using UnityEngine;
using UnityEngine.EventSystems;
using UnityEngine.UI;

public class DraggableUI : MonoBehaviour, IDragHandler, IPointerDownHandler
{
    private RectTransform rectTransform;
    private Canvas canvas;

    public RectTransform target;
    public GameObject button;
    public bool isDone = false;
    private bool isLocked = false;

    private void Awake()
    {
        rectTransform = GetComponent<RectTransform>();
        canvas = GetComponentInParent<Canvas>();
        LockDrag();
    }

    public void OnPointerDown(PointerEventData eventData)
    {
        // 这里可以添加按下时的逻辑，比如记录初始位置
    }

    public void OnDrag(PointerEventData eventData)
    {
        if (isLocked) return;

        Vector3 screenPosition = new Vector3(eventData.position.x, eventData.position.y,
        Camera.main.WorldToScreenPoint(transform.position).z);
        Vector3 move = Camera.main.ScreenToWorldPoint(screenPosition);
        move.z = transform.position.z;
        transform.position = move;
    }

    void Update()
    {
        float distance = Vector3.Distance(transform.position, target.position);

        if (distance <= 1 && !isDone)
        {
            button.SetActive(true);
        }
        else
        {
            button.SetActive(false);
        }
    }

    public void LockDrag()
    {
        isLocked = true;
    }

    public void UnlockDrag()
    {
        isLocked = false;
    }
}