Niconico Live Auto Enter

開場したら自動で入場します

このスクリプトの質問や評価の投稿はこちら通報はこちらへお寄せください。
// ==UserScript==
// @name        Niconico Live Auto Enter
// @description 開場したら自動で入場します
// @version     0.2.4
// @include     https://live.nicovideo.jp/watch/*
// @grant       GM_xmlhttpRequest
// @author      xulapp
// @namespace   https://twitter.com/xulapp
// @license     MIT
// ==/UserScript==
/* eslint-env browser, greasemonkey */
'use strict';

function atLeast(promises, num) {
  return new Promise((resolve, reject) => {
    const resolved = [];
    const rejected = [];

    function ok(arg) {
      resolved.push(arg);
      added();
    }

    function ng(err) {
      rejected.push(err);
      added();
    }

    function added() {
      if (resolved.length + rejected.length < promises.length)
        return;

      if (resolved.length < num)
        reject(rejected);

      else
        resolve(resolved);
    }

    for (let p of promises)
      Promise.resolve(p).then(ok, ng);
  });
}

const getJST = (() => {
  const servers = [
    '//ntp-a1.nict.go.jp/cgi-bin/json',
    '//ntp-b1.nict.go.jp/cgi-bin/json',
  ];

  let diff = 0;

  function getJST() {
    return Date.now() + diff;
  }

  function get(options) {
    if (typeof options === 'string')
      options = {url: options};

    return new Promise((onload, onerror) => {
      GM_xmlhttpRequest(Object.assign({}, options, {onload, onerror}));
    });
  }

  function getJSON(...args) {
    return get(...args).then(res => JSON.parse(res.responseText));
  }

  function fetchDiff(server) {
    return getJSON(`${server}?${Date.now() / 1000}`).then(res => {
      const rt = Date.now() / 1000;
      const {it, st} = res;

      return (st - (it + rt) / 2) * 1000;
    });
  }

  function onload(arr) {
    if (arr.length)
      diff = arr.reduce((a, b) => a + b) / arr.length | 0;

    console.log(`時差を取得しました [${diff < 0 ? '' : '+'}${diff}ms]`);

    return diff;
  }

  function onerror(err) {
    console.log('時差の取得に失敗しました');

    for (let res of err)
      if (res instanceof Error)
        console.log(res.message);

      else
        console.log(`  ${res.status} ${res.statusText} ${res.finalUrl}`);

    return null;
  }

  getJST.ready = atLeast(servers.map(fetchDiff), 1).then(onload, onerror);

  return getJST;
})();

getJST.ready.then(() => {
  const notificationTitle = 'Niconico Live Auto Enter';
  const notificationDefaults = {
    icon: (document.querySelector('meta[itemprop="thumbnail"]') || 0).content,
    tag: 'niconico-live-auto-enter',
    autoClose: 5000,
  };

  const programTitle = (document.querySelector('.program-title[itemprop="name"]') || 0).textContent;
  const published = Date.parse((document.querySelector('.kaijo meta[itemprop="datePublished"]') || 0).content);
  const notified = {};

  if (!published || getRemaining() <= 0)
    return;

  const timer = () => {
    const remaining = getRemaining();

    if (remaining <= 0) {
      notifyEnter();
      enter();
      return;
    }

    const sec = getRemainingSeconds();
    const wait = sec < 1 ? 0 : sec < 10 ? 100 : sec < 3600 ? 1000 : 10000;

    setTimeout(timer, wait);

    const target = roundRemaining(remaining);

    if (target in notified)
      return;

    notifyRemaining(remaining);
    notified[target] = true;
  };

  timer();

  function getRemainingSeconds() {
    return (published - getJST()) / 1000;
  }

  function getRemaining() {
    return Math.ceil(getRemainingSeconds() / 60);
  }

  function roundRemaining(remaining) {
    for (let m of [0, 1, 3, 5, 10, 20, 30])
      if (remaining <= m)
        return m;

    return Math.ceil(remaining / 60) * 60;
  }

  function notify(body, options) {
    options = Object.assign({body}, notificationDefaults, options);

    return new Promise((resolve, reject) => {
      Notification.requestPermission(status => {
        if (status !== 'granted') {
          reject(status);
          return;
        }

        const n = new Notification(notificationTitle, options);

        if (options.autoClose)
          setTimeout(() => n.close(), options.autoClose);

        resolve(n);
      });
    });
  }

  function notifyRemaining(remaining) {
    const minutes = remaining % 60;
    const hours = remaining / 60 % 24 | 0;
    const days = remaining / 60 / 24 | 0;

    const timeStr = [];

    if (days)
      timeStr.push(`${days} 日`);

    if (hours)
      timeStr.push(`${hours} 時間`);

    if (minutes || !timeStr.length)
      timeStr.push(`${minutes} 分`);

    notify(`${programTitle}\n\n開場まで、あと ${timeStr.join(' ')} です。`);
  }

  function notifyEnter() {
    notify('入場します!');
  }

  function enter() {
    location.reload(true);
  }
});