import Axios, {
  type AxiosInstance,
  type AxiosRequestConfig,
  type CustomParamsSerializer
} from "axios";
import type {
  PureHttpError,
  RequestMethods,
  PureHttpResponse,
  PureHttpRequestConfig
} from "./types.d";
import { stringify } from "qs";
import NProgress from "../progress";
import { getToken, formatToken } from "@/utils/auth";
import { useUserStoreHook } from "@/store/modules/user";
// import { string } from "vue-types";
import router from "@/router";
import { ElMessage } from "element-plus";
import { message } from "../message";

/**请求后端的地址 未配置则访问BaseURL */
const apiServiceConfig = {
  userCenter: import.meta.env.VITE_API_USERCENTER_URL,
  usercenter: import.meta.env.VITE_API_USERCENTER_URL
};

function setAPIUrl(c: PureHttpRequestConfig): void {
  let url = c.url;
  let token = url.startsWith("/") ? url.split("/")[1] : url.split("/")[0];
  if (apiServiceConfig[token] != null) {
    c.url = url.replaceAll(token, "");
    c.baseURL = apiServiceConfig[token];
  } else c.baseURL = import.meta.env.VITE_API_BASEURL;
}

const snakeToCamel = (str: string): string => {
  // 处理蛇形命名（user_id → userId）
  let result = str.replace(/_([a-zA-Z0-9])/g, (_, letter) =>
    letter.toUpperCase()
  );

  // 处理大驼峰命名（UserName → userName）
  if (result.length > 0) {
    result = result.charAt(0).toLowerCase() + result.slice(1);
  }

  // 特殊场景：处理连续下划线（__type → Type）
  result = result.replace(/^_+/, "");

  return result;
};

/**
 * 递归转换对象/数组的键名为小驼峰格式
 */
const convertKeysToCamelCase = <T>(data: any): T => {
  if (Array.isArray(data)) {
    return data.map(item => convertKeysToCamelCase(item)) as unknown as T;
  }

  if (data !== null && typeof data === "object") {
    return Object.keys(data).reduce((result, key) => {
      const camelKey = snakeToCamel(key);
      const value = data[key];
      return {
        ...result,
        [camelKey]: convertKeysToCamelCase(value)
      };
    }, {}) as T;
  }

  return data as T;
};

// 相关配置请参考：www.axios-js.com/zh-cn/docs/#axios-request-config-1
const defaultConfig: AxiosRequestConfig = {
  baseURL: import.meta.env.VITE_API_BASEURL,
  // 请求超时时间
  timeout: 30 * 1000,
  headers: {
    Accept: "application/json, text/plain, */*",
    "Content-Type": "application/json",
    "X-Requested-With": "XMLHttpRequest"
  },
  // 数组格式参数序列化（https://github.com/axios/axios/issues/5142）
  paramsSerializer: {
    serialize: stringify as unknown as CustomParamsSerializer
  }
};

class PureHttp {
  constructor() {
    this.httpInterceptorsRequest();
    this.httpInterceptorsResponse();
  }

  /** `token`过期后，暂存待执行的请求 */
  private static requests = [];

  /** 防止重复刷新`token` */
  private static isRefreshing = false;

  /** 初始化配置对象 */
  private static initConfig: PureHttpRequestConfig = {};

  /** 保存当前`Axios`实例对象 */
  private static axiosInstance: AxiosInstance = Axios.create(defaultConfig);

  /** 重连原始请求 */
  private static retryOriginalRequest(config: PureHttpRequestConfig) {
    return new Promise(resolve => {
      PureHttp.requests.push((token: string) => {
        config.headers["Authorization"] = formatToken(token);
        resolve(config);
      });
    });
  }

