From 97ebf382883210c1828a276b9a2685c2f5e071f5 Mon Sep 17 00:00:00 2001
From: Kelvin <2yangk23@gmail.com>
Date: Mon, 28 Aug 2017 00:56:03 -0700
Subject: [PATCH] Use PlaylistList to manage Prev/Next tracks

---
 osu.Game/Overlays/Music/PlaylistItem.cs    |  2 +-
 osu.Game/Overlays/Music/PlaylistList.cs    | 18 ++++++++++++++++++
 osu.Game/Overlays/Music/PlaylistOverlay.cs | 16 ++++++++--------
 3 files changed, 27 insertions(+), 9 deletions(-)

diff --git a/osu.Game/Overlays/Music/PlaylistItem.cs b/osu.Game/Overlays/Music/PlaylistItem.cs
index 6c38755e72..f6ba78c897 100644
--- a/osu.Game/Overlays/Music/PlaylistItem.cs
+++ b/osu.Game/Overlays/Music/PlaylistItem.cs
@@ -29,8 +29,8 @@ namespace osu.Game.Overlays.Music
         private IEnumerable<SpriteText> titleSprites;
         private UnicodeBindableString titleBind;
         private UnicodeBindableString artistBind;
-        private FillFlowContainer<PlaylistItem> Playlist;
 
+        private readonly FillFlowContainer<PlaylistItem> Playlist;
         public readonly BeatmapSetInfo BeatmapSetInfo;
 
         public Action<BeatmapSetInfo> OnSelect;
diff --git a/osu.Game/Overlays/Music/PlaylistList.cs b/osu.Game/Overlays/Music/PlaylistList.cs
index 3cbef8c22e..019049eb96 100644
--- a/osu.Game/Overlays/Music/PlaylistList.cs
+++ b/osu.Game/Overlays/Music/PlaylistList.cs
@@ -46,6 +46,24 @@ namespace osu.Game.Overlays.Music
             }
         }
 
+        public BeatmapSetInfo NextItem
+        {
+            get
+            {
+                var available = items.Children;
+                return (available.SkipWhile(i => !i.Selected).Skip(1).FirstOrDefault() ?? available.FirstOrDefault())?.BeatmapSetInfo;
+            }
+        }
+
+        public BeatmapSetInfo PreviousItem
+        {
+            get
+            {
+                var available = items.Children.Reverse();
+                return (available.SkipWhile(i => !i.Selected).Skip(1).FirstOrDefault() ?? available.FirstOrDefault())?.BeatmapSetInfo;
+            }
+        }
+
         public PlaylistList()
         {
             Children = new Drawable[]
diff --git a/osu.Game/Overlays/Music/PlaylistOverlay.cs b/osu.Game/Overlays/Music/PlaylistOverlay.cs
index 83e92c5554..e987e7a5c1 100644
--- a/osu.Game/Overlays/Music/PlaylistOverlay.cs
+++ b/osu.Game/Overlays/Music/PlaylistOverlay.cs
@@ -126,24 +126,24 @@ namespace osu.Game.Overlays.Music
 
         public void PlayPrevious()
         {
-            var currentID = beatmapBacking.Value?.BeatmapSetInfo.ID ?? -1;
-            var available = BeatmapSets.Reverse();
-
-            var playable = available.SkipWhile(b => b.ID != currentID).Skip(1).FirstOrDefault() ?? available.FirstOrDefault();
+            var playable = list.PreviousItem;
 
             if (playable != null)
+            {
                 playSpecified(playable.Beatmaps[0]);
+                list.SelectedItem = playable;
+            }
         }
 
         public void PlayNext()
         {
-            var currentID = beatmapBacking.Value?.BeatmapSetInfo.ID ?? -1;
-            var available = BeatmapSets;
-
-            var playable = available.SkipWhile(b => b.ID != currentID).Skip(1).FirstOrDefault() ?? available.FirstOrDefault();
+            var playable = list.NextItem;
 
             if (playable != null)
+            {
                 playSpecified(playable.Beatmaps[0]);
+                list.SelectedItem = playable;
+            }
         }
 
         private void playSpecified(BeatmapInfo info)