From 3913a0a9ee688551e9a5d7154d6e0948c178988c Mon Sep 17 00:00:00 2001
From: Huo Yaoyuan <huoyaoyuan@hotmail.com>
Date: Tue, 14 Mar 2017 04:59:44 +0800
Subject: [PATCH] Fix removal of the last one beatmap.

---
 osu.Game/Overlays/MusicController.cs        | 20 +++++++++++++-------
 osu.Game/Screens/Select/BeatmapInfoWedge.cs | 12 +++++++++---
 osu.Game/Screens/Select/PlaySongSelect.cs   |  7 +++----
 3 files changed, 25 insertions(+), 14 deletions(-)

diff --git a/osu.Game/Overlays/MusicController.cs b/osu.Game/Overlays/MusicController.cs
index 1b4692f50e..5c9adb6b20 100644
--- a/osu.Game/Overlays/MusicController.cs
+++ b/osu.Game/Overlays/MusicController.cs
@@ -210,7 +210,7 @@ namespace osu.Game.Overlays
                     }
                 }
             };
-        
+
             this.beatmaps = beatmaps;
             trackManager = osuGame.Audio.Track;
             preferUnicode = config.GetBindable<bool>(OsuConfig.ShowUnicode);
@@ -247,6 +247,8 @@ namespace osu.Game.Overlays
 
                 if (current.Track.HasCompleted && !current.Track.Looping) next();
             }
+            else
+                playButton.Icon = FontAwesome.fa_play_circle_o;
         }
 
         private void preferUnicode_changed(object sender, EventArgs e)
@@ -337,12 +339,16 @@ namespace osu.Game.Overlays
                 Task.Run(() =>
                 {
                     if (beatmap?.Beatmap == null)
-                        //todo: we may need to display some default text here (currently in the constructor).
-                        return;
-
-                    BeatmapMetadata metadata = beatmap.Beatmap.BeatmapInfo.Metadata;
-                    title.Text = unicodeString(metadata.Title, metadata.TitleUnicode);
-                    artist.Text = unicodeString(metadata.Artist, metadata.ArtistUnicode);
+                    {
+                        title.Text = @"Nothing to play";
+                        artist.Text = @"Nothing to play";
+                    }
+                    else
+                    {
+                        BeatmapMetadata metadata = beatmap.Beatmap.BeatmapInfo.Metadata;
+                        title.Text = unicodeString(metadata.Title, metadata.TitleUnicode);
+                        artist.Text = unicodeString(metadata.Artist, metadata.ArtistUnicode);
+                    }
                 });
 
                 MusicControllerBackground newBackground;
diff --git a/osu.Game/Screens/Select/BeatmapInfoWedge.cs b/osu.Game/Screens/Select/BeatmapInfoWedge.cs
index bc3b16079c..eac12f7370 100644
--- a/osu.Game/Screens/Select/BeatmapInfoWedge.cs
+++ b/osu.Game/Screens/Select/BeatmapInfoWedge.cs
@@ -16,7 +16,6 @@ using osu.Game.Database;
 using osu.Framework.Graphics.Colour;
 using osu.Game.Beatmaps.Drawables;
 using System.Linq;
-using osu.Framework.Extensions.IEnumerableExtensions;
 using osu.Framework.MathUtils;
 using osu.Game.Graphics;
 using osu.Game.Graphics.Sprites;
@@ -56,8 +55,15 @@ namespace osu.Game.Screens.Select
         public void UpdateBeatmap(WorkingBeatmap beatmap)
         {
             if (beatmap?.BeatmapInfo == null)
+            {
+                FadeOut(250);
+                beatmapInfoContainer?.FadeOut(250);
+                beatmapInfoContainer?.Expire();
+                beatmapInfoContainer = null;
                 return;
+            }
 
+            FadeIn(250);
             var lastContainer = beatmapInfoContainer;
 
             float newDepth = lastContainer?.Depth + 1 ?? 0;
@@ -84,7 +90,7 @@ namespace osu.Game.Screens.Select
                 }));
 
                 //get statistics fromt he current ruleset.
-                Ruleset.GetRuleset(beatmap.BeatmapInfo.Mode).GetBeatmapStatistics(beatmap).ForEach(s => labels.Add(new InfoLabel(s)));
+                labels.AddRange(Ruleset.GetRuleset(beatmap.BeatmapInfo.Mode).GetBeatmapStatistics(beatmap).Select(s => new InfoLabel(s)));
             }
 
             (beatmapInfoContainer = new BufferedContainer
@@ -191,7 +197,7 @@ namespace osu.Game.Screens.Select
 
         private string getBPMRange(Beatmap beatmap)
         {
-            double bpmMax = beatmap.BPMMaximum; 
+            double bpmMax = beatmap.BPMMaximum;
             double bpmMin = beatmap.BPMMinimum;
 
             if (Precision.AlmostEquals(bpmMin, bpmMax)) return Math.Round(bpmMin) + "bpm";
diff --git a/osu.Game/Screens/Select/PlaySongSelect.cs b/osu.Game/Screens/Select/PlaySongSelect.cs
index 86f9bc30cf..09ba794122 100644
--- a/osu.Game/Screens/Select/PlaySongSelect.cs
+++ b/osu.Game/Screens/Select/PlaySongSelect.cs
@@ -326,8 +326,7 @@ namespace osu.Game.Screens.Select
                 backgroundModeBeatmap.FadeTo(1, 250);
             }
 
-            if (beatmap != null)
-                beatmapInfoWedge.UpdateBeatmap(beatmap);
+            beatmapInfoWedge.UpdateBeatmap(beatmap);
         }
 
         /// <summary>
@@ -337,11 +336,11 @@ namespace osu.Game.Screens.Select
         {
             base.OnBeatmapChanged(beatmap);
 
-            beatmap.Mods.BindTo(modSelect.SelectedMods);
+            beatmap?.Mods.BindTo(modSelect.SelectedMods);
 
             //todo: change background in selectionChanged instead; support per-difficulty backgrounds.
             changeBackground(beatmap);
-            carousel.SelectBeatmap(beatmap.BeatmapInfo);
+            carousel.SelectBeatmap(beatmap?.BeatmapInfo);
         }
 
         /// <summary>