中国大学MOOC-讨论区-停止复读.user.js

// ==UserScript==
// @name         中国大学MOOC-讨论区-停止复读
// @namespace    http://tampermonkey.net/
// @version      0.3.2
// @description  隐藏复读内容（有评论的回复始终显示）
// @license      GPL-3.0-or-later
// @supportURL   https://github.com/YDX-2147483647/BIT-enhanced/issues
// @author       Y.D.X.
// @require      https://gitee.com/YDX-2147483647/BIT-enhanced/raw/main/TamperMonkey/lib/mooc.js
// @match        https://www.icourse163.org/learn*
// @match        https://www.icourse163.org/spoc/learn*
// @grant        none
// ==/UserScript==

(function () {
  'use strict'
  /* global Mooc */

  // interval's unit: ms.
  function wait_until_presence (selector, interval) {
    return new Promise((resolve, reject) => {
      const check = setInterval(function () {
        if (document.querySelector(selector)) {
          clearInterval(check)
          resolve(document.querySelector(selector))
        }
      }, interval)
    })
  }

  let already_add_style_sheet = false

  function add_style_sheet () {
    if (already_add_style_sheet) {
      return
    }

    const sheet = document.createElement('style')
    sheet.innerHTML = `
        .copycat {
            display: none;
        }
        `
    document.head.appendChild(sheet)
    already_add_style_sheet = true
  }

  function get_main_content (reply_div) {
    return reply_div.querySelector('.f-richEditorText').textContent
  }

  function has_comment (reply_div) {
    return reply_div.querySelector('.m-commentWrapper') !== null
  }

  function check_all_copycat () {
    const replies = document.querySelectorAll('.j-reply-all > div > .j-list > .j-data-list > div')

    for (let i = replies.length - 1; i >= 0; i--) {
      const current_reply = replies[i]

      let is_copycat = false
      if (!has_comment(current_reply)) {
        for (let j = replies.length - 1; j > i; j--) {
          const r = replies[j]
          if (r.classList.contains('copycat')) {
            continue
          } else if (get_main_content(r) === get_main_content(current_reply)) {
            is_copycat = true
            break
          }
        }
      }

      if (is_copycat) {
        current_reply.classList.add('copycat')
      } else if (current_reply.classList.contains('copycat')) {
        current_reply.classList.remove('copycat')
      }
    }
  }

  async function main () {
    if (/#\/learn\/forumdetail\?pid=\d+/.test(window.location.hash)) {
      add_style_sheet()

      await wait_until_presence('#courseLearn-inner-box .j-detailBox .rinfobox > h4', 1000)
      check_all_copycat()

      const page_selector = document.querySelector('.j-reply-all > div > .j-list > .j-data-list + .u-pager')
      page_selector.addEventListener('click', function () {
        setTimeout(() => check_all_copycat(), 500)
      })
    }
  }

  Mooc.on_every_loaded(main)
  window.addEventListener('hashchange', () => Mooc.on_every_loaded(main))
})()