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

public class MainCameraLogic : MonoBehaviour
{
    // Start is called before the first frame update
    private GameObject mainCamera;
    //private GameObject emptyCamera;
    public Button btnResetView;

    private bool wPressed;
    private bool sPressed;
    private bool aPressed;
    private bool dPressed;

    //相机跟随的目标物体，一般是一个空物体
    public Transform target;
    private int MouseWheelSensitivity = 3; //滚轮灵敏度设置
    private int MouseZoomMin = -50; //相机距离最小值
    private int MouseZoomMax = 50; //相机距离最大值

    //0.06这个系数是控制平移的速度，要根据相机和目标物体的distance来灵活选择
    const float centerMoveSpeed = 0.01f;
    private const int keyMoveSpeed = 1;
    private float moveSpeed = 5; //相机跟随速度（中键平移时），采用平滑模式时起作用，越大则运动越平滑

    private float xSpeed = 80.0f; //旋转视角时相机x轴转速
    private float ySpeed = 80.0f; //旋转视角时相机y轴转速

    private int yMinLimit = -360;
    private int yMaxLimit = 360;

    private float x = 0.0f; //存储相机的euler角
    private float y = 0.0f; //存储相机的euler角

    private float Distance = 5; //相机和target之间的距离，因为相机的Z轴总是指向target，也就是相机z轴方向上的距离
    private Vector3 targetOnScreenPosition; //目标的屏幕坐标，第三个值为z轴距离
    private Quaternion storeRotation; //存储相机的姿态四元数
    private Vector3 CameraTargetPosition; //target的位置
    private Vector3 initPosition; //平移时用于存储平移的起点位置
    private Vector3 cameraX; //相机的x轴方向向量
    private Vector3 cameraY; //相机的y轴方向向量
    private Vector3 cameraZ; //相机的z轴方向向量

    private Vector3 initScreenPos; //中键刚按下时鼠标的屏幕坐标（第三个值其实没什么用）
    private Vector3 curScreenPos; //当前鼠标的屏幕坐标（第三个值其实没什么用）

    // Start is called before the first frame update
    void Start()
    {

        mainCamera = GameObject.Find("Main Camera");
        //emptyCamera = GameObject.Find("EmptyCamera");

        // Debug.Log("Camera x: "+transform.right);
        // Debug.Log("Camera y: "+transform.up);
        // Debug.Log("Camera z: "+transform.forward);

        // //-------------TEST-----------------
        // testScreenToWorldPoint();
    }

    // Update is called once per frame
    void Update()
    {

        //这里就是设置一下初始的相机视角以及一些其他变量，这里的x和y。。。是和下面getAxis的mouse x与mouse y对应
        var angles = transform.eulerAngles;
        x = angles.y;
        y = angles.x;
        CameraTargetPosition = target.position;
        target.rotation = transform.rotation;
        //CameraTargetPosition = transform.position;
        //storeRotation = Quaternion.Euler(y + 60, x, 0);
        storeRotation = Quaternion.Euler(y, x, 0);
        transform.rotation = storeRotation; //设置相机姿态
        Vector3 position = storeRotation * new Vector3(0.0F, 0.0F, -Distance) + CameraTargetPosition; //四元数表示一个旋转，四元数乘以向量相当于把向量旋转对应角度，然后加上目标物体的位置就是相机位置了
        transform.position = storeRotation * new Vector3(0, 0, -Distance) + CameraTargetPosition; //设置相机位置

        //鼠标右键旋转功能
        if (Input.GetMouseButton(1))
        {
            x += Input.GetAxis("Mouse X") * xSpeed * 0.02f;
            y -= Input.GetAxis("Mouse Y") * ySpeed * 0.02f;

            y = ClampAngle(y, yMinLimit, yMaxLimit);

            //storeRotation = Quaternion.Euler(y + 60, x, 0);
            storeRotation = Quaternion.Euler(y, x, 0);
            var tmpPosition = storeRotation * new Vector3(0.0f, 0.0f, -Distance) + CameraTargetPosition;

            transform.rotation = storeRotation;
            transform.position = tmpPosition;
        }
        else if (Input.GetAxis("Mouse ScrollWheel") != 0) //鼠标滚轮缩放功能
        {
            if (Distance >= MouseZoomMin && Distance <= MouseZoomMax)
            {
                Distance -= Input.GetAxis("Mouse ScrollWheel") * MouseWheelSensitivity;
            }
            if (Distance < MouseZoomMin)
            {
                Distance = MouseZoomMin;
            }
            if (Distance > MouseZoomMax)
            {
                Distance = MouseZoomMax;
            }
            var rotation = transform.rotation;

            transform.position = storeRotation * new Vector3(0.0F, 0.0F, -Distance) + CameraTargetPosition;
        }

        //鼠标中键平移
        if (Input.GetMouseButtonDown(2))
        {
            cameraX = transform.right;
            cameraY = transform.up;
            cameraZ = transform.forward;

            initScreenPos = new Vector3(Input.mousePosition.x, Input.mousePosition.y, targetOnScreenPosition.z);
            Debug.Log("downOnce");

