Core/Spells: Changes in code related to spell explicit target redirection (cleanups, added target validation, prevent unexpected behaviour in some cases)

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

@@ -1884,7 +1884,7 @@ void Unit::AttackerStateUpdate (Unit* victim, WeaponAttackType attType, bool ext
     else
     {
         // attack can be redirected to another target
-        victim = SelectMagnetTarget(victim);
+        victim = GetMeleeHitRedirectTarget(victim);
 
         CalcDamageInfo damageInfo;
         CalculateMeleeDamage(victim, 0, &damageInfo, attType);
@@ -9988,44 +9988,43 @@ int32 Unit::DealHeal(Unit* victim, uint32 addhealth)
     return gain;
 }
 
-Unit* Unit::SelectMagnetTarget(Unit* victim, SpellInfo const* spellInfo)
+Unit* Unit::GetMagicHitRedirectTarget(Unit* victim, SpellInfo const* spellInfo)
-{
-    if (!victim)
-        return NULL;
-
-    // Magic case
-    if (spellInfo && (spellInfo->DmgClass == SPELL_DAMAGE_CLASS_NONE || spellInfo->DmgClass == SPELL_DAMAGE_CLASS_MAGIC))
 {
     // Patch 1.2 notes: Spell Reflection no longer reflects abilities
     if (spellInfo->Attributes & SPELL_ATTR0_ABILITY || spellInfo->AttributesEx & SPELL_ATTR1_CANT_BE_REDIRECTED || spellInfo->Attributes & SPELL_ATTR0_UNAFFECTED_BY_INVULNERABILITY)
         return victim;
-        // I am not sure if this should be redirected.
-        if (spellInfo->DmgClass == SPELL_DAMAGE_CLASS_NONE)
-            return victim;
 
     Unit::AuraEffectList const& magnetAuras = victim->GetAuraEffectsByType(SPELL_AURA_SPELL_MAGNET);
     for (Unit::AuraEffectList::const_iterator itr = magnetAuras.begin(); itr != magnetAuras.end(); ++itr)
+    {
         if (Unit* magnet = (*itr)->GetBase()->GetUnitOwner())
-                if (magnet->isAlive() && IsWithinLOSInMap(magnet))
+            if (spellInfo->CheckExplicitTarget(this, magnet) == SPELL_CAST_OK
+                && spellInfo->CheckTarget(this, magnet, false) == SPELL_CAST_OK
+                && _IsValidAttackTarget(magnet, spellInfo)
+                && IsWithinLOSInMap(magnet))
             {
                 (*itr)->GetBase()->DropCharge(AURA_REMOVE_BY_EXPIRE);
                 return magnet;
             }
     }
-    // Melee && ranged case
+    return victim;
-    else
+}
+
+Unit* Unit::GetMeleeHitRedirectTarget(Unit* victim, SpellInfo const* spellInfo)
 {
     AuraEffectList const& hitTriggerAuras = victim->GetAuraEffectsByType(SPELL_AURA_ADD_CASTER_HIT_TRIGGER);
     for (AuraEffectList::const_iterator i = hitTriggerAuras.begin(); i != hitTriggerAuras.end(); ++i)
+    {
         if (Unit* magnet = (*i)->GetBase()->GetCaster())
-                if (magnet->isAlive() && magnet->IsWithinLOSInMap(this))
+            if (_IsValidAttackTarget(magnet, spellInfo) && magnet->IsWithinLOSInMap(this)
+                && (!spellInfo || (spellInfo->CheckExplicitTarget(this, magnet) == SPELL_CAST_OK
+                && spellInfo->CheckTarget(this, magnet, false) == SPELL_CAST_OK)))
                 if (roll_chance_i((*i)->GetAmount()))
                 {
                     (*i)->GetBase()->DropCharge(AURA_REMOVE_BY_EXPIRE);
                     return magnet;
                 }
     }
-
     return victim;
 }
 

