Add countdown settings to design section

osu.Game/Screens/Edit/Setup/DesignSection.cs

@@ -1,14 +1,28 @@
 // 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.Globalization;
+using System.Linq;
 using osu.Framework.Allocation;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
 using osu.Framework.Localisation;
+using osu.Game.Beatmaps;
 using osu.Game.Graphics.UserInterfaceV2;
+using osuTK;
 
 namespace osu.Game.Screens.Edit.Setup
 {
     internal class DesignSection : SetupSection
     {
+        private const float fade_duration = 250;
+
+        private LabelledSwitchButton enableCountdown;
+        private FillFlowContainer countdownSettings;
+        private LabelledEnumDropdown<CountdownType> countdownSpeed;
+        private LabelledNumberBox countdownOffset;
+
         private LabelledSwitchButton widescreenSupport;
         private LabelledSwitchButton epilepsyWarning;
         private LabelledSwitchButton letterboxDuringBreaks;
@@ -20,6 +34,35 @@ namespace osu.Game.Screens.Edit.Setup
         {
             Children = new[]
             {
+                enableCountdown = new LabelledSwitchButton
+                {
+                    Label = "Enable countdown",
+                    Current = { Value = Beatmap.BeatmapInfo.Countdown != CountdownType.None },
+                    Description = "If enabled, an \"Are you ready? 3, 2, 1, GO!\" countdown will be inserted at the beginning of the beatmap, assuming there is enough time to do so."
+                },
+                countdownSettings = new FillFlowContainer
+                {
+                    RelativeSizeAxes = Axes.X,
+                    AutoSizeAxes = Axes.Y,
+                    Spacing = new Vector2(10),
+                    Direction = FillDirection.Vertical,
+                    Children = new Drawable[]
+                    {
+                        countdownSpeed = new LabelledEnumDropdown<CountdownType>
+                        {
+                            Label = "Countdown speed",
+                            Current = { Value = Beatmap.BeatmapInfo.Countdown != CountdownType.None ? Beatmap.BeatmapInfo.Countdown : CountdownType.Normal },
+                            Items = Enum.GetValues(typeof(CountdownType)).Cast<CountdownType>().Where(type => type != CountdownType.None)
+                        },
+                        countdownOffset = new LabelledNumberBox
+                        {
+                            Label = "Countdown offset",
+                            Current = { Value = Beatmap.BeatmapInfo.CountdownOffset.ToString() },
+                            Description = "If the countdown sounds off-time, use this to make it appear one or more beats early.",
+                        }
+                    }
+                },
+                Empty(),
                 widescreenSupport = new LabelledSwitchButton
                 {
                     Label = "Widescreen support",
@@ -45,13 +88,34 @@ namespace osu.Game.Screens.Edit.Setup
         {
             base.LoadComplete();
 
+            enableCountdown.Current.BindValueChanged(_ => updateCountdownSettingsVisibility(), true);
+            countdownSettings.FinishTransforms(true);
+
+            enableCountdown.Current.BindValueChanged(_ => updateBeatmap());
+            countdownSpeed.Current.BindValueChanged(_ => updateBeatmap());
+            countdownOffset.OnCommit += (_, __) => updateBeatmap();
+
             widescreenSupport.Current.BindValueChanged(_ => updateBeatmap());
             epilepsyWarning.Current.BindValueChanged(_ => updateBeatmap());
             letterboxDuringBreaks.Current.BindValueChanged(_ => updateBeatmap());
         }
 
+        private void updateCountdownSettingsVisibility()
+        {
+            bool countdownEnabled = enableCountdown.Current.Value;
+
+            foreach (var child in countdownSettings)
+            {
+                child.ScaleTo(new Vector2(1, countdownEnabled ? 1 : 0), fade_duration, Easing.OutQuint)
+                     .FadeTo(countdownEnabled ? 1 : 0, fade_duration, Easing.OutQuint);
+            }
+        }
+
         private void updateBeatmap()
         {
+            Beatmap.BeatmapInfo.Countdown = enableCountdown.Current.Value ? countdownSpeed.Current.Value : CountdownType.None;
+            Beatmap.BeatmapInfo.CountdownOffset = int.TryParse(countdownOffset.Current.Value, NumberStyles.None, CultureInfo.InvariantCulture, out int offset) ? offset : 0;
+
             Beatmap.BeatmapInfo.WidescreenStoryboard = widescreenSupport.Current.Value;
             Beatmap.BeatmapInfo.EpilepsyWarning = epilepsyWarning.Current.Value;
             Beatmap.BeatmapInfo.LetterboxInBreaks = letterboxDuringBreaks.Current.Value;