using System;
using System.Collections;
using UnityEngine;
using UnityEngine.XR;
using UnityEngine.XR.Interaction.Toolkit;
using UnityEngine.XR.Interaction.Toolkit.Interactors;

public enum HandSide { Left, Right }

public class InteractionView : MonoBehaviour
{
    public event Action<bool> OnRobotHoverStateChanged;
    public event Action<Vector3> OnRobotGrabStart;
    public event Action<Vector3, Quaternion> OnRobotGrabbed;
    public event Action<RobotData> OnRobotReleased;
    public event Action<int, Vector3> OnPointClicked;
    public event Action<int> OnPointDragStart;
    public event Action<int, Vector3, Quaternion> OnPointDragUpdate;
    public event Action<int> OnPointDragEnd;

    [SerializeField]private NearFarInteractor nearFarInteractor;
    public HandSide handSide;
    private XRBaseInteractor baseInteractor;
    private IXRRayProvider rayProvider;
    private InputDevice hapticDevice;
    private bool isHapticDeviceFound = false;

    [SerializeField]
    [Tooltip("µå·¡±× ½Ã À§Ä¡¸¦ Ç¥½ÃÇÒ ¹ÝÅõ¸í ·Îº¿ ¸ðµ¨")]
    private GameObject ghostRobot;
    [SerializeField]
    [Tooltip("µå·¡±×¿ë ¸¶¿ì½º À̹ÌÁö")]
    private GameObject dragArrow;
    [SerializeField] private float clickTimeThreshold = 0.5f;
    [SerializeField] private float dragMovementThreshold = 0.05f;
    private Coroutine clickOrDragCoroutine = null;
    public Vector3 startGrabPosition;
    public float distance;

    private bool isInitialized = false;
    private bool isGrabbingPoint = false;
    private int currentGrabbedPointIndex = -1;

    public Vector3 currentTargetPosition = Vector3.zero;
    Quaternion currentTargetRotation = Quaternion.identity;

    public bool isGrabbingRobot = false;

    void Update()
    {
        if (!isInitialized || rayProvider == null)
        {
            if (nearFarInteractor == null)
            {
                nearFarInteractor = GetComponentInChildren<NearFarInteractor>(true);
                baseInteractor = nearFarInteractor as XRBaseInteractor;
                rayProvider = nearFarInteractor as IXRRayProvider;
            }
            if (nearFarInteractor != null)
            {
                InitializeInteraction();
            }
        }
        else
        {
            currentTargetPosition = rayProvider.rayEndPoint;
            currentTargetRotation = baseInteractor.attachTransform.rotation;

            if (isGrabbingRobot)
            {
                OnRobotGrabbed?.Invoke(currentTargetPosition, currentTargetRotation);
                return;
            }

            if (isGrabbingPoint)
            {
                OnPointDragUpdate?.Invoke(currentGrabbedPointIndex, currentTargetPosition, currentTargetRotation);
            }
            else if (clickOrDragCoroutine != null)
            {
                distance = Vector3.Distance(startGrabPosition, currentTargetPosition);

                if (distance > dragMovementThreshold)
                {
                    StartDragMode();
                }
            }
        }
    }

    private void InitializeInteraction()
    {
        // XRI À̺¥Æ® ±¸µ¶
        baseInteractor.selectEntered.AddListener(HandleGrabStart);
        baseInteractor.selectExited.AddListener(HandleGrabEnd);
        baseInteractor.hoverEntered.AddListener(OnHoverEntered);
        baseInteractor.hoverExited.AddListener(OnHoverExited);

        TryInitializeHapticDevice();

        isInitialized = true;
        AppManager.Instance.RegisterView(this);
    }

    private void OnDestroy()
    {
        if (baseInteractor != null)
        {
            baseInteractor.selectEntered.RemoveListener(HandleGrabStart);
            baseInteractor.selectExited.RemoveListener(HandleGrabEnd);
        }
    }

    private void TryInitializeHapticDevice()
    {
        XRNode node = (this.handSide == HandSide.Left) ? XRNode.LeftHand : XRNode.RightHand;
        InputDevice device = InputDevices.GetDeviceAtXRNode(node);

        if (device.isValid)
        {
            hapticDevice = device;
            isHapticDeviceFound = true;
        }
    }

    /// <summary>
    /// InputDevice¸¦ »ç¿ëÇÑ ÇÝƽ
    /// </summary>
    public void SendHapticImpulse(float amplitude, float duration)
    {
        // ÄÁÆ®·Ñ·¯°¡ ¿¬°áµÇÁö ¾Ê¾Ò°Å³ª(isValid) ²¨Á®ÀÖÀ» ¼ö ÀÖÀ¸¹Ç·Î ¸Å¹ø È®ÀÎ
        if (!isHapticDeviceFound || !hapticDevice.isValid)
        {
            TryInitializeHapticDevice(); // ´Ù½Ã ã±â ½Ãµµ
            if (!isHapticDeviceFound) return; // ±×·¡µµ ¾øÀ¸¸é Áß´Ü
        }

        // Áøµ¿ ±â´ÉÀÌ ÀÖ´ÂÁö È®ÀÎ
        HapticCapabilities capabilities;
        if (hapticDevice.TryGetHapticCapabilities(out capabilities))
        {
            if (capabilities.supportsImpulse)
            {
                // Áøµ¿ Àü¼Û
                hapticDevice.SendHapticImpulse(0, amplitude, duration);
            }
        }
    }

