From 6a85f7caf3423211840e43387258bb3b4890a8e2 Mon Sep 17 00:00:00 2001
From: Xaver-DaRed <xaver.entropia@gmail.com>
Date: Sun, 28 Jan 2024 20:46:24 +0100
Subject: [PATCH] Implement AoE damage reduction

Only for converted spells.
---
 scripts/enum/mod.lua                    |  1 +
 scripts/globals/spells/damage_spell.lua | 12 ++++++++++++
 src/map/modifier.h                      |  3 ++-
 3 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/scripts/enum/mod.lua b/scripts/enum/mod.lua
index 203396287b0..97ee9f6bc28 100644
--- a/scripts/enum/mod.lua
+++ b/scripts/enum/mod.lua
@@ -185,6 +185,7 @@ xi.mod =
     DMGMAGIC                        = 163,
     DMGMAGIC_II                     = 831, -- Magic Damage Taken II % (Aegis)
     DMGRANGE                        = 164,
+    DMG_AOE                         = 158, -- Damage Taken % when not main target of an AoE action. (Ex: Locus Mobs)
     UDMGPHYS                        = 387,
     UDMGBREATH                      = 388,
     UDMGMAGIC                       = 389,
diff --git a/scripts/globals/spells/damage_spell.lua b/scripts/globals/spells/damage_spell.lua
index 146b0df585f..f8e7dd1953b 100644
--- a/scripts/globals/spells/damage_spell.lua
+++ b/scripts/globals/spells/damage_spell.lua
@@ -812,6 +812,16 @@ xi.spells.damage.calculateHelixMeritMultiplier = function(caster, spellId)
     return helixMeritMultiplier
 end
 
+xi.spells.damage.calculateAreaOfEffectResistance = function(target, spell)
+    local areaOfEffectMultiplier = 1
+
+    if target:getID() ~= spell:getPrimaryTargetID() then
+        areaOfEffectMultiplier = utils.clamp(areaOfEffectMultiplier + target:getMod(xi.mod.DMG_AOE) / 10000, 0, 2)
+    end
+
+    return areaOfEffectMultiplier
+end
+
 xi.spells.damage.calculateNukeAbsorbOrNullify = function(target, spellElement)
     local nukeAbsorbOrNullify = 1
 
@@ -911,6 +921,7 @@ xi.spells.damage.useDamageSpell = function(caster, target, spell)
     local undeadDivinePenalty         = xi.spells.damage.calculateUndeadDivinePenalty(target, skillType)
     local scarletDeliriumMultiplier   = xi.spells.damage.calculateScarletDeliriumMultiplier(caster)
     local helixMeritMultiplier        = xi.spells.damage.calculateHelixMeritMultiplier(caster, spellId)
+    local areaOfEffectResistance      = xi.spells.damage.calculateAreaOfEffectResistance(target, spell)
     local nukeAbsorbOrNullify         = xi.spells.damage.calculateNukeAbsorbOrNullify(target, spellElement)
 
     -- Calculate finalDamage. It MUST be floored after EACH multiplication.
@@ -933,6 +944,7 @@ xi.spells.damage.useDamageSpell = function(caster, target, spell)
     finalDamage = math.floor(finalDamage * undeadDivinePenalty)
     finalDamage = math.floor(finalDamage * scarletDeliriumMultiplier)
     finalDamage = math.floor(finalDamage * helixMeritMultiplier)
+    finalDamage = math.floor(finalDamage * areaOfEffectResistance)
     finalDamage = math.floor(finalDamage * nukeAbsorbOrNullify)
 
     -- Handle "Nuke Wall". It must be handled after all previous calculations, but before clamp.
diff --git a/src/map/modifier.h b/src/map/modifier.h
index 2ed6f5139df..468dd35e81b 100644
--- a/src/map/modifier.h
+++ b/src/map/modifier.h
@@ -211,6 +211,7 @@ enum class Mod
     DMGMAGIC    = 163, // Magic Damage Taken %
     DMGMAGIC_II = 831, // Magic Damage Taken II % (Aegis)
     DMGRANGE    = 164, // Range Damage Taken %
+    DMG_AOE     = 158, // Damage Taken % when not main target of an AoE action. (Ex: Locus Mobs)
 
     // Uncapped damage - 10000 base, 375 = 3.75%
     UDMGPHYS   = 387, // Uncapped Damage Multipliers
@@ -997,7 +998,7 @@ enum class Mod
     //
     // SPARE IDs:
     // 141 to 143
-    // 158, 159
+    // 159
     // 217 to 223
     // 271 to 280
     //