/**
 * Axios API 配置
 * 统一管理 HTTP 请求
 *
 * 功能特性：
 * - 自动添加 Token
 * - Token 自动刷新
 * - 请求重试机制
 * - 请求取消功能
 * - 统一错误处理
 * - 请求/响应日志
 * - Loading 状态管理
 */

import axios, {
  AxiosError,
  AxiosRequestConfig,
  AxiosResponse,
  InternalAxiosRequestConfig,
  CancelTokenSource,
  AxiosRequestHeaders,
} from 'axios';
import AsyncStorage from '@react-native-async-storage/async-storage';
import { router } from 'expo-router';
import { config } from '../config';
import { transformRequest, parseResponse } from './helper';
import { cloneDeep, pick, includes } from 'lodash-es';
import md5 from 'md5';

/**
 * API 响应数据结构
 */
export interface ApiResponse<T = any> {
  code: number;
  message: string;
  data: T;
  success?: boolean;
}

/**
 * API 错误响应
 */
export interface ApiError {
  code: number;
  message: string;
  errors?: Record<string, string[]>;
}

/**
 * 请求配置扩展
 */
export interface RequestConfig extends AxiosRequestConfig {
  /** 是否显示 loading */
  showLoading?: boolean;
  /** 是否显示错误提示 */
  showError?: boolean;
  /** 是否重试 */
  retry?: boolean;
  /** 重试次数 */
  retryCount?: number;
  /** 是否需要 token */
  requiresAuth?: boolean;
  /** 自定义错误处理 */
  customErrorHandler?: (error: AxiosError<ApiError>) => void;
}

// API 基础配置
const API_CONFIG = {
  baseURL: config.api.baseURL,
  timeout: config.api.timeout,
  headers: {
    'Content-Type': 'application/x-www-form-urlencoded; charset=UTF-8',
    Accept: 'application/json, application/xml, text/play, text/html, *.*',
  },
};

// 创建 axios 实例
const api = axios.create(API_CONFIG);

// 请求队列（用于取消请求）
const pendingRequests = new Map<string, CancelTokenSource>();

// 是否正在刷新 token
let isRefreshing = false;

// 刷新 token 时的请求队列
let refreshSubscribers: Array<(token: string) => void> = [];

/**
 * 生成请求唯一标识
 */
function generateRequestKey(config: InternalAxiosRequestConfig): string {
  const cmdId = config.headers.cmdId || config.url;
  const data = cloneDeep(config.method === 'post' ? config.data : config.params);
  return `${cmdId}&${data ? md5(JSON.stringify(data)) : ''}`;
}

/**
 * 添加请求到队列
 */
function addPendingRequest(config: InternalAxiosRequestConfig): void {
  const requestKey = generateRequestKey(config);

  // 如果已存在相同请求，取消之前的请求
  if (pendingRequests.has(requestKey)) {
    const source = pendingRequests.get(requestKey);
    source?.cancel('重复请求已取消');
  }

  // 创建新的取消令牌
  const source = axios.CancelToken.source();
  config.cancelToken = source.token;
  pendingRequests.set(requestKey, source);
}

/**
 * 从队列中移除请求
 */
function removePendingRequest(config: InternalAxiosRequestConfig | AxiosRequestConfig): void {
  const requestKey = generateRequestKey(config as InternalAxiosRequestConfig);
  pendingRequests.delete(requestKey);
}

/**
 * 订阅 token 刷新
 */
function subscribeTokenRefresh(callback: (token: string) => void): void {
  refreshSubscribers.push(callback);
}

/**
 * 通知所有订阅者 token 已刷新
 */
function onTokenRefreshed(token: string): void {
  refreshSubscribers.forEach((callback) => callback(token));
  refreshSubscribers = [];
}

/**
 * 刷新 token
 */
async function refreshAccessToken(): Promise<string | null> {
  try {
    const refreshToken = await AsyncStorage.getItem('refresh_token');

    if (!refreshToken) {
      throw new Error('No refresh token');
    }

    // 调用刷新 token 接口
    const response = await axios.post<ApiResponse<{ token: string; refreshToken: string }>>(
      `${config.api.baseURL}/auth/refresh-token`,
      { refreshToken }
    );

    const { token, refreshToken: newRefreshToken } = response.data.data;

    // 保存新的 token
    await AsyncStorage.setItem('auth_token', token);
    await AsyncStorage.setItem('refresh_token', newRefreshToken);

    return token;
  } catch (error) {
    // 刷新失败，清除所有 token
    await AsyncStorage.multiRemove(['auth_token', 'refresh_token']);
    return null;
  }
}

/**
 * 请求拦截器
 * 在请求发送前添加 token 等信息
 */
api.interceptors.request.use(
  async (config: InternalAxiosRequestConfig) => {
    try {
      // 添加到请求队列（防止重复请求）
      addPendingRequest(config);

      const { apiName } = config.headers;

      const { headers, data } = transformRequest(pick(config, ['headers', 'data']));

      config.headers = {
        ...headers,
        ...(__DEV__ ? { apiName } : {}),
      } as AxiosRequestHeaders;

      config.data = data;

      if (Number(config.headers.cmdId) !== 381120) {
        config.url = '/v2/';
      }

