浙江大学智云课堂小助手

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浙江大学智云课堂小助手

对智云课堂页面的一些功能增强
当前为 2021-11-16 提交的版本，查看最新版本。
换行
// ==UserScript==
// @name         浙江大学智云课堂小助手
// @description  对智云课堂页面的一些功能增强
// @namespace    https://github.com/CoolSpring8/userscript
// @supportURL   https://github.com/CoolSpring8/userscript/issues
// @version      0.5.2
// @author       CoolSpring
// @license      MIT
// @match        *://livingroom.cmc.zju.edu.cn/*
// @match        *://classroom.zju.edu.cn/*
// @grant        none
// @require      https://cdn.jsdelivr.net/npm/[email protected]/worker.js
// @run-at       document-end
// ==/UserScript==

const M3U_EXTGRP_NAME = "ZJU-CMC"

/* polyfill/shim begin */

// requestIdleCallback, for Safari
// source: https://github.com/behnammodi/polyfill/blob/master/window.polyfill.js
if (!window.requestIdleCallback) {
  window.requestIdleCallback = function (callback, options) {
    var options = options || {}
    var relaxation = 1
    var timeout = options.timeout || relaxation
    var start = performance.now()
    return setTimeout(function () {
      callback({
        get didTimeout() {
          return options.timeout
            ? false
            : performance.now() - start - relaxation > timeout
        },
        timeRemaining: function () {
          return Math.max(0, relaxation + (performance.now() - start))
        },
      })
    }, relaxation)
  }
}

/* polyfill/shim end */

const querySelector = (
  window.wrappedJSObject?.document || document
).querySelector.bind(document)
const myWindow = window.wrappedJSObject || window

class CmcHelper {
  constructor() {
    this.loaded = false
    this.features = [
      {
        name: "重新加载播放器",
        className: "cmc-helper-reload-player",
        fn: this.reloadPlayer.bind(this),
        description: "播放卡住了点这个",
      },
      {
        name: "获取当前视频地址",
        className: "cmc-helper-get-current-video-url",
        fn: this.getCurrentVideoURL.bind(this),
        description: "回放和直播中均可用",
      },
      {
        name: "生成字幕",
        className: "cmc-helper-generate-srt",
        fn: this.generateSRT.bind(this),
        description: "可供本地播放器使用。不太靠谱的样子",
      },
      {
        name: "打包下载PPT图片",
        className: "cmc-helper-download-ppt-images",
        fn: this.downloadPPTImages.bind(this),
        description: "如题",
      },
      {
        name: "生成播放列表",
        disabled: true,
        className: "cmc-helper-generate-m3u",
        fn: this.generateM3U.bind(this),
        description: "可以在本地播放器中使用的m3u文件。也许期末很实用",
      },
    ]

    const _init = () => {
      if (this.loaded) {
        return
      }

      const courseElem = querySelector(".course-info__wrapper")
      const playerElem = querySelector("#cmcPlayer_container")

      if (
        !this._isVueReady(courseElem) ||
        !this._isVueReady(playerElem) ||
        !("CmcMediaPlayer" in myWindow)
      ) {
        requestIdleCallback(_init)
        return
      }

      this.courseVue = courseElem.__vue__
      this.playerVue = playerElem.__vue__

      if (!(this.playerVue.player && "setMask" in this.playerVue.player)) {
        requestIdleCallback(_init)
        return
      }

      const helperToolbar = document.createElement("div")
      this.features.forEach((feature) =>
        helperToolbar.append(this._createButton(feature))
      )
      helperToolbar.style.display = "flex"
      helperToolbar.style.marginRight = "1.5px"

      const originalToolbar = querySelector(".course-info__header—toolbar")
      originalToolbar.prepend(helperToolbar)

      setTimeout(this.removeMaskOnce, 500)
      this.enablePPTEnhance()
      this.enableSpeechEnhance()

      this.loaded = true

      console.log(
        // eslint-disable-next-line no-undef
        `[CmcHelper] ${GM.info.script.name} v${GM.info.script.version} has been successfully loaded.`
      )
    }

    requestIdleCallback(_init)
  }

  async downloadPPTImages() {
    const pptList = [...this.courseVue.pptList]

