Added new class for chat lines, that colour the messages after formatting. URLs will become blue, and on hover (also defined here) be turned yellow-ish

osu.Game/Online/Chat/ChatLinkSpriteText.cs

@@ -0,0 +1,63 @@
+// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using OpenTK.Graphics;
+using osu.Framework.Allocation;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Input;
+using osu.Game.Graphics;
+using osu.Game.Graphics.Sprites;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace osu.Game.Online.Chat
+{
+    public class ChatLinkSpriteText : OsuLinkSpriteText
+    {
+        private Color4 hoverColour;
+        private Color4 urlColour;
+
+        protected override bool OnHover(InputState state)
+        {
+            var otherSpritesWithSameLink = ((Container)Parent).Children.Where(child => (child as OsuLinkSpriteText)?.Url == Url && !Equals(child));
+
+            var hoverResult = base.OnHover(state);
+
+            if (!otherSpritesWithSameLink.Any(sprite => sprite.IsHovered))
+                foreach (ChatLinkSpriteText sprite in otherSpritesWithSameLink)
+                    sprite.TriggerOnHover(state);
+
+            Content.FadeColour(hoverColour, 500, Easing.OutQuint);
+
+            return hoverResult;
+        }
+
+        protected override void OnHoverLost(InputState state)
+        {
+            var spritesWithSameLink = ((Container)Parent).Children.Where(child => (child as OsuLinkSpriteText)?.Url == Url);
+
+            if (spritesWithSameLink.Any(sprite => sprite.IsHovered))
+            {
+                // We have to do this so this sprite does not fade its colour back
+                Content.FadeColour(hoverColour, 500, Easing.OutQuint);
+                return;
+            }
+
+            foreach (ChatLinkSpriteText sprite in spritesWithSameLink)
+                sprite.Content.FadeColour(urlColour, 500, Easing.OutQuint);
+
+            base.OnHoverLost(state);
+        }
+
+        [BackgroundDependencyLoader]
+        private void load(OsuColour colours)
+        {
+            hoverColour = colours.Yellow;
+            urlColour = colours.Blue;
+        }
+    }
+}