// Source/TengriPlatformer/Movement/TengriMovementComponent.h

#pragma once

#include "CoreMinimal.h"
#include "Components/ActorComponent.h"
#include "TengriPlatformer/Movement/Core/TengriMovementConfig.h"
#include "TengriMovementComponent.generated.h"

class UCapsuleComponent;

/**
 * Custom movement component for deterministic 3D platformer physics.
 * Handles acceleration, friction, gravity, collision, and ground snapping.
 */
UCLASS(ClassGroup = (Custom), meta = (BlueprintSpawnableComponent))
class TENGRIPLATFORMER_API UTengriMovementComponent : public UActorComponent
{
	GENERATED_BODY()

public:
	UTengriMovementComponent();

protected:
	virtual void BeginPlay() override;

public:
	virtual void TickComponent(float DeltaTime, ELevelTick TickType,
		FActorComponentTickFunction* ThisTickFunction) override;

	// ========================================================================
	//                            BLUEPRINT API
	// ========================================================================

	/**
	 * Sets the movement input vector. Call every frame from PlayerController.
	 * @param NewInput - Raw input (will be clamped to 1.0 and Z zeroed)
	 */
	UFUNCTION(BlueprintCallable, Category = "Tengri Movement")
	void SetInputVector(FVector NewInput);

	// ========================================================================
	//                           CONFIGURATION
	// ========================================================================

	/** Movement parameters data asset */
	UPROPERTY(EditAnywhere, BlueprintReadOnly, Category = "Tengri Movement")
	TObjectPtr<UTengriMovementConfig> MovementConfig;

	// ========================================================================
	//                           RUNTIME STATE
	// ========================================================================

	/** Current velocity in cm/s */
	UPROPERTY(VisibleAnywhere, BlueprintReadOnly, Category = "Tengri Movement|State")
	FVector Velocity;

	/** True when character is on walkable ground */
	UPROPERTY(VisibleAnywhere, BlueprintReadOnly, Category = "Tengri Movement|State")
	bool bIsGrounded = false;

	/** Cached surface thresholds (cosines) for performance */
	UPROPERTY(VisibleAnywhere, Category = "Tengri Movement|Debug")
	FSurfaceThresholds CachedThresholds;

private:
	// ========================================================================
	//                          INTERNAL STATE
	// ========================================================================

	UPROPERTY()
	TObjectPtr<UCapsuleComponent> OwnerCapsule;

	/** Normalized input vector (Z always 0) */
	FVector InputVector = FVector::ZeroVector;

	// ========================================================================
	//                         INITIALIZATION
	// ========================================================================

	void InitializeSystem();

	// ========================================================================
	//                        MOVEMENT PHASES
	// ========================================================================

	/** Phase 1: Apply acceleration toward input direction or friction to stop */
	void ApplyAccelerationAndFriction(float DeltaTime);

	/** Phase 2: Rotate character to face movement direction */
	void ApplyRotation(float DeltaTime) const;

	/** Phase 3: Apply gravity when airborne */
	void ApplyGravity(float DeltaTime);

	/** Phase 4: Resolve movement with collision */
	FVector ResolveMovementWithCollision(float DeltaTime);

	/** Phase 5: Snap to ground to prevent slope jitter */
	bool PerformGroundSnapping(FVector& InOutLocation, FHitResult& OutSnapHit) const;

	/** Phase 6: Update grounded state based on collision results */
	void UpdateGroundedState(bool bMoveBlocked, float HitNormalZ, bool bJustSnapped);
};