    const dtf = new Intl.DateTimeFormat("zh-CN", {
      year: "numeric",
      month: "2-digit",
      day: "2-digit",
      hour: "2-digit",
      minute: "2-digit",
      second: "2-digit",
      hour12: false,
    })
    // eslint-disable-next-line no-undef
    const blob = await downloadZip(
      this._lazyFetch(
        pptList.map((ppt) => ppt.imgSrc.replace(/^http:/, "https:")),
        (resp, url) => {
          const [filename_without_ext, ext] = this._splitFilenameFromURL(url)
          const p = dtf.formatToParts(new Date(Number(filename_without_ext)))
          return {
            input: resp,
            name: `${p[0].value}-${p[2].value}-${p[4].value}_${p[6].value}-${p[8].value}-${p[10].value}.${ext}`,
          }
        }
      )
    ).blob()
    const archiveFilename = document.title

    this._saveBlobToFile(blob, archiveFilename)
  }

  enablePPTEnhance() {
    const _init = () => {
      this.pptVue = this.pptVue || querySelector(".ppt_container").__vue__

      // feat: 允许PPT直接跳转到特定页码
      const slider = document.createElement("input")
      slider.type = "range"
      slider.name = "ppt-index"
      slider.min = 1
      slider.max = this.pptVue.pptList.length
      slider.value = this.pptVue.currentPPTIdx + 1
      // TODO：和实际的页码保持同步
      slider.style.height = "16px"
      slider.style.margin = "-10px 0"
      slider.style.zIndex = 1

      slider.addEventListener("input", (e) => {
        this.pptVue.currentPPTIdx = Number(e.currentTarget.value - 1)
      })

      querySelector("#ppt").after(slider)

      // feat: 避免白色背景PPT切换页码时出现闪烁
      querySelector("#ppt_canvas").getContext("2d").clearRect = () => {}

      // feat: 允许禁用PPT跟随
      // TODO：现在官方提供了lockPPTFlag，研究此功能是否已可被替代
      const t = document.createElement("div")
      t.className = "ppt-thumbtack"
      t.title = "不自动跳转到PPT最新一页"
      t.style.display = "inline"
      t.style.verticalAlign = "middle"
      t.style.cursor = "pointer"
      t.style.marginRight = "20px"
      t.style.color = "#fff"

      // icons from tabler-icons.io, licensed under MIT
      // https://github.com/tabler/tabler-icons/blob/master/LICENSE
      const iconPinned = `<svg xmlns="http://www.w3.org/2000/svg" id="ppt-pinned" class="icon icon-tabler icon-tabler-pinned" width="24" height="24" viewBox="0 0 24 24" stroke-width="2" stroke="currentColor" fill="none" stroke-linecap="round" stroke-linejoin="round" display="none">
          <path stroke="none" d="M0 0h24v24H0z" fill="none"></path>
          <path d="M9 4v6l-2 4v2h10v-2l-2 -4v-6"></path>
          <line x1="12" y1="16" x2="12" y2="21"></line>
          <line x1="8" y1="4" x2="16" y2="4"></line>
       </svg>`

      const iconPinnedOff = `<svg xmlns="http://www.w3.org/2000/svg" id="ppt-pinned-off" class="icon icon-tabler icon-tabler-pinned-off" width="24" height="24" viewBox="0 0 24 24" stroke-width="2" stroke="currentColor" fill="none" stroke-linecap="round" stroke-linejoin="round">
   <path stroke="none" d="M0 0h24v24H0z" fill="none"></path>
   <line x1="3" y1="3" x2="21" y2="21"></line>
   <path d="M15 4.5l-3.249 3.249m-2.57 1.433l-2.181 .818l-1.5 1.5l7 7l1.5 -1.5l.82 -2.186m1.43 -2.563l3.25 -3.251"></path>
   <line x1="9" y1="15" x2="4.5" y2="19.5"></line>
   <line x1="14.5" y1="4" x2="20" y2="9.5"></line>
</svg>`

      t.insertAdjacentHTML("afterbegin", iconPinned)
      t.insertAdjacentHTML("afterbegin", iconPinnedOff)

      t.addEventListener("click", (e) => {
        const q = e.currentTarget.querySelector.bind(e.currentTarget)

        if (!this.pptPinned) {
          // 直播
          this.__initCanvas = this.pptVue.initCanvas
          this.pptVue.initCanvas = (type) => {
            if (type !== "latest") {
              this.__initCanvas(type)
            }
          }

