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

public class FreeCameraController : MonoSingleton<FreeCameraController>
{
    // 模型
    public Transform model;
    // 旋转速度
    public float rotateSpeed = 32f;
    public float rotateLerp = 8;
    // 移动速度
    public float moveSpeed = 1f;
    public float moveLerp = 10f;
    // 镜头拉伸速度
    public float zoomSpeed = 10f;
    public float zoomLerp = 4f;

    // 计算移动
    private Vector3 position, targetPosition;
    // 计算旋转
    private Quaternion rotation, targetRotation;
    // 计算距离
    private float distance, targetDistance;
    // 默认距离
    private const float default_distance = 40f;
    // y轴旋转范围
    private const float min_angle_y = -89f;
    private const float max_angle_y = 89f;

    public float maxDistance = 30;

    private FreeCameraData currentCameraData;
    private FreeCameraData allModelData;

    public float GetCurrentDistance
    {
        get { return distance; }
    }
    // Use this for initialization
    void Start()
    {
        Init();
        /*
        // 旋转归零
        //targetRotation = Quaternion.Euler(30,200,0);
        targetRotation = Quaternion.Euler(10, 180, 0);
        // 初始位置是模型
        targetPosition = model.position;
        // 初始镜头拉伸
        targetDistance = 85;*/
    }

    private void Init()
    {
        allModelData = this.GetComponent<FreeCameraData>();
        if (allModelData == null)
        {
            allModelData = new FreeCameraData() { targetRot = new Vector3(10, 180, 0), model = this.model, targetDistance = 85 };
        }
        InitCameraPos(allModelData);
    }

    private void OnEnable()
    {
        Init();
    }

    private void OnDisable()
    {
        Init();
    }

    // Update is called once per frame
    void Update()
    {
        //if (Input.GetMouseButton(0) || Input.GetMouseButton(1) || Input.GetMouseButton(2))
        //{
        //    if (IsPointerOverGameObject(Input.mousePosition))
        //    {
        //        //Debug.Log("点击到UI");
        //        return;
        //    }
        //}

        float dx = Input.GetAxis("Mouse X");
        float dy = Input.GetAxis("Mouse Y");

        // 异常波动
        if (Mathf.Abs(dx) > 5f || Mathf.Abs(dy) > 5f)
        {
            return;
        }

        float d_target_distance = targetDistance;
        if (d_target_distance < 2f)
        {
            d_target_distance = 2f;
        }


        // 鼠标右键移动
        if (Input.GetMouseButton(1))
        {
            dx *= moveSpeed * d_target_distance / default_distance;
            dy *= moveSpeed * d_target_distance / default_distance;
            targetPosition -= transform.up * dy + transform.right * dx;
        }

        // 鼠标左键旋转
        if (Input.GetMouseButton(0) || Input.GetMouseButton(2))
        {
            dx *= rotateSpeed;
            dy *= rotateSpeed;
            if (Mathf.Abs(dx) > 0 || Mathf.Abs(dy) > 0)
            {
                // 获取摄像机欧拉角
                Vector3 angles = transform.rotation.eulerAngles;
                // 欧拉角表示按照坐标顺序旋转，比如angles.x=30，表示按x轴旋转30°，dy改变引起x轴的变化
                angles.x = Mathf.Repeat(angles.x + 180f, 360f) - 180f;
                angles.y += dx;
                angles.x -= dy;
                angles.x = ClampAngle(angles.x, min_angle_y, max_angle_y);
                // 计算摄像头旋转
                targetRotation.eulerAngles = new Vector3(angles.x, angles.y, 0);
                // 随着旋转，摄像头位置自动恢复
                // Vector3 temp_position =
                //        Vector3.Lerp(targetPosition, model.position, Time.deltaTime * moveLerp);
                // targetPosition = Vector3.Lerp(targetPosition, temp_position, Time.deltaTime * moveLerp);
            }
        }

        if (Input.GetKey(KeyCode.R))
        {
            // 获取摄像机欧拉角
            Vector3 angles = transform.rotation.eulerAngles;
            // 欧拉角表示按照坐标顺序旋转，比如angles.x=30，表示按x轴旋转30°，dy改变引起x轴的变化
            angles.x = Mathf.Repeat(angles.x + 180f, 360f) - 180f;
            angles.y -= 3;
            angles.x = ClampAngle(angles.x, min_angle_y, max_angle_y);
            // 计算摄像头旋转
            targetRotation.eulerAngles = new Vector3(angles.x, angles.y, 0);
        }

