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

module.exports = async (req, res) => {
  const bodydata = JSON.parse(req.body);
  console.log('Requested Join - UID - ', bodydata.uid, '\n\tRoom - ', bodydata.partyName);
  // GET ROOM EXISTS, ROOM SOURCE, & ROOM PIN
  const [exists, roomSource, roomPin, adminUid] = await admin
    .firestore()
    .collection('rooms')
    .doc(bodydata.partyName)
    .get()
    .then((roomSnap) => [
      roomSnap.exists,
      roomSnap.exists ? roomSnap.data().player.source : '',
      roomSnap.exists ? roomSnap.data().pin : '',
      roomSnap.exists ? roomSnap.data().adminUid : '',
    ])
    .catch((err) => {
      console.error(
        `Failed to get room when joining room : \n\t Room: ${bodydata.partyName} \n\t User: ${bodydata.uid}`,
        err
      );
    });
  if (exists && roomPin !== bodydata.partyPin)
    return res.status(401).send({ message: 'Incorrect party pin' });
  if (adminUid === bodydata.uid) {
    await admin
      .firestore()
      .collection('rooms')
      .doc(bodydata.partyName)
      .collection('users')
      .doc(bodydata.uid)
      .set({
        admin: true,
        name: bodydata.userName,
      });
  }
  // GET IF USER EXISTS AND IS ADMIN
  const [userExists, userAdmin, userName] = await admin
    .firestore()
    .collection('rooms')
    .doc(bodydata.partyName)
    .collection('users')
    .doc(bodydata.uid)
    .get()
    .then((userSnap) => [
      userSnap.exists,
      userSnap.exists ? userSnap.data().admin : false,
      userSnap.exists ? userSnap.data().name : '',
    ])
    .catch((err) => {
      console.error(
        `Failed to get user when joining room : \n\t Room: ${bodydata.partyName} \n\t User: ${bodydata.uid}`,
        err
      );
    });
  // IF USER PRE-EXISTS AND SAME SOURCE - JOIN
  if (userExists && exists && roomSource === bodydata.source) {
    // UPDATE NAME IF NEEDED
    if (userName !== bodydata.userName) {
      await admin
        .firestore()
        .collection('rooms')
        .doc(bodydata.partyName)
        .collection('users')
        .doc(bodydata.uid)
        .update({ name: bodydata.userName });
    }
    res.status(200).send({ partyName: bodydata.partyName, message: 'Joined a party' });
  }
  // USER DOES NOT PRE-EXIST BUT SAME SOURCE AND RIGHT PIN
  else if (
    !userExists &&
    exists &&
    bodydata.partyName &&
    bodydata.userName &&
    roomSource === bodydata.source &&
    roomPin === bodydata.partyPin
  ) {
    await admin
      .firestore()
      .collection('rooms')
      .doc(bodydata.partyName)
      .collection('messages')
      .add({
        uid: '<system>',
        name: '',
        text: `${bodydata.userName} joined the party.`,
        time: new Date(),
      })
      .catch((err) => {
        console.error(
          `Failed to add system join party message : \n\t Room: ${partyName} \n\t ${bodydata.uid}`,
          err
        );
      });
    await admin
      .firestore()
      .collection('rooms')
      .doc(bodydata.partyName)
      .collection('users')
      .doc(bodydata.uid)
      .set({
        admin: false,
        name: bodydata.userName,
      })
      .catch((err) => {
        console.error(
          `Failed to set admin when joining party : \n\t Room: ${partyName} \n\t User: ${bodydata.uid}`,
          err
        );
      });
    res.status(200).send({ partyName: bodydata.partyName, message: 'Joined a party' });
  }
  // ONLY WRONG SOURCE
  else if (exists && roomSource !== bodydata.source) {
    // MOVE SOURCE IF ADMIN
    if (userAdmin === true) {
      await admin
        .firestore()
        .collection('rooms')
        .doc(bodydata.partyName)
        .update({
          player: {
            showName: null,
            source: bodydata.source,
            status: 'NOT_PLAYING',
            time: 0,
            updatedBy: bodydata.uid,
          },
        })
        .catch(() => {
          console.error(
            `Failed to update player source when admin joining party \n\t Room: ${partyName} \n\t User: ${bodydata.uid}`
          );
          res.status(500).send({ message: 'Unable to move party, please try again' });
        });
      res.status(200).send({ message: `Moved party to ${roomSource}` });
    } else res.status(417).send({ message: `This party is on ${roomSource}` });
  } else res.status(404).send({ message: 'Party Not Found' });
};