// Copyright 2025 https://yuewu.dev/en  All Rights Reserved.

#pragma once

#include "CoreMinimal.h"
#include "GCS_TraceStructLibrary.h"
#include "DrawDebugHelpers.h"
#include "WorldCollision.h"
#include "Kismet/KismetSystemLibrary.h"
#include "Subsystems/WorldSubsystem.h"
#include "GCS_TraceSubsystem.generated.h"

UCLASS()
class GENERICCOMBATSYSTEM_API UGCS_TraceSubsystem : public UTickableWorldSubsystem
{
	GENERATED_BODY()

public:
	virtual void Initialize(FSubsystemCollectionBase& Collection) override;

	virtual void Tick(float DeltaTime) override;
	virtual bool IsTickable() const override { return true; }
	virtual TStatId GetStatId() const override { return TStatId(); }

	FCriticalSection CriticalSection;
	bool IsValidStateIdx(int32 StateIdx) const;
	FGCS_TraceState& GetTraceStateAt(int Index);

	int32 AddTraceState();
	void RemoveTraceState(int Idx, FGuid Guid);

protected:
	TArray<FGCS_TraceState> TraceStates;
	bool RemovalLock = false;
	uint32 TickIdx = 0;
	void RemoveTraceStateAt(int Idx, FGuid Guid);

	void PreTraceTick(const float DeltaTime);
	void PostTraceTick();

	// 计算所有用于碰撞检测的必须数据。
	virtual void PrepareSubTicks(const float DeltaTime);
	virtual void PerformSubTicks(const float DeltaTime);

	static void PerformAsyncTrace(const FTransform& StartTransform, const FTransform& EndTransform, const FTransform& AverageTransform, UWorld* World,
	                              const FGCS_TraceSweepSetting& TraceSettings,
	                              const FCollisionShape& CollisionShape, const FCollisionQueryParams& CollisionParams,
	                              const FCollisionResponseParams& CollisionResponseParams,
	                              const FCollisionObjectQueryParams& ObjectQueryParams, const FTraceDelegate* InDelegate = nullptr);

	virtual void HandleTraceResults(const FTraceHandle& InTraceHandle, FTraceDatum& InTraceDatum, int32 TraceStateIdx, uint32 InTickIdx, float InShapeTime);

#if ENABLE_DRAW_DEBUG
	static void DrawDebug(const FVector& Start, const FVector& End, const FQuat& Rot, TArray<FHitResult> Hits, const FCollisionShape& CollisionShape, const UWorld* World,
	                      const EDrawDebugTrace::Type DrawDebugType, float DrawDebugTime, const FLinearColor& DrawDebugColor, const FLinearColor& DrawDebugHitColor);
#endif

	// 新增：用于批量移除的Pending列表，避免边遍历边修改
	TArray<TPair<int32, FGuid>> PendingRemovals;
};