let isRefreshing = false;
let refreshSubscribers = [];

const instance = axios.create({
  baseURL: Config.API_URL,
});

instance.interceptors.response.use(response => {
  return response;
}, error => {
  const { config, response: { status } } = error;
  const originalRequest = config;

  if (status === 498) {
    if (!isRefreshing) {
      isRefreshing = true;
      refreshAccessToken()
        .then(newToken => {
          isRefreshing = false;
          onRrefreshed(newToken);
        });
    }

    const retryOrigReq = new Promise((resolve, reject) => {
      subscribeTokenRefresh(token => {
        // replace the expired token and retry
        originalRequest.headers['Authorization'] = 'Bearer ' + token;
        resolve(axios(originalRequest));
      });
    });
    return retryOrigReq;
  } else {
    return Promise.reject(error);
  }
});

subscribeTokenRefresh(cb) {
  refreshSubscribers.push(cb);
}

onRrefreshed(token) {
  refreshSubscribers.map(cb => cb(token));
}