using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.EventSystems;

public class ResizePanel : MonoBehaviour, IDragHandler, IPointerDownHandler,IPointerUpHandler
{
    public Vector2 minSize = new Vector2(100, 100);
    public Vector2 maxSize = new Vector2(400, 400);
    public Transform canvas;
    public Camera thirdPersonCamera;
    private RectTransform _panelRectTransform; //父物体
    private Vector2 _originalLocalPointerPos; //初始位置
    private Vector2 _originalSizeDelta; //初始大小

    private void Awake()
    {
        _panelRectTransform = transform.parent.GetComponent<RectTransform>();
    }

    public void OnPointerDown(PointerEventData eventData)
    {
        thirdPersonCamera.GetComponent<ThirdPersonCamera>().enabled = false;
        _originalSizeDelta = _panelRectTransform.sizeDelta;
        RectTransformUtility.ScreenPointToLocalPointInRectangle(canvas as RectTransform, eventData.position, eventData.pressEventCamera, out _originalLocalPointerPos);
    }

    public void OnDrag(PointerEventData eventData)
    {
        if (_panelRectTransform == null)
            return;

        Vector2 vec;
        RectTransformUtility.ScreenPointToLocalPointInRectangle(canvas as RectTransform, eventData.position, eventData.pressEventCamera, out vec);

        Vector3 offect = vec - _originalLocalPointerPos;
        Vector2 sizeDelta = _originalSizeDelta + new Vector2(offect.x, -offect.y);
        sizeDelta = new Vector2(
            Mathf.Clamp(sizeDelta.x, minSize.x, maxSize.x),
            Mathf.Clamp(sizeDelta.y, minSize.y, maxSize.y)
            );

        _panelRectTransform.sizeDelta = sizeDelta;
    }

    public void OnPointerUp(PointerEventData eventData)
    {
        thirdPersonCamera.GetComponent<ThirdPersonCamera>().enabled = true;
    }
}