Core/Combat: reset the ThreatManager update interval upon engaging the creature and move ThreatClear packet sending into the update cycle to mimic retail behavior (#29949)

src/server/game/Combat/ThreatManager.cpp

@@ -189,7 +189,7 @@ void ThreatReference::HeapNotifyDecreased()
     return true;
 }
 
-ThreatManager::ThreatManager(Unit* owner) : _owner(owner), _ownerCanHaveThreatList(false), _needClientUpdate(false), _updateTimer(THREAT_UPDATE_INTERVAL),
+ThreatManager::ThreatManager(Unit* owner) : _owner(owner), _ownerCanHaveThreatList(false), _needClientUpdate(false), _needThreatClearUpdate(false), _updateTimer(THREAT_UPDATE_INTERVAL),
     _sortedThreatList(std::make_unique<Heap>()), _currentVictimRef(nullptr), _fixateRef(nullptr)
 {
     for (int8 i = 0; i < MAX_SPELL_SCHOOL; ++i)
@@ -210,17 +210,31 @@ void ThreatManager::Initialize()
 
 void ThreatManager::Update(uint32 tdiff)
 {
-    if (!CanHaveThreatList() || IsThreatListEmpty(true))
+    if (!CanHaveThreatList())
         return;
+
     if (_updateTimer <= tdiff)
     {
-        UpdateVictim();
+        if (_needThreatClearUpdate)
+        {
+            SendClearAllThreatToClients();
+            _needThreatClearUpdate = false;
+        }
+
+        if (!IsThreatListEmpty(true))
+            UpdateVictim();
+
         _updateTimer = THREAT_UPDATE_INTERVAL;
     }
     else
         _updateTimer -= tdiff;
 }
 
+void ThreatManager::ResetUpdateTimer()
+{
+    _updateTimer = THREAT_UPDATE_INTERVAL;
+}
+
 Unit* ThreatManager::GetCurrentVictim()
 {
     if (!_currentVictimRef || _currentVictimRef->ShouldBeOffline())
@@ -539,7 +553,7 @@ void ThreatManager::ClearAllThreat()
 {
     if (!_myThreatListEntries.empty())
     {
-        SendClearAllThreatToClients();
+        _needThreatClearUpdate = true;
         do
             _myThreatListEntries.begin()->second->UnregisterAndFree();
         while (!_myThreatListEntries.empty());

src/server/game/Combat/ThreatManager.h

@@ -95,6 +95,9 @@ class TC_GAME_API ThreatManager
         // called from Creature::Update (only creatures can have their own threat list)
         // should not be called from anywhere else
         void Update(uint32 tdiff);
+        // called from Creature::AtEngage
+        // should not be called from anywhere else
+        void ResetUpdateTimer();
 
         // never nullptr
         Unit* GetOwner() const { return _owner; }
@@ -197,6 +200,7 @@ class TC_GAME_API ThreatManager
         void PurgeThreatListRef(ObjectGuid const& guid);
 
         bool _needClientUpdate;
+        bool _needThreatClearUpdate;
         uint32 _updateTimer;
         std::unique_ptr<Heap> _sortedThreatList;
         std::unordered_map<ObjectGuid, ThreatReference*> _myThreatListEntries;

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

@@ -743,6 +743,8 @@ void Creature::Update(uint32 diff)
 
     UpdateMovementCapabilities();
 
+    GetThreatManager().Update(diff);
+
     switch (m_deathState)
     {
         case JUST_RESPAWNED:
@@ -829,7 +831,6 @@ void Creature::Update(uint32 diff)
             if (!IsAlive())
                 break;
 
-            GetThreatManager().Update(diff);
             if (_spellFocusInfo.Delay)
             {
                 if (_spellFocusInfo.Delay <= diff)
@@ -3595,6 +3596,8 @@ void Creature::AtEngage(Unit* target)
 {
     Unit::AtEngage(target);
 
+    GetThreatManager().ResetUpdateTimer();
+
     if (!HasFlag(CREATURE_STATIC_FLAG_2_ALLOW_MOUNTED_COMBAT))
         Dismount();