#pragma once

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

class UPointLightComponent;

/** One request to the light pool: a light for this frame only (section 7.5). */
struct FDescentLightRequest
{
	FVector PositionUU = FVector::ZeroVector;
	FLinearColor Color = FLinearColor::White;
	float Intensity = 1.f;
	float RadiusM = 10.f;
	/** Higher wins: the score is distance^2 / radius^2 - Priority. */
	float Priority = 0.f;
};

/**
 * The light pool (DESIGN_UE.md section 7.5; v2 `commitVL` with 14 lights, here 24): shadowless point lights that
 * flares, drill glow, bioluminescence, jellies, beacons and the refinery borrow. Systems Submit requests during their
 * step; the Light-pool late step calls Commit once, which keeps the 24 best (lowest score, and only below 9) and
 * moves a real light onto each. Requests are cleared by Commit.
 */
UCLASS()
class THEDESCENT_API UDescentLightPool : public UActorComponent
{
	GENERATED_BODY()

public:
	UDescentLightPool();

	virtual void BeginPlay() override;

	void Submit(const FDescentLightRequest& Request) { Requests.Add(Request); }
	/** Picks the winners for a camera at CameraUU, lights them, hides the other lights, clears the requests. */
	void Commit(const FVector& CameraUU);

	int32 NumLit() const { return NumLitLights; }
	int32 NumRequestsLastCommit() const { return NumRequestsSeen; }

	/** The selection rule alone, for tests: indices of the requests that win, best first. */
	static void Select(const TArray<FDescentLightRequest>& Requests, const FVector& CameraUU, int32 MaxLights, double MaxScore, TArray<int32>& OutWinners);

private:
	UPROPERTY()
	TArray<TObjectPtr<UPointLightComponent>> Lights;
	TArray<FDescentLightRequest> Requests;
	int32 NumLitLights = 0;
	int32 NumRequestsSeen = 0;
};