Core/Auras: reworked multiplicative AuraEffects calculation

- Splitted containers for flat modifiers and pct modifiers, as they now have different handling
- Amount is now multiplied only on apply; on unapply, iterate through auras and reset the counter
- Fixes many cases of rounding error due to applying/unapplying of small factors
- Allows amounts to be zeroed (ie with an AuraEffect of amount -100)
- Do a partial revert of 6dc37a9add631888fe5fbcd43d19c2b07bed8a57, auras should update amounts only for items allowed (ie no more giving crit to a sword while having an axe in the other hand and being Poleaxe spec'd)
- SPELL_AURA_MOD_SCALE now scales additively, rather than multiplicatively (checked in sniffs)

Closes #18687

3 files changed, 29 insertions, 8 deletions

diff --git a/src/server/scripts/EasternKingdoms/ZulGurub/boss_arlokk.cpp b/src/server/scripts/EasternKingdoms/ZulGurub/boss_arlokk.cpp
index 5438014f20d..6a2435e2147 100644
--- a/src/server/scripts/EasternKingdoms/ZulGurub/boss_arlokk.cpp
+++ b/src/server/scripts/EasternKingdoms/ZulGurub/boss_arlokk.cpp
@@ -86,6 +86,13 @@ Position const PosMoveOnSpawn[1] =
     { -11561.9f, -1627.868f, 41.29941f, 0.0f }
 };
 
+// AWFUL HACK WARNING
+// To whoever reads this: Zul'Gurub needs your love
+// Need to do this calculation to increase/decrease Arlokk's damage by 35% (probably some aura missing)
+// This is only to compile the scripts after the aura calculation revamp
+float const DamageIncrease = 35.0f;
+float const DamageDecrease = 100.f / (1.f + DamageIncrease / 100.f) - 100.f;
+
 class boss_arlokk : public CreatureScript
 {
     public: boss_arlokk() : CreatureScript("boss_arlokk") { }
@@ -106,7 +113,7 @@ class boss_arlokk : public CreatureScript
             void Reset() override
             {
                 if (events.IsInPhase(PHASE_TWO))
-                    me->HandleStatModifier(UNIT_MOD_DAMAGE_MAINHAND, TOTAL_PCT, 35.0f, false); // hack
+                    me->ApplyStatPctModifier(UNIT_MOD_DAMAGE_MAINHAND, TOTAL_PCT, DamageDecrease); // hack
                 _Reset();
                 Initialize();
                 me->SetUInt32Value(UNIT_VIRTUAL_ITEM_SLOT_ID + 0, uint32(WEAPON_DAGGER));
@@ -267,7 +274,7 @@ class boss_arlokk : public CreatureScript
                             events.ScheduleEvent(EVENT_RAVAGE, urand(10000, 14000), 0, PHASE_TWO);
                             events.ScheduleEvent(EVENT_TRANSFORM_BACK, urand(15000, 18000), 0, PHASE_TWO);
                             events.SetPhase(PHASE_TWO);
-                            me->HandleStatModifier(UNIT_MOD_DAMAGE_MAINHAND, TOTAL_PCT, 35.0f, true); // hack
+                            me->ApplyStatPctModifier(UNIT_MOD_DAMAGE_MAINHAND, TOTAL_PCT, DamageIncrease); // hack
                             break;
                         case EVENT_RAVAGE:
                             DoCastVictim(SPELL_RAVAGE, true);
@@ -285,7 +292,7 @@ class boss_arlokk : public CreatureScript
                             me->SetBaseWeaponDamage(BASE_ATTACK, MAXDAMAGE, (cinfo->maxdmg));
                             me->UpdateDamagePhysical(BASE_ATTACK);
                             */
-                            me->HandleStatModifier(UNIT_MOD_DAMAGE_MAINHAND, TOTAL_PCT, 35.0f, false); // hack
+                            me->ApplyStatPctModifier(UNIT_MOD_DAMAGE_MAINHAND, TOTAL_PCT, DamageDecrease); // hack
                             events.ScheduleEvent(EVENT_SHADOW_WORD_PAIN, urand(4000, 7000), 0, PHASE_ONE);
                             events.ScheduleEvent(EVENT_GOUGE, urand(12000, 15000), 0, PHASE_ONE);
                             events.ScheduleEvent(EVENT_TRANSFORM, urand(16000, 20000), 0, PHASE_ONE);
diff --git a/src/server/scripts/EasternKingdoms/ZulGurub/boss_marli.cpp b/src/server/scripts/EasternKingdoms/ZulGurub/boss_marli.cpp
index 74ad31c0673..03bc99d177a 100644
--- a/src/server/scripts/EasternKingdoms/ZulGurub/boss_marli.cpp
+++ b/src/server/scripts/EasternKingdoms/ZulGurub/boss_marli.cpp
@@ -69,6 +69,13 @@ enum Misc
     NPC_SPIDER                = 15041
 };
 
