Added randomize/reverse songs logic. Added initial UI-side locking logic.

Harmonia.Core/Playlists/Playlist.cs

@@ -14,6 +14,36 @@ public class Playlist
 
     public event EventHandler<PlaylistUpdatedEventArgs>? PlaylistUpdated;
 
+    public void Lock()
+    {
+        IsLocked = true;
+
+        PlaylistUpdatedEventArgs eventArgs = new()
+        {
+            Action = PlaylistUpdateAction.Lock,
+            Index = -1,
+            Count = 0,
+            Songs = []
+        };
+
+        PlaylistUpdated?.Invoke(this, eventArgs);
+    }
+
+    public void Unlock()
+    {
+        IsLocked = false;
+
+        PlaylistUpdatedEventArgs eventArgs = new()
+        {
+            Action = PlaylistUpdateAction.Unlock,
+            Index = -1,
+            Count = 0,
+            Songs = []
+        };
+
+        PlaylistUpdated?.Invoke(this, eventArgs);
+    }
+
     public void AddSong(Song song, int? index = null)
     {
         AddSongs([song], index);
@@ -83,6 +113,9 @@ public class Playlist
 
     public void SortSongs(PlaylistSong[] playlistSongs, SortOption[] sortOptions)
     {
+        if (IsLocked)
+            return;
+
         Dictionary<int, PlaylistSong> oldPlaylistSongs = playlistSongs
             .OrderBy(Songs.IndexOf)
             .ToDictionary(Songs.IndexOf, playlistSong => playlistSong);
@@ -116,6 +149,50 @@ public class Playlist
         PlaylistUpdated?.Invoke(this, eventArgs);
     }
 
+    public void Randomize(PlaylistSong[] playlistSongs)
+    {
+        if (IsLocked)
+            return;
+
+        int[] originalIndexes = [.. playlistSongs.Select(playlistSong => Songs.IndexOf(playlistSong))];
+        PlaylistSong[] shuffledSongs = [.. playlistSongs.Shuffle()];
+
+        for (int i = 0; i < originalIndexes.Length; i++)
+            Songs[originalIndexes[i]] = shuffledSongs[i];
+
+        PlaylistUpdatedEventArgs eventArgs = new()
+        {
+            Action = PlaylistUpdateAction.Reset,
+            Index = -1,
+            Count = playlistSongs.Length,
+            Songs = playlistSongs
+        };
+
+        PlaylistUpdated?.Invoke(this, eventArgs);
+    }
+
+    public void Reverse(PlaylistSong[] playlistSongs)
+    {
+        if (IsLocked)
+            return;
+
+        int[] originalIndexes = [.. playlistSongs.Select(playlistSong => Songs.IndexOf(playlistSong))];
+        PlaylistSong[] reversedSongs = [.. originalIndexes.Select(i => Songs[i]).Reverse()];
+
+        for (int i = 0; i < originalIndexes.Length; i++)
+            Songs[originalIndexes[i]] = reversedSongs[i];
+
+        PlaylistUpdatedEventArgs eventArgs = new()
+        {
+            Action = PlaylistUpdateAction.Reset,
+            Index = -1,
+            Count = playlistSongs.Length,
+            Songs = playlistSongs
+        };
+
+        PlaylistUpdated?.Invoke(this, eventArgs);
+    }
+
     public void RemoveSong(int index)
     {
         RemoveSongs(index, 1);

Harmonia.Core/Playlists/PlaylistUpdateAction.cs

@@ -21,5 +21,7 @@ public enum PlaylistUpdateAction
     /// <summary>
     /// The tags of the songs in the collection were refreshed.
     /// </summary>
-    Refresh
+    Refresh,
+    Lock,
+    Unlock
 }

Harmonia.WinUI/Resources/Styles.xaml

@@ -16,6 +16,15 @@
         <Setter Property="FontFamily" Value="Lexend,Noto Sans JP" />
     </Style>
 
