From f7364de01af250ec7e292702086544b6b4fe8f36 Mon Sep 17 00:00:00 2001
From: Joseph Madamba <madamba.joehu@outlook.com>
Date: Tue, 10 Dec 2024 18:18:34 -0800
Subject: [PATCH] Add test and null protections

---
 .../TestSceneBeatmapRecommendations.cs        | 44 +++++++++++++++++++
 osu.Game/Beatmaps/DifficultyRecommender.cs    |  3 +-
 .../BeatmapSearchGeneralFilterRow.cs          | 12 ++++-
 3 files changed, 56 insertions(+), 3 deletions(-)

diff --git a/osu.Game.Tests/Visual/SongSelect/TestSceneBeatmapRecommendations.cs b/osu.Game.Tests/Visual/SongSelect/TestSceneBeatmapRecommendations.cs
index bd5c43d242..4c8c1d7ad2 100644
--- a/osu.Game.Tests/Visual/SongSelect/TestSceneBeatmapRecommendations.cs
+++ b/osu.Game.Tests/Visual/SongSelect/TestSceneBeatmapRecommendations.cs
@@ -13,9 +13,12 @@ using osu.Framework.Testing;
 using osu.Game.Beatmaps;
 using osu.Game.Database;
 using osu.Game.Extensions;
+using osu.Game.Graphics.Sprites;
 using osu.Game.Online.API;
 using osu.Game.Online.API.Requests;
 using osu.Game.Online.API.Requests.Responses;
+using osu.Game.Overlays;
+using osu.Game.Overlays.BeatmapListing;
 using osu.Game.Rulesets;
 using osu.Game.Rulesets.Catch;
 using osu.Game.Rulesets.Mania;
@@ -23,6 +26,8 @@ using osu.Game.Rulesets.Osu;
 using osu.Game.Rulesets.Taiko;
 using osu.Game.Tests.Resources;
 using osu.Game.Users;
+using osu.Game.Utils;
+using osuTK.Input;
 
 namespace osu.Game.Tests.Visual.SongSelect
 {
@@ -170,6 +175,45 @@ namespace osu.Game.Tests.Visual.SongSelect
             presentAndConfirm(() => maniaSet, 5);
         }
 
+        [Test]
+        public void TestBeatmapListingFilter()
+        {
+            AddStep("set playmode to taiko", () => ((DummyAPIAccess)API).LocalUser.Value.PlayMode = "taiko");
+
+            AddStep("open beatmap listing", () =>
+            {
+                InputManager.PressKey(Key.ControlLeft);
+                InputManager.PressKey(Key.B);
+                InputManager.ReleaseKey(Key.B);
+                InputManager.ReleaseKey(Key.ControlLeft);
+            });
+
+            AddUntilStep("wait for load", () => Game.ChildrenOfType<BeatmapListingOverlay>().SingleOrDefault()?.IsLoaded, () => Is.True);
+
+            checkRecommendedDifficulty(3);
+
+            AddStep("change mode filter to osu!", () => Game.ChildrenOfType<BeatmapSearchRulesetFilterRow>().Single().ChildrenOfType<FilterTabItem<RulesetInfo>>().ElementAt(1).TriggerClick());
+
+            checkRecommendedDifficulty(2);
+
+            AddStep("change mode filter to osu!taiko", () => Game.ChildrenOfType<BeatmapSearchRulesetFilterRow>().Single().ChildrenOfType<FilterTabItem<RulesetInfo>>().ElementAt(2).TriggerClick());
+
+            checkRecommendedDifficulty(3);
+
+            AddStep("change mode filter to osu!catch", () => Game.ChildrenOfType<BeatmapSearchRulesetFilterRow>().Single().ChildrenOfType<FilterTabItem<RulesetInfo>>().ElementAt(3).TriggerClick());
+
+            checkRecommendedDifficulty(4);
+
+            AddStep("change mode filter to osu!mania", () => Game.ChildrenOfType<BeatmapSearchRulesetFilterRow>().Single().ChildrenOfType<FilterTabItem<RulesetInfo>>().ElementAt(4).TriggerClick());
+
+            checkRecommendedDifficulty(5);
+
+            void checkRecommendedDifficulty(double starRating)
+                => AddAssert($"recommended difficulty is {starRating}",
+                    () => Game.ChildrenOfType<BeatmapSearchGeneralFilterRow>().Single().ChildrenOfType<OsuSpriteText>().ElementAt(1).Text.ToString(),
+                    () => Is.EqualTo($"Recommended difficulty ({starRating.FormatStarRating()})"));
+        }
+
         private BeatmapSetInfo importBeatmapSet(IEnumerable<RulesetInfo> difficultyRulesets)
         {
             var rulesets = difficultyRulesets.ToArray();
diff --git a/osu.Game/Beatmaps/DifficultyRecommender.cs b/osu.Game/Beatmaps/DifficultyRecommender.cs
index bd864422d1..a5c7371b4d 100644
--- a/osu.Game/Beatmaps/DifficultyRecommender.cs
+++ b/osu.Game/Beatmaps/DifficultyRecommender.cs
@@ -83,7 +83,8 @@ namespace osu.Game.Beatmaps
             StarRatingUpdated?.Invoke();
         }
 
-        public double GetRecommendedStarRatingFor(RulesetInfo ruleset) => recommendedDifficultyMapping[ruleset.ShortName];
+        public double? GetRecommendedStarRatingFor(RulesetInfo ruleset)
+            => recommendedDifficultyMapping.TryGetValue(ruleset.ShortName, out double starRating) ? starRating : null;
 
         /// <summary>
         /// Find the recommended difficulty from a selection of available difficulties for the current local user.
diff --git a/osu.Game/Overlays/BeatmapListing/BeatmapSearchGeneralFilterRow.cs b/osu.Game/Overlays/BeatmapListing/BeatmapSearchGeneralFilterRow.cs
index 42d788dad7..66a0a16549 100644
--- a/osu.Game/Overlays/BeatmapListing/BeatmapSearchGeneralFilterRow.cs
+++ b/osu.Game/Overlays/BeatmapListing/BeatmapSearchGeneralFilterRow.cs
@@ -91,8 +91,16 @@ namespace osu.Game.Overlays.BeatmapListing
             {
                 // fallback to profile default game mode if beatmap listing mode filter is set to Any
                 // TODO: find a way to update `PlayMode` when the profile default game mode has changed
-                var ruleset = Ruleset.Value.IsLegacyRuleset() ? Ruleset.Value : rulesets.GetRuleset(api.LocalUser.Value.PlayMode)!;
-                Text.Text = LocalisableString.Interpolate($"{Value.GetLocalisableDescription()} ({recommender?.GetRecommendedStarRatingFor(ruleset).FormatStarRating()})");
+                RulesetInfo? ruleset = Ruleset.Value.IsLegacyRuleset() ? Ruleset.Value : rulesets.GetRuleset(api.LocalUser.Value.PlayMode);
+
+                if (ruleset == null) return;
+
+                double? starRating = recommender?.GetRecommendedStarRatingFor(ruleset);
+
+                if (starRating != null)
+                    Text.Text = LocalisableString.Interpolate($"{Value.GetLocalisableDescription()} ({starRating.Value.FormatStarRating()})");
+                else
+                    Text.Text = Value.GetLocalisableDescription();
             }
         }