text: const errors = require('@tryghost/errors');
  const tpl = require('@tryghost/tpl');
  const {Buffer} = require('buffer');
  const {randomBytes} = require('crypto');
  const {URL} = require('url');
  
  const config = require('../../../shared/config');
  const urlUtils = require('../../../shared/url-utils');
  
  const messages = {
      incorrectState: 'State did not match.'
  };
  
  const STATE_PROP = 'stripe-connect-state';
  
  const liveClientID = 'ca_8LBuZWhYshxF0A55KgCXu8PRTquCKC5x';
  const testClientID = 'ca_8LBum4Ctv3mmJ1oD0ZRmxjdAhNrrBUy3';
  const redirectURI = 'https://stripe.ghost.org';
  
  /**
   * @function getStripeConnectOAuthUrl
   * @desc Returns a url for the auth endpoint for Stripe Connect, generates state and stores it on the session.
   *
   * @param {(prop: string, val: any) => Promise<void>} setSessionProp - A function to set data on the current session
   * @param {'live' | 'test'} mode - Which stripe mode to set up
   *
   * @returns {Promise<URL>}
   */
  async function getStripeConnectOAuthUrl(setSessionProp, mode = 'live') {
      checkCanConnect();
      const randomState = randomBytes(16).toString('hex');
      const state = Buffer.from(JSON.stringify({
          mode,
          randomState
      })).toString('base64');
  
      await setSessionProp(STATE_PROP, state);
  
      const clientID = mode === 'live' ? liveClientID : testClientID;
  
      const authUrl = new URL('https://connect.stripe.com/oauth/authorize');
      authUrl.searchParams.set('response_type', 'code');
      authUrl.searchParams.set('scope', 'read_write');
      authUrl.searchParams.set('client_id', clientID);
      authUrl.searchParams.set('redirect_uri', redirectURI);
      authUrl.searchParams.set('state', state);
  
      return authUrl;
  }
  
  /**
   * @function getStripeConnectTokenData
   * @desc Returns the api keys and the livemode for a Stripe Connect integration after validating the state.
   *
   * @param {string} encodedData - A string encoding the response from Stripe Connect
   * @param {(prop: string) => Promise<any>} getSessionProp - A function to retrieve data from the current session
   *
   * @returns {Promise<{secret_key: string, public_key: string, livemode: boolean, display_name: string, account_id: string}>}
   */
  async function getStripeConnectTokenData(encodedData, getSessionProp) {
      const data = JSON.parse(Buffer.from(encodedData, 'base64').toString());
  
      const state = await getSessionProp(STATE_PROP);
  
      if (state !== data.s) {
          throw new errors.NoPermissionError(tpl(messages.incorrectState));
      }
  
      return {
          public_key: data.p,
          secret_key: data.a,
          livemode: data.l,
          display_name: data.n,
          account_id: data.i
      };
  }
  
  function checkCanConnect() {
      const siteUrl = urlUtils.getSiteUrl();
      const productionMode = config.get('env') === 'production';
      const siteUrlUsingSSL = /^https/.test(siteUrl);
      const cannotConnectToStripe = productionMode && !siteUrlUsingSSL;
      if (cannotConnectToStripe) {
          throw new errors.BadRequestError('Cannot connect to stripe unless site is using https://');
      }
  }
  
  module.exports = {
      getStripeConnectOAuthUrl,
      getStripeConnectTokenData,
      STATE_PROP
  };
  