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

public class FollowItemView : MonoBehaviour {


    [SerializeField]
    private FollowItemConfig MTarget;
    private LineRenderer mLine;
    private float RayCd = 0.0f;//找新的位置
    private float lastCheckTime = float.MinValue;
    void Start()
    {
        mLine = this.GetComponent<LineRenderer>();
    }

    private void LateUpdate()
    {
        RefreshPoint();
    }

    void OnDrawGizmos()
    {
        var direction = transform.TransformDirection(Vector3.up) * 5;  //    在物体的前方绘制一个5米长的线
        Gizmos.color = Color.green;
        Gizmos.DrawRay(transform.position, direction);
        Gizmos.color = Color.red;
        Gizmos.DrawRay(transform.position, transform.TransformDirection(Vector3.forward) * 5);
    }

    private Transform LookTarget
    {
        get
        {
            return Camera.main.transform;
        }
    }

    //这个点不能在别人家的碰撞框里面
    //这个点不能被射线遮挡
    //这个点和模型的中心点

    private Vector3 Point;
    private void CheckVert()
    {
        Vector3[] vertices = MTarget.TriggerCol.sharedMesh.vertices;
        Vector3 pos;
        float maxAngle = float.MinValue;
        Vector3 selectPos = this.transform.position;
        float checkAngle;
        for (int i = 0; i < vertices.Length; i++)
        {
            pos = MTarget.transform.TransformPoint(vertices[i] * MTarget.TriggerCol.transform.localScale.x);
            if (!CameraZhedang(pos))
            {
                Debug.DrawLine(MTarget.transform.position, pos, Color.red);
                checkAngle = GetAngle(pos);
                if (maxAngle < checkAngle && checkAngle < 90)
                {
                    maxAngle = checkAngle;
                    selectPos = pos;
                }
            }
        }
        Point = selectPos;

    }

    private Vector3[] LinePoints = new Vector3[3];
    private void RefreshPoint()
    {
        if (Time.realtimeSinceStartup >= lastCheckTime + RayCd)
        {
            lastCheckTime = Time.realtimeSinceStartup;
            CheckVert();
            this.transform.position = Point;
            LinePoints[0] = this.transform.position;
            LinePoints[2] = MTarget.ClosePoint(this.transform.position); ;
            LinePoints[1] = Vector3.Lerp(this.transform.position, LinePoints[2], 0.3f);
            LinePoints[1].y = this.transform.position.y;
            this.mLine.SetPositions(LinePoints);
        }
        this.transform.LookAt(LookTarget);
    }

    private bool CameraZhedang(Vector3 pos)
    {
        Ray mRay = new Ray(LookTarget.position, (pos - LookTarget.position));
        RaycastHit hitInfo;
        if (Physics.Raycast(mRay, out hitInfo,100, 10))
        {
            return true;
        }
        return false;
    }

    private float GetAngle(Vector3 pos)
    {
        return Vector3.Angle((MTarget.transform.position - pos), (LookTarget.transform.position - pos));
    }
}