Core/Unit: Some charm fixes:

* Properly restore react state after possession expires. Closes #20769.
* Possessed creatures now don't override player control with random/waypoint motion
* SmartAI creatures now properly re-aggress charmer after charm expires

src/server/game/AI/SmartScripts/SmartAI.cpp

@@ -679,8 +679,13 @@ void SmartAI::OnCharmed(bool /*isNew*/)
         else
             me->SetWalk(!mRun);
 
-        if (Unit* charmer = me->GetCharmer())
-            AttackStart(charmer);
+        if (me->LastCharmerGUID)
+        {
+            if (!me->HasReactState(REACT_PASSIVE))
+                if (Unit* lastCharmer = ObjectAccessor::GetUnit(*me, me->LastCharmerGUID))
+                    me->EngageWithTarget(lastCharmer);
+            me->LastCharmerGUID.Clear();
+        }
     }
 
     GetScript()->ProcessEventsFor(SMART_EVENT_CHARMED, nullptr, 0, 0, charmed);

src/server/game/Entities/Unit/Unit.cpp

@@ -9573,10 +9573,10 @@ CharmInfo::CharmInfo(Unit* unit)
     for (uint8 i = 0; i < MAX_SPELL_CHARM; ++i)
         _charmspells[i].SetActionAndType(0, ACT_DISABLED);
 
-    if (_unit->GetTypeId() == TYPEID_UNIT)
+    if (Creature* creature = _unit->ToCreature())
     {
-        _oldReactState = _unit->ToCreature()->GetReactState();
-        _unit->ToCreature()->SetReactState(REACT_PASSIVE);
+        _oldReactState = creature->GetReactState();
+        creature->SetReactState(REACT_PASSIVE);
     }
 }
 
@@ -11358,26 +11358,12 @@ bool Unit::SetCharmedBy(Unit* charmer, CharmType type, AuraApplication const* au
         GetMotionMaster()->Clear(MOTION_PRIORITY_NORMAL);
 
         StopMoving();
-
-        // AI will schedule its own change if appropriate
-        if (UnitAI* ai = GetAI())
-            ai->OnCharmed(false);
-        else
-            ScheduleAIChange();
     }
     else if (Player* player = ToPlayer())
     {
         if (player->isAFK())
             player->ToggleAFK();
 
-        if (charmer->GetTypeId() == TYPEID_UNIT) // we are charmed by a creature
-        {
-            // change AI to charmed AI on next Update tick
-            if (UnitAI* ai = GetAI())
-                ai->OnCharmed(false);
-            else
-                player->ScheduleAIChange();
-        }
         player->SetClientControl(this, false);
     }
 
@@ -11438,6 +11424,15 @@ bool Unit::SetCharmedBy(Unit* charmer, CharmType type, AuraApplication const* au
     }
 
     AddUnitState(UNIT_STATE_CHARMED);
+
+    if ((GetTypeId() != TYPEID_PLAYER) || (charmer->GetTypeId() != TYPEID_PLAYER))
+    {
+        // AI will schedule its own change if appropriate
+        if (UnitAI* ai = GetAI())
+            ai->OnCharmed(false);
+        else
+            ScheduleAIChange();
+    }
     return true;
 }
 
@@ -11446,15 +11441,12 @@ void Unit::RemoveCharmedBy(Unit* charmer)
     if (!IsCharmed())
         return;
 
-    if (!charmer)
+    if (charmer)
+        ASSERT(charmer == GetCharmer());
+    else
         charmer = GetCharmer();
-    if (charmer != GetCharmer()) // one aura overrides another?
-    {
-//        TC_LOG_FATAL("entities.unit", "Unit::RemoveCharmedBy: this: " UI64FMTD " true charmer: " UI64FMTD " false charmer: " UI64FMTD,
-//            GetGUID(), GetCharmerGUID(), charmer->GetGUID());
-//        ABORT();
-        return;
-    }
+
+    ASSERT(charmer);
 
     CharmType type;
     if (HasUnitState(UNIT_STATE_POSSESSED))
@@ -11480,11 +11472,7 @@ void Unit::RemoveCharmedBy(Unit* charmer)
 