+    <Style TargetType="MenuFlyoutSubItem" BasedOn="{StaticResource DefaultMenuFlyoutSubItemStyle}">
+        <Setter Property="FontFamily" Value="Lexend,Noto Sans JP" />
+    </Style>
+
+    <Style TargetType="ToggleMenuFlyoutItem" BasedOn="{StaticResource DefaultToggleMenuFlyoutItemStyle}">
+        <Setter Property="FontFamily" Value="Lexend,Noto Sans JP" />
+    </Style>
+
+
     <Style TargetType="ListViewItem" BasedOn="{StaticResource DefaultListViewItemStyle}">
         <Setter Property="FontFamily" Value="Lexend,Noto Sans JP" />
     </Style>

Harmonia.WinUI/ViewModels/PlaylistDetailViewModel.cs

@@ -147,6 +147,11 @@ public partial class PlaylistDetailViewModel : ViewModelBase
     public IAsyncRelayCommand DeletePlaylistCommand { get; }
     public IRelayCommand<SortItem> SortAllCommand { get; }
     public IRelayCommand<SortItem> SortSelectedCommand { get; }
+    public IRelayCommand RandomizeAllCommand { get; }
+    public IRelayCommand RandomizeSelectedCommand { get; }
+    public IRelayCommand ReverseAllCommand { get; }
+    public IRelayCommand ReverseSelectedCommand { get; }
+    public IRelayCommand ToggleLockCommand { get; }
 
     public bool IsUserUpdating { get; set; }
     private bool _isUserInitiatingSongChange;
@@ -195,6 +200,11 @@ public partial class PlaylistDetailViewModel : ViewModelBase
         DeletePlaylistCommand = new AsyncRelayCommand(DeletePlaylistAsync);
         SortAllCommand = new RelayCommand<SortItem>(SortAllSongs);
         SortSelectedCommand = new RelayCommand<SortItem>(SortSelectedSongs, _ => AreMultipleSongsSelected());
+        RandomizeAllCommand = new RelayCommand(RandomizeAllSongs);
+        RandomizeSelectedCommand = new RelayCommand(RandomizeSelectedSongs, AreMultipleSongsSelected);
+        ReverseAllCommand = new RelayCommand(ReverseAllSongs);
+        ReverseSelectedCommand = new RelayCommand(ReverseSelectedSongs, AreMultipleSongsSelected);
+        ToggleLockCommand = new RelayCommand(ToggleLock);
 
         FilteredPlaylistSongs.CollectionChanged += OnFilteredPlaylistSongsCollectionChanged;
 
@@ -211,6 +221,8 @@ public partial class PlaylistDetailViewModel : ViewModelBase
         PasteSongsCommand.NotifyCanExecuteChanged();
         OpenFileLocationCommand.NotifyCanExecuteChanged();
         SortSelectedCommand.NotifyCanExecuteChanged();
+        RandomizeSelectedCommand.NotifyCanExecuteChanged();
+        ReverseSelectedCommand.NotifyCanExecuteChanged();
     }
 
     private void OnFilteredPlaylistSongsCollectionChanged(object? sender, NotifyCollectionChangedEventArgs e)
@@ -669,7 +681,75 @@ public partial class PlaylistDetailViewModel : ViewModelBase
         if (SelectedPlaylistSongs.Count < 2)
             return;
 
