manifold/functions/src/on-update-user.ts

import * as functions from 'firebase-functions'
import * as admin from 'firebase-admin'
import { REFERRAL_AMOUNT, User } from '../../common/user'
import { HOUSE_LIQUIDITY_PROVIDER_ID } from '../../common/antes'
import { createNotification } from './create-notification'
import { ReferralTxn } from '../../common/txn'
import { Contract } from '../../common/contract'
const firestore = admin.firestore()

export const onUpdateUser = functions.firestore
  .document('users/{userId}')
  .onUpdate(async (change, context) => {
    const prevUser = change.before.data() as User
    const user = change.after.data() as User
    const { eventId } = context

    if (prevUser.referredByUserId !== user.referredByUserId) {
      await handleUserUpdatedReferral(user, eventId)
    }
  })

async function handleUserUpdatedReferral(user: User, eventId: string) {
  // Only create a referral txn if the user has a referredByUserId
  if (!user.referredByUserId) {
    console.log(`Not set: referredByUserId ${user.referredByUserId}`)
    return
  }
  const referredByUserId = user.referredByUserId

  await firestore.runTransaction(async (transaction) => {
    // get user that referred this user
    const referredByUserDoc = firestore.doc(`users/${referredByUserId}`)
    const referredByUserSnap = await transaction.get(referredByUserDoc)
    if (!referredByUserSnap.exists) {
      console.log(`User ${referredByUserId} not found`)
      return
    }
    const referredByUser = referredByUserSnap.data() as User

    let referredByContract: Contract | undefined = undefined
    if (user.referredByContractId) {
      const referredByContractDoc = firestore.doc(
        `contracts/${user.referredByContractId}`
      )
      referredByContract = await transaction
        .get(referredByContractDoc)
        .then((snap) => snap.data() as Contract)
    }
    console.log(`referredByContract: ${referredByContract}`)

    const txns = (
      await firestore
        .collection('txns')
        .where('toId', '==', referredByUserId)
        .where('category', '==', 'REFERRAL')
        .get()
    ).docs.map((txn) => txn.ref)
    if (txns.length > 0) {
      const referralTxns = await transaction.getAll(...txns).catch((err) => {
        console.error('error getting txns:', err)
        throw err
      })
      // If the referring user already has a referral txn due to referring this user, halt
      if (
        referralTxns.map((txn) => txn.data()?.description).includes(user.id)
      ) {
        console.log('found referral txn with the same details, aborting')
        return
      }
    }
    console.log('creating referral txns')
    const fromId = HOUSE_LIQUIDITY_PROVIDER_ID

    // if they're updating their referredId, create a txn for both
    const txn: ReferralTxn = {
      id: eventId,
      createdTime: Date.now(),
      fromId,
      fromType: 'BANK',
      toId: referredByUserId,
      toType: 'USER',
      amount: REFERRAL_AMOUNT,
      token: 'M$',
      category: 'REFERRAL',
      description: `Referred new user id: ${user.id} for ${REFERRAL_AMOUNT}`,
    }

    const txnDoc = await firestore.collection(`txns/`).doc(txn.id)
    await transaction.set(txnDoc, txn)
    console.log('created referral with txn id:', txn.id)
    // We're currently not subtracting M$ from the house, not sure if we want to for accounting purposes.
    transaction.update(referredByUserDoc, {
      balance: referredByUser.balance + REFERRAL_AMOUNT,
      totalDeposits: referredByUser.totalDeposits + REFERRAL_AMOUNT,
    })

    await createNotification(
      user.id,
      'user',
      'updated',
      user,
      eventId,
      txn.amount.toString(),
      referredByContract,
      'user',
      referredByUser.id,
      referredByContract?.slug,
      referredByContract?.question
    )
  })
}