String trackId, Artist artist) async {
     await playFromTrackList(tracks, trackId, QueueSource(

lib/ui/menu.dart

@@ -7,6 +7,7 @@ import 'package:fluttertoast/fluttertoast.dart';
 import 'package:freezer/api/cache.dart';
 import 'package:freezer/api/deezer.dart';
 import 'package:freezer/api/download.dart';
+import 'package:freezer/api/player.dart';
 import 'package:freezer/ui/details_screens.dart';
 import 'package:freezer/ui/error.dart';
 import 'package:freezer/translations.i18n.dart';
@@ -132,6 +133,7 @@ class MenuSheet {
       addToPlaylist(track),
       downloadTrack(track),
       shareTile('track', track.id),
+      playMix(track),
       showAlbum(track.album),
       ...List.generate(track.artists.length, (i) => showArtist(track.artists[i])),
       ...options
@@ -289,6 +291,14 @@ class MenuSheet {
     },
   );
 
+  Widget playMix(Track track) => ListTile(
+    title: Text('Play mix'.i18n),
+    leading: Icon(Icons.online_prediction),
+    onTap: () async {
+      playerHelper.playMix(track.id, track.title);
+      _close();
+    },
+  );
 
   //===================
   // ALBUM