          // 回放
          this.__computedPPTIndex = this.courseVue.computedPPTIndex
          this.courseVue.computedPPTIndex = () => {}

          this.pptPinned = true
          q("#ppt-pinned-off").setAttribute("display", "none")
          q("#ppt-pinned").removeAttribute("display")
          return
        }

        this.pptVue.initCanvas = this.__initCanvas
        this.courseVue.computedPPTIndex = this.__computedPPTIndex
        this.pptPinned = false
        q("#ppt-pinned").setAttribute("display", "none")
        q("#ppt-pinned-off").removeAttribute("display")
      })

      querySelector(".ppt_page_btn").prepend(t)
    }

    // 因为每次大小窗口切换时部分页面元素都会被重新创建，所以需要再次修改
    const observer = new MutationObserver((mutations) => {
      mutations
        .filter(
          (mutation) =>
            mutation.type === "childList" &&
            [...mutation.addedNodes].find(
              (node) => node.className === "ppt_container"
            ) !== undefined
        )
        .forEach(_init)
    })

    observer.observe(querySelector(".course-info__main"), { childList: true })
  }

  enableSpeechEnhance() {
    const scopeId = this.courseVue.$options._scopeId
    const preventedTag = "data-cmchelper-prevented"

    const d = document.createElement("div")
    d.setAttribute(scopeId, "") // for style
    d.setAttribute(preventedTag, "false")
    d.className = "choose-item-info"

    const s = document.createElement("span")
    s.setAttribute(scopeId, "")
    s.innerText = "阻止滚动"
    s.innerHTML += " " // align with other switches

    const i = document.createElement("i")
    i.setAttribute(scopeId, "")
    i.className = "el-icon-check"
    i.style.display = "none"

    d.append(s, i)

    d.addEventListener("click", (e) => {
      const wrap = this.courseVue.$refs.spokenLanguageScrollbar.wrap
      const st = Object.getOwnPropertyDescriptor(Element.prototype, "scrollTop")

      if (e.currentTarget.getAttribute(preventedTag) === "false") {
        Object.defineProperty(wrap, "scrollTop", {
          get: function () {
            return st.get.apply(this, arguments)
          },
          set: function () {},
          configurable: true,
        })
        e.currentTarget.setAttribute(preventedTag, "true")
        i.style.removeProperty("display")
        return
      }
      Object.defineProperty(wrap, "scrollTop", {
        get: function () {
          return st.get.apply(this, arguments)
        },
        set: function () {
          st.set.apply(this, arguments)
        },
        configurable: true,
      })
      e.currentTarget.setAttribute("data-cmchelper-prevented", "false")
      i.style.display = "none"
    })

    querySelector(".choose-item").prepend(d)
  }

  generateM3U() {
    const courseName = this.courseVue.courseName
    const teacherName = this.courseVue.teacherName
    // FIXME: a workaround for "Error: Permission denied to access object" in Firefox + Greasemonkey env
    const menuData = [...this.courseVue.menuData]
    const academicYear = JSON.parse(this.courseVue.liveInfo.information).kkxn
    const semester = JSON.parse(this.courseVue.liveInfo.information).kkxq

    const m3u = `#EXTM3U

#PLAYLIST:${courseName}
#EXTGRP:${M3U_EXTGRP_NAME}
#EXTALB:${courseName}
#EXTART:${teacherName}

${menuData
  .filter((menu) => "playback" in menu.content)
  .map(
    (menu) =>
      `#EXTINF:${menu.duration},${menu.title}\n${menu.content.playback.url[0]}\n`
  )
  .join("\n")}`

    this._saveTextToFile(
      m3u,
      `${courseName}-${teacherName}-${academicYear}${semester}.m3u`
    )
  }

  generateSRT() {
    const url = this.playerVue.player.playervars.url
    const [filename_without_ext] = this._splitFilenameFromURL(url)

