using UnityEngine;
using UnityEngine.XR.Interaction.Toolkit;
using UnityEngine.XR.Interaction.Toolkit.Interactables;

public class SteeringKeyXR : MonoBehaviour
{
    [Header("References")]
    [SerializeField] private XRGrabInteractable grabInteractable;
    [SerializeField] private Transform keyPivot;

    [Header("Steering")]
    [SerializeField] private float maxAngle = 45f;

    [Header("Return")]
    [SerializeField] private bool returnToCenter = true;
    [SerializeField] private float returnSpeed = 5f;

    private Transform currentInteractor;
    private bool isGrabbed;
    private bool warnedMissingGrabInteractable;

    private Quaternion initialPivotRotation;
    private float currentAngle;

    public float SteeringValue
    {
        get
        {
            if (Mathf.Approximately(maxAngle, 0f))
                return 0f;

            return Mathf.Clamp(currentAngle / maxAngle, -1f, 1f);
        }
    }

    private void Awake()
    {
        if (keyPivot == null)
            keyPivot = transform;

        ResolveGrabInteractable();
        initialPivotRotation = keyPivot.localRotation;
    }

    private void OnEnable()
    {
        ResolveGrabInteractable();

        if (grabInteractable != null)
        {
            grabInteractable.selectEntered.AddListener(OnGrab);
            grabInteractable.selectExited.AddListener(OnRelease);
        }
    }

    private void OnDisable()
    {
        if (grabInteractable != null)
        {
            grabInteractable.selectEntered.RemoveListener(OnGrab);
            grabInteractable.selectExited.RemoveListener(OnRelease);
        }
    }

    private void Update()
    {
        if (isGrabbed && currentInteractor != null)
        {
            UpdateAngleFromHand();
        }
        else if (returnToCenter)
        {
            currentAngle = Mathf.Lerp(currentAngle, 0f, returnSpeed * Time.deltaTime);
            ApplyRotation();
        }
    }

    private void OnGrab(SelectEnterEventArgs args)
    {
        isGrabbed = true;
        currentInteractor = args.interactorObject.transform;
    }

    private void OnRelease(SelectExitEventArgs args)
    {
        isGrabbed = false;
        currentInteractor = null;
    }

    private void UpdateAngleFromHand()
    {
        Vector3 worldDir = currentInteractor.position - keyPivot.position;
        Vector3 localDir = GetInitialPivotSpaceDirection(worldDir);

        float targetAngle = Mathf.Atan2(localDir.x, localDir.z) * Mathf.Rad2Deg;

        currentAngle = Mathf.Clamp(targetAngle, -maxAngle, maxAngle);

        ApplyRotation();
    }

    private void ApplyRotation()
    {
        keyPivot.localRotation =
            initialPivotRotation * Quaternion.Euler(0f, currentAngle, 0f);
    }

    private Vector3 GetInitialPivotSpaceDirection(Vector3 worldDirection)
    {
        Quaternion referenceRotation = keyPivot.parent != null
            ? keyPivot.parent.rotation * initialPivotRotation
            : initialPivotRotation;

        return Quaternion.Inverse(referenceRotation) * worldDirection;
    }

    private void ResolveGrabInteractable()
    {
        if (grabInteractable != null)
            return;

        grabInteractable = GetComponentInChildren<XRGrabInteractable>(true);

        if (grabInteractable == null && !warnedMissingGrabInteractable)
        {
            warnedMissingGrabInteractable = true;
            Debug.LogWarning("[SteeringKeyXR] XRGrabInteractable 참조가 없어 키를 잡아도 조향 이벤트를 받을 수 없습니다.", this);
        }
    }
}