import axios, { AxiosResponse, AxiosInstance, AxiosRequestConfig } from 'axios';

export interface RetryOptions {
  retriesCount?: number; // values are validated with API_RETRIES_COUNT const below
  requestTimeout?: number; // values are validated with API_REQUEST_TIMEOUT const below
}

export const API_RETRIES_COUNT = {
  minValue: 0,
  defaultValue: 3,
  maxValue: 5
} as const;
const ENV_API_RETRIES_COUNT = process.env.API_RETRIES_COUNT ? parseInt(process.env.API_RETRIES_COUNT, 10) : API_RETRIES_COUNT.defaultValue;

export const API_REQUEST_TIMEOUT = {
  minValue: 500,
  defaultValue: 15000,
  maxValue: 120000
} as const;

/**
 * if values are higher or lower the limit - they'll be overwritten.
 * returns valid values for RetryOptions
 */
export const getRetryOptions = (): RetryOptions => {
  const ENV_API_REQUEST_TIMEOUT = process.env.API_REQUEST_TIMEOUT ? parseInt(process.env.API_REQUEST_TIMEOUT, 10) : API_REQUEST_TIMEOUT.defaultValue;
  return {
    retriesCount: (ENV_API_RETRIES_COUNT > API_RETRIES_COUNT.maxValue || ENV_API_RETRIES_COUNT < API_RETRIES_COUNT.minValue)
      ? API_RETRIES_COUNT.defaultValue
      : ENV_API_RETRIES_COUNT,
    requestTimeout: (ENV_API_REQUEST_TIMEOUT > API_REQUEST_TIMEOUT.maxValue || ENV_API_REQUEST_TIMEOUT < API_REQUEST_TIMEOUT.minValue)
      ? API_REQUEST_TIMEOUT.defaultValue
      : ENV_API_REQUEST_TIMEOUT
  };
};

export const exponentialDelay = (currentRetries: number) => {
  const maxBackoff = 15000;
  const delay = (2 ** currentRetries) * 100;
  const randomSum = delay * 0.2 * Math.random(); // 0-20% of the delay
  return Math.min(delay + randomSum, maxBackoff);
};

export const sleep = async (ms: number) => new Promise((resolve) => {
  setTimeout(resolve, ms);
});

export const exponentialSleep = async (currentRetries: number) => sleep(exponentialDelay(currentRetries));

export const getErrMsg = (errResponse: AxiosResponse) => {
  const statusText = errResponse?.statusText || 'unknown';
  const status = errResponse?.status || 'unknown';
  const data = errResponse?.data || 'no body found';
  return `Got error "${statusText}", status - "${status}", body: ${JSON.stringify(data)}`;
};

export const axiosReqWithRetryOnServerError = async function (options: AxiosRequestConfig, axiosInstance: AxiosInstance = axios) {
  const { retriesCount, requestTimeout } = getRetryOptions();
  let response;
  let currentRetry = 0;
  let error;
  while (currentRetry < retriesCount) {
    try {
      response = await axiosInstance.request({
        ...options,
        timeout: requestTimeout,
        validateStatus: (status) => (status >= 200 && status < 300) || (status === 404 && this.cfg.doNotThrow404)
      });
      return response;
    } catch (err) {
      this.logger.error(getErrMsg(err.response));
      error = err;
      if (err.response?.status < 500) {
        throw error;
      }
      this.logger.info(`URL: "${options.url}", method: ${options.method}, Error message: "${err.message}"`);
      this.logger.info(`Request failed, retrying(${1 + currentRetry})`);
      await exponentialSleep(currentRetry);
      currentRetry++;
    }
  }
  throw error;
};

export const getFacelessRetriesCount = () => {
  const FACELESS_RETRIES_COUNT = {
    minValue: 0,
    defaultValue: 3,
    maxValue: 5,
  };
  const ENV_FACELESS_RETRIES_COUNT = process.env.FACELESS_RETRIES_COUNT ? parseInt(process.env.FACELESS_RETRIES_COUNT, 10) : FACELESS_RETRIES_COUNT.defaultValue;
  return (ENV_FACELESS_RETRIES_COUNT > FACELESS_RETRIES_COUNT.maxValue || ENV_FACELESS_RETRIES_COUNT < FACELESS_RETRIES_COUNT.minValue)
    ? FACELESS_RETRIES_COUNT.defaultValue
    : ENV_FACELESS_RETRIES_COUNT;
};