using DG.Tweening;
using System;
using Unity.Mathematics;
using Unity.VisualScripting;
using UnityEngine;
using UnityEngine.EventSystems;

public class CameraBird : MonoBehaviour
{

    public Transform target; // 目标对象，摄像头将朝向此对象
    public float smoothSpeed = 0.125f; // 摄像头平滑移动的速度
    public float scrollSensitivity = 5f; // 鼠标滚轮的灵敏度
    public float rotateSpeed = 0.25f;
    public float translateSpeed = 3f;
    public float minDistance = 5f; // 摄像头与目标对象的最小距离
    public float maxDistance = 50f; // 摄像头与目标对象的最大距离

    public float currentDistance; // 当前摄像头与目标对象的距离
    private Vector3 offset; // 摄像头与目标对象的偏移量
    private Vector3 velocity = Vector3.zero; // 摄像头移动的速度
    private bool isDragging = false; // 是否正在拖拽
    private Vector3 lastMousePosition; // 上一帧鼠标位置

    public float rotateYAngle = 0.0f;
    public float rotateXAngle = 0.0f;

    bool isRotate = false;

    bool onUI = false;
    void Start()
    {
        // 初始化当前距离为初始偏移量的距离
        currentDistance = Vector3.Distance(transform.position, target.position);
        // 确保初始距离在允许的范围内
        currentDistance = Mathf.Clamp(currentDistance, minDistance, maxDistance);
        // 计算偏移量
        offset = transform.position - target.position;
    }

    private bool IsPointerOverUIElement()
    {
        // 检查当前鼠标位置是否在 UI 上
        return EventSystem.current.IsPointerOverGameObject();
    }
    void LateUpdate()
    {
        onUI = false;
        if (IsPointerOverUIElement()) onUI = true;

        // 鼠标滚轮控制摄像头远近
        if (Input.GetAxis("Mouse ScrollWheel") != 0 && !onUI)
        {
            // 更新当前距离
            currentDistance -= Input.GetAxis("Mouse ScrollWheel") * scrollSensitivity;
            // 确保距离在允许的范围内
            currentDistance = Mathf.Clamp(currentDistance, minDistance, maxDistance);

            

            //this.GetComponent<DepthFog>().Height = 400000 / currentDistance;
        }
        translateSpeed = currentDistance / 600f;

        scrollSensitivity = currentDistance / 16.0f * currentDistance / 16.0f;

        scrollSensitivity = Mathf.Clamp(scrollSensitivity, 10, 4000);

        if (Input.GetMouseButton(2))
        {
            rotateXAngle -= Input.GetAxis("Mouse Y") * rotateSpeed;
            rotateYAngle += Input.GetAxis("Mouse X") * rotateSpeed;
            isRotate = true;
        }
        else {
            isRotate = false;
        }

        // 鼠标左键拖拽平移摄像头
        if (Input.GetMouseButtonDown(0) && !onUI)
        {
            isDragging = true;
            lastMousePosition = Input.mousePosition;
        }
        else if (Input.GetMouseButtonUp(0))
        {
            isDragging = false;
        }

        if (isDragging)
        {
            // 计算鼠标移动的偏移量
            Vector3 mouseOffset = Input.mousePosition - lastMousePosition;
            // 根据偏移量计算摄像头的目标位置
            Vector3 moveDirection = new Vector3(transform.forward.x, 0, transform.forward.z) * -mouseOffset.y * translateSpeed + new Vector3(transform.right.x, 0, transform.right.z) * -mouseOffset.x * translateSpeed;
            // 平滑移动摄像头到目标位置
            target.position += moveDirection;

            // 计算目标位置
            Vector3 targetPosition = target.position + Quaternion.Euler(new Vector3(rotateXAngle, rotateYAngle, 0)) * offset.normalized * currentDistance;

            // 摄像头平滑移动到目标位置
            transform.position = Vector3.Lerp(transform.position, targetPosition, Time.deltaTime * smoothSpeed * 2);
        }
        else
        {


            if (isRotate)
            {
                Blink();
            }
            else
            {
                // 计算目标位置
                Vector3 targetPosition = target.position + Quaternion.Euler(new Vector3(rotateXAngle, rotateYAngle, 0)) * offset.normalized * currentDistance;

                // 摄像头平滑移动到目标位置
                transform.position = Vector3.Lerp(transform.position, targetPosition, Time.deltaTime * smoothSpeed);
            }


        }


        lastMousePosition = Input.mousePosition;
    }

    public void Blink()
    {
        // 计算目标位置
        Vector3 targetPosition = target.position + Quaternion.Euler(new Vector3(rotateXAngle, rotateYAngle, 0)) * offset.normalized * currentDistance;

        // 摄像头平滑移动到目标位置
        transform.position = targetPosition;

        //摄像头朝向目标对象
        transform.rotation = Quaternion.LookRotation(target.position - this.transform.position, Vector3.up);

    }


    public void SetCameraToCenterFade(Vector3 centerPos,float distance = 300)
    {
        MeshRenderer fader = this.transform.GetChild(0).GetComponent<MeshRenderer>();
        fader.gameObject.SetActive(true);
        fader.material.DOColor(Color.white, 0.1f).onComplete = () =>
        {
            fader.material.DOColor(Color.clear, 1.5f).onComplete = () =>
            {
                fader.gameObject.SetActive(false);
            };

        };

        this.target.localPosition = centerPos;
        DOTween.To(()=>this.currentDistance,x=>this.currentDistance=x, distance,0.5f);
        this.Blink();
    }

    void Update()
    {

    }
}