Set creatures in combat with vehicle passengers

This will avoid the situation when hostile targets evade when a vehicle
dies.
Also fix threat logic as vehicles shouldn't be second choice targets
Finally remove the UNIT_FLAG_PET_IN_COMBAT for vehicles

Signed-off-by: Xfurry <xfurry.cmangos@outlook.com>

src/game/AI/BaseAI/CreatureAI.cpp

@@ -18,6 +18,7 @@
 
 #include "AI/BaseAI/CreatureAI.h"
 #include "Entities/Creature.h"
+#include "Entities/Vehicle.h"
 #include "Server/DBCStores.h"
 #include "Spells/Spell.h"
 #include "Spells/SpellMgr.h"
@@ -247,6 +248,39 @@ void CreatureAI::AttackStart(Unit* who)
             m_creature->CastSpell(m_creature, 43783, TRIGGERED_OLD_TRIGGERED);
 
         HandleMovementOnAttackStart(who);
+
+        // for controlled vehicles set the creature in combat with the passengers
+        if (who->IsVehicle())
+            AttackPassengersIfCan(who);
+    }
+}
+
+void CreatureAI::AttackPassengersIfCan(Unit* who)
+{
+    if (!who->IsVehicle())
+        return;
+
+    // set the victim's passengers in combat (if possible)
+    for (uint8 i = 0; i < MAX_VEHICLE_SEAT; ++i)
+    {
+        uint32 seatId = who->GetVehicleInfo()->GetVehicleEntry()->m_seatID[i];
+        if (!seatId)
+            continue;
+
+        Unit* passenger = who->GetVehicleInfo()->GetPassenger(i);
+        if (!passenger)
+            continue;
+
+        if (VehicleSeatEntry const* seatEntry = sVehicleSeatStore.LookupEntry(seatId))
+        {
+            // validate seat flags
+            if (seatEntry->m_flags & SEAT_FLAG_NOT_SELECTABLE || seatEntry->m_flags & SEAT_FLAG_HIDE_PASSENGER)
+                continue;
+
+            m_creature->AddThreat(passenger);
+            m_creature->SetInCombatWith(passenger);
+            passenger->SetInCombatWith(m_creature);
+        }
     }
 }
 

src/game/AI/BaseAI/CreatureAI.h

@@ -316,6 +316,9 @@ class CreatureAI
         /// This function is used to do the actual melee damage (if possible)
         bool DoMeleeAttackIfReady() const;
 
+        /// Helper function which handles the combat reaction for vehicle passengers
+        void AttackPassengersIfCan(Unit* who);
+
         /// Internal helper function, to check if a spell can be cast
         CanCastResult CanCastSpell(Unit* target, const SpellEntry* spellInfo, bool isTriggered) const;
 

src/game/Entities/Unit.cpp

@@ -8877,7 +8877,7 @@ void Unit::ClearInCombat()
     m_CombatTimer = 0;
     RemoveFlag(UNIT_FIELD_FLAGS, UNIT_FLAG_IN_COMBAT);
 
-    if (HasCharmer() || (GetTypeId() != TYPEID_PLAYER && ((Creature*)this)->IsPet()))
+    if (HasCharmer() || (GetTypeId() != TYPEID_PLAYER && (((Creature*)this)->IsPet() || ((Creature*)this)->IsVehicle())))
         RemoveFlag(UNIT_FIELD_FLAGS, UNIT_FLAG_PET_IN_COMBAT);
 
     if (GetTypeId() == TYPEID_PLAYER)
@@ -9713,7 +9713,7 @@ bool Unit::IsSecondChoiceTarget(Unit* pTarget, bool taunt, bool checkThreatArea)
     const Creature* thisCreature = GetTypeId() == TYPEID_UNIT ? static_cast<const Creature*>(this) : nullptr;
 
     return
-        pTarget->IsTargetUnderControl(*this) ||
+        (!pTarget->IsVehicle() && pTarget->IsTargetUnderControl(*this)) ||
         (!taunt && pTarget->IsImmuneToDamage(GetMeleeDamageSchoolMask())) ||
         pTarget->hasNegativeAuraWithInterruptFlag(AURA_INTERRUPT_FLAG_DAMAGE) ||
         (thisCreature && checkThreatArea && thisCreature->IsOutOfThreatArea(pTarget));