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

@@ -2008,7 +2008,8 @@ class Unit : public WorldObject
         uint32 BuildAuraStateUpdateForTarget(Unit* target) const;
         bool HasAuraState(AuraStateType flag, SpellInfo const* spellProto = NULL, Unit const* Caster = NULL) const ;
         void UnsummonAllTotems();
-        Unit* SelectMagnetTarget(Unit* victim, SpellInfo const* spellInfo = NULL);
+        Unit* GetMagicHitRedirectTarget(Unit* victim, SpellInfo const* spellInfo);
+        Unit* GetMeleeHitRedirectTarget(Unit* victim, SpellInfo const* spellInfo = NULL);
         int32 SpellBaseDamageBonus(SpellSchoolMask schoolMask);
         int32 SpellBaseHealingBonus(SpellSchoolMask schoolMask);
         int32 SpellBaseDamageBonusForVictim(SpellSchoolMask schoolMask, Unit* pVictim);

src/server/game/Spells/Spell.cpp

@@ -674,8 +674,39 @@ void Spell::InitExplicitTargets(SpellCastTargets const& targets)
         m_targets.RemoveSrc();
 }
 
+void Spell::SelectExplicitTargets()
+{
+    // here go all explicit target changes made to explicit targets after spell prepare phase is finished
+    if (Unit* target = m_targets.GetUnitTarget())
+    {
+        // check for explicit target redirection, for Grounding Totem for example
+        if (m_spellInfo->GetExplicitTargetMask() & TARGET_FLAG_UNIT_ENEMY
+            || (m_spellInfo->GetExplicitTargetMask() & TARGET_FLAG_UNIT && !m_spellInfo->IsPositive()))
+        {
+            Unit* redirect;
+            switch (m_spellInfo->DmgClass)
+            {
+                case SPELL_DAMAGE_CLASS_MAGIC:
+                    redirect = m_caster->GetMagicHitRedirectTarget(target, m_spellInfo);
+                    break;
+                case SPELL_DAMAGE_CLASS_MELEE:
+                case SPELL_DAMAGE_CLASS_RANGED:
+                    redirect = m_caster->GetMeleeHitRedirectTarget(target, m_spellInfo);
+                    break;
+                default:
+                    redirect = NULL;
+                    break;
+            }
+            if (redirect && (redirect != target))
+                m_targets.SetUnitTarget(redirect);
+        }
+    }
+}
+
 void Spell::SelectSpellTargets()
 {
+    // select targets for cast phase
+    SelectExplicitTargets();
     uint32 processedTargets = 0;
     for (uint32 i = 0; i < MAX_SPELL_EFFECTS; ++i)
     {
@@ -2079,16 +2110,7 @@ uint32 Spell::SelectEffectTargets(uint32 i, SpellImplicitTargetInfo const& cur)
             switch (cur.GetTarget())
             {
                 case TARGET_UNIT_TARGET_ENEMY:
-                    if (Unit* magnet = m_caster->SelectMagnetTarget(target, m_spellInfo))
-                        if (magnet != target)
-                            m_targets.SetUnitTarget(magnet);
-                    pushType = PUSH_CHAIN;
-                    break;
                 case TARGET_UNIT_TARGET_ANY:
-                    if (!m_spellInfo->IsPositive())
-                        if (Unit* magnet = m_caster->SelectMagnetTarget(target, m_spellInfo))
-                            if (magnet != target)
-                                m_targets.SetUnitTarget(magnet);
                     pushType = PUSH_CHAIN;
                     break;
                 case TARGET_UNIT_TARGET_CHAINHEAL_ALLY:

src/server/game/Spells/Spell.h

@@ -405,6 +405,7 @@ class Spell
         void WriteAmmoToPacket(WorldPacket* data);
 
         void InitExplicitTargets(SpellCastTargets const& targets);
+        void SelectExplicitTargets();
         void SelectSpellTargets();
         void SelectEffectTypeImplicitTargets(uint8 effIndex);
         uint32 SelectEffectTargets(uint32 i, SpellImplicitTargetInfo const& cur);