Core/Auras: Use recalculated aura max duration on spell hit for duration calculations.

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

@@ -3113,7 +3113,10 @@ void Unit::DeMorph()
 
 Aura* Unit::_TryStackingOrRefreshingExistingAura(SpellEntry const* newAura, uint8 effMask, Unit* caster, int32* baseAmount /*= NULL*/, Item* castItem /*= NULL*/, uint64 casterGUID /*= 0*/)
 {
-    ASSERT(casterGUID);
+    ASSERT(casterGUID || caster);
+    if (!casterGUID)
+        casterGUID = caster->GetGUID();
+
     // passive and Incanter's Absorption and auras with different type can stack with themselves any number of times
     if (!IsPassiveSpell(newAura) && newAura->Id != 44413)
     {

src/server/game/Spells/Auras/SpellAuras.cpp

@@ -334,24 +334,13 @@ m_isRemoved(false), m_isSingleTarget(false)
     if (m_spellProto->manaPerSecond || m_spellProto->manaPerSecondPerLevel)
         m_timeCla = 1 * IN_MILLISECONDS;
 
-    Player* modOwner = NULL;
+    m_maxDuration = CalcMaxDuration(caster);
-
-    if (caster)
-    {
-        modOwner = caster->GetSpellModOwner();
-        m_maxDuration = caster->CalcSpellDuration(m_spellProto);
-    }
-    else
-        m_maxDuration = GetSpellDuration(m_spellProto);
-
-    if (IsPassive() && m_spellProto->DurationIndex == 0)
-        m_maxDuration = -1;
-
-    if (!IsPermanent() && modOwner)
-        modOwner->ApplySpellMod(GetId(), SPELLMOD_DURATION, m_maxDuration);
-
     m_duration = m_maxDuration;
 
+    Player* modOwner = NULL;
+    if (caster)
+        modOwner = caster->GetSpellModOwner();
+
     m_procCharges = m_spellProto->procCharges;
     if (modOwner)
         modOwner->ApplySpellMod(GetId(), SPELLMOD_CHARGES, m_procCharges);
@@ -700,6 +689,27 @@ void Aura::Update(uint32 diff, Unit * caster)
     }
 }
 
+int32 Aura::CalcMaxDuration(Unit* caster) const
+{
+    Player* modOwner = NULL;
+    int32 maxDuration;
+
+    if (caster)
+    {
+        modOwner = caster->GetSpellModOwner();
+        maxDuration = caster->CalcSpellDuration(m_spellProto);
+    }
+    else
+        maxDuration = GetSpellDuration(m_spellProto);
+
+    if (IsPassive() && m_spellProto->DurationIndex == 0)
+        maxDuration = -1;
+
+    if (!IsPermanent() && modOwner)
+        modOwner->ApplySpellMod(GetId(), SPELLMOD_DURATION, maxDuration);
+    return maxDuration;
+}
+
 void Aura::SetDuration(int32 duration, bool withMods)
 {
     if (withMods)

src/server/game/Spells/Auras/SpellAuras.h

@@ -121,6 +121,8 @@ class Aura
         time_t GetApplyTime() const { return m_applyTime; }
         int32 GetMaxDuration() const { return m_maxDuration; }
         void SetMaxDuration(int32 duration) { m_maxDuration = duration; }
+        int32 CalcMaxDuration() const { return CalcMaxDuration(GetCaster()); } 
+        int32 CalcMaxDuration(Unit * caster) const;
         int32 GetDuration() const { return m_duration; }
         void SetDuration(int32 duration, bool withMods = false);
         void RefreshDuration();

src/server/game/Spells/Spell.cpp

@@ -1427,8 +1427,9 @@ SpellMissInfo Spell::DoSpellHitOnUnit(Unit *unit, const uint32 effectMask, bool
 
         if (m_originalCaster)
         {
+            bool refresh;
             m_spellAura = Aura::TryRefreshStackOrCreate(aurSpellInfo, effectMask, unit,
-                m_originalCaster, (aurSpellInfo == m_spellInfo)? &m_spellValue->EffectBasePoints[0] : &basePoints[0], m_CastItem);
+                m_originalCaster, (aurSpellInfo == m_spellInfo)? &m_spellValue->EffectBasePoints[0] : &basePoints[0], m_CastItem, 0, &refresh);
             if (m_spellAura)
             {
                 // Set aura stack amount to desired value
@@ -1436,7 +1437,8 @@ SpellMissInfo Spell::DoSpellHitOnUnit(Unit *unit, const uint32 effectMask, bool
                     m_spellAura->SetStackAmount(m_spellValue->AuraStackAmount);
 
                 // Now Reduce spell duration using data received at spell hit
-                int32 duration = m_spellAura->GetMaxDuration();
+                // if we're refreshing aura, recalculate max duration, to avoid applying mods twice
+                int32 duration = refresh ? m_spellAura->CalcMaxDuration() : m_spellAura->GetMaxDuration();
                 int32 limitduration = GetDiminishingReturnsLimitDuration(m_diminishGroup, aurSpellInfo);
                 float diminishMod = unit->ApplyDiminishingToDuration(m_diminishGroup, duration, m_originalCaster, m_diminishLevel, limitduration);