Show total songs and total duration for each playlist.

Harmonia.Core/Playlists/PlaylistRepository.cs

@@ -6,27 +6,6 @@ public class PlaylistRepository : JsonFileRepository<Playlist>, IPlaylistReposit
 {
     protected override string DirectoryName => Path.Combine("Playlists");
 
-    //public PlaylistRepository()
-    //{
-    //    List<Playlist> playlists = Get();
-
-    //    foreach (Playlist playlist in playlists)
-    //    {
-    //        playlist.PlaylistUpdated += OnPlaylistUpdated;
-    //    }
-
-    //    if (playlists.Count == 0)
-    //        AddPlaylist();
-    //}
-
-    //private void OnPlaylistUpdated(object? sender, PlaylistUpdatedEventArgs e)
-    //{
-    //    if (sender is not Playlist playlist)
-    //        return;
-
-    //    Save(playlist);
-    //}
-
     public Playlist? GetPlaylist(PlaylistSong playlistSong)
     {
         return Get().FirstOrDefault(playlist => playlist.Songs.Contains(playlistSong));
@@ -45,28 +24,4 @@ public class PlaylistRepository : JsonFileRepository<Playlist>, IPlaylistReposit
 
         throw new Exception("Unable to determine new fileName");
     }
-
-    //public event EventHandler<PlaylistAddedEventArgs>? PlaylistAdded;
-    //public event EventHandler<PlaylistRemovedEventArgs>? PlaylistRemoved;
-
-    //public void AddPlaylist()
-    //{
-    //    Playlist playlist = new()
-    //    {
-    //        Name = "New Playlist"
-    //    };
-
-    //    playlist.PlaylistUpdated += OnPlaylistUpdated;
-
-    //    Save(playlist);
-    //    PlaylistAdded?.Invoke(this, new(playlist));
-    //}
-
-    //public void RemovePlaylist(Playlist playlist)
-    //{
-    //    playlist.PlaylistUpdated -= OnPlaylistUpdated;
-
-    //    Delete(playlist);
-    //    PlaylistRemoved?.Invoke(this, new(playlist));
-    //}
 }

Harmonia.WinUI/ViewModels/PlaylistDetailViewModel.cs

@@ -43,7 +43,12 @@ public partial class PlaylistDetailViewModel : ViewModelBase
 
     private DispatcherQueueTimer? _filterTimer;
 
-    public Playlist? Playlist { get; private set; }
+    private Playlist? _playlist;
+    public Playlist? Playlist
+    {
+        get => _playlist;
+        private set => SetProperty(ref _playlist, value);
+    }
 
     private PlaylistSong? _playingSong;
     public PlaylistSong? PlayingSong

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);
+        }
     }
 }

Harmonia.WinUI/Views/PlaylistDetailView.xaml.cs

@@ -58,6 +58,22 @@ public sealed partial class PlaylistDetailView : UserControl
 
             UpdateListViewItemStyle(listViewItem, true);
         }
+        else if (e.PropertyName == nameof(_viewModel.Playlist))
+        {
+            ScrollToTop();
+        }
+    }
+
+    private void ScrollToTop()
+    {
+        if (PlaylistListView.FindDescendant<ScrollViewer>() is ScrollViewer scrollViewer)
+        {
+            scrollViewer.ChangeView(null, 0, null, disableAnimation: false);
+        }
+        else if (_viewModel.FilteredPlaylistSongs.FirstOrDefault() is PlaylistSong firstSong)
+        {
+            PlaylistListView.ScrollIntoView(firstSong);
+        }
     }
 
     private void UpdateListViewItemStyle(FrameworkElement listViewItem, bool isPlaying)

Harmonia.WinUI/Views/PlaylistsView.xaml

@@ -12,13 +12,33 @@
     d:DataContext="{d:DesignInstance Type=vm:PlaylistsViewModel, IsDesignTimeCreatable=True}"
     mc:Ignorable="d">
     <UserControl.Resources>
-        <DataTemplate x:Key="PlaylistTemplate" x:DataType="playlists:Playlist">
-            <StackPanel Orientation="Horizontal" Spacing="8" VerticalAlignment="Bottom">
+        <SolidColorBrush x:Key="PlaylistItemSubtitleBrush" Color="#aaaaaa"/>
+        
+        <!-- Playlist Item Subtitle Text Block -->
+        <Style x:Key="PlaylistSubtitleTextBlock" TargetType="TextBlock">
+            <Setter Property="Foreground" Value="{StaticResource PlaylistItemSubtitleBrush}"/>
+            <Setter Property="FontSize" Value="13"/>
+            <Setter Property="LineStackingStrategy" Value="BlockLineHeight"/>
+            <Setter Property="TextTrimming" Value="CharacterEllipsis"/>
+            <Setter Property="LineHeight" Value="0"/>
+        </Style>
+
+        <DataTemplate x:Key="PlaylistTemplate" x:DataType="vm:PlaylistItemViewModel">
+            <Grid>
+                <Grid.ColumnDefinitions>
+                    <ColumnDefinition Width="*" />
+                    <ColumnDefinition Width="200" />
+                </Grid.ColumnDefinitions>
+                <StackPanel Grid.Column="0" Orientation="Horizontal" Spacing="8" VerticalAlignment="Center">
                     <Viewbox Height="24" Width="24">
                         <PathIcon Data="{StaticResource MusicNoteList}" />
                     </Viewbox>
-                <TextBlock Text="{x:Bind Name}" FontSize="16" VerticalAlignment="Center" />
+                    <TextBlock Text="{x:Bind Playlist.Name}" FontSize="16" VerticalAlignment="Center" />
                 </StackPanel>
+                <StackPanel Grid.Column="1" Orientation="Horizontal" HorizontalAlignment="Right" VerticalAlignment="Center" Spacing="8">
+                    <TextBlock Text="{x:Bind Summary, Mode=OneWay}" Style="{StaticResource PlaylistSubtitleTextBlock}" />
+                </StackPanel>
+            </Grid>
         </DataTemplate>
     </UserControl.Resources>
     <Grid Margin="10">