const admin = require('firebase-admin');

module.exports = async (req, res) => {
  const { conference, partyName, partyPin, userName, uid } = JSON.parse(req.body);
  // GET ROOM PIN
  const [exists, roomPin, conferencePending, partyConference] = await admin
    .firestore()
    .collection('rooms')
    .doc(partyName)
    .get()
    .then((roomSnap) => {
      const data = roomSnap.exists ? roomSnap.data() : {};
      return [roomSnap.exists, data.pin, data.conferencePending, data.conference];
    });
  // CHECK IF ROOM EXISTS
  if (exists === true) {
    if (roomPin) {
      // CHECK FOR CORRECT PIN
      if (roomPin === partyPin) {
        if (conferencePending) {
          if (conferencePending === uid) {
            // UPDATE CONFERENCE DETAILS
            await admin
              .firestore()
              .collection('rooms')
              .doc(partyName)
              .update({ conference })
              .catch((err) =>
                res.status(500).send({
                  message: 'Unable to update the call details',
                  error: err,
                })
              );
            // REMOVE PENDING STATUS
            await admin
              .firestore()
              .collection('rooms')
              .doc(partyName)
              .update({
                conferencePending: admin.firestore.FieldValue.delete(),
              })
              .catch((err) => console.error('Failed to remove pending status', err));
            // ADD SYSTEM MESSAGE
            await admin
              .firestore()
              .collection('rooms')
              .doc(partyName)
              .collection('messages')
              .add({
                uid: '<system>',
                name: '',
                text: `${userName} started the call, everyone can join now.`,
                time: new Date(),
              })
              .catch((err) => console.error('Failed to add update conference message', err));
            res.status(200).send({ message: 'Started the conference' });
          } else {
            res.status(409).send({
              message: 'Looks like someone is already starting a call',
            });
          }
        } else if (partyConference) {
          res.status(409).send({
            message: 'Call already exists',
            conference: partyConference,
          });
        }
      } else {
        // WRONG ROOM PIN
        res.status(401).send({ message: 'Wrong party pin, try rejoining' });
      }
    }
  } else {
    // ROOM DOESN'T EXIST
    res.status(404).send({ message: 'Party Not Found' });
  }
  return;
};