Show total songs and total duration for each playlist.

Harmonia.WinUI/ViewModels/PlaylistItemViewModel.cs

@@ -0,0 +1,47 @@
+using CommunityToolkit.Mvvm.ComponentModel;
+using Harmonia.Core.Playlists;
+using System;
+using System.Linq;
+
+namespace Harmonia.WinUI.ViewModels;
+
+public partial class PlaylistItemViewModel : ObservableObject
+{
+    public Playlist Playlist { get; private set; }
+
+    private string _summary = string.Empty;
+    public string Summary
+    {
+        get
+        {
+            return _summary;
+        }
+        set
+        {
+            SetProperty(ref _summary, value);
+        }
+    }
+
+    public PlaylistItemViewModel(Playlist playlist)
+    {
+        Playlist = playlist;
+        Playlist.PlaylistUpdated += OnPlaylistUpdated;
+        UpdateMetaData();
+    }
+
+    public void Unsubscribe()
+    {
+        Playlist.PlaylistUpdated -= OnPlaylistUpdated;
+    }
+
+    private void OnPlaylistUpdated(object? sender, EventArgs e)
+    {
+        UpdateMetaData();
+    }
+
+    private void UpdateMetaData()
+    {
+        TimeSpan total = TimeSpan.FromSeconds(Playlist.Songs.Sum(s => s.Song.Length.TotalSeconds));
+        Summary = $"{Playlist.Songs.Count} songs / {total:h\\:mm\\:ss}";
+    }
+}

Harmonia.WinUI/ViewModels/PlaylistsViewModel.cs

@@ -1,6 +1,8 @@
-using Harmonia.Core.Playlists;
+using CommunityToolkit.Mvvm.ComponentModel;
+using Harmonia.Core.Playlists;
 using System;
 using System.Collections.ObjectModel;
+using System.Linq;
 
 namespace Harmonia.WinUI.ViewModels;
 
@@ -8,8 +10,8 @@ public partial class PlaylistsViewModel : ViewModelBase
 {
     private readonly IPlaylistManager _playlistManager;
 
-    private ObservableCollection<Playlist> _playlists = [];
-    public ObservableCollection<Playlist> Playlists
+    private ObservableCollection<PlaylistItemViewModel> _playlists = [];
+    public ObservableCollection<PlaylistItemViewModel> Playlists
     {
         get
         {
@@ -21,8 +23,8 @@ public partial class PlaylistsViewModel : ViewModelBase
         }
     }
 
-    private Playlist? _selectedPlaylist = null;
-    public Playlist? SelectedPlaylist
+    private PlaylistItemViewModel? _selectedPlaylist = null;
+    public PlaylistItemViewModel? SelectedPlaylist
     {
         get
         {
@@ -32,7 +34,7 @@ public partial class PlaylistsViewModel : ViewModelBase
         {
             if (SetProperty(ref _selectedPlaylist, value))
             {
-                _playlistManager.CurrentPlaylist = value;
+                _playlistManager.CurrentPlaylist = value?.Playlist;
             }
         }
     }
@@ -44,22 +46,28 @@ public partial class PlaylistsViewModel : ViewModelBase
         _playlistManager.PlaylistRemoved += OnPlaylistRemoved;
         _playlistManager.CurrentPlaylistChanged += OnCurrentPlaylistChanged;
 
-        _playlists = new(_playlistManager.Playlists);
-        _selectedPlaylist = _playlistManager.CurrentPlaylist;
+        _playlists = new ObservableCollection<PlaylistItemViewModel>(_playlistManager.Playlists.Select(p => new PlaylistItemViewModel(p)));
+        _selectedPlaylist = _playlists.FirstOrDefault(pv => pv.Playlist == _playlistManager.CurrentPlaylist);
     }
 
     private void OnCurrentPlaylistChanged(object? sender, EventArgs e)
     {
-        SelectedPlaylist = _playlistManager.CurrentPlaylist;
+        SelectedPlaylist = _playlists.FirstOrDefault(pv => pv.Playlist == _playlistManager.CurrentPlaylist);
     }
 
     private void OnPlaylistAdded(object? sender, PlaylistAddedEventArgs e)
     {
-        Playlists.Add(e.Playlist);
+        Playlists.Add(new PlaylistItemViewModel(e.Playlist));
     }
 
     private void OnPlaylistRemoved(object? sender, PlaylistRemovedEventArgs e)
     {
-        Playlists.Remove(e.Playlist);
+        var playlistView = Playlists.FirstOrDefault(pv => pv.Playlist == e.Playlist);
+
+        if (playlistView != null)
+        {
+            playlistView.Unsubscribe();
+            Playlists.Remove(playlistView);
+        }
     }
 }