Aura-TopDownRPG-GAS/Source/Aura/Private/AbilitySystem/MMC/ExecCalc_Damage.cpp

// Copyright Echo Devgroup


#include "AbilitySystem/MMC/ExecCalc_Damage.h"

#include "AbilitySystemComponent.h"
#include "AuraGameplayTags.h"
#include "AbilitySystem/AuraAbilitySystemLibrary.h"
#include "AbilitySystem/AuraAttributeSet.h"
#include "AbilitySystem/Data/CharacterClassInfo.h"
#include "Interact/CombatInterface.h"

struct AuraDamageStatics
{
	DECLARE_ATTRIBUTE_CAPTUREDEF(Armor);
	DECLARE_ATTRIBUTE_CAPTUREDEF(ArmorPenetration);
	DECLARE_ATTRIBUTE_CAPTUREDEF(BlockChance);
	DECLARE_ATTRIBUTE_CAPTUREDEF(CriticalChance);
	DECLARE_ATTRIBUTE_CAPTUREDEF(CriticalResistance);
	DECLARE_ATTRIBUTE_CAPTUREDEF(CriticalDamage);
	AuraDamageStatics()
	{
		DEFINE_ATTRIBUTE_CAPTUREDEF(UAuraAttributeSet, Armor, Target, false);
		DEFINE_ATTRIBUTE_CAPTUREDEF(UAuraAttributeSet, ArmorPenetration, Source, false);
		DEFINE_ATTRIBUTE_CAPTUREDEF(UAuraAttributeSet, BlockChance, Target, false);
		DEFINE_ATTRIBUTE_CAPTUREDEF(UAuraAttributeSet, CriticalChance, Source, false);
		DEFINE_ATTRIBUTE_CAPTUREDEF(UAuraAttributeSet, CriticalResistance, Target, false);
		DEFINE_ATTRIBUTE_CAPTUREDEF(UAuraAttributeSet, CriticalDamage, Source, false);
		
	}
};

static const AuraDamageStatics DamageStatics()
{
	static AuraDamageStatics DStatics;
	return DStatics;
}

UExecCalc_Damage::UExecCalc_Damage()
{
	RelevantAttributesToCapture.Add(DamageStatics().ArmorDef);
	RelevantAttributesToCapture.Add(DamageStatics().BlockChanceDef);
	RelevantAttributesToCapture.Add(DamageStatics().ArmorPenetrationDef);
	RelevantAttributesToCapture.Add(DamageStatics().CriticalChanceDef);
	RelevantAttributesToCapture.Add(DamageStatics().CriticalResistanceDef);
	RelevantAttributesToCapture.Add(DamageStatics().CriticalDamageDef);
}

void UExecCalc_Damage::Execute_Implementation(const FGameplayEffectCustomExecutionParameters& ExecutionParams,
	FGameplayEffectCustomExecutionOutput& OutExecutionOutput) const
{
	//Set Gameplay Effect variables
	const FGameplayEffectSpec& Spec = ExecutionParams.GetOwningSpec();
	//Get Source info
	const UAbilitySystemComponent* SourceASC = ExecutionParams.GetSourceAbilitySystemComponent();
	AActor* SourceAvatar = SourceASC ? SourceASC->GetAvatarActor() : nullptr;
	ICombatInterface* SourceCombatInterface = Cast<ICombatInterface>(SourceAvatar);
	const FGameplayTagContainer* SourceTags = Spec.CapturedSourceTags.GetAggregatedTags();
	//Get Target info
	const UAbilitySystemComponent* TargetASC = ExecutionParams.GetTargetAbilitySystemComponent();
	AActor* TargetAvatar = TargetASC ? TargetASC->GetAvatarActor() : nullptr;
	ICombatInterface* TargetCombatInterface = Cast<ICombatInterface>(TargetAvatar);
	const FGameplayTagContainer* TargetTags = Spec.CapturedTargetTags.GetAggregatedTags();

	FAggregatorEvaluateParameters EvaluateParams;

	EvaluateParams.SourceTags = SourceTags;
	EvaluateParams.TargetTags = TargetTags;

