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

public class CameraSurround : MonoBehaviour
{
    public static CameraSurround instance;

    /// <summary>
    /// 旋转点
    /// </summary>
    private Vector3 m_RotationPoint;

    private void Awake()
    {
        instance = this;
    }

    private void Update()
    {
        CameraCtrlRotate();
        CameraCtrlMove();
        CameraCtrlMouseScrllMove();
    }

    /// <summary>
    /// 相机聚焦定位
    /// </summary>
    /// <param name="reset"></param>
    public void SetCameraPosition(bool reset = false)
    {
        Bounds tmpBounds = GetBounds(DeviceController.instance.transform);

        //物体最大长度
        float a = tmpBounds.size.magnitude;

        if (tmpBounds.size != Vector3.zero)
        {
            if (reset)
            {
                if (tmpBounds.size.x > tmpBounds.size.z)
                {
                    transform.position = tmpBounds.center +((tmpBounds.center + new Vector3(0.2f, 0, 1)) - tmpBounds.center).normalized * a / 2 * 1.9f;
                }
                else
                {
                    transform.position = tmpBounds.center +
                  ((tmpBounds.center + new Vector3(1, 0.2f, 0)) - tmpBounds.center).normalized
                   * a / 2 * 1.9f;
                }
            }
            else
            {
                transform.position = tmpBounds.center + (transform.position - tmpBounds.center).normalized * a / 2 * 1.9f;
            }
        }

        m_RotationPoint = tmpBounds.center;
        transform.LookAt(m_RotationPoint);
    }

    public void CameraCtrlMove()
    {
        if (Input.GetAxis("Mouse ScrollWheel") > 0)
        {
            transform.Translate(Vector3.forward * 1f);
        }

        if (Input.GetAxis("Mouse ScrollWheel") < 0)
        {
            transform.Translate(Vector3.forward * -1f);
        }

    }

    Vector3 PreMouseMPos;
    public void CameraCtrlMouseScrllMove()
    {
        if (Input.GetMouseButton(2))
        {
            if (PreMouseMPos.x <= 0)
            {
                PreMouseMPos = new Vector3(Input.mousePosition.x, Input.mousePosition.y, 0.0f);
            }
            else
            {
                Vector3 CurMouseMPos = new Vector3(Input.mousePosition.x, Input.mousePosition.y, 0.0f);
                Vector3 offset = CurMouseMPos - PreMouseMPos;
                offset = -offset * 0.01f;//0.1这个数字的大小可以调节速度  
                transform.Translate(offset);
                PreMouseMPos = CurMouseMPos;
            }
        }
        else
        {
            PreMouseMPos = new Vector3(0.0f, 0.0f, 0.0f);
        }
    }

    private void CameraCtrlRotate()
    {
        var mouse_X = Input.GetAxis("Mouse X");

        var mouse_Y = Input.GetAxis("Mouse Y");

        if (Input.GetKey(KeyCode.Mouse1))
        {
            if (m_RotationPoint.x.ToString() != "NaN" && m_RotationPoint.y.ToString() != "NaN" && m_RotationPoint.z.ToString() != "NaN")
            {
                transform.RotateAround(m_RotationPoint, Vector3.up, mouse_X * 5);

                transform.RotateAround(m_RotationPoint, transform.right, mouse_Y * -5);
            }
            else
            {
                SetCameraPosition(true);
            }
        }
    }

    /// <summary>
    /// 获取Transform及其子级的包围盒（MeshRenderer），若MeshRenderer包围盒长度为0，则获取BoxCollider包围盒
    /// </summary>
    /// <param name="transform"></param>
    /// <returns></returns>
    private static Bounds GetBounds(Transform target)
    {
        PartMark[] tmpPartMarks = target.GetComponentsInChildren<PartMark>(true);

        List<MeshRenderer> tmpMeshRenders = new List<MeshRenderer>();

        foreach (var item in tmpPartMarks)
        {
            tmpMeshRenders.AddRange(item.GetMeshRender(item.transform));
        }

        Bounds bounds = new Bounds(GetModelGroupBoundesConent(tmpMeshRenders.ToArray()), Vector3.zero);

        foreach (Renderer renderer in tmpMeshRenders)
        {
            bounds.Encapsulate(renderer.bounds);
        }

        return bounds;
    }

    /// <summary>
    /// 获取所以模型组的Boundes中心点
    /// </summary>
    private static Vector3 GetModelGroupBoundesConent(Renderer[] renderers)
    {
        Vector3 conent = Vector3.zero;

        for (int i = 0; i < renderers.Length; i++) conent += renderers[i].bounds.center;

        //获取到中心点
        conent /= renderers.Length;

        return conent;
    }
}