// Copyright ExByte Studios. Item Interaction Ecosystem.

#pragma once

#include "CoreMinimal.h"
#include "UObject/Object.h"
#include "InteractionTypes.h"
#include "InteractionResolver.generated.h"

class APawn;

/**
 * Central, stateless resolver (section 8.3). Given who is interacting and what
 * they look at, it produces the ordered list of available options. Run on the
 * client for predictive UI AND re-run on the server to authorize a request, so
 * it must be deterministic and side-effect free.
 */
UCLASS()
class ITEMINTERACTION_API UInteractionResolver : public UObject
{
	GENERATED_BODY()

public:
	/** Assembles the interaction context for an instigator/target pair. */
	UFUNCTION(BlueprintCallable, Category = "Interaction", meta = (WorldContext = "Instigator"))
	static FInteractionContext BuildContext(APawn* Instigator, AActor* TargetActor);

	/** All options available, highest priority first (section 8.6). */
	UFUNCTION(BlueprintCallable, Category = "Interaction")
	static void GetAvailableInteractions(APawn* Instigator, AActor* TargetActor, TArray<FInteractionOption>& OutOptions);

	/** Convenience: the single best (highest priority, enabled) option. */
	UFUNCTION(BlueprintCallable, Category = "Interaction")
	static bool GetPrimaryInteraction(APawn* Instigator, AActor* TargetActor, FInteractionOption& OutOption);

	/** Finds the held item on an instigator via IHeldItemInterface (actor or component). */
	static bool ResolveHeldItem(APawn* Instigator, FItemInstanceData& OutItem);

private:
	static void GatherCapabilityOptions(const FInteractionContext& Ctx, TArray<FInteractionOption>& Out);
	static void GatherContainerOptions(const FInteractionContext& Ctx, TArray<FInteractionOption>& Out);
	static void GatherDataDrivenOptions(const FInteractionContext& Ctx, TArray<FInteractionOption>& Out);
	static void GatherActionClassOptions(const FInteractionContext& Ctx, TArray<FInteractionOption>& Out);
};