server.js

'use strict'

const fs = require('fs')
const express = require('express')
const http = require('http')
const socketio = require('socket.io')

const PROD = process.env.NODE_ENV === 'production'
const ASSETS_BASE = PROD? '/' : 'http://localhost:3000/'
const TICK_DELAY = 400

const app = express()
const server = http.Server(app)
const io = socketio(server)

const freqs = JSON.parse(fs.readFileSync('frequencies.json', 'utf8'))
const users = require('./server/users')()

const getBetsPerLine = (users, content) => {
  const bets = users.getAllBets()
  return content.split('').reduce((o, letter, i) => {
    if (o[letter]) return o
    if (bets[letter]) {
      o[letter] = bets[letter]
    }
    return o
  }, {})
}

const createPoemLines = () => {
  const poem = fs.readFileSync('poem.txt', 'utf8')
                 .split('\n').filter(line => line.trim())
  let index = 0
  return () => {
    index = index >= poem.length - 1? 0 : index + 1
    return {
      content: poem[index],
      index: index,
      bets: getBetsPerLine(users, poem[index]),
    }
  }
}
const poemLine = createPoemLines()

let history = []
let i = 0
const tick = () => {
  setTimeout(tick, TICK_DELAY)
  const line = poemLine()
  history = [...history.slice(-39), line]
  io.emit('text-line', line)
  io.emit('users', users.updateAmounts(line, freqs).getAllUsers())

  users.users.forEach(user => {
    user.socket.emit('bet-history', user.betHistory)
    if (user.amount === 0) {
      user.gameEnded = true
      user.socket.emit('end-game')
    }
  })

  io.emit('history', users.updateAmounts(line, freqs).getAllUsers())
}
tick()

io.on('connection', socket => {
  console.log('Hi ' + socket.id)

  // Emit the user id
  socket.emit('user-id', socket.id)

  // Broadcast the updated list of users
  io.emit('users', users.add(socket).getAllUsers())

  // Emit the history
  socket.emit('text-history', history)

  socket.on('start-bet', letter => {
    console.log(`${socket.id} started a bet on ${letter}`)
    io.emit('users', users.addBet(socket.id, letter).getAllUsers())
  })

  socket.on('end-bet', letter => {
    console.log(`${socket.id} ended a bet on ${letter}`)
    io.emit('users', users.rmBet(socket.id, letter).getAllUsers())

    const user = users.get(socket.id)
    if (user) {
      socket.emit('bet-history', user.betHistory)
    }
  })

  socket.on('disconnect', () => {
    console.log('Bye ' + socket.id)
    io.emit('users', users.rm(socket.id).getAllUsers())
  })
})

const homepage = fs.readFileSync(__dirname + '/public/index.html', 'utf8')
                   .replace(/\{BASE\}/g, ASSETS_BASE)

app.get('/', (req, res) => {
  res.send(homepage)
})

app.use(express.static(__dirname + '/public'))

const port = 8080
server.listen(port)
console.log('Express server started on port %s', port)