     // Vehicle should not attack its passenger after he exists the seat
     if (type != CHARM_TYPE_VEHICLE)
-        LastCharmerGUID = ASSERT_NOTNULL(charmer)->GetGUID();
-
-    // If charmer still exists
-    if (!charmer)
-        return;
+        LastCharmerGUID = charmer->GetGUID();
 
     ASSERT(type != CHARM_TYPE_POSSESS || charmer->GetTypeId() == TYPEID_PLAYER);
     ASSERT(type != CHARM_TYPE_VEHICLE || (GetTypeId() == TYPEID_UNIT && IsVehicle()));
@@ -11527,6 +11515,19 @@ void Unit::RemoveCharmedBy(Unit* charmer)
         }
     }
 
+    if (Player* player = ToPlayer())
+        player->SetClientControl(this, true);
+
+    if (playerCharmer && this != charmer->GetFirstControlled())
+        playerCharmer->SendRemoveControlBar();
+
+    // a guardian should always have charminfo
+    if (!IsGuardian())
+        DeleteCharmInfo();
+
+    // reset confused movement for example
+    ApplyControlStatesIfNeeded();
+
     if (GetTypeId() != TYPEID_PLAYER || charmer->GetTypeId() == TYPEID_UNIT)
     {
         if (UnitAI* charmedAI = GetAI())
@@ -11534,18 +11535,6 @@ void Unit::RemoveCharmedBy(Unit* charmer)
         else
             ScheduleAIChange();
     }
-
-    if (Player* player = ToPlayer())
-        player->SetClientControl(this, true);
-
-    // a guardian should always have charminfo
-    if (playerCharmer && this != charmer->GetFirstControlled())
-        playerCharmer->SendRemoveControlBar();
-    else if (GetTypeId() == TYPEID_PLAYER || (GetTypeId() == TYPEID_UNIT && !IsGuardian()))
-        DeleteCharmInfo();
-
-    // reset confused movement for example
-    ApplyControlStatesIfNeeded();
 }
 
 void Unit::RestoreFaction()

src/server/game/Entities/Unit/UnitDefines.h

@@ -340,7 +340,7 @@ enum ReactStates
     REACT_DEFENSIVE  = 1,
     REACT_AGGRESSIVE = 2
 };
-static char const* DescribeReactState(ReactStates state) {
+static char const* TC_GAME_API DescribeReactState(ReactStates state) {
     switch (state)
     {
         case REACT_PASSIVE:     return "PASSIVE";

src/server/game/Movement/MovementGenerators/RandomMovementGenerator.cpp

@@ -86,7 +86,7 @@ void RandomMovementGenerator<Creature>::SetRandomLocation(Creature* owner)
     if (!owner)
         return;
 
-    if (owner->HasUnitState(UNIT_STATE_NOT_MOVE) || owner->IsMovementPreventedByCasting())
+    if (owner->HasUnitState(UNIT_STATE_NOT_MOVE | UNIT_STATE_LOST_CONTROL) || owner->IsMovementPreventedByCasting())
     {
         AddFlag(MOVEMENTGENERATOR_FLAG_INTERRUPTED);
         owner->StopMoving();

src/server/game/Movement/MovementGenerators/WaypointMovementGenerator.cpp

@@ -139,7 +139,7 @@ bool WaypointMovementGenerator<Creature>::DoUpdate(Creature* owner, uint32 diff)
     if (HasFlag(MOVEMENTGENERATOR_FLAG_FINALIZED | MOVEMENTGENERATOR_FLAG_PAUSED) || !_path || _path->nodes.empty())
         return true;
 
-    if (owner->HasUnitState(UNIT_STATE_NOT_MOVE) || owner->IsMovementPreventedByCasting())
+    if (owner->HasUnitState(UNIT_STATE_NOT_MOVE | UNIT_STATE_LOST_CONTROL) || owner->IsMovementPreventedByCasting())
     {
         AddFlag(MOVEMENTGENERATOR_FLAG_INTERRUPTED);
         owner->StopMoving();