Add tooltips to start button to explain why it's not clickable

osu.Game/Screens/OnlinePlay/Components/ReadyButton.cs

@@ -3,13 +3,15 @@
 
 using osu.Framework.Allocation;
 using osu.Framework.Bindables;
+using osu.Framework.Graphics.Cursor;
+using osu.Framework.Localisation;
 using osu.Game.Graphics.UserInterface;
 using osu.Game.Online;
 using osu.Game.Online.Rooms;
 
 namespace osu.Game.Screens.OnlinePlay.Components
 {
-    public abstract class ReadyButton : TriangleButton
+    public abstract class ReadyButton : TriangleButton, IHasTooltip
     {
         public new readonly BindableBool Enabled = new BindableBool();
 
@@ -24,6 +26,18 @@ namespace osu.Game.Screens.OnlinePlay.Components
             Enabled.BindValueChanged(_ => updateState(), true);
         }
 
-        private void updateState() => base.Enabled.Value = availability.Value.State == DownloadState.LocallyAvailable && Enabled.Value;
+        private void updateState() =>
+            base.Enabled.Value = availability.Value.State == DownloadState.LocallyAvailable && Enabled.Value;
+
+        public virtual LocalisableString TooltipText
+        {
+            get
+            {
+                if (Enabled.Value)
+                    return string.Empty;
+
+                return "Beatmap not downloaded";
+            }
+        }
     }
 }

osu.Game/Screens/OnlinePlay/Playlists/PlaylistsReadyButton.cs

@@ -2,8 +2,10 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using System;
+using System.Linq;
 using osu.Framework.Allocation;
 using osu.Framework.Bindables;
+using osu.Framework.Localisation;
 using osu.Game.Beatmaps;
 using osu.Game.Graphics;
 using osu.Game.Online.Rooms;
@@ -16,6 +18,12 @@ namespace osu.Game.Screens.OnlinePlay.Playlists
         [Resolved(typeof(Room), nameof(Room.EndDate))]
         private Bindable<DateTimeOffset?> endDate { get; set; }
 
+        [Resolved(typeof(Room), nameof(Room.MaxAttempts))]
+        private Bindable<int?> maxAttempts { get; set; }
+
+        [Resolved(typeof(Room), nameof(Room.UserScore))]
+        private Bindable<PlaylistAggregateScore> userScore { get; set; }
+
         [Resolved]
         private IBindable<WorkingBeatmap> gameBeatmap { get; set; }
 
@@ -56,6 +64,23 @@ namespace osu.Game.Screens.OnlinePlay.Playlists
             Enabled.Value = hasRemainingAttempts && enoughTimeLeft;
         }
 
+        public override LocalisableString TooltipText
+        {
+            get
+            {
+                if (Enabled.Value)
+                    return string.Empty;
+
+                if (!enoughTimeLeft)
+                    return "No time left!";
+
+                if (!hasRemainingAttempts)
+                    return "Attempts exhausted!";
+
+                return base.TooltipText;
+            }
+        }
+
         private bool enoughTimeLeft =>
             // This should probably consider the length of the currently selected item, rather than a constant 30 seconds.
             endDate.Value != null && DateTimeOffset.UtcNow.AddSeconds(30).AddMilliseconds(gameBeatmap.Value.Track.Length) < endDate.Value;