From aa9861162dd0305da7b8161fbdba030c9aae229d Mon Sep 17 00:00:00 2001
From: Brian Bicknell <brister388@gmail.com>
Date: Sun, 26 Jul 2026 17:07:49 -0400
Subject: [PATCH] Optimized filtering playlist songs.

---
 .../ViewModels/PlaylistViewModel.cs           | 76 ++++++++-----------
 1 file changed, 33 insertions(+), 43 deletions(-)

diff --git a/Harmonia.WinUI/ViewModels/PlaylistViewModel.cs b/Harmonia.WinUI/ViewModels/PlaylistViewModel.cs
index 5320bef..617bf03 100644
--- a/Harmonia.WinUI/ViewModels/PlaylistViewModel.cs
+++ b/Harmonia.WinUI/ViewModels/PlaylistViewModel.cs
@@ -20,11 +20,10 @@ using System.Linq;
 using System.Text.Json;
 using System.Threading;
 using System.Threading.Tasks;
-using System.Timers;
 using System.Windows.Input;
 using Windows.ApplicationModel.DataTransfer;
 using DispatcherQueue = Microsoft.UI.Dispatching.DispatcherQueue;
-using Timer = System.Timers.Timer;
+using DispatcherQueueTimer = Microsoft.UI.Dispatching.DispatcherQueueTimer;
 
 namespace Harmonia.WinUI.ViewModels;
 
@@ -40,7 +39,7 @@ public partial class PlaylistViewModel : ViewModelBase
     private readonly DispatcherQueue _dispatcherQueue;
     private readonly ConcurrentDictionary<int, CancellationTokenSource> _imageCancellationTokens = [];
 
-    private Timer? _filterTimer;
+    private DispatcherQueueTimer? _filterTimer;
 
     public Playlist? Playlist { get; private set; }
 
@@ -300,26 +299,19 @@ public partial class PlaylistViewModel : ViewModelBase
     {
         if (_filterTimer == null)
         {
-            _filterTimer = new Timer(300);
-            _filterTimer.Elapsed += OnFilterTimerElapsed;
-            _filterTimer.Start();
+            _filterTimer = _dispatcherQueue.CreateTimer();
+            _filterTimer.Interval = TimeSpan.FromMilliseconds(300);
+            _filterTimer.IsRepeating = false;
+            _filterTimer.Tick += OnFilterTimerTick;
         }
-        else
-        {
-            _filterTimer.Interval = 300;
-        }
-    }
-
-    private void OnFilterTimerElapsed(object? sender, ElapsedEventArgs e)
-    {
-        if (_filterTimer == null)
-            return;
 
         _filterTimer.Stop();
-        _filterTimer.Dispose();
-        _filterTimer = null;
+        _filterTimer.Start();
+    }
 
-        _dispatcherQueue.TryEnqueue(UpdateFilteredSongs);
+    private void OnFilterTimerTick(DispatcherQueueTimer sender, object args)
+    {
+        UpdateFilteredSongs();
     }
 
     private void UpdateFilteredSongs()
@@ -327,61 +319,59 @@ public partial class PlaylistViewModel : ViewModelBase
         if (Playlist == null)
             return;
 
-        List<PlaylistSong> filteredPlaylistSongs = [.. Playlist.Songs.Where(playlistSong => IsFiltered(playlistSong.Song))];
-        //FilteredPlaylistSongs = [.. filteredPlaylistSongs];
+        string? filter = Filter;
+        HashSet<PlaylistSong> updatedFilterSet = [.. Playlist.Songs.Where(playlistSong => IsFiltered(playlistSong.Song, filter))];
 
         for (int i = FilteredPlaylistSongs.Count - 1; i >= 0; i--)
         {
             PlaylistSong playlistSong = FilteredPlaylistSongs[i];
 
-            bool inPlaylist = Playlist.Songs.Contains(playlistSong);
-            bool inFilter = filteredPlaylistSongs.Contains(playlistSong);
+            bool inFilterSet = updatedFilterSet.Contains(playlistSong);
 
-            if (!inPlaylist || !inFilter)
-            {
-                FilteredPlaylistSongs.Remove(playlistSong);
-            }
+            if (!inFilterSet)
+                FilteredPlaylistSongs.RemoveAt(i);
         }
 
+        HashSet<PlaylistSong> currentSet = [.. FilteredPlaylistSongs];
         int insertionIndex = 0;
 
         foreach (PlaylistSong playlistSong in Playlist.Songs)
         {
-            bool inFilter = filteredPlaylistSongs.Contains(playlistSong);
-            bool inCurrentFilteredList = FilteredPlaylistSongs.Contains(playlistSong);
+            bool inFilterSet = updatedFilterSet.Contains(playlistSong);
+            bool inCurrentSet = currentSet.Contains(playlistSong);
 
-            if (inFilter)
+            if (!inFilterSet)
+                continue;
+
+            if (!inCurrentSet)
             {
-                if (!inCurrentFilteredList)
-                {
-                    FilteredPlaylistSongs.Insert(insertionIndex, playlistSong);
-                }
-
-                insertionIndex++;
+                FilteredPlaylistSongs.Insert(insertionIndex, playlistSong);
             }
+
+            insertionIndex++;
         }
     }
 
-    private bool IsFiltered(Song song)
+    private static bool IsFiltered(Song song, string? filter)
     {
-        if (string.IsNullOrWhiteSpace(Filter))
+        if (string.IsNullOrWhiteSpace(filter))
             return true;
 
         var shortFileName = Path.GetFileName(song.FileName);
 
-        if (shortFileName.Contains(Filter, StringComparison.OrdinalIgnoreCase))
+        if (shortFileName.Contains(filter, StringComparison.OrdinalIgnoreCase))
             return true;
 
-        if (string.IsNullOrWhiteSpace(song.Title) == false && song.Title.Contains(Filter, StringComparison.OrdinalIgnoreCase))
+        if (string.IsNullOrWhiteSpace(song.Title) == false && song.Title.Contains(filter, StringComparison.OrdinalIgnoreCase))
             return true;
 
-        if (string.IsNullOrWhiteSpace(song.Album) == false && song.Album.Contains(Filter, StringComparison.OrdinalIgnoreCase))
+        if (string.IsNullOrWhiteSpace(song.Album) == false && song.Album.Contains(filter, StringComparison.OrdinalIgnoreCase))
             return true;
 
-        if (song.AlbumArtists.Any(x => x.Contains(Filter, StringComparison.OrdinalIgnoreCase)))
+        if (song.AlbumArtists.Any(x => x.Contains(filter, StringComparison.OrdinalIgnoreCase)))
             return true;
 
-        if (song.Artists.Any(x => x.Contains(Filter, StringComparison.OrdinalIgnoreCase)))
+        if (song.Artists.Any(x => x.Contains(filter, StringComparison.OrdinalIgnoreCase)))
             return true;
 
         return false;