quiz/public/monitor.js

"use strict"

/* global document, window */
const location = document.location
const performance = window.performance

import {
  clear,
  ms_ns,
  node,
  q,
  s_ns,
  servertime_now_ns,
  session_id,
  session_url,
} from "./shared.js"

let socket,
  servertime,
  toffset_ms,
  clients = {},
  me

function setup_url() {
  const sid = session_id() || ""
  location.hash = sid
}

function send(type, value) {
  // console.debug('sending', value)
  socket.send(JSON.stringify({ type, value }))
}

function prettynum(n) {
  let i = Math.abs(n) | 0
  let s = []
  while (true) {
    const m = i % 1000
    i = (i / 1000) | 0
    if (i === 0) {
      s.unshift(String(m))
      break
    } else {
      s.unshift(String(m).padStart(3, "0"))
    }
  }
  return (n < 0 ? "-" : "") + s.join("'")
}

function assert(expected, got) {
  if (expected !== got) {
    throw Error("Assertion failed.")
  }
}

function test_prettynum() {
  assert("0", prettynum(0))
  assert("1", prettynum(1))
  assert("1'000", prettynum(1000))
  assert("36'000", prettynum(36000))
  assert("0", prettynum(-0))
  assert("-1", prettynum(-1))
  assert("-1'000", prettynum(-1000))
  assert("-36'000", prettynum(-36000))
  assert("-36'600", prettynum(-36600))
}
test_prettynum()

const player_list = q("#info")
function redraw_clients(me, clients) {
  if (!me) {
    return
  }
  clear(player_list)
  for (const c of Object.values(clients)) {
    if (c.id === me.id) {
      continue
    }
    const player = node("div", { data: { cid: c.id }, cls: "player" })
    node("div", { cls: "points", text: prettynum(c.points), appendTo: player })
    node("div", { cls: "box", appendTo: player })
    node("div", { cls: "name", text: c.name, appendTo: player })
    player_list.appendChild(player)
  }
}

let highlighted = false
function highlight(client_id, until_ns) {
  if (highlighted) {
    return
  }
  const timeout_ms = (until_ns - servertime_now_ns()) / ms_ns
  if (timeout_ms <= 10) {
    console.warn("That highlight timeout was ridiculously low:", client_id, timeout_ms)
    return
  }
  for (const li of player_list.children) {
    if (li.dataset.cid === client_id) {
      li.classList.add("buzzing")
      highlighted = true
      setTimeout(() => {
        highlighted = false
        li.classList.remove("buzzing")
      }, timeout_ms)
      return
    }
  }
}

function setup_ws() {
  const sid = session_id()
  socket = new WebSocket(session_url(sid))
  socket.addEventListener("open", function (event) {
    send("name", "Monitor")
  })
  socket.addEventListener("message", function (event) {
    const msg = JSON.parse(event.data)
    const { type, value } = msg
    if (msg.type === "time") {
      servertime = value.time
      toffset_ms = performance.now()
    } else if (msg.type === "id") {
      me = value
      redraw_clients(me, clients)
    } else if (msg.type === "buzz") {
      const buzztime_ns = value.time
      const client_id = value.client
      const duration_ns = 12 * s_ns
      const until_ns = buzztime_ns + duration_ns
      highlight(client_id, until_ns)
    } else if (msg.type === "clients") {
      clients = Object.fromEntries(value.clients.map((c) => [c.id, c]))
      redraw_clients(me, clients)
    } else if (msg.type === "client") {
      const client = value.client
      clients[client.id] = client
      redraw_clients(me, clients)
    } else if (type === "session_key") {
      // ignore
    } else if (type === "error") {
      console.error(`Error: ${value.reason}`)
    } else {
      console.error(`Unknown message: ${event.data}`)
    }
  })
}

setup_url()
setup_ws()