fix(Core/Spells): Beacon of Light no longer copies target healing modifiers (#24796)

Co-authored-by: blinkysc <blinkysc@users.noreply.github.com>

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

@@ -386,6 +386,7 @@ private:
     Unit* const m_healer;
     Unit* const m_target;
     uint32 m_heal;
+    uint32 m_healBeforeTakenMods;
     uint32 m_effectiveHeal;
     uint32 m_absorb;
     SpellInfo const* const m_spellInfo;
@@ -393,7 +394,7 @@ private:
     uint32 m_hitMask;
 public:
     explicit HealInfo(Unit* _healer, Unit* _target, uint32 _heal, SpellInfo const* _spellInfo, SpellSchoolMask _schoolMask)
-        : m_healer(_healer), m_target(_target), m_heal(_heal), m_spellInfo(_spellInfo), m_schoolMask(_schoolMask), m_hitMask(0)
+        : m_healer(_healer), m_target(_target), m_heal(_heal), m_healBeforeTakenMods(0), m_spellInfo(_spellInfo), m_schoolMask(_schoolMask), m_hitMask(0)
     {
         m_absorb = 0;
         m_effectiveHeal = 0;
@@ -414,6 +415,11 @@ public:
         m_heal = amount;
     }
 
+    void SetHealBeforeTakenMods(uint32 amount)
+    {
+        m_healBeforeTakenMods = amount;
+    }
+
     void SetEffectiveHeal(uint32 amount)
     {
         m_effectiveHeal = amount;
@@ -422,6 +428,7 @@ public:
     [[nodiscard]] Unit* GetHealer() const { return m_healer; }
     [[nodiscard]] Unit* GetTarget() const { return m_target; }
     [[nodiscard]] uint32 GetHeal() const { return m_heal; }
+    [[nodiscard]] uint32 GetHealBeforeTakenMods() const { return m_healBeforeTakenMods; }
     [[nodiscard]] uint32 GetEffectiveHeal() const { return m_effectiveHeal; }
     [[nodiscard]] uint32 GetAbsorb() const { return m_absorb; }
     [[nodiscard]] SpellInfo const* GetSpellInfo() const { return m_spellInfo; };

src/server/game/Spells/Spell.cpp

@@ -649,6 +649,7 @@ Spell::Spell(Unit* caster, SpellInfo const* info, TriggerCastFlags triggerFlags,
     m_diminishGroup = DIMINISHING_NONE;
     m_damage = 0;
     m_healing = 0;
+    m_damageBeforeTakenMods = 0;
     m_procAttacker = 0;
     m_procVictim = 0;
     m_procEx = 0;
@@ -2337,6 +2338,7 @@ void Spell::AddUnitTarget(Unit* target, uint32 effectMask, bool checkIfValid /*=
     targetInfo.processed  = false;                              // Effects not apply on target
     targetInfo.alive      = target->IsAlive();
     targetInfo.damage     = 0;
+    targetInfo.damageBeforeTakenMods = 0;
     targetInfo.crit       = false;
     targetInfo.scaleAura  = false;
     if (m_auraScaleMask && targetInfo.effectMask == m_auraScaleMask && m_caster != target)
@@ -2712,6 +2714,17 @@ void Spell::DoAllEffectOnTarget(TargetInfo* target)
 
         HealInfo healInfo(caster, unitTarget, addhealth, m_spellInfo, m_spellInfo->GetSchoolMask());
 
+        // Heal amount before SpellHealingBonusTaken, used by Beacon of Light
+        if (target->damageBeforeTakenMods != 0)
+        {
+            uint32 healBeforeTakenMods = uint32(-target->damageBeforeTakenMods);
+            if (crit)
+                healBeforeTakenMods = Unit::SpellCriticalHealingBonus(caster, m_spellInfo, healBeforeTakenMods, nullptr);
+            healInfo.SetHealBeforeTakenMods(healBeforeTakenMods);
+        }
+        else
+            healInfo.SetHealBeforeTakenMods(addhealth);
+
         // Set hitMask based on crit
         if (crit)
             healInfo.AddHitMask(PROC_HIT_CRITICAL);
@@ -8297,6 +8310,7 @@ void Spell::DoAllEffectOnLaunchTarget(TargetInfo& targetInfo, float* multiplier)
         {
             m_damage = 0;
             m_healing = 0;
+            m_damageBeforeTakenMods = 0;
 