  /** 请求拦截 */
  private httpInterceptorsRequest(): void {
    PureHttp.axiosInstance.interceptors.request.use(
      async (config: PureHttpRequestConfig): Promise<any> => {
        // 开启进度条动画
        NProgress.start();
        if (config.url.indexOf("http") === -1) {
          setAPIUrl(config);
        }
        // 优先判断post/get等方法是否传入回调，否则执行初始化设置等回调
        if (typeof config.beforeRequestCallback === "function") {
          config.beforeRequestCallback(config);
          return config;
        }
        if (PureHttp.initConfig.beforeRequestCallback) {
          PureHttp.initConfig.beforeRequestCallback(config);
          return config;
        }
        /** 请求白名单，放置一些不需要`token`的接口（通过设置请求白名单，防止`token`过期后再请求造成的死循环问题） */
        const whiteList = ["/refresh-token", "/login"];
        return whiteList.some(url => config.url.endsWith(url))
          ? config
          : new Promise(resolve => {
              const data = getToken();
              if (data) {
                const now = new Date().getTime();
                const expired = parseInt(data.expires) - now <= 0;
                if (expired) {
                  if (!PureHttp.isRefreshing) {
                    PureHttp.isRefreshing = true;
                    // token过期刷新
                    useUserStoreHook()
                      .handRefreshToken({ refreshToken: data.refreshToken })
                      .then(res => {
                        const token = res.data.accessToken;
                        config.headers["Authorization"] = formatToken(token);
                        PureHttp.requests.forEach(cb => cb(token));
                        PureHttp.requests = [];
                      })
                      .finally(() => {
                        PureHttp.isRefreshing = false;
                      });
                  }
                  resolve(PureHttp.retryOriginalRequest(config));
                } else {
                  config.headers["Authorization"] = formatToken(
                    data.accessToken
                  );
                  resolve(config);
                }
              } else {
                resolve(config);
              }
            });
      },
      error => {
        return Promise.reject(error);
      }
    );
  }

  /** 响应拦截 */
  private httpInterceptorsResponse(): void {
    const instance = PureHttp.axiosInstance;
    instance.interceptors.response.use(
      (response: PureHttpResponse) => {
        const $config = response.config;
        // 关闭进度条动画
        NProgress.done();
        if (!(response.data instanceof Blob))
          response.data = convertKeysToCamelCase(response.data);
        // 优先判断post/get等方法是否传入回调，否则执行初始化设置等回调
        if (typeof $config.beforeResponseCallback === "function") {
          $config.beforeResponseCallback(response);
          return response.data;
        }
        if (PureHttp.initConfig.beforeResponseCallback) {
          PureHttp.initConfig.beforeResponseCallback(response);
          return response.data;
        }
        return response.data;
      },
      (error: PureHttpError) => {
        const $error = error;
        $error.isCancelRequest = Axios.isCancel($error);
        // 关闭进度条动画
        NProgress.done();
        if (error.response?.status === 403) {
          // 跳转到403页面
          router.push({
            path: "/error/403"
          });
        }
        // 所有的响应异常 区分来源为取消请求/非取消请求
        return Promise.reject($error);
      }
    );
  }

  /** 通用请求工具函数 */
  public request<T>(
    method: RequestMethods,
    url: string,
    param?: AxiosRequestConfig,
    axiosConfig?: PureHttpRequestConfig
  ): Promise<T> {
    const config = {
      method,
      url,
      ...param,
      ...axiosConfig
    } as PureHttpRequestConfig;

    // 单独处理自定义请求/响应回调
    return new Promise((resolve, reject) => {
      PureHttp.axiosInstance
        .request(config)
        .then((response: any) => {
          if (response.code != null && response.code !== 200) { 
            
              message(response.message, { type: "error" });
          } resolve(response);
        })
        .catch(error => {
          if (error.status != 200) {
              ElMessage.warning("请求失败" + error.message);
          } 
          reject(error);
        });
    });
  }

  /** 单独抽离的`post`工具函数 */
  public post<T, P>(
    url: string,
    params?: AxiosRequestConfig<P>,
    config?: PureHttpRequestConfig
  ): Promise<T> {
    return this.request<T>("post", url, params, config);
  }

  /** 单独抽离的`get`工具函数 */
  public get<T, P>(
    url: string,
    params?: AxiosRequestConfig<P>,
    config?: PureHttpRequestConfig
  ): Promise<T> {
    return this.request<T>("get", url, params, config);
  }
}

export const http = new PureHttp();