            //targetOnScreenPosition.z为目标物体到相机xmidbuttonDownPositiony平面的法线距离
            targetOnScreenPosition = Camera.main.WorldToScreenPoint(CameraTargetPosition);
            initPosition = CameraTargetPosition;
        }

        if (Input.GetMouseButton(2))
        {
            curScreenPos = new Vector3(Input.mousePosition.x, Input.mousePosition.y, targetOnScreenPosition.z);
           
            
            target.position = initPosition - centerMoveSpeed * ((curScreenPos.x - initScreenPos.x) * cameraX + (curScreenPos.y - initScreenPos.y) * cameraY);

            //重新计算位置
            Vector3 mPosition = storeRotation * new Vector3(0.0F, 0.0F, -Distance) + target.position;
            transform.position = mPosition;

            // //用这个会让相机的平移变得更平滑，但是可能在你buttonup时未使相机移动到应到的位置，导致再进行旋转与缩放操作时出现短暂抖动
            //transform.position=Vector3.Lerp(transform.position,mPosition,Time.deltaTime*moveSpeed);

        }
        if (Input.GetMouseButtonUp(2))
        {
            Debug.Log("upOnce");
            //平移结束把cameraTargetPosition的位置更新一下，不然会影响缩放与旋转功能
            CameraTargetPosition = target.position;
        }

        if (Input.GetKeyDown(KeyCode.D))
        {
            dPressed = true;
        }
        if (Input.GetKeyDown(KeyCode.A))
        {
            aPressed = true;
        }
        if (Input.GetKeyUp(KeyCode.A))
        {
            Debug.Log("A up");
            aPressed = false;

        }
        if (Input.GetKeyUp(KeyCode.W))
        {
            Debug.Log("W up");
            wPressed = false;

        }
        if (Input.GetKeyUp(KeyCode.S))
        {
            Debug.Log("s up");
            sPressed = false;

        }
        if (Input.GetKeyUp(KeyCode.D))
        {
            Debug.Log("d up");
            dPressed = false;

        }
        if (Input.GetKeyDown(KeyCode.W))
        {
            wPressed = true;
            Debug.Log("W Pressed"); 

        }
        if (Input.GetKeyDown(KeyCode.S))
        {
            sPressed = true;
        }
        keyMove();

    }
    void keyMove()
    {
        if (wPressed)
        {
          

            target.transform.Translate(0, 0, keyMoveSpeed * Time.deltaTime, Space.Self);
        }
        if (sPressed)
        {
         
            target.transform.Translate(0, 0, -keyMoveSpeed * Time.deltaTime, Space.Self);
        }
        if (dPressed)
        {
            // x +=  xSpeed * 0.002f;
            //// y -=  ySpeed * 0.02f;

            // y = ClampAngle(y, yMinLimit, yMaxLimit);

            // //storeRotation = Quaternion.Euler(y + 60, x, 0);
            // storeRotation = Quaternion.Euler(y, x, 0);
            // var tmpPosition = storeRotation * new Vector3(0.0f, 0.0f, -Distance) + CameraTargetPosition;

            // transform.rotation = storeRotation;
            // transform.position = tmpPosition;
            target.transform.Translate(keyMoveSpeed * Time.deltaTime, 0, 0, Space.Self);
        }
        if (aPressed)
        {
            //x -= xSpeed * 0.002f;
            //y -= ySpeed * 0.02f;

            //y = ClampAngle(y, yMinLimit, yMaxLimit);

            //storeRotation = Quaternion.Euler(y + 60, x, 0);
            //storeRotation = Quaternion.Euler(y, x, 0);
            //var tmpPosition = storeRotation * new Vector3(0.0f, 0.0f, -Distance) + CameraTargetPosition;

            //transform.rotation = storeRotation;
            //transform.position = tmpPosition;
            target.transform.Translate(-keyMoveSpeed * Time.deltaTime,0,0, Space.Self);
        }
    }

    //将angle限制在min~max之间
    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);
    }

    void testScreenToWorldPoint()
    {
        //第三个坐标指的是在相机z轴指向方向上的距离
        Vector3 screenPoint = Camera.main.WorldToScreenPoint(CameraTargetPosition);
        Debug.Log("ScreenPoint: " + screenPoint);

        // var worldPosition = Camera.main.ScreenToWorldPoint(new Vector3(1,1,10));
        // Debug.Log("worldPosition: "+worldPosition);
    }

    /**
     * 重置主镜头视角
     * 
     */
    public void ResetView()
    {
        Debug.Log("Reset View!!!");
        Vector3 position = new Vector3(62f, 78f, -322f);
        mainCamera.transform.position = position;
        target.transform.position = position;
        Quaternion rotation = Quaternion.Euler(32, 183, 0);
        mainCamera.transform.rotation = rotation;
       // target.transform.rotation = rotation;
        Distance = 5;

    }
}