[Spell] Extra attack: instant or on the next swing

Known issue: wrong combat logging order. Though the timestamp for spelleffect and instant extra attack is the same, the spelleffect appears later in the log.
Was tested on the Windfury weapon only. Main idea was taken from the TC.

src/game/Object/Unit.cpp

@@ -2102,14 +2102,8 @@ void Unit::AttackerStateUpdate(Unit* pVictim, WeaponAttackType attType, bool ext
 
         // not recent extra attack only at any non extra attack (melee spell case)
         if (!extra && extraAttacks)
-        {
-            while (m_extraAttacks)
-            {
-                AttackerStateUpdate(pVictim, BASE_ATTACK, true);
-                if (m_extraAttacks > 0)
-                    { --m_extraAttacks; }
-            }
-        }
+            HandleProcExtraAttackFor(pVictim);
+
         return;
     }
 
@@ -2133,13 +2127,15 @@ void Unit::AttackerStateUpdate(Unit* pVictim, WeaponAttackType attType, bool ext
 
     // extra attack only at any non extra attack (normal case)
     if (!extra && extraAttacks)
+        HandleProcExtraAttackFor(pVictim);
+}
+
+void Unit::HandleProcExtraAttackFor(Unit* victim)
+{
+    while (m_extraAttacks)
     {
-        while (m_extraAttacks)
-        {
-            AttackerStateUpdate(pVictim, BASE_ATTACK, true);
-            if (m_extraAttacks > 0)
-                { --m_extraAttacks; }
-        }
+        --m_extraAttacks;
+        AttackerStateUpdate(victim, BASE_ATTACK, true);
     }
 }
 

src/game/Object/Unit.h

@@ -1971,7 +1971,10 @@ class Unit : public WorldObject
          * @param durabilityLoss whether or not durability loss should happen
          */
         void DealMeleeDamage(CalcDamageInfo* damageInfo, bool durabilityLoss);
-
+        /**
+        * Handles all extra attacks set up by a spell
+        */
+        void HandleProcExtraAttackFor(Unit* victim);
         /**
          * Calculates how much damage a spell should do, it will do some bonus damage according
          * to which SpellNonMeleeDamage::DmgClass it belongs to, ie: SPELL_DAMAGE_CLASS_RANGED

src/game/Server/DBCStructure.h

@@ -921,6 +921,13 @@ struct SpellEntry
         */
         inline bool HasAttribute(SpellAttributesEx4 attribute) const { return AttributesEx4 & attribute; }
 
+        inline bool HasSpellEffect(uint16 effect) const
+        {
+            for (uint8 i = EFFECT_INDEX_0; i <= EFFECT_INDEX_2; ++i)
+                if (Effect[i] == effect)
+                    return true;
+            return false;
+        }
     private:
         // prevent creating custom entries (copy data from original in fact)
         SpellEntry(SpellEntry const&);                      // DON'T must have implementation

src/game/WorldHandlers/Spell.cpp

@@ -2950,6 +2950,22 @@ void Spell::_handle_finish_phase()
     // spell log
     if (m_needSpellLog)
         { SendLogExecute(); }
+
+    if (m_caster->m_extraAttacks && m_spellInfo->HasSpellEffect(SPELL_EFFECT_ADD_EXTRA_ATTACKS))
+    {
+        switch (m_spellInfo->Id)
+        {
+        case 15494:
+        case 18797:
+        case 21919:
+        case 20178: // paladin reckoning proc
+            break;
+        default:
+            if (Unit* victim = m_caster->getVictim())
+                m_caster->HandleProcExtraAttackFor(victim);
+            break;
+        }
+    }
 }
 
 void Spell::SendSpellCooldown()