    // --- XRI À̺¥Æ® Çڵ鷯 ---

    private void HandleGrabStart(SelectEnterEventArgs args)
    {
        GameObject grabbedGO = args.interactableObject.transform.gameObject;

        RobotPoint point = grabbedGO.GetComponent<RobotPoint>();
        if (point != null)
        {
            isGrabbingPoint = true;
            isGrabbingRobot = false;
            currentGrabbedPointIndex = point.pointIndex;

            // ŸÀÌ¸Ó ½ÃÀÛ
            startGrabPosition = rayProvider.rayEndPoint;
            if (clickOrDragCoroutine != null) 
                StopCoroutine(clickOrDragCoroutine);
            clickOrDragCoroutine = StartCoroutine(ClickOrDragTimer());

            //OnPointDragStart?.Invoke(currentGrabbedPointIndex);
        }
        else if (grabbedGO.CompareTag("RobotArm"))
        {
            isGrabbingPoint = false;
            isGrabbingRobot = true;
            currentGrabbedPointIndex = -1;

            OnRobotGrabStart?.Invoke(startGrabPosition);
            OnPointDragStart?.Invoke(currentGrabbedPointIndex);
        }
    }

    private void HandleGrabEnd(SelectExitEventArgs args)
    {
        if (isGrabbingRobot)
        {
            OnRobotReleased?.Invoke(new RobotData());
        }
        else
        {
            if (clickOrDragCoroutine != null)
            {
                StopCoroutine(clickOrDragCoroutine);
                clickOrDragCoroutine = null;

                OnPointClicked?.Invoke(currentGrabbedPointIndex, currentTargetPosition);
            }
            else if (isGrabbingPoint)
            {
                OnPointDragEnd?.Invoke(currentGrabbedPointIndex);
            }
        }

        // »óÅ ÃʱâÈ­
        clickOrDragCoroutine = null;
        isGrabbingPoint = false;
        isGrabbingRobot = false;
        currentGrabbedPointIndex = -1;
    }

    private void OnHoverEntered(HoverEnterEventArgs args)
    {
        // È£¹öÇÑ ¹°Ã¼°¡ '·Îº¿'ÀÎÁö È®ÀÎ
        if (args.interactableObject.transform.CompareTag("RobotArm"))
        {
            OnRobotHoverStateChanged?.Invoke(true);
        }
    }

    // È£¹ö Á¾·á ½Ã È£Ãâ
    private void OnHoverExited(HoverExitEventArgs args)
    {
        if (args.interactableObject.transform.CompareTag("RobotArm"))
        {
            OnRobotHoverStateChanged?.Invoke(false);
        }
    }

    // Ŭ¸¯/µå·¡±× ±¸ºÐÇϴ ŸÀÌ¸Ó ÄÚ·çƾ
    private IEnumerator ClickOrDragTimer()
    {
        yield return new WaitForSeconds(clickTimeThreshold);

        if (clickOrDragCoroutine != null)
        {
            Debug.Log("½Ã°£ ÃÊ°ú·Î µå·¡±× ½ÃÀÛ (OnPointDragStart)");
            StartDragMode();
        }
    }

    // ŸÀÌ¸Ó ÁßÁöÇÏ°í µå·¡±× ¸ðµå·Î Àüȯ
    private void StartDragMode()
    {
        if (clickOrDragCoroutine != null)
        {
            StopCoroutine(clickOrDragCoroutine);
            clickOrDragCoroutine = null;
        }

        isGrabbingPoint = true;
        OnPointDragStart?.Invoke(currentGrabbedPointIndex);
    }

    // °í½ºÆ® ·Îº¿ÀÇ À§Ä¡/ȸÀü ¼³Á¤
    public void ShowGhostRobot()
    {
        if (ghostRobot == null)
        {
            Debug.LogWarning("Ghost RobotÀÌ Inspector¿¡ ÇÒ´çµÇÁö ¾Ê¾Ò½À´Ï´Ù.");
            return;
        }

        ghostRobot.SetActive(true);
    }

    // °í½ºÆ® ·Îº¿ ºñÈ°¼ºÈ­
    public void HideGhostRobot()
    {
        if (ghostRobot != null)
        {
            ghostRobot.SetActive(false);
        }
    }

    // µå·¡±× È­»ìÇ¥ È°¼ºÈ­ ¹× À§Ä¡ ¼³Á¤
    public void ShowDragArrow(Vector3 position)
    {
        if (dragArrow == null)
        {
            Debug.LogWarning("Drag Arrow°¡ Inspector¿¡ ÇÒ´çµÇÁö ¾Ê¾Ò½À´Ï´Ù.");
            return;
        }

        dragArrow.SetActive(true);
        dragArrow.transform.position = position;
    }

    // µå·¡±× È­»ìÇ¥ ºñÈ°¼ºÈ­
    public void HideDragArrow()
    {
        if (dragArrow != null)
        {
            dragArrow.SetActive(false);
        }
    }

    // ±¤¼± ³¡ À§Ä¡ ¹Ýȯ
    public Vector3 GetCurrentRayPosition()
    {
        if (rayProvider != null)
        {
            return rayProvider.rayEndPoint;
        }

        if (baseInteractor != null)
        {
            return baseInteractor.attachTransform.position;
        }

        return transform.position;
    }
}