Core/Spells: Delay combat flagging for spell targets until spell missile lands

(cherry picked from commit b59706c8b6856bdfe084a38330773725d3404f05)

src/server/game/Combat/CombatManager.cpp

@@ -171,7 +171,7 @@ Unit* CombatManager::GetAnyTarget() const
     return nullptr;
 }
 
-bool CombatManager::SetInCombatWith(Unit* who)
+bool CombatManager::SetInCombatWith(Unit* who, bool suppressPvpSecond)
 {
     // Are we already in combat? If yes, refresh pvp combat
     auto it = _pvpRefs.find(who->GetGUID());
@@ -190,7 +190,12 @@ bool CombatManager::SetInCombatWith(Unit* who)
     // ...then create new reference
     CombatReference* ref;
     if (_owner->IsControlledByPlayer() && who->IsControlledByPlayer())
-        ref = new PvPCombatReference(_owner, who);
+    {
+        PvPCombatReference* refPvp = new PvPCombatReference(_owner, who);
+        if (suppressPvpSecond)
+            refPvp->SuppressFor(who);
+        ref = refPvp;
+    }
     else
         ref = new CombatReference(_owner, who);
 

src/server/game/Combat/CombatManager.h

@@ -114,7 +114,7 @@ class TC_GAME_API CombatManager
         Unit* GetAnyTarget() const;
 
         // return value is the same as calling IsInCombatWith immediately after this returns
-        bool SetInCombatWith(Unit* who);
+        bool SetInCombatWith(Unit* who, bool suppressPvpSecond = false);
         bool IsInCombatWith(ObjectGuid const& who) const;
         bool IsInCombatWith(Unit const* who) const;
         void InheritCombatStatesFrom(Unit const* who);

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

@@ -1150,7 +1150,7 @@ class TC_GAME_API Unit : public WorldObject
 
         bool IsInCombat() const { return HasUnitFlag(UNIT_FLAG_IN_COMBAT); }
         bool IsInCombatWith(Unit const* who) const { return who && m_combatManager.IsInCombatWith(who); }
-        void SetInCombatWith(Unit* enemy) { if (enemy) m_combatManager.SetInCombatWith(enemy); }
+        void SetInCombatWith(Unit* enemy, bool suppressPvpTargetCombat = false) { if (enemy) m_combatManager.SetInCombatWith(enemy, suppressPvpTargetCombat); }
         void ClearInCombat() { m_combatManager.EndAllCombat(); }
         void UpdatePetCombatState();
         // Threat handling

src/server/game/Spells/Spell.cpp

@@ -2253,6 +2253,37 @@ void Spell::CleanupTargetList()
     m_delayMoment = 0;
 }
 
+class ProcImpactDelayed : public BasicEvent
+{
+public:
+    ProcImpactDelayed(Unit* owner, ObjectGuid casterGUID, const bool enterCombat, bool enablePVP) : _owner(owner), _casterGUID(casterGUID), _enterCombat(enterCombat), _enablePVP(enablePVP) { }
+
+    bool Execute(uint64 /*e_time*/, uint32 /*p_time*/) override
+    {
+        if(!_owner)
+            return true;
+
+        Unit* caster = ObjectAccessor::GetUnit(*_owner, _casterGUID);
+        if (!caster)
+            return true;
+
+        // This will only cause combat - the target will engage once the projectile hits (in DoAllEffectOnTarget)
+        if (_enterCombat)
+            _owner->SetInCombatWith(caster);
+
+        if (_enablePVP && caster->ToPlayer())
+            caster->ToPlayer()->UpdatePvP(true);
+
+        return true;
+    }
+
+private:
+    Unit*  _owner;
+    ObjectGuid _casterGUID;
+    bool _enterCombat;
+    bool _enablePVP;
+};
+
 class ProcReflectDelayed : public BasicEvent
 {
     public:
@@ -2322,8 +2353,13 @@ void Spell::AddUnitTarget(Unit* target, uint32 effectMask, bool checkIfValid /*=
 
