icynet-admin/pages/api/callback.ts

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

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

const redirect = `${PUBLIC_URL}/api/callback`;

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

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

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

    res.redirect('/');
  }
}