    // FIXME: a workaround for "Error: Permission denied to access object" in Firefox + Greasemonkey env
    const data = [...this.courseVue.videoTransContent]
    const subtitle = data
      .map(
        (item, index) => `${index}
${item.markTime},000 --> ${this._addTime(
          item.markTime,
          item.endPlayMs - item.playMs
        )},000
${item.zhtext}`
      )
      .join("\n\n")

    this._saveTextToFile(subtitle, `${filename_without_ext}.srt`)
  }

  getCurrentVideoURL() {
    if (this.playerVue.liveType === "live") {
      // may be changed to `multi` someday
      const sources = JSON.parse(
        cmcHelper.playerVue.liveUrl.replace("mutli-rate: ", "")
      )
      prompt(
        "请复制到支持HLS的播放器（例如MPC-HC、PotPlayer、mpv）中使用",
        sources[0].url
      )
      return
    }
    const url = querySelector("#cmc_player_video").src
    prompt("已选中，请自行复制到剪贴板", url)
  }

  reloadPlayer() {
    const time = this.playerVue.player.getPlayTime()
    this.playerVue.player.destroy()
    this.playerVue.initPlayer()
    setTimeout(() => {
      this.playerVue.player.seekPlay(time)
      this.removeMaskOnce()
    }, 500)
  }

  removeMaskOnce() {
    // this.playerVue.player.setMask({}) // not working in Firefox
    try {
      querySelector(".expand-mask").remove()
    } catch (e) {
      console.error(`[CmcHelper] ${e}`)
    }
  }

  // there may be some better solutions
  _addTime(anchor, duration) {
    let hour = Number(anchor.slice(0, 2))
    let minute = Number(anchor.slice(3, 5))
    let second = Number(anchor.slice(6, 8))

    second += duration

    if (second >= 60) {
      second -= 60
      minute += 1
    }
    if (minute >= 60) {
      minute -= 60
      hour += 1
    }

    this._twoDigitFormat =
      this._twoDigitFormat || new Intl.NumberFormat({ minimumIntegerDigits: 2 })
    const f = this._twoDigitFormat

    return `${f.format(hour)}:${f.format(minute)}:${f.format(second)}`
  }

  _createButton({ name, disabled, className, fn, description }) {
    const button = document.createElement("button")
    button.innerText = name
    button.disabled = disabled
    button.title = disabled
      ? "由于智云课堂系统升级，该功能暂不可用"
      : description
    button.className = className
    button.style.margin = "1.5px"
    button.addEventListener("click", fn)
    return button
  }

  _downloadSmallCrossOriginFile(url, filename) {
    fetch(url)
      .then((resp) => resp.blob())
      .then((blob) => this._saveBlobToFile(blob, filename))
      .catch((e) => alert(`[CmcHelper] 下载失败：${e}`))
  }

  _isVueReady(elem) {
    return elem !== null && "__vue__" in elem
  }

  // TODO: handle errors
  async *_lazyFetch(urls, respCallback) {
    for (const url of urls) {
      try {
        const resp = await fetch(url)
        yield respCallback(resp, url)
      } catch (e) {
        console.error(`[CmcHelper] ${e}`)
      }
    }
  }

  _saveBlobToFile(blob, filename) {
    const url = URL.createObjectURL(blob)
    this._triggerDownload(url, filename)
    URL.revokeObjectURL(url)
  }

  _saveTextToFile(text, filename) {
    const blob = new Blob([text])
    this._saveBlobToFile(blob, filename)
  }

  _splitFilenameFromURL(url) {
    const filename = new URL(url).pathname.split("/").pop()
    const tmp = filename.split(".")
    const ext = tmp.pop()
    const filename_without_ext = tmp.join(".")
    return [filename_without_ext, ext]
  }

  _triggerDownload(url, filename) {
    const a = document.createElement("a")
    a.href = url
    a.download = filename
    a.click()
  }
}

const cmcHelper = new CmcHelper()
// For debugging purposes
myWindow.cmcHelper = cmcHelper