From 18e760ee91916bcca6071a51cdca628498dd8439 Mon Sep 17 00:00:00 2001
From: Henry Lin <henry.ys.lin@gmail.com>
Date: Thu, 29 Jul 2021 14:52:18 +0800
Subject: [PATCH] Extract metronome from `OsuModTarget`

---
 osu.Game.Rulesets.Osu/Mods/OsuModTarget.cs    | 45 +---------------
 .../Rulesets/Mods/MetronomeBeatContainer.cs   | 53 +++++++++++++++++++
 2 files changed, 54 insertions(+), 44 deletions(-)
 create mode 100644 osu.Game/Rulesets/Mods/MetronomeBeatContainer.cs

diff --git a/osu.Game.Rulesets.Osu/Mods/OsuModTarget.cs b/osu.Game.Rulesets.Osu/Mods/OsuModTarget.cs
index e21d1da009..576cc2da13 100644
--- a/osu.Game.Rulesets.Osu/Mods/OsuModTarget.cs
+++ b/osu.Game.Rulesets.Osu/Mods/OsuModTarget.cs
@@ -4,8 +4,6 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
-using osu.Framework.Allocation;
-using osu.Framework.Audio.Track;
 using osu.Framework.Bindables;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Sprites;
@@ -16,7 +14,6 @@ using osu.Game.Beatmaps.ControlPoints;
 using osu.Game.Beatmaps.Timing;
 using osu.Game.Configuration;
 using osu.Game.Graphics;
-using osu.Game.Graphics.Containers;
 using osu.Game.Overlays.Settings;
 using osu.Game.Rulesets.Mods;
 using osu.Game.Rulesets.Objects;
@@ -29,7 +26,6 @@ using osu.Game.Rulesets.Osu.UI;
 using osu.Game.Rulesets.Osu.Utils;
 using osu.Game.Rulesets.Scoring;
 using osu.Game.Rulesets.UI;
-using osu.Game.Skinning;
 using osuTK;
 using osuTK.Graphics;
 
@@ -341,46 +337,7 @@ namespace osu.Game.Rulesets.Osu.Mods
 
         public void ApplyToDrawableRuleset(DrawableRuleset<OsuHitObject> drawableRuleset)
         {
-            drawableRuleset.Overlays.Add(new TargetBeatContainer(drawableRuleset.Beatmap.HitObjects.First().StartTime));
-        }
-
-        public class TargetBeatContainer : BeatSyncedContainer
-        {
-            private readonly double firstHitTime;
-
-            private PausableSkinnableSound sample;
-
-            public TargetBeatContainer(double firstHitTime)
-            {
-                this.firstHitTime = firstHitTime;
-                AllowMistimedEventFiring = false;
-                Divisor = 1;
-            }
-
-            [BackgroundDependencyLoader]
-            private void load()
-            {
-                InternalChildren = new Drawable[]
-                {
-                    sample = new PausableSkinnableSound(new SampleInfo("Gameplay/catch-banana"))
-                };
-            }
-
-            protected override void OnNewBeat(int beatIndex, TimingControlPoint timingPoint, EffectControlPoint effectPoint, ChannelAmplitudes amplitudes)
-            {
-                base.OnNewBeat(beatIndex, timingPoint, effectPoint, amplitudes);
-
-                if (!IsBeatSyncedWithTrack) return;
-
-                int timeSignature = (int)timingPoint.TimeSignature;
-
-                // play metronome from one measure before the first object.
-                if (BeatSyncClock.CurrentTime < firstHitTime - timingPoint.BeatLength * timeSignature)
-                    return;
-
-                sample.Frequency.Value = beatIndex % timeSignature == 0 ? 1 : 0.5f;
-                sample.Play();
-            }
+            drawableRuleset.Overlays.Add(new MetronomeBeatContainer(drawableRuleset.Beatmap.HitObjects.First().StartTime));
         }
 
         #endregion
diff --git a/osu.Game/Rulesets/Mods/MetronomeBeatContainer.cs b/osu.Game/Rulesets/Mods/MetronomeBeatContainer.cs
new file mode 100644
index 0000000000..c5bb2c918f
--- /dev/null
+++ b/osu.Game/Rulesets/Mods/MetronomeBeatContainer.cs
@@ -0,0 +1,53 @@
+// 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 osu.Framework.Allocation;
+using osu.Framework.Audio.Track;
+using osu.Framework.Graphics;
+using osu.Game.Audio;
+using osu.Game.Beatmaps.ControlPoints;
+using osu.Game.Graphics.Containers;
+using osu.Game.Skinning;
+
+namespace osu.Game.Rulesets.Mods
+{
+    public class MetronomeBeatContainer : BeatSyncedContainer
+    {
+        private readonly double firstHitTime;
+
+        private PausableSkinnableSound sample;
+
+        /// <param name="firstHitTime">Start time of the first hit object, used for providing a count down.</param>
+        public MetronomeBeatContainer(double firstHitTime)
+        {
+            this.firstHitTime = firstHitTime;
+            AllowMistimedEventFiring = false;
+            Divisor = 1;
+        }
+
+        [BackgroundDependencyLoader]
+        private void load()
+        {
+            InternalChildren = new Drawable[]
+            {
+                sample = new PausableSkinnableSound(new SampleInfo("Gameplay/catch-banana"))
+            };
+        }
+
+        protected override void OnNewBeat(int beatIndex, TimingControlPoint timingPoint, EffectControlPoint effectPoint, ChannelAmplitudes amplitudes)
+        {
+            base.OnNewBeat(beatIndex, timingPoint, effectPoint, amplitudes);
+
+            if (!IsBeatSyncedWithTrack) return;
+
+            int timeSignature = (int)timingPoint.TimeSignature;
+
+            // play metronome from one measure before the first object.
+            if (BeatSyncClock.CurrentTime < firstHitTime - timingPoint.BeatLength * timeSignature)
+                return;
+
+            sample.Frequency.Value = beatIndex % timeSignature == 0 ? 1 : 0.5f;
+            sample.Play();
+        }
+    }
+}