     // Calculate hit result
     WorldObject* caster = m_originalCaster ? m_originalCaster : m_caster;
+    Unit* unitCaster = m_caster->ToUnit();
     targetInfo.MissCondition = caster->SpellHitResult(target, m_spellInfo, m_canReflect && !(IsPositive() && m_caster->IsFriendlyTo(target)));
 
+    // This will only cause combat - the target will engage once the projectile hits (in DoAllEffectOnTarget)
+    if (m_originalCaster && targetInfo.MissCondition != SPELL_MISS_EVADE && !m_originalCaster->IsFriendlyTo(target) && (!m_spellInfo->IsPositive() || m_spellInfo->HasEffect(SPELL_EFFECT_DISPEL)) && (m_spellInfo->HasInitialAggro() || target->IsEngaged()))
+        m_originalCaster->SetInCombatWith(target, true);
+
     // Spell have speed - need calculate incoming time
     // Incoming time is zero for self casts. At least I think so.
     if (m_caster != target)
@@ -2358,6 +2394,15 @@ void Spell::AddUnitTarget(Unit* target, uint32 effectMask, bool checkIfValid /*=
         }
 
         targetInfo.TimeDelay += uint64(std::floor(hitDelay * 1000.0f));
+
+        if (unitCaster && targetInfo.MissCondition != SPELL_MISS_EVADE)
+        {
+            bool enterCombat = !caster->IsFriendlyTo(target) && (!m_spellInfo->IsPositive() || m_spellInfo->HasEffect(SPELL_EFFECT_DISPEL)) && (m_spellInfo->HasInitialAggro() || target->IsEngaged());
+            bool enablePVP = targetInfo.IsPVPEnabling();
+
+            if (enterCombat || enablePVP)
+                target->m_Events.AddEvent(new ProcImpactDelayed(target, m_originalCasterGUID, enterCombat, enablePVP), target->m_Events.CalculateTime(Milliseconds(targetInfo.TimeDelay)));
+        }
     }
     else
         targetInfo.TimeDelay = 0ULL;
@@ -2366,7 +2411,7 @@ void Spell::AddUnitTarget(Unit* target, uint32 effectMask, bool checkIfValid /*=
     if (targetInfo.MissCondition == SPELL_MISS_REFLECT)
     {
         // Calculate reflected spell result on caster (shouldn't be able to reflect gameobject spells)
-        Unit* unitCaster = ASSERT_NOTNULL(m_caster->ToUnit());
+        ASSERT(unitCaster);
         targetInfo.ReflectResult = unitCaster->SpellHitResult(unitCaster, m_spellInfo, false); // can't reflect twice
 
         // Proc spell reflect aura when missile hits the original target
@@ -8181,10 +8226,6 @@ void Spell::DoEffectOnLaunchTarget(TargetInfo& targetInfo, float multiplier, Spe
     if (!unit)
         return;
 
-    // This will only cause combat - the target will engage once the projectile hits (in DoAllEffectOnTarget)
-    if (m_originalCaster && targetInfo.MissCondition != SPELL_MISS_EVADE && !m_originalCaster->IsFriendlyTo(unit) && (!m_spellInfo->IsPositive() || m_spellInfo->HasEffect(SPELL_EFFECT_DISPEL)) && (m_spellInfo->HasInitialAggro() || unit->IsEngaged()))
-        m_originalCaster->SetInCombatWith(unit);
-
     m_damage = 0;
     m_healing = 0;
 

src/server/game/Spells/Spell.h

@@ -742,6 +742,8 @@ class TC_GAME_API Spell
             void DoTargetSpellHit(Spell* spell, SpellEffectInfo const& spellEffectInfo) override;
             void DoDamageAndTriggers(Spell* spell) override;
 
+            bool IsPVPEnabling() const { return _enablePVP; }
+
             ObjectGuid TargetGUID;
             uint64 TimeDelay = 0ULL;
             int32 Damage = 0;