Enable/disable the view beatmap + ready buttons based on beatmap presence

osu.Game/Screens/Multi/Match/Components/Info.cs

@@ -41,6 +41,8 @@ namespace osu.Game.Screens.Multi.Match.Components
             RelativeSizeAxes = Axes.X;
             AutoSizeAxes = Axes.Y;
 
+            ReadyButton readyButton;
+            ViewBeatmapButton viewBeatmapButton;
             BeatmapTypeInfo beatmapTypeInfo;
             OsuSpriteText name;
             ModDisplay modDisplay;
@@ -103,8 +105,8 @@ namespace osu.Game.Screens.Multi.Match.Components
                             Direction = FillDirection.Horizontal,
                             Children = new Drawable[]
                             {
-                                new ViewBeatmapButton(),
+                                viewBeatmapButton = new ViewBeatmapButton(),
-                                new ReadyButton
+                                readyButton = new ReadyButton
                                 {
                                     Action = () => OnStart?.Invoke()
                                 }
@@ -118,6 +120,9 @@ namespace osu.Game.Screens.Multi.Match.Components
             beatmapTypeInfo.Type.BindTo(Type);
             modDisplay.Current.BindTo(Mods);
 
+            viewBeatmapButton.Beatmap.BindTo(Beatmap);
+            readyButton.Beatmap.BindTo(Beatmap);
+
             Availability.BindValueChanged(_ => updateAvailabilityStatus());
             Status.BindValueChanged(_ => updateAvailabilityStatus());
             Name.BindValueChanged(n => name.Text = n);

osu.Game/Screens/Multi/Match/Components/ReadyButton.cs

@@ -1,13 +1,22 @@
 // Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
 // Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
 
+using System.Linq;
+using osu.Framework.Allocation;
+using osu.Framework.Configuration;
 using osu.Framework.Graphics;
+using osu.Game.Beatmaps;
 using osuTK;
 
 namespace osu.Game.Screens.Multi.Match.Components
 {
     public class ReadyButton : HeaderButton
     {
+        public readonly IBindable<BeatmapInfo> Beatmap = new Bindable<BeatmapInfo>();
+
+        [Resolved]
+        private BeatmapManager beatmaps { get; set; }
+
         public ReadyButton()
         {
             RelativeSizeAxes = Axes.Y;
@@ -15,5 +24,37 @@ namespace osu.Game.Screens.Multi.Match.Components
 
             Text = "Start";
         }
+
+        [BackgroundDependencyLoader]
+        private void load()
+        {
+            beatmaps.ItemAdded += beatmapAdded;
+
+            Beatmap.BindValueChanged(updateEnabledState, true);
+        }
+
+        private void updateEnabledState(BeatmapInfo beatmap)
+        {
+            if (beatmap?.OnlineBeatmapID == null)
+            {
+                Enabled.Value = false;
+                return;
+            }
+
+            Enabled.Value = beatmaps.QueryBeatmap(b => b.OnlineBeatmapID == beatmap.OnlineBeatmapID) != null;
+        }
+
+        private void beatmapAdded(BeatmapSetInfo model, bool existing, bool silent)
+        {
+            if (model.Beatmaps.Any(b => b.OnlineBeatmapID == Beatmap.Value.OnlineBeatmapID))
+                Schedule(() => Enabled.Value = true);
+        }
+
+        protected override void Dispose(bool isDisposing)
+        {
+            base.Dispose(isDisposing);
+
+            beatmaps.ItemAdded -= beatmapAdded;
+        }
     }
 }

osu.Game/Screens/Multi/Match/Components/ViewBeatmapButton.cs

@@ -1,13 +1,21 @@
 // Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
 // Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
 
+using osu.Framework.Allocation;
+using osu.Framework.Configuration;
 using osu.Framework.Graphics;
+using osu.Game.Beatmaps;
 using osuTK;
 
 namespace osu.Game.Screens.Multi.Match.Components
 {
     public class ViewBeatmapButton : HeaderButton
     {
+        public readonly IBindable<BeatmapInfo> Beatmap = new Bindable<BeatmapInfo>();
+
+        [Resolved(CanBeNull = true)]
+        private OsuGame osuGame { get; set; }
+
         public ViewBeatmapButton()
         {
             RelativeSizeAxes = Axes.Y;
@@ -15,5 +23,24 @@ namespace osu.Game.Screens.Multi.Match.Components
 
             Text = "View beatmap";
         }
+
+        [BackgroundDependencyLoader]
+        private void load()
+        {
+            if (osuGame != null)
+                Beatmap.BindValueChanged(updateAction, true);
+        }
+
+        private void updateAction(BeatmapInfo beatmap)
+        {
+            if (beatmap == null)
+            {
+                Enabled.Value = false;
+                return;
+            }
+
+            Action = () => osuGame.ShowBeatmap(beatmap.OnlineBeatmapID ?? 0);
+            Enabled.Value = true;
+        }
     }
 }

osu.Game/Screens/Multi/Match/MatchScreen.cs

@@ -140,6 +140,7 @@ namespace osu.Game.Screens.Multi.Match
             info.Beatmap.Value = item.Beatmap;
             info.Mods.Value = item.RequiredMods;
 
+            // Todo: item.Beatmap can be null here...
             Beatmap.Value = beatmapManager.GetWorkingBeatmap(item.Beatmap);
         }