+        string[] selectedPlaylistSongIds = [.. SelectedPlaylistSongs.Select(x => x.UID)];
+
         Playlist.SortSongs([.. SelectedPlaylistSongs], [.. sortItem.SortOptions]);
+
+        RestoreSelectedSongs(selectedPlaylistSongIds);
+    }
+
+    private void RestoreSelectedSongs(string[] playlistSongIds)
+    {
+        _dispatcherQueue.TryEnqueue(() =>
+        {
+            PlaylistSong[] selectedPlaylistSongs = [.. Playlist?.Songs.Where(x => playlistSongIds.Contains(x.UID)) ?? []];
+            SelectedPlaylistSongs = new ObservableCollection<PlaylistSong>(selectedPlaylistSongs);
+        });
+    }
+
+    private void RandomizeAllSongs()
+    {
+        if (Playlist == null || Playlist.Songs.Count < 2)
+            return;
+
+        Playlist.Randomize([.. Playlist.Songs]);
+    }
+
+    private void RandomizeSelectedSongs()
+    {
+        if (Playlist == null || SelectedPlaylistSongs.Count < 2)
+            return;
+
+        string[] selectedPlaylistSongIds = [.. SelectedPlaylistSongs.Select(x => x.UID)];
+
+        Playlist.Randomize([.. SelectedPlaylistSongs]);
+
+        RestoreSelectedSongs(selectedPlaylistSongIds);
+    }
+
+    private void ReverseAllSongs()
+    {
+        if (Playlist == null || Playlist.Songs.Count < 2)
+            return;
+
+        Playlist.Reverse([.. Playlist.Songs]);
+    }
+
+    private void ReverseSelectedSongs()
+    {
+        if (Playlist == null || SelectedPlaylistSongs.Count < 2)
+            return;
+
+        string[] selectedPlaylistSongIds = [.. SelectedPlaylistSongs.Select(x => x.UID)];
+
+        Playlist.Reverse([.. SelectedPlaylistSongs]);
+
+        RestoreSelectedSongs(selectedPlaylistSongIds);
+    }
+
+    private void ToggleLock()
+    {
+        if (Playlist == null)
+            return;
+
+        if (Playlist.IsLocked)
+        {
+            Playlist.Unlock();
+        }
+        else
+        {
+            Playlist.Lock();
+        }
     }
 
     #endregion

Harmonia.WinUI/Views/PlaylistDetailView.xaml

@@ -167,9 +167,9 @@
                             
                             <MenuFlyoutItem Text="Remove Missing" Command="{Binding RemoveMissingSongsCommand}">
                             </MenuFlyoutItem>
-                            
+
-                            <MenuFlyoutItem Text="Lock Playlist">
+                            <ToggleMenuFlyoutItem Text="Lock Playlist" IsChecked="{Binding Playlist.IsLocked}">
-                            </MenuFlyoutItem>
+                            </ToggleMenuFlyoutItem>
                             
                             <MenuFlyoutSeparator></MenuFlyoutSeparator>
                             
@@ -179,6 +179,11 @@
                             <MenuFlyoutSeparator></MenuFlyoutSeparator>
 
                             <MenuFlyoutSubItem x:Name="SortByMenuFlyoutSubItem" Text="Sort By...">
+                                <MenuFlyoutSeparator></MenuFlyoutSeparator>
+                                <MenuFlyoutItem Text="Randomize" Command="{Binding RandomizeAllCommand}">
+                                </MenuFlyoutItem>
+                                <MenuFlyoutItem Text="Reverse" Command="{Binding ReverseAllCommand}">
+                                </MenuFlyoutItem>
                             </MenuFlyoutSubItem>
 
                             <MenuFlyoutSeparator></MenuFlyoutSeparator>
@@ -238,6 +243,11 @@
                         <MenuFlyoutSubItem.Icon>
                             <PathIcon Data="{StaticResource SortIcon}"></PathIcon>
                         </MenuFlyoutSubItem.Icon>
+                        <MenuFlyoutSeparator></MenuFlyoutSeparator>
+                        <MenuFlyoutItem Text="Randomize" Command="{Binding RandomizeSelectedCommand}">
+                        </MenuFlyoutItem>
+                        <MenuFlyoutItem Text="Reverse" Command="{Binding ReverseSelectedCommand}">
+                        </MenuFlyoutItem>
                     </MenuFlyoutSubItem>
                     <MenuFlyoutSeparator></MenuFlyoutSeparator>
                     <MenuFlyoutItem Text="Cut" Command="{Binding CutSongsCommand}">

Harmonia.WinUI/Views/PlaylistDetailView.xaml.cs

@@ -1,5 +1,4 @@
 using CommunityToolkit.WinUI;
-using Harmonia.Core.Imaging;
 using Harmonia.Core.Playlists;
 using Harmonia.WinUI.ViewModels;
 using Microsoft.UI.Dispatching;
@@ -7,14 +6,10 @@ using Microsoft.UI.Xaml;
 using Microsoft.UI.Xaml.Controls;
 using Microsoft.UI.Xaml.Data;
 using Microsoft.UI.Xaml.Input;
-using Microsoft.UI.Xaml.Media;
 using Microsoft.UI.Xaml.Media.Imaging;
 using System;
-using System.Collections.Generic;
 using System.ComponentModel;
 using System.Linq;
-using System.Threading.Tasks;
-using Windows.UI.Popups;
 
 namespace Harmonia.WinUI.Views;
 
