using UnityEngine;
using UnityEngine.EventSystems;
using UnityEngine.UI;

public class Show3DCamera : MonoBehaviour
{
    public Transform target; // 围绕旋转的目标点
    public float rotateSpeed = 10f; // 旋转速度
    public float moveSpeed = 10f; // 移动速度
    public float distance = 10f; // 相机与目标的距离
    public Vector2 pitchMinMax = new Vector2(-20, 80); // 相机俯仰角范围

    private Vector3 offset; // 相机与目标的偏移量
    private float yaw = 0f; // 偏航角（左右旋转）
    private float pitch = 0f; // 俯仰角（上下旋转）

    public static Show3DCamera instance;

    int rawWidth;
    int rawHeight;
    Camera self;

    private void Awake()
    {
        instance = this;
        self = transform.GetComponent<Camera>();
        DontDestroyOnLoad(this);
        gameObject.SetActive(false);
    }
    public void Set(int width,int height, Transform target, float rotateSpeed = 10, float moveSpeed = 0.1f, float distance = 0.1f, float pitchMin = -20, float pitchMax = 80)
    {
        if (target == null)
        {
            Debug.LogError("Target is not assigned!");
            return;
        }
        this.rawWidth = width;
        this.rawHeight = height;
        yaw = 0;
        pitch = 0;
        this.target = target.transform;
        this.rotateSpeed = rotateSpeed;
        this.moveSpeed = moveSpeed;
        this.distance = distance;
        this.pitchMinMax = new Vector2(pitchMin, pitchMax);
        // 初始化相机位置
        offset = new Vector3(0, 0, -distance);
        UpdateCameraPosition();
    }

    public void Clear()
    {
        target = null;
    }

    void Update()
    {
        if (target != null)
        {
            // 按住鼠标左键时旋转相机
            if (Input.GetMouseButton(0))
            {
                RotateCamera();
            }

            // 鼠标滚轮缩放
            float scroll = Input.GetAxis("Mouse ScrollWheel");
            if (scroll != 0)
            {
                ZoomCamera(scroll);
            }


            // 按住鼠标右键时移动目标点
            if (Input.GetMouseButton(1))
            {
                MoveTarget();
            }

            DetectHoveredObject();
        }
    }

    // 检测鼠标悬停的物体
    private void DetectHoveredObject()
    {
        // 从相机发射射线
        Ray ray = self.ScreenPointToRay(ConvertScreenToRenderTextureCoordinates(Input.mousePosition));
        if (Physics.Raycast(ray, out RaycastHit hit))
        {
            // 打印物体名称
            Debug.LogError("Hovered Object: " + hit.collider.gameObject.name);
        }
        Debug.DrawLine(ray.origin, hit.point, Color.red);
    }

    private Vector3 ConvertScreenToRenderTextureCoordinates(Vector3 screenPosition)
    {
        // 获取屏幕分辨率
        int screenWidth = Screen.width;
        int screenHeight = Screen.height;


        // 计算比例
        float scaleX = (float)rawWidth / screenWidth;
        float scaleY = (float)rawHeight / screenHeight;

        // 转换鼠标位置
        Vector3 renderTexturePosition = new Vector3(
            screenPosition.x * scaleX,
            screenPosition.y * scaleY,
            screenPosition.z
        );

        return renderTexturePosition;
    }


    // 移动目标点
    private void MoveTarget()
    {
        float mouseX = Input.GetAxis("Mouse X") * moveSpeed;
        float mouseY = Input.GetAxis("Mouse Y") * moveSpeed;

        transform.Translate(new Vector3(-mouseX, -mouseY, 0));
    }
    // 缩放相机
    private void ZoomCamera(float scroll)
    {
        distance -= scroll * 5f; // 调整缩放速度
        distance = Mathf.Clamp(distance, 0.2f, 20f); // 限制距离范围
        offset = new Vector3(0, 0, -distance);
        UpdateCameraPosition();
    }

    // 旋转相机
    private void RotateCamera()
    {
        // 获取鼠标移动量
        float mouseX = Input.GetAxis("Mouse X") * rotateSpeed;
        float mouseY = Input.GetAxis("Mouse Y") * rotateSpeed;

        // 更新偏航角和俯仰角
        yaw += mouseX;
        pitch -= mouseY; // 注意：鼠标 Y 轴移动方向与俯仰角相反
        pitch = Mathf.Clamp(pitch, pitchMinMax.x, pitchMinMax.y); // 限制俯仰角范围

        // 更新相机位置
        UpdateCameraPosition();
    }

    // 更新相机位置和朝向
    private void UpdateCameraPosition()
    {
        // 计算旋转后的偏移量
        Quaternion rotation = Quaternion.Euler(pitch, yaw, 0);
        Vector3 rotatedOffset = rotation * offset;

        // 更新相机位置
        transform.position = target.position + rotatedOffset;

        // 相机始终朝向目标点
        transform.LookAt(target);
    }
}