Tidy up all remaining usages

osu.Game/Screens/Select/Carousel/GroupedDifficultyIcon.cs

@@ -0,0 +1,62 @@
+// 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 System.Collections.Generic;
+using System.Linq;
+using osu.Framework.Graphics;
+using osu.Framework.Input.Events;
+using osu.Game.Beatmaps.Drawables;
+using osu.Game.Graphics;
+using osu.Game.Graphics.Sprites;
+using osu.Game.Rulesets;
+using osuTK.Graphics;
+
+namespace osu.Game.Screens.Select.Carousel
+{
+    /// <summary>
+    /// A difficulty icon that contains a counter on the right-side of it.
+    /// </summary>
+    /// <remarks>
+    /// Used in cases when there are too many difficulty icons to show.
+    /// </remarks>
+    public class GroupedDifficultyIcon : DifficultyIcon
+    {
+        public readonly List<CarouselBeatmap> Items;
+
+        public GroupedDifficultyIcon(List<CarouselBeatmap> items, RulesetInfo ruleset)
+            : base(items.OrderBy(b => b.BeatmapInfo.StarRating).Last().BeatmapInfo, ruleset)
+        {
+            Items = items;
+
+            foreach (var item in items)
+                item.Filtered.BindValueChanged(_ => Scheduler.AddOnce(updateFilteredDisplay));
+
+            AddInternal(new OsuSpriteText
+            {
+                Anchor = Anchor.CentreRight,
+                Origin = Anchor.CentreRight,
+                Padding = new MarginPadding { Left = Size.X },
+                Margin = new MarginPadding { Left = 2, Right = 5 },
+                Font = OsuFont.GetFont(size: 14, weight: FontWeight.SemiBold),
+                Text = items.Count.ToString(),
+                Colour = Color4.White,
+            });
+
+            updateFilteredDisplay();
+        }
+
+        protected override bool OnClick(ClickEvent e)
+        {
+            Items.First().State.Value = CarouselItemState.Selected;
+            return true;
+        }
+
+        private void updateFilteredDisplay()
+        {
+            // for now, fade the whole group based on the ratio of hidden items.
+            this.FadeTo(1 - 0.9f * ((float)Items.Count(i => i.Filtered.Value) / Items.Count), 100);
+        }
+    }
+}