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

/// <summary>
/// 相机漫游控制
/// </summary>
public class CameraController : MonoBehaviour
{
    public static CameraController instance;

    [Header("是否可移动")]
    public bool canMove = true;
    [Header("是否可转动")]
    public bool camRotate = true;

    public bool _isCouldCrossCollider = false;//是否可穿碰撞器
    public float _moveSpeed = 10f;//移动速度
    public float _xSpeed = 250.0f;//X轴视角旋转速度
    public float _ySpeed = 120.0f;//Y轴视角旋转速度
    public float _mouseSpeed = 500f;//鼠标中间滚轮的拉近拉远速度
    public float _yMinLimit = -20;//视角旋转向下最小限制
    public float _yMaxLimit = 80;//视角旋转向上最大限制
    public float _speedLimit = 0.2f;//鼠标中键移动速度限制

    private float _angleX = 0.0f;
    private float _angleY = 0.0f;
    private float _moveV = 0.0f;
    private float _moveH = 0.0f;
    private Vector3 _movePos;

    private float xMax;
    private float xMin;
    private float yMax;
    private float yMin;
    private float zMax;
    private float zMin;

    private Vector3 initPostion;
    private Quaternion initRotation;

    /// <summary>
    /// 初始化摄像机，避免产生空引用
    /// </summary>
    void Start()
    {
        initPostion = transform.position;
        initRotation = transform.rotation;
        instance = this;
        ResetInfo();
    }

    public void SetCamerPositionAndRotation(Vector3 positon, Vector3 rotation)
    {
        _movePos = positon;
        this.transform.position = positon;
        transform.eulerAngles = rotation;
    }

    public void SetInitPositionAndRotation()
    {
        transform.position = initPostion;
        transform.rotation = initRotation;
    }

    /// <summary>
    /// 重置位置信息
    /// </summary>
    public void ResetInfo()
    {
        var angles = transform.eulerAngles;
        _angleX = angles.y;
        _angleY = angles.x;

        _movePos = this.transform.position;
    }

    //Update is called once per frame
    void Update()
    {
        if (EventSystem.current.IsPointerOverGameObject()) return;

        if (canMove)
        {
            moveCamera();
            riseCamera();

        }
        if (camRotate) rotateView();

        viewScale();
        SetMovePosToThis();
    }

    /// <summary>
    /// 前后移动摄像机
    /// </summary>
    void moveCamera()
    {
        _moveV = Input.GetAxis("Vertical") * Time.deltaTime * _moveSpeed;
        _moveH = Input.GetAxis("Horizontal") * Time.deltaTime * _moveSpeed;
        _movePos = this.transform.position + this.transform.forward * _moveV + this.transform.right * _moveH;
    }

    /// <summary>
    /// 自身位置赋值
    /// </summary>
    private void SetMovePosToThis()
    {
        if (_isCouldCrossCollider)
        {
            this.transform.position = _movePos;
        }
        else
        {
            if (CameraRestraint.CheckThePos(this.transform, _movePos))
            {
                this.transform.position = _movePos;
            }
        }

    }

    public void SetCameraPosLimite(float _xMin, float _xMax, float _yMin, float _yMax, float _zMin, float _zMax)
    {
        xMax = _xMax; xMin = _xMin;
        yMax = _yMax; yMin = _yMin;
        zMax = _zMax; zMin = _zMin;
    }

    /// <summary>
    /// 鼠标中键控制相机移动
    /// </summary>
    void riseCamera()
    {
        if (Input.GetMouseButton(2))
        {
            _moveV = -Input.GetAxis("Mouse Y") * _moveSpeed;

            _moveH = -Input.GetAxis("Mouse X") * _moveSpeed;

            _movePos = this.transform.position + this.transform.up * _moveV * Time.deltaTime + this.transform.right * _moveH * Time.deltaTime;
        }
    }

    /// <summary>
    /// 鼠标右键控制视角旋转
    /// </summary>
    void rotateView()
    {
        if (Input.GetMouseButton(1))
        {
            _angleX += Input.GetAxis("Mouse X") * _xSpeed * 0.02f;
            _angleY -= Input.GetAxis("Mouse Y") * _ySpeed * 0.02f;
            _angleY = ClampAngle(_angleY, _yMinLimit, _yMaxLimit);
            var rotation = Quaternion.Euler(_angleY, _angleX, 0);
            transform.rotation = rotation;
        }
    }

    /// <summary>
    /// 滑轮控制视角移动
    /// </summary>
    void viewScale()
    {
        if (Input.GetAxis("Mouse ScrollWheel") != 0)
        {
            _movePos = this.transform.position + this.transform.forward * Input.GetAxis("Mouse ScrollWheel") * Time.deltaTime * _mouseSpeed;

        }
    }

    /// <summary>
    /// 控制摄像机的旋转角度大小
    /// </summary>
    /// <param 角度值="angle"></param>
    /// <param 最小角度="min"></param>
    /// <param 最大角度="max"></param>
    /// <returns></returns>
    static float ClampAngle(float angle, float min, float max)
    {
        if (angle < -360)
        {
            angle += 360;
        }
        if (angle > 360)
        {
            angle -= 360;
        }
        return Mathf.Clamp(angle, min, max);
    }
}