manifold/functions/src/transact.ts
2022-04-30 08:52:24 -04:00

89 lines
2.6 KiB
TypeScript

import * as functions from 'firebase-functions'
import * as admin from 'firebase-admin'
import { User } from '../../common/user'
import { Txn } from '../../common/txn'
import { removeUndefinedProps } from '../../common/util/object'
export const transact = functions
.runWith({ minInstances: 1 })
.https.onCall(async (data: Omit<Txn, 'id' | 'createdTime'>, context) => {
const userId = context?.auth?.uid
if (!userId) return { status: 'error', message: 'Not authorized' }
const { amount, fromType, fromId, toId, toType, description } = data
if (fromType !== 'USER')
return {
status: 'error',
message: "From type is only implemented for type 'user'.",
}
if (fromId !== userId)
return {
status: 'error',
message: 'Must be authenticated with userId equal to specified fromId.',
}
if (amount <= 0 || isNaN(amount) || !isFinite(amount))
return { status: 'error', message: 'Invalid amount' }
// Run as transaction to prevent race conditions.
return await firestore.runTransaction(async (transaction) => {
const fromDoc = firestore.doc(`users/${userId}`)
const fromSnap = await transaction.get(fromDoc)
if (!fromSnap.exists) {
return { status: 'error', message: 'User not found' }
}
const fromUser = fromSnap.data() as User
if (fromUser.balance < amount) {
return {
status: 'error',
message: `Insufficient balance: ${fromUser.username} needed ${amount} but only had ${fromUser.balance} `,
}
}
if (toType === 'USER') {
const toDoc = firestore.doc(`users/${toId}`)
const toSnap = await transaction.get(toDoc)
if (!toSnap.exists) {
return { status: 'error', message: 'User not found' }
}
const toUser = toSnap.data() as User
transaction.update(toDoc, {
balance: toUser.balance + amount,
totalDeposits: toUser.totalDeposits + amount,
})
}
const newTxnDoc = firestore.collection(`txns/`).doc()
const txn: Txn = removeUndefinedProps({
id: newTxnDoc.id,
createdTime: Date.now(),
fromId,
fromType,
toId,
toType,
amount,
// TODO: Unhardcode once we have non-donation txns
token: 'M$',
category: 'CHARITY',
description,
})
transaction.create(newTxnDoc, txn)
transaction.update(fromDoc, {
balance: fromUser.balance - amount,
totalDeposits: fromUser.totalDeposits - amount,
})
return { status: 'success', txn }
})
})
const firestore = admin.firestore()