using UnityEngine;
using UnityEngine.EventSystems;

public class UIDrag : MonoBehaviour, IBeginDragHandler, IDragHandler, IEndDragHandler, IPointerDownHandler, IPointerUpHandler
{
    //按下回调
    public System.Action OnPointerDownCall;
    public System.Action OnPointerUpCall;
    //开始拖动回调
    public System.Action OnBeginDragCall;

    //拖动中回调
    public System.Action<PointerEventData> OnDragCall;

    //拖动结束回调
    public System.Action OnEndDragCall;
    bool isdrag = false;
    public bool isTouchTwo = false;

    public void OnPointerDown(PointerEventData eventData)
    {
        OnPointerDownCall?.Invoke();
    }

    public void OnPointerUp(PointerEventData eventData)
    {
        OnPointerUpCall?.Invoke();
    }

    public void OnBeginDrag(PointerEventData eventData)
    {
#if UNITY_EDITOR
        if (Input.GetMouseButton(0))
#else
        if (Input.touchCount == 1 || Input.touchCount == 2)
#endif
        {
            OnBeginDragCall?.Invoke();
            isdrag = true;
        }
    }

    public void OnDrag(PointerEventData eventData)
    {
        OnDragCall?.Invoke(eventData);
        if (isTouchTwo)
        {
#if !UNITY_EDITOR
            //if (Input.touchCount == 1)
            //{
            //    if (!isdrag)
            //    {
            //        OnBeginDragCall?.Invoke();
            //        isdrag = true;
            //    }
            //}
            //else 
            if (Input.touchCount == 2)
            {
                //双指操作
                if (isdrag)
                {
                    OnEndDragCall?.Invoke();
                    isdrag = false;
                }
            }
#endif
        }
    }

    public void OnEndDrag(PointerEventData eventData)
    {
        if (isdrag)
        {
            OnEndDragCall?.Invoke();
            isdrag = false;
        }
    }
    //双指操作
}