Core/Spell: implemented dispel reflection

Closes #18323

(cherry picked from commit f0772eea98c66f7fd2e745c0cfb8599d6c21ef19)

# Conflicts:
#	src/server/game/Spells/Spell.cpp
#	src/server/game/Spells/Spell.h
#	src/server/game/Spells/SpellEffects.cpp

2 files changed, 46 insertions, 9 deletions

diff --git a/src/server/game/Entities/Unit/Unit.cpp b/src/server/game/Entities/Unit/Unit.cpp
index 847a8e6f51e..f0af80b721e 100644
--- a/src/server/game/Entities/Unit/Unit.cpp
+++ b/src/server/game/Entities/Unit/Unit.cpp
@@ -105,6 +105,11 @@ float playerBaseMoveSpeed[MAX_MOVE_TYPE] =
     3.14f                  // MOVE_PITCH_RATE
 };
 
+bool DispelableAura::RollDispel() const
+{
+    return roll_chance_i(_chance);
+}
+
 DamageInfo::DamageInfo(Unit* attacker, Unit* victim, uint32 damage, SpellInfo const* spellInfo, SpellSchoolMask schoolMask, DamageEffectType damageType, WeaponAttackType attackType)
     : m_attacker(attacker), m_victim(victim), m_damage(damage), m_spellInfo(spellInfo), m_schoolMask(schoolMask), m_damageType(damageType), m_attackType(attackType),
     m_absorb(0), m_resist(0), m_block(0), m_hitMask(0)
@@ -4261,13 +4266,13 @@ Aura* Unit::GetAuraOfRankedSpell(uint32 spellId, ObjectGuid casterGUID, ObjectGu
     return aurApp ? aurApp->GetBase() : NULL;
 }
 
-void Unit::GetDispellableAuraList(Unit* caster, uint32 dispelMask, DispelChargesList& dispelList)
+void Unit::GetDispellableAuraList(Unit* caster, uint32 dispelMask, DispelChargesList& dispelList, bool isReflect /*= false*/)  const
 {
     AuraMap const& auras = GetOwnedAuras();
-    for (AuraMap::const_iterator itr = auras.begin(); itr != auras.end(); ++itr)
+    for (auto itr = auras.begin(); itr != auras.end(); ++itr)
     {
         Aura* aura = itr->second;
-        AuraApplication * aurApp = aura->GetApplicationOfTarget(GetGUID());
+        AuraApplication const* aurApp = aura->GetApplicationOfTarget(GetGUID());
         if (!aurApp)
             continue;
 
@@ -4278,17 +4283,23 @@ void Unit::GetDispellableAuraList(Unit* caster, uint32 dispelMask, DispelCharges
         if (aura->GetSpellInfo()->GetDispelMask() & dispelMask)
         {
             // do not remove positive auras if friendly target
-            //               negative auras if non-friendly target
-            if (aurApp->IsPositive() == IsFriendlyTo(caster))
+            //               negative auras if non-friendly
+            // unless we're reflecting (dispeller eliminates one of it's benefitial buffs)
+            if (isReflect != (aurApp->IsPositive() == IsFriendlyTo(caster)))
+                continue;
+
+            // 2.4.3 Patch Notes: "Dispel effects will no longer attempt to remove effects that have 100% dispel resistance."
+            int32 chance = aura->CalcDispelChance(this, !IsFriendlyTo(caster));
+            if (!chance)
                 continue;
 
             // The charges / stack amounts don't count towards the total number of auras that can be dispelled.
             // Ie: A dispel on a target with 5 stacks of Winters Chill and a Polymorph has 1 / (1 + 1) -> 50% chance to dispell
             // Polymorph instead of 1 / (5 + 1) -> 16%.
-            bool dispelCharges = aura->GetSpellInfo()->HasAttribute(SPELL_ATTR7_DISPEL_CHARGES);
+            bool const dispelCharges = aura->GetSpellInfo()->HasAttribute(SPELL_ATTR7_DISPEL_CHARGES);
             uint8 charges = dispelCharges ? aura->GetCharges() : aura->GetStackAmount();
             if (charges > 0)
-                dispelList.push_back(std::make_pair(aura, charges));
+                dispelList.emplace_back(aura, chance, charges);
         }
     }
 }
diff --git a/src/server/game/Entities/Unit/Unit.h b/src/server/game/Entities/Unit/Unit.h
index b5a023620da..6d8f9c81cbd 100644
--- a/src/server/game/Entities/Unit/Unit.h
+++ b/src/server/game/Entities/Unit/Unit.h
@@ -228,7 +228,33 @@ namespace WorldPackets
 }
 
 typedef std::list<Unit*> UnitList;
-typedef std::list<std::pair<Aura*, uint8>> DispelChargesList;
+
+class DispelableAura
+{
+    public:
+        DispelableAura(Aura* aura, int32 dispelChance, uint8 dispelCharges) :
+            _aura(aura), _chance(dispelChance), _charges(dispelCharges) { }
+
+        Aura* GetAura() const { return _aura; }
+        bool RollDispel() const;
+        uint8 GetDispelCharges() const { return _charges; }
+
+        void IncrementCharges() { ++_charges; }
+        bool DecrementCharge()
+        {
+            if (!_charges)
+                return false;
+
+            --_charges;
+            return _charges > 0;
+        }
+
+    private:
+        Aura* _aura;
+        int32 _chance;
+        uint8 _charges;
+};
+typedef std::vector<DispelableAura> DispelChargesList;
 
 typedef std::unordered_multimap<uint32 /*type*/, uint32 /*spellId*/> SpellImmuneContainer;
 
@@ -1471,7 +1497,7 @@ class TC_GAME_API Unit : public WorldObject
         AuraApplication * GetAuraApplicationOfRankedSpell(uint32 spellId, ObjectGuid casterGUID = ObjectGuid::Empty, ObjectGuid itemCasterGUID = ObjectGuid::Empty, uint32 reqEffMask = 0, AuraApplication * except = NULL) const;
         Aura* GetAuraOfRankedSpell(uint32 spellId, ObjectGuid casterGUID = ObjectGuid::Empty, ObjectGuid itemCasterGUID = ObjectGuid::Empty, uint32 reqEffMask = 0) const;
 
-        void GetDispellableAuraList(Unit* caster, uint32 dispelMask, DispelChargesList& dispelList);
+        void GetDispellableAuraList(Unit* caster, uint32 dispelMask, DispelChargesList& dispelList, bool isReflect = false) const;
 
         bool HasAuraEffect(uint32 spellId, uint8 effIndex, ObjectGuid caster = ObjectGuid::Empty) const;
         uint32 GetAuraCount(uint32 spellId) const;