#pragma once

#include "CoreMinimal.h"
#include "Components/ActorComponent.h"
#include "InventoryComponent.generated.h"

DECLARE_DYNAMIC_MULTICAST_DELEGATE_TwoParams(FOnEquipItem, int32, ItemIndex, bool, isItemEquped);
DECLARE_DYNAMIC_MULTICAST_DELEGATE_OneParam(FOnItemUse, int32, ItemIndex);

USTRUCT(BlueprintType)
struct FEquipableItem : public FTableRowBase
{
GENERATED_BODY()

UPROPERTY(EditAnywhere, BlueprintReadWrite)
int32 CurrentAmount;

UPROPERTY(EditAnywhere, BlueprintReadWrite)
int32 MaxAmount;

UPROPERTY(EditAnywhere, BlueprintReadWrite)
TSubclassOf<AActor> ItemClass;

UPROPERTY(EditAnywhere, BlueprintReadWrite)
TSubclassOf<AActor> ItemPickupClass;

UPROPERTY(EditAnywhere, BlueprintReadWrite)
FTransform PickupTransform;
};

USTRUCT(BlueprintType)
struct FKeyItem : public FTableRowBase
{
GENERATED_BODY()

UPROPERTY(EditAnywhere, BlueprintReadWrite)
int32 KeyType;

UPROPERTY(EditAnywhere, BlueprintReadWrite)
TSubclassOf<AActor> KeyPickupClass;

UPROPERTY(EditAnywhere, BlueprintReadWrite)
FTransform PickupTransform;
};

UCLASS( ClassGroup=(Custom), meta=(BlueprintSpawnableComponent), Blueprintable)
class COLDTURKEY_API UInventoryComponent : public UActorComponent
{
GENERATED_BODY()

public:
// Sets default values for this component's properties
UInventoryComponent();

protected:
// Called when the game starts
virtual void BeginPlay() override;

UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Inventory")
TArray<FEquipableItem> inventory;

UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Inventory")
TArray<FEquipableItem> savedInventory;

UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Inventory")
TArray<FKeyItem> KeyInventory;

UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Inventory")
int32 equipedItemIndex;

UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Inventory")
float maxFlareTime;

UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Inventory")
float currentFlareTime;

UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Inventory")
bool isItemEquped;

UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Inventory")
bool isFlareActive;

UFUNCTION(BlueprintCallable, Category = "Inventory")
void UseItem(int32 ItemIndex);

UFUNCTION(BlueprintCallable, Category = "Inventory")
void SetEquipedItemIndex(int32 ItemIndex);

UFUNCTION(BlueprintCallable, Category = "Inventory")
void UnequipItem();

UFUNCTION(BlueprintCallable, Category = "Inventory")
void ReduceItemAmountAtIndex(int32 ItemIndex);

UFUNCTION(BlueprintCallable, Category = "Inventory")
bool AddItemAmountAtIndex(int32 ItemIndex);

UFUNCTION(BlueprintCallable, Category = "Inventory")
void AddKey(FKeyItem Key);

UFUNCTION(BlueprintCallable, BlueprintPure, Category = "Inventory")
bool HasKey(int32 Key);

UFUNCTION(BlueprintCallable, Category = "Inventory")
void SaveInventory();

UFUNCTION(BlueprintCallable, Category = "Inventory")
void LoadInventory();

public:
// Called every frame
virtual void TickComponent(float DeltaTime, ELevelTick TickType, FActorComponentTickFunction* ThisTickFunction) override;

UPROPERTY(BlueprintAssignable)
FOnEquipItem OnEquipItem;


UPROPERTY(BlueprintAssignable)
FOnItemUse OnItemUse;
};#include "InventoryComponent.h"

void UInventoryComponent::UseItem(int32 ItemIndex)
{
if (equipedItemIndex == -1)
{
UE_LOG(LogTemp, Warning, TEXT("Item at index %d is not equipped"), ItemIndex);
return;
}

OnItemUse.Broadcast(ItemIndex);
}

void UInventoryComponent::SetEquipedItemIndex(int32 ItemIndex)
{
if (ItemIndex != equipedItemIndex)
{
isItemEquped = true;
equipedItemIndex = ItemIndex;
}
else
{
isItemEquped = false;
equipedItemIndex = -1;
}

OnEquipItem.Broadcast(ItemIndex, isItemEquped);
}

void UInventoryComponent::UnequipItem()
{
equipedItemIndex = -1;
isItemEquped = false;
}

void UInventoryComponent::ReduceItemAmountAtIndex(int32 ItemIndex)
{
inventory[ItemIndex].CurrentAmount--;
}

bool UInventoryComponent::AddItemAmountAtIndex(int32 ItemIndex)
{
if (inventory[ItemIndex].CurrentAmount + 1 > inventory[ItemIndex].MaxAmount)
{
UE_LOG(LogTemp, Warning, TEXT("Cannot add more items, max amount reached for item at index %d"), ItemIndex);
return false;
}

inventory[ItemIndex].CurrentAmount++;
return true;
}

void UInventoryComponent::AddKey(FKeyItem Key)
{
for (const FKeyItem& ExistingKey : KeyInventory)
{
if (ExistingKey.KeyType == Key.KeyType)
{
UE_LOG(LogTemp, Warning, TEXT("Key %d already exists in the inventory"), Key.KeyType);
return;
}
}

KeyInventory.Add(Key);
UE_LOG(LogTemp, Log, TEXT("Key %d added to the inventory"), Key.KeyType);
}

bool UInventoryComponent::HasKey(int32 Key)
{
for (const FKeyItem& ExistingKey : KeyInventory)
{
if (ExistingKey.KeyType == Key)
{
UE_LOG(LogTemp, Warning, TEXT("Has the key type: %d"), Key);
return true;
}
}

return false;
}

void UInventoryComponent::SaveInventory()
{
savedInventory = inventory;
}

void UInventoryComponent::LoadInventory()
{
inventory = savedInventory;
}

This shows the inventory component script where I have implemented some needed simple functions that can be used in blueprints. For example, the use items function where it just broadcasts to the equipped item that has been used. The add and reduce the item count function. And I also have saved inventory that is just a copy of the inventory that gets saved when you enter a checkpoint or the radio tower. So if the player dies, we can use this saved inventory to restore it back to its previous state.

And the implementation in blueprints is done where when the player clicks keys 1 through 4, first it calls the "Before Item Switch" function where it just checks if an animation montage is playing and also does a hotbar flash. Then it continues to the "Set Equiped Item Index" where it just calls back to the "Equip Items To Hand" function where it handles the different states the item can be at, if it should switch the item to the new one or should it just unequip it and so on. It sends the an event message to the equipped item through an interface where it calls its own implementation of the item. Right bellow is a snipet of blueprint code of how the heatpack handles each case and also the "On Item Use" event call.