firebase-example.js

const _ = require("lodash")
const firebase = require('firebase-admin')
//firebase config
const config = require('./config')
//firebase credentials
const serviceAccount = 'credentials.json'
firebase.initializeApp({
  credential: firebase.credential.cert(serviceAccount),
  databaseURL: config.firebase.databaseURL
})

let db = firebase.database()
let users = db.ref('users')
let payments = db.ref('payments')
let transactions = payments.child('transactions')
let minimum = 85
let vig = .1

//Testing
users.set(null)
payments.set({ pool: { balance: 0 }, transactions: [] })

users.on('child_changed', checkForAutoPayment)
transactions.on('child_added', processPendingTransactions)

_.times(50, function() {
    users.push(mockuser())
})

function checkForAutoPayment(snap) {
  let user = snap.val()
  if (user.balance >= minimum) {
    let fee = user.balance * vig
    let payout = user.balance - fee
    transactions
      .push({
        created: firebase.database.ServerValue.TIMESTAMP,
        to: snap.key,
        amount: user.balance,
        fee: fee,
        payout: payout
        processed: false
      })
    snap.ref.update({ balance: 0 })
  }
}

function processPendingTransactions (snap) {
    /*
     * Here is where the business logic would go
     */
    snap.ref.update({
        completed: firebase.database.ServerValue.TIMESTAMP,
        processed: true,
    })
    payments.child('pool').once('value').then(function(poolSnap) {
      let pool = poolSnap.val()
      poolSnap.ref.update({balance: pool.balance + fee})
    }).catch(function(e) { console.error(e)} )
}

//firebase.app().delete()

function mockuser () {
    return {
        name: Math.random().toString(36).substring(7),
        balance: Math.random() * 100
    }
}