using System.Collections;
using System.Collections.Generic;
using System;
using UnityEngine;
using UnityEngine.UI;
using UnityEngine.EventSystems;
using DG.Tweening;

/// <summary>
/// 虚拟摇杆
/// </summary>
public class Joystick : MonoBehaviour, IDragHandler, IPointerDownHandler, IPointerUpHandler
{
    //事件
    public Action OnTouchDown;
    public Action<Vector2> OnTouchMove;
    public Action OnTouchUp;

    public static float h, v;  //传出hv
    public float maxDis;    //最大距离
    private Vector2 v2Data = Vector2.zero;

    private RectTransform rectTransform;
    private RectTransform childRectTrans;
    void Start()
    {
        rectTransform = transform as RectTransform;
        childRectTrans = transform.GetChild(0) as RectTransform;
    }

    /// <summary>
    /// 重设摇杆
    /// </summary>
    public void ResetJoystick()
    {
        if (OnTouchUp != null)
        {
            OnTouchUp();
        }

        //当结束拖动，要将物体归0,为了加一点缓冲效果
        childRectTrans.DOAnchorPos(Vector2.zero, 0.25f).OnUpdate(GetHV);
    }

    /// <summary>
    /// 按下
    /// </summary>
    /// <param name="eventData"> 事件数据 </param>
    public void OnPointerDown(PointerEventData eventData)
    {
        if (OnTouchDown != null)
        {
            OnTouchDown();
        }

        Vector3 outPos;
        if (RectTransformUtility.ScreenPointToWorldPointInRectangle(this.transform as RectTransform, eventData.position, eventData.pressEventCamera, out outPos))
        {
            childRectTrans.position = outPos;
            //限制拖拽距离
            childRectTrans.anchoredPosition = Vector2.ClampMagnitude(childRectTrans.anchoredPosition, maxDis);
            GetHV();
        }
    }

    /// <summary>
    /// 抬起
    /// </summary>
    /// <param name="eventData"> 事件数据 </param>
    public void OnPointerUp(PointerEventData eventData)
    {
        if (OnTouchUp != null)
        {
            OnTouchUp();
        }

        //当结束拖动，要将物体归0,为了加一点缓冲效果
        childRectTrans.DOAnchorPos(Vector2.zero, 0.25f).OnUpdate(GetHV);
    }
    public void OnDrag(PointerEventData eventData)
    {
        Vector3 outPos;
        if (RectTransformUtility.ScreenPointToWorldPointInRectangle(this.transform as RectTransform, eventData.position, eventData.pressEventCamera, out outPos))
        {
            childRectTrans.position = outPos;
            //限制拖拽距离
            childRectTrans.anchoredPosition = Vector2.ClampMagnitude(childRectTrans.anchoredPosition, maxDis);
            GetHV();
        }
    }
    private void GetHV()
    {
        h = childRectTrans.anchoredPosition.x / maxDis;
        v = childRectTrans.anchoredPosition.y / maxDis;
        v2Data.Set(h, v);

        if (OnTouchMove != null)
        {
            OnTouchMove(v2Data);
        }
    }
}