@@ -33,24 +28,28 @@ public sealed partial class PlaylistDetailView : UserControl
 
         foreach (MenuFlyoutItemBase item in PlaylistListViewMenuFlyout.Items)
         {
-            item.DataContextChanged += Item_DataContextChanged;
+            HookDataContextChanged(item);
         }
 
+        int currentSortItemIndex = 0;
+
         foreach (SortItem sortItem in _viewModel.SortItems)
         {
-            SortByMenuFlyoutSubItem.Items.Add(new MenuFlyoutItem
+            SortByMenuFlyoutSubItem.Items.Insert(currentSortItemIndex, new MenuFlyoutItem
             {
                 Text = sortItem.Name,
                 Command = _viewModel.SortAllCommand,
                 CommandParameter = sortItem
             });
 
-            SortSelectedByMenuFlyoutSubItem.Items.Add(new MenuFlyoutItem
+            SortSelectedByMenuFlyoutSubItem.Items.Insert(currentSortItemIndex, new MenuFlyoutItem
             {
                 Text = sortItem.Name,
                 Command = _viewModel.SortSelectedCommand,
                 CommandParameter = sortItem
             });
+
+            currentSortItemIndex++;
         }
 
         _viewModel.SortSelectedCommand.CanExecuteChanged += (_, _) =>
@@ -74,15 +73,44 @@ public sealed partial class PlaylistDetailView : UserControl
 
     private void OnViewModelPropertyChanged(object? sender, PropertyChangedEventArgs e)
     {
-        if (e.PropertyName == nameof(_viewModel.PlayingSong))
+        switch (e.PropertyName)
         {
-            ListViewItem listViewItem = (ListViewItem)PlaylistListView.ContainerFromItem(_viewModel.PlayingSong);
+            case nameof(_viewModel.PlayingSong):
-
+                ListViewItem listViewItem = (ListViewItem)PlaylistListView.ContainerFromItem(_viewModel.PlayingSong);
-            UpdateListViewItemStyle(listViewItem, true);
+                UpdateListViewItemStyle(listViewItem, true);
+                break;
+            case nameof(_viewModel.Playlist):
+                ScrollToTop();
+                break;
+            case nameof(_viewModel.SelectedPlaylistSongs):
+                SyncListViewSelection();
+                break;
         }
-        else if (e.PropertyName == nameof(_viewModel.Playlist))
+    }
+
+    private bool _isSyncingSelection;
+
+    private void SyncListViewSelection()
+    {
+        _isSyncingSelection = true;
+
+        try
         {
-            ScrollToTop();
+            PlaylistListView.DeselectAll();
+
+            foreach (PlaylistSong playlistSong in _viewModel.SelectedPlaylistSongs)
+            {
+                int index = PlaylistListView.Items.IndexOf(playlistSong);
+
+                if (index >= 0)
+                {
+                    PlaylistListView.SelectRange(new ItemIndexRange(index, 1));
+                }
+            }
+        }
+        finally
+        {
+            _isSyncingSelection = false;
         }
     }
 
@@ -170,6 +198,19 @@ public sealed partial class PlaylistDetailView : UserControl
         }
     }
 
+    private void HookDataContextChanged(MenuFlyoutItemBase item)
+    {
+        item.DataContextChanged += Item_DataContextChanged;
+
+        if (item is MenuFlyoutSubItem subItem)
+        {
+            foreach (MenuFlyoutItemBase childItem in subItem.Items)
+            {
+                HookDataContextChanged(childItem);
+            }
+        }
+    }
+
     private void Item_DataContextChanged(FrameworkElement sender, DataContextChangedEventArgs args)
     {
         if (sender is not MenuFlyoutItemBase item)
@@ -268,6 +309,9 @@ public sealed partial class PlaylistDetailView : UserControl
 
     private void PlaylistListView_SelectionChanged(object sender, SelectionChangedEventArgs e)
     {
+        if (_isSyncingSelection)
+            return;
+
         if (sender is not ListView listView)
             return;