From 105aca4707b30f19f45cab09f732f5cf522e3b0d Mon Sep 17 00:00:00 2001
From: EliteMasterEric <ericmyllyoja@gmail.com>
Date: Thu, 21 Mar 2024 19:44:02 -0400
Subject: [PATCH] Fix an issue where hidden difficulties could end up in the
 difficulty list.

---
 source/funkin/play/song/Song.hx | 21 ++++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

diff --git a/source/funkin/play/song/Song.hx b/source/funkin/play/song/Song.hx
index 1b7740408..42266a6ae 100644
--- a/source/funkin/play/song/Song.hx
+++ b/source/funkin/play/song/Song.hx
@@ -367,11 +367,14 @@ class Song implements IPlayStateScriptedClass implements IRegistryEntry<SongMeta
 
   /**
    * List all the difficulties in this song.
+   *
    * @param variationId Optionally filter by a single variation.
    * @param variationIds Optionally filter by multiple variations.
+   * @param showHidden Include charts which are not accessible to the player.
+   *
    * @return The list of difficulties.
    */
-  public function listDifficulties(?variationId:String, ?variationIds:Array<String>):Array<String>
+  public function listDifficulties(?variationId:String, ?variationIds:Array<String>, showHidden:Bool = false):Array<String>
   {
     if (variationIds == null) variationIds = [];
     if (variationId != null) variationIds.push(variationId);
@@ -387,6 +390,15 @@ class Song implements IPlayStateScriptedClass implements IRegistryEntry<SongMeta
       return difficulty.difficulty;
     }).nonNull().unique();
 
+    diffFiltered = diffFiltered.filter(function(diffId:String):Bool {
+      if (showHidden) return true;
+      for (targetVariation in variationIds)
+      {
+        if (isDifficultyVisible(diffId, targetVariation)) return true;
+      }
+      return false;
+    });
+
     diffFiltered.sort(SortUtil.defaultsThenAlphabetically.bind(Constants.DEFAULT_DIFFICULTY_LIST));
 
     return diffFiltered;
@@ -405,6 +417,13 @@ class Song implements IPlayStateScriptedClass implements IRegistryEntry<SongMeta
     return false;
   }
 
+  public function isDifficultyVisible(diffId:String, variationId:String):Bool
+  {
+    var variation = _metadata.get(variationId);
+    if (variation == null) return false;
+    return variation.playData.difficulties.contains(diffId);
+  }
+
   /**
    * Purge the cached chart data for each difficulty of this song.
    */