Add OnBeforeCreatureSelectLevel() hook

- allows modules to alter the level of a creature just before it is set

src/server/game/Entities/Creature/Creature.cpp

@@ -1487,7 +1487,10 @@ void Creature::SelectLevel(bool changelevel)
     uint8 maxlevel = std::max(cInfo->maxlevel, cInfo->minlevel);
     uint8 level = minlevel == maxlevel ? minlevel : urand(minlevel, maxlevel);
     if (changelevel)
+    {
+        sScriptMgr->OnBeforeCreatureSelectLevel(cInfo, this, level);
         SetLevel(level);
+    }
 
     CreatureBaseStats const* stats = sObjectMgr->GetCreatureBaseStats(level, cInfo->unit_class);
 

src/server/game/Scripting/ScriptDefines/AllCreatureScript.cpp

@@ -48,6 +48,15 @@ void ScriptMgr::OnCreatureSaveToDB(Creature* creature)
     });
 }
 
+void OnBeforeCreatureSelectLevel(const CreatureTemplate* cinfo, Creature* creature, uint8& level)
+{
+    ExecuteScript<AllCreatureScript>([&](AllCreatureScript* script)
+    {
+        script->OnBeforeCreatureSelectLevel(cinfo, creature, level);
+    });
+
+}
+
 void ScriptMgr::Creature_SelectLevel(const CreatureTemplate* cinfo, Creature* creature)
 {
     ExecuteScript<AllCreatureScript>([&](AllCreatureScript* script)

src/server/game/Scripting/ScriptMgr.h

@@ -555,6 +555,9 @@ public:
     // Called from End of Creature Update.
     virtual void OnAllCreatureUpdate(Creature* /*creature*/, uint32 /*diff*/) { }
 
+    // Called just before the level of the creature is set.
+    virtual void OnBeforeCreatureSelectLevel(const CreatureTemplate* /*cinfo*/, Creature* /*creature*/, uint8& /*level*/) { }
+
     // Called from End of Creature SelectLevel.
     virtual void Creature_SelectLevel(const CreatureTemplate* /*cinfo*/, Creature* /*creature*/) { }
 
@@ -2555,6 +2558,7 @@ public: /* MovementHandlerScript */
 public: /* AllCreatureScript */
     //listener function (OnAllCreatureUpdate) is called by OnCreatureUpdate
     //void OnAllCreatureUpdate(Creature* creature, uint32 diff);
+    void OnBeforeCreatureSelectLevel(const CreatureTemplate* cinfo, Creature* creature, uint8& level);
     void Creature_SelectLevel(const CreatureTemplate* cinfo, Creature* creature);
     void OnCreatureSaveToDB(Creature* creature);