fix(Core/Spells): cache reflection target information for reflected thunderstorm direction (#23762)

src/server/game/Spells/Spell.cpp

@@ -643,6 +643,8 @@ Spell::Spell(Unit* caster, SpellInfo const* info, TriggerCastFlags triggerFlags,
     gameObjTarget = nullptr;
     destTarget = nullptr;
     damage = 0;
+    m_reflectionTarget = nullptr;
+    m_reflectionTargetGuid.Clear();
     effectHandleMode = SPELL_EFFECT_HANDLE_LAUNCH;
     m_diminishLevel = DIMINISHING_LEVEL_1;
     m_diminishGroup = DIMINISHING_NONE;
@@ -2591,6 +2593,7 @@ void Spell::DoAllEffectOnTarget(TargetInfo* target)
     //Spells with this flag cannot trigger if effect is casted on self
     bool canEffectTrigger = !m_spellInfo->HasAttribute(SPELL_ATTR3_SUPPRESS_CASTER_PROCS) && unitTarget->CanProc() && (CanExecuteTriggersOnHit(mask) || missInfo == SPELL_MISS_IMMUNE2);
     bool reflectedSpell = missInfo == SPELL_MISS_REFLECT;
+    Unit* reflectionSource = nullptr;
     Unit* spellHitTarget = nullptr;
 
     if (missInfo == SPELL_MISS_NONE)                          // In case spell hit target, do all effect on that target
@@ -2602,6 +2605,7 @@ void Spell::DoAllEffectOnTarget(TargetInfo* target)
         {
             spellHitTarget = m_caster;
             unitTarget = m_caster;
+            reflectionSource = effectUnit;
             if (m_caster->IsCreature())
                 m_caster->ToCreature()->LowerPlayerDamageReq(target->damage);
         }
@@ -2609,7 +2613,24 @@ void Spell::DoAllEffectOnTarget(TargetInfo* target)
 
     if (spellHitTarget)
     {
+        if (reflectionSource)
+        {
+            m_reflectionTarget = reflectionSource;
+            m_reflectionTargetGuid = reflectionSource->GetGUID();
+            m_reflectionTargetPosition.Relocate(reflectionSource);
+        }
+        else
+        {
+            m_reflectionTarget = nullptr;
+            m_reflectionTargetGuid.Clear();
+            m_reflectionTargetPosition = Position();
+        }
+
         SpellMissInfo missInfo2 = DoSpellHitOnUnit(spellHitTarget, mask, target->scaleAura);
+
+        m_reflectionTarget = nullptr;
+        m_reflectionTargetGuid.Clear();
+        m_reflectionTargetPosition = Position();
         if (missInfo2 != SPELL_MISS_NONE)
         {
             if (missInfo2 != SPELL_MISS_MISS)

src/server/game/Spells/Spell.h

@@ -666,6 +666,9 @@ public:
     WorldLocation* destTarget;
     int32 damage;
     SpellEffectHandleMode effectHandleMode;
+    Unit* m_reflectionTarget;
+    ObjectGuid m_reflectionTargetGuid;
+    Position m_reflectionTargetPosition;
     // used in effects handlers
     Aura* m_spellAura;
 

src/server/game/Spells/SpellEffects.cpp

@@ -5013,7 +5013,24 @@ void Spell::EffectKnockBack(SpellEffIndex effIndex)
         return;
 
     float x, y;
-    if (m_spellInfo->Effects[effIndex].Effect == SPELL_EFFECT_KNOCK_BACK_DEST)
+    Unit* reflectionSource = m_reflectionTarget;
+
+    if (!reflectionSource && !m_reflectionTargetGuid.IsEmpty())
+    {
+        if (Unit* resolvedSource = ObjectAccessor::GetUnit(*m_caster, m_reflectionTargetGuid))
+            reflectionSource = resolvedSource;
+    }
+
+    if (reflectionSource)
+    {
+        reflectionSource->GetPosition(x, y);
+    }
+    else if (!m_reflectionTargetGuid.IsEmpty())
+    {
+        x = m_reflectionTargetPosition.GetPositionX();
+        y = m_reflectionTargetPosition.GetPositionY();
+    }
+    else if (m_spellInfo->Effects[effIndex].Effect == SPELL_EFFECT_KNOCK_BACK_DEST)
     {
         if (m_targets.HasDst())
             destTarget->GetPosition(x, y);