      // if (__DEV__ && apiName) {
      //   config.url = `${config.url}?${apiName}`;
      // }

      // // 从本地存储获取 token
      // const token = await AsyncStorage.getItem('auth_token');
      //
      // // 添加 token 到请求头
      // if (token && config.headers) {
      //   config.headers.Authorization = `Bearer ${token}`;
      // }

      // 添加请求时间戳（用于计算请求耗时）
      (config as any).metadata = { startTime: Date.now() };

      // 打印请求信息（开发环境）
      if (__DEV__) {
        console.log('📤 API Request:', {
          method: config.method?.toUpperCase(),
          url: config.url,
          baseURL: config.baseURL,
          fullURL: `${config.baseURL}${config.url}`,
          params: config.params,
          headers: config.headers,
        });
      }

      return config;
    } catch (error) {
      console.error('❌ Request interceptor error:', error);
      return Promise.reject(error);
    }
  },
  (error) => {
    console.error('❌ Request error:', error);
    return Promise.reject(error);
  }
);

/**
 * 响应拦截器
 * 统一处理响应和错误
 */
api.interceptors.response.use(
  async (response: AxiosResponse) => {
    // 从请求队列中移除
    removePendingRequest(response.config);

    // 计算请求耗时
    const duration = Date.now() - (response.config as any).metadata?.startTime;

    const resData: any = await parseResponse(response);

    // 打印响应信息（开发环境）
    // if (__DEV__) {
    //   console.log('📥 API Response:', {
    //     url: response.config.url,
    //     status: response.status,
    //     duration: `${duration}ms`,
    //     data: response.data,
    //   });
    // }

    // 统一处理响应数据格式
    // const apiResponse = response.data as ApiResponse;

    // 如果后端返回的数据结构包含 code 和 data
    // if (apiResponse && typeof apiResponse === 'object' && 'code' in apiResponse) {
    //   // 检查业务状态码
    //   if (apiResponse.code !== 0 && apiResponse.code !== 200) {
    //     // 业务错误
    //     const error = new Error(apiResponse.message || '请求失败') as any;
    //     error.code = apiResponse.code;
    //     error.response = response;
    //     return Promise.reject(error);
    //   }
    //
    //   // 返回 data 字段
    //   return apiResponse.data;
    // }

    // 直接返回响应数据
    // return response.data;
    return Promise.resolve(resData);
  },
  async (error: AxiosError<ApiError>) => {
    // 从请求队列中移除
    if (error.config) {
      removePendingRequest(error.config);
    }

    // 如果是取消的请求，直接返回
    if (axios.isCancel(error)) {
      if (__DEV__) {
        console.log('🚫 Request cancelled:', error.message);
      }
      return Promise.reject(error);
    }

    const originalRequest = error.config as RequestConfig & { _retry?: boolean };

    // 打印错误信息
    if (__DEV__) {
      console.error('❌ API Error:', {
        method: error.config?.method,
        cmdId: error.config?.headers?.cmdId,
        status: error.response?.status,
        message: error.message,
        data: error.response?.data,
      });
    }

    if (includes([500, 502, 503], error.response?.status) && includes(['371130'], `${error.config?.headers?.cmdId}`)) {
      router.replace('/maintenance' as any);
    }

    // 处理不同的错误状态码
    if (error.response) {
      const { status, data } = error.response;

      switch (status) {
        case 401: {
          // Token 过期，尝试刷新
          if (!originalRequest._retry) {
            if (isRefreshing) {
              // 如果正在刷新，将请求加入队列
              return new Promise((resolve) => {
                subscribeTokenRefresh((token: string) => {
                  if (originalRequest.headers) {
                    originalRequest.headers.Authorization = `Bearer ${token}`;
                  }
                  resolve(api(originalRequest));
                });
              });
            }

            originalRequest._retry = true;
            isRefreshing = true;

            try {
              const newToken = await refreshAccessToken();

              if (newToken) {
                // Token 刷新成功
                isRefreshing = false;
                onTokenRefreshed(newToken);

                // 重试原请求
                if (originalRequest.headers) {
                  originalRequest.headers.Authorization = `Bearer ${newToken}`;
                }
                return api(originalRequest);
              } else {
                // Token 刷新失败，跳转到登录页
                isRefreshing = false;
                await AsyncStorage.multiRemove(['auth_token', 'refresh_token']);

                // 跳转到登录页
                if (router.canGoBack()) {
                  router.replace('/(auth)/login' as any);
                }
              }
            } catch (refreshError) {
              isRefreshing = false;
              await AsyncStorage.multiRemove(['auth_token', 'refresh_token']);

