// Request Games © All rights reserved

// Source/TengriPlatformer/Movement/Collision/TengriCollisionResolver.h

#pragma once

#include "CoreMinimal.h"
#include "Kismet/BlueprintFunctionLibrary.h"
#include "TengriPlatformer/Domains/Movement/Config/TengriMovementConfig.h"
#include "TengriPlatformer/Domains/Movement/Collision/TengriSweepResult.h"
#include "TengriCollisionResolver.generated.h"

class UCapsuleComponent;

/**
 * Static collision resolution utilities for Tengri Movement System.
 * Handles swept collision, wall sliding, step-up, and ground snapping.
 */
UCLASS()
class TENGRIPLATFORMER_API UTengriCollisionResolver : public UBlueprintFunctionLibrary
{
	GENERATED_BODY()

public:
	// ════════════════════════════════════════════════════════════════════
	//                         MAIN RESOLUTION
	// ════════════════════════════════════════════════════════════════════

	/**
	 * Resolve movement with collision: slide along walls, step up obstacles.
	 * @param WorldContext - Object providing world context
	 * @param StartLocation - Starting position
	 * @param DesiredDelta - Desired movement this frame
	 * @param Capsule - Collision capsule
	 * @param Thresholds - Surface classification thresholds
	 * @param MaxStepHeight - Maximum step-up height
	 * @param MaxIterations - Maximum slide iterations
	 * @return Final position and collision info
	 */
	static FTengriSweepResult ResolveMovement(
		const UObject* WorldContext,
		const FVector& StartLocation,
		const FVector& DesiredDelta,
		const UCapsuleComponent* Capsule,
		const FSurfaceThresholds& Thresholds,
		float MaxStepHeight,
		int32 MaxIterations
	);

	// ════════════════════════════════════════════════════════════════════
	//                           PRIMITIVES
	// ════════════════════════════════════════════════════════════════════

	/** Perform a simple capsule sweep from Start to End */
	static FTengriSweepResult PerformSweep(
		const UObject* WorldContext,
		const FVector& Start,
		const FVector& End,
		const UCapsuleComponent* Capsule
	);

	/** Attempt to step up over an obstacle */
	static bool StepUp(
		const UObject* WorldContext,
		const FVector& StartLocation,
		const FVector& DesiredDelta,
		const FHitResult& ImpactHit,
		const UCapsuleComponent* Capsule,
		float MaxStepHeight,
		FVector& OutLocation
	);

	/** Snap character to ground surface below */
	static bool SnapToGround(
		const UObject* WorldContext,
		const UCapsuleComponent* Capsule,
		float SnapDistance,
		const FSurfaceThresholds& Thresholds,
		FVector& OutLocation,
		FHitResult& OutHit
	);

	// ════════════════════════════════════════════════════════════════════
	//                        VELOCITY MATH
	// ════════════════════════════════════════════════════════════════════

	/** Remove velocity component going into the surface */
	static FVector ClipVelocity(const FVector& Velocity, const FVector& Normal);

	/** Project velocity along surface, preserving magnitude */
	static FVector ProjectVelocity(const FVector& Velocity, const FVector& Normal);
};