Core/Spells: Grounding Totem: - correctly magnet spells and dies - let missile spells fly on it and destroys all spells during the travel time of first one

Thx @amsjunior1

Closes #13147
Fixes #5611

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

@@ -3460,7 +3460,7 @@ void Unit::_UnapplyAura(AuraApplicationMap::iterator &i, AuraRemoveMode removeMo
     ASSERT(!aurApp->GetEffectMask());
 
     // Remove totem at next update if totem loses its aura
-    if (aurApp->GetRemoveMode() == AURA_REMOVE_BY_EXPIRE && GetTypeId() == TYPEID_UNIT && ToCreature()->IsTotem()&& ToTotem()->GetSummonerGUID() == aura->GetCasterGUID())
+    if (aurApp->GetRemoveMode() == AURA_REMOVE_BY_EXPIRE && GetTypeId() == TYPEID_UNIT && ToCreature()->IsTotem())
     {
         if (ToTotem()->GetSpell() == aura->GetId() && ToTotem()->GetTotemType() == TOTEM_PASSIVE)
             ToTotem()->setDeathState(JUST_DIED);
@@ -9584,6 +9584,15 @@ int32 Unit::DealHeal(Unit* victim, uint32 addhealth)
     return gain;
 }
 
+bool Unit::IsMagnet() const
+{
+    // Grounding Totem 
+    if (GetUInt32Value(UNIT_CREATED_BY_SPELL) == 8177) /// @todo: find a more generic solution
+        return true;
+
+    return false;
+}
+
 Unit* Unit::GetMagicHitRedirectTarget(Unit* victim, SpellInfo const* spellInfo)
 {
     // Patch 1.2 notes: Spell Reflection no longer reflects abilities
@@ -9599,7 +9608,16 @@ Unit* Unit::GetMagicHitRedirectTarget(Unit* victim, SpellInfo const* spellInfo)
                 && _IsValidAttackTarget(magnet, spellInfo))
             {
                 /// @todo handle this charge drop by proc in cast phase on explicit target
-                (*itr)->GetBase()->DropCharge(AURA_REMOVE_BY_EXPIRE);
+                if (victim && spellInfo->Speed > 0.0f)
+                {
+                    // Set up missile speed based delay
+                    uint32 delay = uint32(std::floor(std::max<float>(victim->GetDistance(this), 5.0f) / spellInfo->Speed * 1000.0f));
+                    // Schedule charge drop
+                    (*itr)->GetBase()->DropChargeDelayed(delay,AURA_REMOVE_BY_EXPIRE);
+                }
+                else
+                    (*itr)->GetBase()->DropCharge(AURA_REMOVE_BY_EXPIRE);
+
                 return magnet;
             }
     }

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

@@ -1971,6 +1971,7 @@ class Unit : public WorldObject
         uint32 BuildAuraStateUpdateForTarget(Unit* target) const;
         bool HasAuraState(AuraStateType flag, SpellInfo const* spellProto = NULL, Unit const* Caster = NULL) const;
         void UnsummonAllTotems();
+        bool IsMagnet() const;
         Unit* GetMagicHitRedirectTarget(Unit* victim, SpellInfo const* spellInfo);
         Unit* GetMeleeHitRedirectTarget(Unit* victim, SpellInfo const* spellInfo = NULL);
 

src/server/game/Spells/SpellInfo.cpp

@@ -1738,6 +1738,11 @@ bool SpellInfo::CheckTargetCreatureType(Unit const* target) const
         else
             return true;
     }
+
+    // if target is magnet (i.e Grounding Totem) the check is skipped
+    if (target->IsMagnet())
+        return true;
+
     uint32 creatureType = target->GetCreatureTypeMask();
     return !TargetCreatureType || !creatureType || (creatureType & TargetCreatureType);
 }