login.js

const express = require('express');
const config = require('../config.js');
const cookie = require('../cookie.js');
const pkce = require('../pkce.js');
const redirectState = require('../redirectState.js');

const router = express.Router();

router.get('/', async (req, res) => {
  console.log("accepting request for login");

  console.log(`client_id is ${req.query.client_id}`);
  const newState = redirectState.pushRedirectUrlToState(req.query.redirect_uri, req.query.state);
  console.log(`newState is ${newState}`);
  const code = await pkce.generatePKCE();
  cookie.setSecure(res, 'codeVerifier', code.code_verifier);
  const token_exchange_uri = `${req.protocol}://${req.get('host')}/app/callback`;
  
  const queryParams = {
      client_id: req.query.client_id,
      scope: req.query.scope ?? 'openid offline_access',
      response_type: 'code',
      redirect_uri: token_exchange_uri,
      code_challenge: code.code_challenge,
      code_challenge_method: 'S256',
      state: newState,
  };
  const fullUrl = generateUrl(queryParams);

  res.redirect(fullUrl);
});

function generateUrl(queryParams) {
    const query = new URLSearchParams(queryParams);
    return `${config.fusionAuthBaseUrl}/oauth2/authorize?${query}`;
}

module.exports = router;