using System;
using UnityEngine;
using UnityEngine.EventSystems;

public class DraggableCard : MonoBehaviour, IPointerDownHandler, IDragHandler, IPointerUpHandler
{
    private Vector3 originalPosition;
    private CanvasGroup canvasGroup;

    private void Start()
    {
        canvasGroup = GetComponent<CanvasGroup>();
    }

    public void OnPointerDown(PointerEventData eventData)
    {
        originalPosition = transform.position;
        canvasGroup.alpha = 0.5f;
    }

    public void OnDrag(PointerEventData eventData)
    {
        transform.position = Input.mousePosition;
        Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
        RaycastHit hit;
        if (Physics.Raycast(ray, out hit) && hit.collider.tag == "Ground") // Ground 태그로 변경하였습니다.
        {
            canvasGroup.alpha = 0; // 마우스가 Ground 위에 있을 때 투명도 변경
        }
        else
        {
            canvasGroup.alpha = 0.5f;
        }
    }

    public void OnPointerUp(PointerEventData eventData)
    {
        canvasGroup.alpha = 1;
        
        // 지형에 올바르게 드롭되지 않으면 원래 위치로 되돌림
        if (!IsDroppedOnTarget())
        {
            transform.position = originalPosition;
        }
    }

    private bool IsDroppedOnTarget()
    {
        Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
            RaycastHit hit;
        
            if (Physics.Raycast(ray, out hit))
            {
                if (hit.collider.tag == "Ground")
                {
                    Destroy(gameObject);
                    return true;
                }
            }
            return false;
    }
}