             HandleEffects(unit, nullptr, nullptr, i, SPELL_EFFECT_HANDLE_LAUNCH_TARGET);
 
@@ -8322,6 +8336,7 @@ void Spell::DoAllEffectOnLaunchTarget(TargetInfo& targetInfo, float* multiplier)
                 m_damageMultipliers[i] *= multiplier[i];
             }
             targetInfo.damage += m_damage;
+            targetInfo.damageBeforeTakenMods += m_damageBeforeTakenMods;
         }
     }
 

src/server/game/Spells/Spell.h

@@ -273,6 +273,7 @@ struct TargetInfo
     bool   crit:1;
     bool   scaleAura:1;
     int32  damage;
+    int32  damageBeforeTakenMods;
 };
 
 static const uint32 SPELL_INTERRUPT_NONPLAYER = 32747;
@@ -683,6 +684,7 @@ public:
     // Damage and healing in effects need just calculate
     int32 m_damage;           // Damge   in effects count here
     int32 m_healing;          // Healing in effects count here
+    int32 m_damageBeforeTakenMods;
 
     // ******************************************
     // Spell trigger system

src/server/game/Spells/SpellEffects.cpp

@@ -1557,11 +1557,13 @@ void Spell::EffectHeal(SpellEffIndex effIndex)
         else if (m_spellInfo->SpellFamilyName == SPELLFAMILY_DEATHKNIGHT && m_spellInfo->SpellFamilyFlags[0] & 0x00080000)
         {
             addhealth = caster->SpellHealingBonusDone(unitTarget, m_spellInfo, int32(caster->CountPctFromMaxHealth(damage)), HEAL, effIndex);
+            m_damageBeforeTakenMods -= addhealth;
             addhealth = unitTarget->SpellHealingBonusTaken(caster, m_spellInfo, addhealth, HEAL);
         }
         else if (m_spellInfo->Id != 33778) // not lifebloom
         {
             addhealth = caster->SpellHealingBonusDone(unitTarget, m_spellInfo, addhealth, HEAL, effIndex);
+            m_damageBeforeTakenMods -= addhealth;
             addhealth = unitTarget->SpellHealingBonusTaken(caster, m_spellInfo, addhealth, HEAL);
         }
 
@@ -1593,6 +1595,7 @@ void Spell::EffectHealPct(SpellEffIndex effIndex)
         return;
 
     uint32 heal = m_originalCaster->SpellHealingBonusDone(unitTarget, m_spellInfo, unitTarget->CountPctFromMaxHealth(damage), HEAL, effIndex);
+    m_damageBeforeTakenMods -= heal;
     heal = unitTarget->SpellHealingBonusTaken(m_originalCaster, m_spellInfo, heal, HEAL);
 
     m_damage -= heal;
@@ -1611,6 +1614,7 @@ void Spell::EffectHealMechanical(SpellEffIndex effIndex)
         return;
 
     uint32 heal = m_originalCaster->SpellHealingBonusDone(unitTarget, m_spellInfo, uint32(damage), HEAL, effIndex);
+    m_damageBeforeTakenMods -= heal;
 
     m_damage -= unitTarget->SpellHealingBonusTaken(m_originalCaster, m_spellInfo, heal, HEAL);
 }

src/server/scripts/Spells/spell_paladin.cpp

@@ -2148,7 +2148,10 @@ class spell_pal_light_s_beacon : public AuraScript
         // Holy Light heals for 100%, Flash of Light heals for 50%
         uint32 healSpellId = procSpell->IsRankOf(sSpellMgr->AssertSpellInfo(SPELL_PALADIN_HOLY_LIGHT_R1)) ?
             SPELL_PALADIN_BEACON_OF_LIGHT_FLASH : SPELL_PALADIN_BEACON_OF_LIGHT_HOLY;
-        int32 heal = CalculatePct(healInfo->GetHeal(), aurEff->GetAmount());
+
+        // Use heal amount before target-specific modifiers to avoid copying them
+        uint32 healAmount = healInfo->GetHealBeforeTakenMods();
+        int32 heal = CalculatePct(healAmount, aurEff->GetAmount());
 
         Unit* beaconTarget = GetCaster();
         if (!beaconTarget || !beaconTarget->HasAura(SPELL_PALADIN_BEACON_OF_LIGHT_AURA, eventInfo.GetActor()->GetGUID()))