From 8646d5d1e081d850482766f60dd471734663c214 Mon Sep 17 00:00:00 2001
From: Dean Herbert <pe@ppy.sh>
Date: Wed, 13 Dec 2017 21:47:42 +0900
Subject: [PATCH] Add testing and fix filtering only some difficulties

---
 .../Visual/TestCaseBeatmapCarousel.cs         | 12 ++++++++++-
 osu.Game/Screens/Select/BeatmapCarousel.cs    | 21 ++++++++++++++++---
 2 files changed, 29 insertions(+), 4 deletions(-)

diff --git a/osu.Game.Tests/Visual/TestCaseBeatmapCarousel.cs b/osu.Game.Tests/Visual/TestCaseBeatmapCarousel.cs
index e77337d488..f034dc7baf 100644
--- a/osu.Game.Tests/Visual/TestCaseBeatmapCarousel.cs
+++ b/osu.Game.Tests/Visual/TestCaseBeatmapCarousel.cs
@@ -79,6 +79,8 @@ namespace osu.Game.Tests.Visual
 
             AddUntilStep(() => carousel.Beatmaps.Any(), "Wait for load");
 
+            // test traversal
+
             advanceSelection(direction: 1, diff: false);
             checkSelected(1, 1);
 
@@ -98,6 +100,8 @@ namespace osu.Game.Tests.Visual
             advanceSelection(direction: -1, diff: true);
             checkSelected(4, 3);
 
+            // test basic filtering
+
             AddStep("Filter", () => carousel.Filter(new FilterCriteria { SearchText = "set #3" }, false));
             checkVisibleItemCount(diff: false, count: 1);
             checkVisibleItemCount(diff: true, count: 3);
@@ -111,7 +115,13 @@ namespace osu.Game.Tests.Visual
             checkVisibleItemCount(diff: false, count: 4);
             checkVisibleItemCount(diff: true, count: 3);
 
-            setSelected(1, diff: 2);
+            // test filtering some difficulties (and keeping current beatmap set selected).
+
+            setSelected(1, 2);
+            AddStep("Filter some difficulties", () => carousel.Filter(new FilterCriteria { SearchText = "Normal" }, false));
+            checkSelected(1, 1);
+            AddStep("Un-filter", () => carousel.Filter(new FilterCriteria(), false));
+            checkSelected(1, 1);
         }
 
         private BeatmapSetInfo createTestBeatmapSet(int i)
diff --git a/osu.Game/Screens/Select/BeatmapCarousel.cs b/osu.Game/Screens/Select/BeatmapCarousel.cs
index 9f210e023b..5e3efb55c9 100644
--- a/osu.Game/Screens/Select/BeatmapCarousel.cs
+++ b/osu.Game/Screens/Select/BeatmapCarousel.cs
@@ -94,6 +94,7 @@ namespace osu.Game.Screens.Select
         private readonly Stack<CarouselBeatmap> randomSelectedBeatmaps = new Stack<CarouselBeatmap>();
 
         private CarouselBeatmap selectedBeatmap;
+        private CarouselBeatmapSet selectedBeatmapSet => carouselSets.FirstOrDefault(s => s.State == CarouselItemState.Selected);
 
         public BeatmapCarousel()
         {
@@ -291,14 +292,28 @@ namespace osu.Game.Screens.Select
             {
                 FilterTask = null;
 
+                var lastSet = selectedBeatmapSet;
+                var lastBeatmap = selectedBeatmap;
+
                 carouselSets.ForEach(s => s.Filter(criteria));
 
                 yPositionsCache.Invalidate();
 
-                if (selectedBeatmap?.Visible != true)
-                    SelectNext();
-                else
+                if (selectedBeatmap?.Filtered == false)
                     select(selectedBeatmap);
+                else if (lastBeatmap != null && !lastSet.Filtered)
+                {
+                    var searchable = lastSet.Beatmaps.AsEnumerable();
+
+                    // search forwards first then backwards if nothing found.
+                    var nextAvailable =
+                        searchable.SkipWhile(b => b != lastBeatmap).FirstOrDefault(b => !b.Filtered) ??
+                        searchable.Reverse().SkipWhile(b => b != lastBeatmap).FirstOrDefault(b => !b.Filtered);
+
+                    select(nextAvailable);
+                }
+                else
+                    SelectNext();
             };
 
             FilterTask?.Cancel();