Core/DataStores: Rewrite DB2Manager::GetDefaultMapDifficulty to only return entries that point to valid Difficulty.db2 rows

(cherry picked from commit 441d7e5dc1522680d52fde03e0f3cbe751350f3b)

1 files changed, 19 insertions, 17 deletions

diff --git a/src/server/game/DataStores/DB2Stores.cpp b/src/server/game/DataStores/DB2Stores.cpp
index 734c0caa392..fe635b9ffd2 100644
--- a/src/server/game/DataStores/DB2Stores.cpp
+++ b/src/server/game/DataStores/DB2Stores.cpp
@@ -2094,32 +2094,34 @@ uint32 DB2Manager::GetLiquidFlags(uint32 liquidType)
 
 MapDifficultyEntry const* DB2Manager::GetDefaultMapDifficulty(uint32 mapId, Difficulty* difficulty /*= nullptr*/) const
 {
-    auto itr = _mapDifficulties.find(mapId);
-    if (itr == _mapDifficulties.end())
+    std::unordered_map<uint32, MapDifficultyEntry const*>* difficultiesForMap = Trinity::Containers::MapGetValuePtr(_mapDifficulties, mapId);
+    if (!difficultiesForMap)
         return nullptr;
 
-    if (itr->second.empty())
-        return nullptr;
+    auto difficultyEnd = difficultiesForMap->end();
 
-    for (auto& p : itr->second)
-    {
-        DifficultyEntry const* difficultyEntry = sDifficultyStore.LookupEntry(p.first);
-        if (!difficultyEntry)
-            continue;
+    // first find any valid difficulty
+    auto foundDifficulty = std::ranges::find_if(difficultiesForMap->begin(), difficultyEnd,
+        [](std::pair<uint32 const, MapDifficultyEntry const*> const& p) { return sDifficultyStore.HasRecord(p.first); });
 
-        if (difficultyEntry->Flags & DIFFICULTY_FLAG_DEFAULT)
-        {
-            if (difficulty)
-                *difficulty = Difficulty(p.first);
+    if (foundDifficulty == difficultyEnd)
+        return nullptr; // nothing valid was found
 
-            return p.second;
-        }
+    if (!(sDifficultyStore.AssertEntry(foundDifficulty->first)->Flags & DIFFICULTY_FLAG_DEFAULT))
+    {
+        // first valid difficulty wasn't default, try finding one
+        auto defaultDifficulty = std::ranges::find_if(foundDifficulty, difficultyEnd,
+            [](DifficultyEntry const* difficultyEntry) { return difficultyEntry && (difficultyEntry->Flags & DIFFICULTY_FLAG_DEFAULT) != 0; },
+            [](std::pair<uint32 const, MapDifficultyEntry const*> const& p) { return sDifficultyStore.LookupEntry(p.first); });
+
+        if (defaultDifficulty != difficultyEnd)
+            foundDifficulty = defaultDifficulty; // got a default
     }
 
     if (difficulty)
-        *difficulty = Difficulty(itr->second.begin()->first);
+        *difficulty = Difficulty(foundDifficulty->first);
 
-    return itr->second.begin()->second;
+    return foundDifficulty->second;
 }
 
 MapDifficultyEntry const* DB2Manager::GetMapDifficultyData(uint32 mapId, Difficulty difficulty) const