From 0287c49ca8a9971ccb747d397e64b10c288d98ef Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bart=C5=82omiej=20Dach?= <dach.bartlomiej@gmail.com>
Date: Sat, 23 Jul 2022 23:35:56 +0200
Subject: [PATCH] Implement user selection logic for mod presets

---
 osu.Game/Overlays/Mods/ModPresetPanel.cs | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/osu.Game/Overlays/Mods/ModPresetPanel.cs b/osu.Game/Overlays/Mods/ModPresetPanel.cs
index c3c4fdff94..a259645479 100644
--- a/osu.Game/Overlays/Mods/ModPresetPanel.cs
+++ b/osu.Game/Overlays/Mods/ModPresetPanel.cs
@@ -1,7 +1,9 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using System;
 using System.Collections.Generic;
+using System.Linq;
 using osu.Framework.Allocation;
 using osu.Framework.Bindables;
 using osu.Framework.Graphics.Cursor;
@@ -25,7 +27,7 @@ namespace osu.Game.Overlays.Mods
         private IDialogOverlay? dialogOverlay { get; set; }
 
         [Resolved]
-        private IBindable<IReadOnlyList<Mod>> selectedMods { get; set; } = null!;
+        private Bindable<IReadOnlyList<Mod>> selectedMods { get; set; } = null!;
 
         private ModSettingChangeTracker? settingChangeTracker;
 
@@ -35,6 +37,8 @@ namespace osu.Game.Overlays.Mods
 
             Title = preset.Value.Name;
             Description = preset.Value.Description;
+
+            Action = toggleRequestedByUser;
         }
 
         [BackgroundDependencyLoader]
@@ -50,6 +54,17 @@ namespace osu.Game.Overlays.Mods
             selectedMods.BindValueChanged(_ => selectedModsChanged(), true);
         }
 
+        private void toggleRequestedByUser()
+        {
+            // if the preset is not active at the point of the user click, then set the mods using the preset directly, discarding any previous selections.
+            // if the preset is active when the user has clicked it, then it means that the set of active mods is exactly equal to the set of mods in the preset
+            // (there are no other active mods than what the preset specifies, and the mod settings match exactly).
+            // therefore it's safe to just clear selected mods, since it will have the effect of toggling the preset off.
+            selectedMods.Value = !Active.Value
+                ? Preset.Value.Mods.ToArray()
+                : Array.Empty<Mod>();
+        }
+
         private void selectedModsChanged()
         {
             settingChangeTracker?.Dispose();