        //// 上移
        //if (Input.GetKey(KeyCode.UpArrow) || Input.GetKey(KeyCode.W))
        //{
        //    targetPosition -= transform.up * d_target_distance / (2f * default_distance);
        //}

        //// 下移
        //if (Input.GetKey(KeyCode.DownArrow) || Input.GetKey(KeyCode.S))
        //{
        //    targetPosition += transform.up * d_target_distance / (2f * default_distance);
        //}

        //// 左移
        //if (Input.GetKey(KeyCode.LeftArrow) || Input.GetKey(KeyCode.A))
        //{
        //    targetPosition += transform.right * d_target_distance / (2f * default_distance);
        //}

        //// 右移
        //if (Input.GetKey(KeyCode.RightArrow) || Input.GetKey(KeyCode.D))
        //{
        //    targetPosition -= transform.right * d_target_distance / (2f * default_distance);
        //}

        // 鼠标滚轮拉伸
        targetDistance -= Input.GetAxis("Mouse ScrollWheel") * zoomSpeed;

        if (targetDistance > maxDistance)
        {
            targetDistance = maxDistance;
        }
    }

    // 控制旋转角度范围：min max
    float ClampAngle(float angle, float min, float max)
    {
        // 控制旋转角度不超过360
        if (angle < -360f) angle += 360f;
        if (angle > 360f) angle -= 360f;
        return Mathf.Clamp(angle, min, max);
    }

    private void FixedUpdate()
    {
        rotation = Quaternion.Slerp(rotation, targetRotation, Time.deltaTime * rotateLerp);
        position = Vector3.Lerp(position, targetPosition, Time.deltaTime * moveLerp);
        distance = Mathf.Lerp(distance, targetDistance, Time.deltaTime * zoomLerp);
        // 设置摄像头旋转
        transform.rotation = rotation;
        // 设置摄像头位置
        transform.position = position - rotation * new Vector3(0, 0, distance);
    }

    public void InitModelPos()
    {
        InitCameraPos(allModelData);
    }

    public void InitCameraPos(FreeCameraData data)
    {
        if (data == null) return;
        currentCameraData = data;
        InitCameraPos();
    }

    /// <summary>
    /// 初始化摄像机围殴之
    /// </summary>
    public void InitCameraPos()
    {
        //// 旋转归零
        targetRotation = Quaternion.Euler(currentCameraData.targetRot);
        //// 初始位置是模型
        targetPosition = currentCameraData.model.position;
        //// 初始镜头拉伸
        targetDistance = currentCameraData.targetDistance;
    }

    public void SetPosAndRot(Vector3 pos, Quaternion rot)
    {
        transform.position = pos;
        transform.rotation = rot;
    }

    /// <summary>
    /// 检测是否点击UI
    /// </summary>
    /// <param name="mousePosition"></param>
    /// <returns></returns>
    private bool IsPointerOverGameObject(Vector2 mousePosition)
    {
        //创建一个点击事件
        PointerEventData eventData = new PointerEventData(EventSystem.current);
        eventData.position = mousePosition;
        List<RaycastResult> raycastResults = new List<RaycastResult>();
        //向点击位置发射一条射线，检测是否点击UI
        EventSystem.current.RaycastAll(eventData, raycastResults);
        if (raycastResults.Count > 0)
        {
            if (raycastResults.Count == 1 && raycastResults.Find(p => p.gameObject.CompareTag("UIIgnore")).gameObject != null)
            {
                return false;
            }
            return true;
        }
        else
        {
            return false;
        }
    }
}