import * as admin from 'firebase-admin'
const {
  FIREBASE_INFO,
  FIREBASE_DATABASE_URL
} = process.env

let serviceAccount = JSON.parse(FIREBASE_INFO)

admin.initializeApp({
  credential: admin.credential.cert(serviceAccount),
  databaseURL: FIREBASE_DATABASE_URL
})

// when decoded successfully, the ID Token content will be added as `req.user`.
export function validateFirebaseIdToken(req, res, next) {
  // Unauthenticated routes go here
  if (['/health', '/users/emails'].includes(req.path)) return next();

  if ((!req.headers.authorization || !req.headers.authorization.startsWith('Bearer ')) &&
    !(req.cookies && req.cookies.__session)) {
    res.status(403).send('Unauthorized');
    return;
  }

  let idToken;
  if (req.headers.authorization && req.headers.authorization.startsWith('Bearer ')) {
    // Read the ID Token from the Authorization header.
    idToken = req.headers.authorization.split('Bearer ')[1];
  } else if(req.cookies) {
    // Read the ID Token from cookie.
    idToken = req.cookies.__session;
  } else {
    // No cookie
    res.status(403).send('Unauthorized');
    return;
  }
  admin.auth().verifyIdToken(idToken).then((decodedIdToken) => {
    req.user = decodedIdToken;
    return next();
  }).catch((error) => {
    res.status(403).send('Unauthorized');
  });