using System;
using System.Collections.Generic;
using DG.Tweening;
using Unity.Mathematics;
using Unity.VisualScripting;
using UnityEngine;
using UnityEngine.EventSystems;
using UnityEngine.UI;

public class CameraBirdSec : MonoBehaviour
{
    public Action beginDrag;

    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 Canvas canvas;

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

    public Action<float> OnDistanceChange;

    public float min_X;
    public float max_X;
    public float min_Y;
    public float max_Y;

    public bool fixMoveRange = false;
    public bool detailLod = false;
    
    bool isRotate = false;

    bool onUI = false;
    void Start()
    {
        // 计算偏移量
        offset = transform.position - target.position;
    }

    private bool GetPointerOverUIElement(out GameObject uiElement)
    {
        uiElement = null;
        PointerEventData pointerEventData = new PointerEventData(EventSystem.current)
        {
            position = Input.mousePosition
        };

        RaycastResult raycastResult = new RaycastResult();
        List<RaycastResult> results = new List<RaycastResult>();
        GraphicRaycaster raycaster = canvas.GetComponent<GraphicRaycaster>();

        if (raycaster != null)
        {
            raycaster.Raycast(pointerEventData, results);
            if (results.Count > 0)
            {
                raycastResult = results[0];
                uiElement = raycastResult.gameObject;
                return true;
            }
        }
        return false;
    }

    private bool IsPointerOverUIElement()
    {
        bool specialUI = false;
        if (GetPointerOverUIElement(out GameObject uiElement))
        {
            
            // 获取 UI 元素的类型
            if (uiElement.TryGetComponent<Button>(out Button button))
            {
                
                if (uiElement.transform.TryGetComponent<RuntimePoint>(out RuntimePoint rp)) {
                    specialUI = true;
                }
            }
        }
        // 检查当前鼠标位置是否在 UI 上
        return EventSystem.current.IsPointerOverGameObject() && !specialUI;
    }
    void LateUpdate()
    {
        onUI = false;
        if (IsPointerOverUIElement()) onUI = true;

        translateSpeed = currentDistance / 1000.0f; 
        // 鼠标滚轮控制摄像头远近
        if (Input.GetAxis("Mouse ScrollWheel") != 0 && !onUI)
        {
            if (detailLod)
            {
                scrollSensitivity = math.clamp(currentDistance, 0, 10);
                // 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;
                OnDistanceChange?.Invoke(currentDistance);
            }
            else
            {
                OnDistanceChange?.Invoke(Input.GetAxis("Mouse ScrollWheel"));
            }

            if (Input.GetAxis("Mouse ScrollWheel") > 0)
            {
                //Debug.Log($"{Input.mousePosition} {Screen.width*0.5f}:{Screen.height*0.5f}");
                float offSetX =  Screen.width * 0.5f-Input.mousePosition.x;
                float offSetY =   Screen.height * 0.5f-Input.mousePosition.y;
                Vector3 moveDirection = Vector3.down * offSetY*translateSpeed + Vector3.left * offSetX*translateSpeed;
                // 平滑移动摄像头到目标位置
                float cameraDistanceRange = Mathf.Clamp(currentDistance * 1.0f / maxDistance * 1.0f, 0.5f, 0.9f); 
                target.position += moveDirection.normalized*cameraDistanceRange;
                //限制移动范围
                if (fixMoveRange)
                {
                    Vector3 finalPos=target.localPosition;
                    finalPos.x = Mathf.Clamp(finalPos.x, min_X, max_X);
                    finalPos.y = Mathf.Clamp(finalPos.y, min_Y, max_Y);
                    target.localPosition = finalPos;
                }
                Vector3 targetPosition = target.position + Quaternion.Euler(new Vector3(rotateXAngle, 0, 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);
            }
        }
      
        // 鼠标左键拖拽平移摄像头
        if (Input.GetMouseButtonDown(0) && !onUI)
        {
            beginDrag?.Invoke();
            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 = Vector3.down * mouseOffset.y * translateSpeed + Vector3.left * mouseOffset.x * translateSpeed;
            // 平滑移动摄像头到目标位置
            target.position += moveDirection;
            //限制移动范围
            if (fixMoveRange)
            {
                Vector3 finalPos=target.localPosition;
                finalPos.x = Mathf.Clamp(finalPos.x, min_X, max_X);
                finalPos.y = Mathf.Clamp(finalPos.y, min_Y, max_Y);
                target.localPosition = finalPos;
            }
            
            // 计算目标位置
            Vector3 targetPosition = target.position + Quaternion.Euler(new Vector3(rotateXAngle, 0, 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);
                //if (Vector3.Distance(transform.position, targetPosition) < 1) {
                //    transform.position = targetPosition;
                //}
            }


        }


        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 SetRange(float _minX,float _maxX,float _minY,float _maxY)
    {
        min_X = _minX;
        max_X = _maxX;
        min_Y = _minY;
        max_Y = _maxY;
        
        //限制移动范围
        if (fixMoveRange)
        {
            Vector3 finalPos=target.localPosition;
            finalPos.x = Mathf.Clamp(finalPos.x, min_X, max_X);
            finalPos.y = Mathf.Clamp(finalPos.y, min_Y, max_Y);
            target.localPosition = finalPos;
        }
    }


    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()
    {

    }
}