	//Get Damage set by caller magnitude
	float Damage = Spec.GetSetByCallerMagnitude(FAuraGameplayTags::Get().Damage);

	//Capture BlockChance on Target, and determine if there was a successful block
	//If blocked, reduce damage to 50% damage
	float TargetBlockChance = 0.f;
	ExecutionParams.AttemptCalculateCapturedAttributeMagnitude(DamageStatics().BlockChanceDef, EvaluateParams, TargetBlockChance);
	TargetBlockChance = FMath::Max<float>(TargetBlockChance, 0.f);
	const bool bBlocked = FMath::RandRange(1, 100) < TargetBlockChance;
	Damage = bBlocked ? Damage / 2.f : Damage;
	
	//TODO: Elemental weaknesses

	//TODO: Add Resistances

	const UCharacterClassInfo* CharacterClassInfo = UAuraAbilitySystemLibrary::GetCharacterClassInfo(SourceAvatar);
	const FRealCurve* ArmorPenetrationCurve = CharacterClassInfo->DamageCalculationCoefficients->FindCurve(FName("ArmorPenetration"), FString());
	const float ArmorPenetrationCoefficient = ArmorPenetrationCurve->Eval(SourceCombatInterface->GetPlayerLevel());
	const FRealCurve* EffectiveArmorCurve = CharacterClassInfo->DamageCalculationCoefficients->FindCurve(FName("EffectiveArmor"), FString());
	const float EffectiveArmorCoefficient = ArmorPenetrationCurve->Eval(TargetCombatInterface->GetPlayerLevel());
	
	//Armor calculations
	//Get the Target's armor
	float TargetArmor = 0.f;
	ExecutionParams.AttemptCalculateCapturedAttributeMagnitude(DamageStatics().ArmorDef, EvaluateParams, TargetArmor);
	TargetArmor = FMath::Max<float>(TargetArmor, 0.f);
	//Source Armor Penetration, ignores a percentage of the Target's Armor.
	float SourceArmorPenetration = 0.f;
	ExecutionParams.AttemptCalculateCapturedAttributeMagnitude(DamageStatics().ArmorPenetrationDef, EvaluateParams, SourceArmorPenetration);
	SourceArmorPenetration = FMath::Max<float>(SourceArmorPenetration, 0.f);

	//4 points Armor penetration is 1% armor ignored
	const float EffectiveArmor = TargetArmor *= (100 - SourceArmorPenetration * ArmorPenetrationCoefficient) / 100.f;
	//Damage reduced by Armor % where 5 armor = 1%
	Damage *= (100 - EffectiveArmor * EffectiveArmorCoefficient) / 100.f;

	//Critical Hit Chance
	float SourceCriticalChance = 0.f;
	ExecutionParams.AttemptCalculateCapturedAttributeMagnitude(DamageStatics().CriticalChanceDef, EvaluateParams, SourceCriticalChance);
	SourceCriticalChance = FMath::Max<float>(SourceCriticalChance, 0.f);

	float TargetCriticalResistance = 0.f;
	ExecutionParams.AttemptCalculateCapturedAttributeMagnitude(DamageStatics().CriticalResistanceDef, EvaluateParams, TargetCriticalResistance);
	TargetCriticalResistance = FMath::Max<float>(TargetCriticalResistance, 0.f);
	
	float SourceCriticalDamage = 0.f;
	ExecutionParams.AttemptCalculateCapturedAttributeMagnitude(DamageStatics().CriticalDamageDef, EvaluateParams, SourceCriticalDamage);
	SourceCriticalDamage = FMath::Max<float>(SourceCriticalDamage, 0.f);

	
	const bool bCritical = FMath::RandRange(1, 100) < (SourceCriticalChance - TargetCriticalResistance);
	Damage = bCritical ? Damage * 1+SourceCriticalDamage : Damage;


	
	const FGameplayModifierEvaluatedData EvaluatedData(UAuraAttributeSet::GetIncomingDamageAttribute(), EGameplayModOp::Additive, Damage);
	OutExecutionOutput.AddOutputModifier(EvaluatedData);
}