const functions = require('firebase-functions');
const admin = require('firebase-admin');
const secret = require('./FirebaseSecret.json');
const express = require('express');
const cors = require('cors');

const authenticator = (req,res,next) => {
  if (req.method === 'OPTIONS') {
    res.status(200).send();
    return next();
  }
  
  const token = req.headers.authorization.split(' ')[1];
  const reqToken = token.split(':')[0];
  const reqUid = token.split(':')[1];
  admin.auth().verifyIdToken(reqToken).then( user => {
    if (user.uid === reqUid) {
      console.log('Verified Token - UID - ', reqUid);
      if (req.method === 'POST') {
        const bodydata = JSON.parse(req.body);
        bodydata.uid = user.uid;
        req.body = JSON.stringify(bodydata);
      }
      if (req.method === 'GET') {
        req.body = JSON.stringify({uid: user.uid});
      }
      return next();
    } else {
      return res.status(401).send('Unauthorized');
    }
  }).catch(err => {
    console.log('Failed Auth - ', req.headers.authorization, '\n', err);
    return res.status(500).send(err);
  });
  return null;
};

const createRoom = async (req,res) => {
  const bodydata = JSON.parse(req.body);
  console.log('Requested Create - UID - ', bodydata.uid);
  if (!bodydata.userName) res.status(400).send('Missing user name');
  const roomId = await admin.firestore().collection('rooms').add({
    name: bodydata.roomName,
    createdAt: new Date().toISOString(),
    updatedAt: new Date().toISOString(),
  }).then(ref => ref.id)
  .catch(err => {
    console.error(err);
  });
  await admin.firestore().collection('rooms').doc(roomId).collection('messages').add({
    uid: '<system>',
    name: '',
    text: `${bodydata.userName} started the party.`,
    time: new Date().toISOString(),
  });
  await admin.firestore().collection('rooms').doc(roomId).collection('users').doc(bodydata.uid).set({
    admin: true,
    name: bodydata.userName,
  });
  res.status(201).send({ roomId });
}

const joinRoom = async (req, res) => {
  const bodydata = JSON.parse(req.body);
  console.log('Requested Create - UID - ', bodydata.uid, '\n\tRoom - ', bodydata.roomId);
  const exists = await admin.firestore().collection('rooms').doc(bodydata.roomId).get().then(roomSnap => roomSnap.exists);
  const userExists = await admin.firestore().collection('rooms').doc(bodydata.roomId).collection('users').doc(bodydata.uid).get().then(userSnap => userSnap.exists);
  if (userExists) return res.status(200).send({roomId: bodydata.roomId});
  if (exists && bodydata.roomId && bodydata.userName) {
    await admin.firestore().collection('rooms').doc(bodydata.roomId).collection('messages').add({
      uid: '<system>',
      name: '',
      text: `${bodydata.userName} joined the party.`,
      time: new Date().toISOString(),
    });
    await admin.firestore().collection('rooms').doc(bodydata.roomId).collection('users').doc(bodydata.uid).set({
      admin: false,
      name: bodydata.userName,
    });
    res.status(200).send({roomId: bodydata.roomId});
  }
  if (!bodydata.userName) res.status(400).send('Missing user name');
  else res.status(404).send('Party Not Found');
}

const app = express();
app.use(cors({origin: true}));
app.use(authenticator);

admin.initializeApp({
  credential: admin.credential.cert(secret),
  databaseURL: "https://watch-party-crx.firebaseio.com"
});

app.post('/create', createRoom);
app.post('/join', joinRoom);

exports.widgets = functions.https.onRequest(app);