+// AWFUL HACK WARNING
+// To whoever reads this: Zul'Gurub needs your love
+// Need to do this calculation to increase/decrease Mar'li's damage by 35% (probably some aura missing)
+// This is only to compile the scripts after the aura calculation revamp
+float const DamageIncrease = 35.0f;
+float const DamageDecrease = 100.f / (1.f + DamageIncrease / 100.f) - 100.f;
+
 class boss_marli : public CreatureScript
 {
     public: boss_marli() : CreatureScript("boss_marli") { }
@@ -80,7 +87,7 @@ class boss_marli : public CreatureScript
             void Reset() override
             {
                 if (events.IsInPhase(PHASE_THREE))
-                    me->HandleStatModifier(UNIT_MOD_DAMAGE_MAINHAND, TOTAL_PCT, 35.0f, false); // hack
+                    me->ApplyStatPctModifier(UNIT_MOD_DAMAGE_MAINHAND, TOTAL_PCT, DamageDecrease); // hack
                 _Reset();
             }
 
@@ -150,7 +157,7 @@ class boss_marli : public CreatureScript
                             me->SetBaseWeaponDamage(BASE_ATTACK, MAXDAMAGE, (cinfo->maxdmg +((cinfo->maxdmg/100) * 35)));
                             me->UpdateDamagePhysical(BASE_ATTACK);
                             */
-                            me->HandleStatModifier(UNIT_MOD_DAMAGE_MAINHAND, TOTAL_PCT, 35.0f, true); // hack
+                            me->ApplyStatPctModifier(UNIT_MOD_DAMAGE_MAINHAND, TOTAL_PCT, DamageIncrease); // hack
                             DoCastVictim(SPELL_ENVOLWINGWEB);
                             if (DoGetThreat(me->GetVictim()))
                                 DoModifyThreatPercent(me->GetVictim(), -100);
@@ -186,7 +193,7 @@ class boss_marli : public CreatureScript
                             me->SetBaseWeaponDamage(BASE_ATTACK, MAXDAMAGE, (cinfo->maxdmg +((cinfo->maxdmg/100) * 1)));
                             me->UpdateDamagePhysical(BASE_ATTACK);
                             */
-                            me->HandleStatModifier(UNIT_MOD_DAMAGE_MAINHAND, TOTAL_PCT, 35.0f, false); // hack
+                            me->ApplyStatPctModifier(UNIT_MOD_DAMAGE_MAINHAND, TOTAL_PCT, DamageDecrease); // hack
                             events.ScheduleEvent(EVENT_ASPECT_OF_MARLI, 12000, 0, PHASE_TWO);
                             events.ScheduleEvent(EVENT_TRANSFORM, 45000, 0, PHASE_TWO);
                             events.ScheduleEvent(EVENT_POISON_VOLLEY, 15000);
diff --git a/src/server/scripts/EasternKingdoms/ZulGurub/boss_thekal.cpp b/src/server/scripts/EasternKingdoms/ZulGurub/boss_thekal.cpp
index e468026fcf9..afe5fed0014 100644
--- a/src/server/scripts/EasternKingdoms/ZulGurub/boss_thekal.cpp
+++ b/src/server/scripts/EasternKingdoms/ZulGurub/boss_thekal.cpp
@@ -76,6 +76,13 @@ enum Phases
     PHASE_TWO                 = 2
 };
 
+// AWFUL HACK WARNING
+// To whoever reads this: Zul'Gurub needs your love
+// Need to do this calculation to increase/decrease Thekal's damage by 40% (probably some aura missing)
+// This is only to compile the scripts after the aura calculation revamp
+float const DamageIncrease = 40.0f;
+float const DamageDecrease = 100.f / (1.f + DamageIncrease / 100.f) - 100.f;
+
 class boss_thekal : public CreatureScript
 {
     public:
@@ -100,7 +107,7 @@ class boss_thekal : public CreatureScript
             void Reset() override
             {
                 if (events.IsInPhase(PHASE_TWO))
-                    me->HandleStatModifier(UNIT_MOD_DAMAGE_MAINHAND, TOTAL_PCT, 35.0f, false); // hack
+                    me->ApplyStatPctModifier(UNIT_MOD_DAMAGE_MAINHAND, TOTAL_PCT, DamageDecrease); // hack
                 _Reset();
                 Initialize();
             }
@@ -162,7 +169,7 @@ class boss_thekal : public CreatureScript
                                 me->SetBaseWeaponDamage(BASE_ATTACK, MAXDAMAGE, (cinfo->maxdmg +((cinfo->maxdmg/100) * 40)));
                                 me->UpdateDamagePhysical(BASE_ATTACK);
                                 */
-                                me->HandleStatModifier(UNIT_MOD_DAMAGE_MAINHAND, TOTAL_PCT, 40.0f, true); // hack
+                                me->ApplyStatPctModifier(UNIT_MOD_DAMAGE_MAINHAND, TOTAL_PCT, DamageIncrease); // hack
                                 DoResetThreat();
                                 events.ScheduleEvent(EVENT_FRENZY, 30000, 0, PHASE_TWO);          // Phase 2
                                 events.ScheduleEvent(EVENT_FORCEPUNCH, 4000, 0, PHASE_TWO);       // Phase 2