Highlight active playlist. Various optimizations and fixes.

Harmonia.Core/Playlists/PlaylistManager.cs

@@ -4,6 +4,7 @@ public class PlaylistManager : IPlaylistManager
 {
     private readonly IPlaylistRepository playlistRepository;
     private readonly List<Playlist> _playlists = [];
+    private readonly Dictionary<string, Playlist> _playlistsBySongUid = [];
 
     public IReadOnlyList<Playlist> Playlists => _playlists;
 
@@ -37,6 +38,11 @@ public class PlaylistManager : IPlaylistManager
         foreach (Playlist playlist in _playlists)
         {
             playlist.PlaylistUpdated += OnPlaylistUpdated;
+
+            foreach (PlaylistSong song in playlist.Songs)
+            {
+                _playlistsBySongUid[song.UID] = playlist;
+            }
         }
 
         CurrentPlaylist = _playlists.Count > 0 ? _playlists[0] : await AddPlaylistAsync();
@@ -44,14 +50,16 @@ public class PlaylistManager : IPlaylistManager
 
     public async Task<Playlist> AddPlaylistAsync()
     {
-        Playlist playlist = new()
-        {
-            Name = "New Playlist"
-        };
+        Playlist playlist = new("New Playlist");
 
         playlist.PlaylistUpdated += OnPlaylistUpdated;
         _playlists.Add(playlist);
 
+        foreach (PlaylistSong song in playlist.Songs)
+        {
+            _playlistsBySongUid[song.UID] = playlist;
+        }
+
         await playlistRepository.SaveAsync(playlist);
 
         PlaylistAdded?.Invoke(this, new(playlist));
@@ -64,14 +72,19 @@ public class PlaylistManager : IPlaylistManager
         playlist.PlaylistUpdated -= OnPlaylistUpdated;
         _playlists.Remove(playlist);
 
+        foreach (PlaylistSong song in playlist.Songs)
+        {
+            _playlistsBySongUid.Remove(song.UID);
+        }
+
         playlistRepository.Delete(playlist);
 
         PlaylistRemoved?.Invoke(this, new(playlist));
     }
 
-    public Playlist? GetPlaylist(PlaylistSong playlistSong)
+    public Playlist? FindPlaylistContaining(PlaylistSong playlistSong)
     {
-        return _playlists.FirstOrDefault(playlist => playlist.Songs.Any(song => song.UID == playlistSong.UID));
+        return _playlistsBySongUid.GetValueOrDefault(playlistSong.UID);
     }
 
     private async void OnPlaylistUpdated(object? sender, PlaylistUpdatedEventArgs e)
@@ -79,6 +92,22 @@ public class PlaylistManager : IPlaylistManager
         if (sender is not Playlist playlist)
             return;
 
+        switch (e.Action)
+        {
+            case PlaylistUpdateAction.Add:
+                foreach (PlaylistSong song in e.Songs)
+                {
+                    _playlistsBySongUid[song.UID] = playlist;
+                }
+                break;
+            case PlaylistUpdateAction.Remove:
+                foreach (PlaylistSong song in e.Songs)
+                {
+                    _playlistsBySongUid.Remove(song.UID);
+                }
+                break;
+        }
+
         await playlistRepository.SaveAsync(playlist);
     }
 }