              // 跳转到登录页
              if (router.canGoBack()) {
                router.replace('/(auth)/login' as any);
              }

              return Promise.reject(refreshError);
            }
          }
          break;
        }

        case 403:
          // 禁止访问
          console.error('❌ 403: 没有权限访问该资源');
          break;

        case 404:
          // 资源不存在
          console.error('❌ 404: 请求的资源不存在');
          break;

        case 422:
          // 表单验证错误
          console.error('❌ 422: 表单验证失败', data);
          break;

        case 429:
          // 请求过于频繁
          console.error('❌ 429: 请求过于频繁，请稍后再试');
          break;

        case 500:
          // 服务器错误
          console.error('❌ 500: 服务器内部错误');
          break;

        case 502:
          // 网关错误
          console.error('❌ 502: 网关错误');
          break;

        case 503:
          // 服务不可用
          console.error('❌ 503: 服务暂时不可用');
          break;

        default:
          console.error(`❌ ${status}: 未知错误`);
      }
    } else if (error.request) {
      // 请求已发送但没有收到响应
      console.error('❌ 网络错误: 请检查网络连接');
    } else {
      // 请求配置出错
      console.error('❌ 请求配置错误:', error.message);
    }

    // 自定义错误处理
    if (originalRequest?.customErrorHandler) {
      originalRequest.customErrorHandler(error);
    }

    return Promise.reject(error);
  }
);

/**
 * 取消所有待处理的请求
 */
export function cancelAllRequests(message = '请求已取消'): void {
  pendingRequests.forEach((source) => {
    source.cancel(message);
  });
  pendingRequests.clear();
}

/**
 * 取消指定 URL 的请求
 */
export function cancelRequest(url: string): void {
  pendingRequests.forEach((source, key) => {
    if (key.includes(url)) {
      source.cancel('请求已取消');
      pendingRequests.delete(key);
    }
  });
}

/**
 * 通用请求方法（增强版）
 */
export const request = {
  /**
   * GET 请求
   */
  get: <T = any>(url: string, config?: RequestConfig) => api.get<T, T>(url, config),

  /**
   * POST 请求
   */
  post: <T = any>(url: string, data?: any, config?: RequestConfig) =>
    api.post<T, T>(url, data, config),

  /**
   * PUT 请求
   */
  put: <T = any>(url: string, data?: any, config?: RequestConfig) =>
    api.put<T, T>(url, data, config),

  /**
   * DELETE 请求
   */
  delete: <T = any>(url: string, config?: RequestConfig) => api.delete<T, T>(url, config),

  /**
   * PATCH 请求
   */
  patch: <T = any>(url: string, data?: any, config?: RequestConfig) =>
    api.patch<T, T>(url, data, config),

  /**
   * 上传文件
   */
  upload: <T = any>(
    url: string,
    file: File | Blob,
    onProgress?: (progress: number) => void,
    config?: RequestConfig
  ) => {
    const formData = new FormData();
    formData.append('file', file);

    return api.post<T, T>(url, formData, {
      ...config,
      headers: {
        'Content-Type': 'multipart/form-data',
        ...config?.headers,
      },
      onUploadProgress: (progressEvent) => {
        if (onProgress && progressEvent.total) {
          const progress = Math.round((progressEvent.loaded * 100) / progressEvent.total);
          onProgress(progress);
        }
      },
    });
  },

  /**
   * 下载文件
   */
  download: async (
    url: string,
    filename?: string,
    onProgress?: (progress: number) => void,
    config?: RequestConfig
  ) => {
    const response: any = await api.get(url, {
      ...config,
      responseType: 'blob',
      onDownloadProgress: (progressEvent) => {
        if (onProgress && progressEvent.total) {
          const progress = Math.round((progressEvent.loaded * 100) / progressEvent.total);
          onProgress(progress);
        }
      },
    });

    // 创建下载链接
    const blob = new Blob([response]);
    const downloadUrl = window.URL.createObjectURL(blob);
    const link = document.createElement('a');
    link.href = downloadUrl;
    link.download = filename || 'download';
    document.body.appendChild(link);
    link.click();
    document.body.removeChild(link);
    window.URL.revokeObjectURL(downloadUrl);

    return response;
  },

  /**
   * 并发请求
   */
  all: <T = any>(requests: Promise<T>[]) => Promise.all(requests),

  /**
   * 串行请求
   */
  series: async <T = any>(requests: (() => Promise<T>)[]): Promise<T[]> => {
    const results: T[] = [];
    for (const request of requests) {
      const result = await request();
      results.push(result);
    }
    return results;
  },
};

/**
 * 创建带重试的请求
 */
export function createRetryRequest<T = any>(
  requestFn: () => Promise<T>,
  maxRetries = 3,
  retryDelay = 1000
): Promise<T> {
  return new Promise((resolve, reject) => {
    let retries = 0;

    const attempt = async () => {
      try {
        const result = await requestFn();
        resolve(result);
      } catch (error) {
        retries++;

        if (retries < maxRetries) {
          if (__DEV__) {
            console.log(`🔄 Retrying request (${retries}/${maxRetries})...`);
          }
          setTimeout(attempt, retryDelay * retries);
        } else {
          reject(error);
        }
      }
    };

    attempt();
  });
}

export default api;