icynet-admin/pages/api/callback.ts

import { NextApiRequest, NextApiResponse } from 'next';
import { getAccessToken } from '../../lib/api/remote';

import Cookies from 'cookies';
import { COOKIE_KEYS, REDIRECT_URL } from '../../lib/constants';
import { decrypt } from '../../lib/utils/crypto';

export default async function handler(
  req: NextApiRequest,
  res: NextApiResponse
) {
  if (!req.query.code || !req.query.state) {
    return res.redirect('/');
  }

  const getAuth = await getAccessToken(req.query.code as string);
  const cookies = new Cookies(req, res, { keys: COOKIE_KEYS });

  if (getAuth) {
    const decrypted = decrypt(req.query.state as string);
    const stateToken = cookies.get('validation', { signed: true });
    const parsedState = JSON.parse(decrypted);

    if (
      parsedState.state !== stateToken ||
      parsedState.redirect_uri !== REDIRECT_URL
    ) {
      return res.redirect('/');
    }

    cookies.set('authorization', getAuth.access_token, {
      expires: new Date(Date.now() + getAuth.expires_in * 1000),
      secure: process.env.NODE_ENV === 'production',
      sameSite: 'strict',
      signed: true,
    });

    cookies.set('validation', undefined, {
      expires: new Date(0),
      secure: process.env.NODE_ENV === 'production',
      sameSite: 'strict',
      signed: true,
    });
  }

  res.redirect('/');
}