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

namespace Level23
{
    //给空间添加监听事件要实现的一些接口
    public class MyDrag : MonoBehaviour, IPointerDownHandler, IDragHandler, IPointerUpHandler,
        IEndDragHandler, IPointerEnterHandler, IPointerExitHandler
    {
        public RectTransform canvas;          //得到canvas的ugui坐标
        public Level23 lvRoot;
        private RectTransform imgRect;        //得到图片的ugui坐标

        Vector2 offset = new Vector3();    //用来得到鼠标和图片的差值
        Vector3 imgReduceScale = new Vector3(0.6f, 0.6f, 1);   //设置图片缩放
        Vector3 imgNormalScale = new Vector3(1, 1, 1);   //正常大小
        Vector3 selfV3 = Vector3.zero;
        // Use this for initialization
        void Start()
        {
            imgRect = GetComponent<RectTransform>();
            selfV3 = transform.localPosition;
        }

        //当鼠标按下时调用 接口对应  IPointerDownHandler
        public void OnPointerDown(PointerEventData eventData)
        {
            if (!lvRoot.isDrag) return;
            Vector2 mouseDown = eventData.position;    //记录鼠标按下时的屏幕坐标
            Vector2 mouseUguiPos = new Vector2();   //定义一个接收返回的ugui坐标
            bool isRect = RectTransformUtility.ScreenPointToLocalPointInRectangle(canvas, mouseDown, eventData.enterEventCamera, out mouseUguiPos);
            if (isRect)   //如果在
            {
                //计算图片中心和鼠标点的差值
                offset = imgRect.anchoredPosition - mouseUguiPos;
            }
        }

        //当鼠标拖动时调用   对应接口 IDragHandler
        public void OnDrag(PointerEventData eventData)
        {
            if (!lvRoot.isDrag) return;
            Vector2 mouseDrag = eventData.position;   //当鼠标拖动时的屏幕坐标
            Vector2 uguiPos = new Vector2();   //用来接收转换后的拖动坐标
                                               //和上面类似
            bool isRect = RectTransformUtility.ScreenPointToLocalPointInRectangle(canvas, mouseDrag, eventData.enterEventCamera, out uguiPos);

            if (isRect)
            {
                //设置图片的ugui坐标与鼠标的ugui坐标保持不变
                imgRect.anchoredPosition = offset + uguiPos;
                imgRect.localScale = imgReduceScale;   //缩小图片
            }
        }

        //当鼠标抬起时调用  对应接口  IPointerUpHandler
        public void OnPointerUp(PointerEventData eventData)
        {
            if (!lvRoot.isDrag) return;
            offset = Vector2.zero;
            imgRect.localScale = imgNormalScale;   //回复图片
            if(Vector3.Distance(Input.mousePosition, GameObject.Find("zhishideng3").transform.position) < 50f)
            {
                lvRoot.SetZhiModel(gameObject.name);
                Destroy(gameObject);
            }
            else
            {
                transform.localPosition = selfV3;
            }
            //if (eventData.pointerCurrentRaycast.gameObject.name.Equals("zhishideng3"))
            //{
            //    lvRoot.SetZhiModel(gameObject.name);
            //    Destroy(gameObject);
            //}
            //else
            //    transform.localPosition = selfV3;
        }

        //当鼠标结束拖动时调用   对应接口  IEndDragHandler
        public void OnEndDrag(PointerEventData eventData)
        {
            if (!lvRoot.isDrag) return;
            offset = Vector2.zero;
        }

        //当鼠标进入图片时调用   对应接口   IPointerEnterHandler
        public void OnPointerEnter(PointerEventData eventData)
        {
            //Debug.LogError("OnPointerEnter");
            //imgRect.localScale = imgReduceScale;   //缩小图片
        }

        //当鼠标退出图片时调用   对应接口   IPointerExitHandler
        public void OnPointerExit(PointerEventData eventData)
        {
            //Debug.LogError("OnPointerExit");
            //imgRect.localScale = imgNormalScale;   //回复图片
        }
    }
}