From c05263c3c39e5828d320ba5d11bac9b2ec1436d1 Mon Sep 17 00:00:00 2001
From: James <51536154+tsunyoku@users.noreply.github.com>
Date: Tue, 12 Jul 2022 23:07:26 +0100
Subject: [PATCH] add Single Tap mod

---
 osu.Game.Rulesets.Osu/Mods/OsuModSingleTap.cs | 38 +++++++++++++++++++
 osu.Game.Rulesets.Osu/OsuRuleset.cs           |  2 +-
 2 files changed, 39 insertions(+), 1 deletion(-)
 create mode 100644 osu.Game.Rulesets.Osu/Mods/OsuModSingleTap.cs

diff --git a/osu.Game.Rulesets.Osu/Mods/OsuModSingleTap.cs b/osu.Game.Rulesets.Osu/Mods/OsuModSingleTap.cs
new file mode 100644
index 0000000000..22211b70c1
--- /dev/null
+++ b/osu.Game.Rulesets.Osu/Mods/OsuModSingleTap.cs
@@ -0,0 +1,38 @@
+// 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.
+
+#nullable disable
+
+using osu.Framework.Graphics;
+
+namespace osu.Game.Rulesets.Osu.Mods
+{
+    public class OsuModSingleTap : InputBlockingMod
+    {
+        public override string Name => @"Single Tap";
+        public override string Acronym => @"ST";
+        public override string Description => @"You must only use one key!";
+
+        protected override bool CheckCorrectAction(OsuAction action)
+        {
+            if (base.CheckCorrectAction(action))
+                return true;
+
+            if (LastActionPressed == null)
+            {
+                // First keypress, store the expected action.
+                LastActionPressed = action;
+                return true;
+            }
+
+            if (LastActionPressed == action)
+            {
+                // User singletapped correctly.
+                return true;
+            }
+
+            Ruleset.Cursor.FlashColour(Colour4.Red, FLASH_DURATION, Easing.OutQuint);
+            return false;
+        }
+    }
+}
diff --git a/osu.Game.Rulesets.Osu/OsuRuleset.cs b/osu.Game.Rulesets.Osu/OsuRuleset.cs
index ba0ef9ec3a..302194e91a 100644
--- a/osu.Game.Rulesets.Osu/OsuRuleset.cs
+++ b/osu.Game.Rulesets.Osu/OsuRuleset.cs
@@ -172,7 +172,7 @@ namespace osu.Game.Rulesets.Osu
                         new OsuModClassic(),
                         new OsuModRandom(),
                         new OsuModMirror(),
-                        new OsuModAlternate(),
+                        new MultiMod(new OsuModAlternate(), new OsuModSingleTap())
                     };
 
                 case ModType.Automation: