#pragma once

#include "CoreMinimal.h"
#include "Core/DescentHandle.h"
#include "Core/DescentWorldSubsystem.h"
#include "DescentTools.generated.h"

class ADescentCharacter;
class UPointLightComponent;
class UStaticMeshComponent;

/** Hand tools of DESIGN_UE.md section 6.11 (M8: V9, V11): thrown flares and marker beacons. The flashlight is the character's own lamp. */
UCLASS()
class THEDESCENT_API UDescentToolsSubsystem : public UDescentWorldSubsystem
{
	GENERATED_BODY()

public:
	static UDescentToolsSubsystem* Get(const UWorld* World);
	virtual void OnWorldBeginPlay(UWorld& InWorld) override;
	virtual void Deinitialize() override;

	/** LMB with the selected hotbar item out. Returns whether the item did something. */
	bool UseSelected(ADescentCharacter* User, bool bSwimming);
	bool ThrowFlare(const FVector& FromM, const FVector& Dir);
	bool DropBeacon(const FVector& PosM);

	int32 FlaresAlive() const { return Flares.Num(); }
	int32 FlaresThrown = 0;
	TArray<FVector> Markers;   // beacons, world metres (the map and the HUD draw them)

private:
	struct FFlare
	{
		FVector P = FVector::ZeroVector, V = FVector::ZeroVector;
		double Age = 0.0;
		bool bRest = false;
		TWeakObjectPtr<UPointLightComponent> Light;
		TWeakObjectPtr<UStaticMeshComponent> Mesh;
	};
	void Step(double Dt);
	void EnsureActor();
	TArray<FFlare> Flares;
	FDescentHandle StepHandle;
	UPROPERTY(Transient) TObjectPtr<AActor> Visual;
	UPROPERTY(Transient) TArray<TObjectPtr<UStaticMeshComponent>> BeaconMeshes;
};