let isMathjaxConfig = false//用于标识是否配置
const initMathjaxConfig = () => {
  if (!window.MathJax) {
    return
  }
  window.MathJax.Hub.Config({
    showProcessingMessages: false, //关闭js加载过程信息
    messageStyle: 'none', //不显示信息
    jax: ['input/TeX', 'output/HTML-CSS'],
    tex2jax: {
      inlineMath: [['$', '$'], ['\\(', '\\)']], //行内公式选择符
      displayMath: [['$$', '$$'], ['\\[', '\\]']], //段内公式选择符
      skipTags: ['script', 'noscript', 'style', 'textarea', 'pre', 'code', 'a'] //避开某些标签
    },
    'HTML-CSS': {
      availableFonts: ['STIX', 'TeX'], //可选字体
      showMathMenu: false //关闭右击菜单显示
    }
  })
  isMathjaxConfig = true //配置完成，改为true
}
const _ensureMathjaxInit = function() {
  if (!isMathjaxConfig) initMathjaxConfig()
}
const _transferTikuQuestionImageUrls = function(docEle) {
  const imgList = docEle.getElementsByTagName('img')
  for (var i = 0; i < imgList.length; i++) {
    const img = imgList[i]
    const supportTagConfigs = [
      { tag: 'tikuimages', prefix: 'https://file.mingxuejinbang.com/tikubao/tikuimages' },
      { tag: 'mathJye', prefix: 'https://file.mingxuejinbang.com/tikubao/mathJye' }]
    for (let index = 0; index < supportTagConfigs.length; index++) {
      const config = supportTagConfigs[index]
      if (_transferTikuQuestionImageUrlsByTag(img, config)) break
    }
  }
}

const _transferTikuQuestionImageUrlsByTag = function(img, config) {
  let srcParams = img.src.split(config.tag)
  if (srcParams.length > 1) {
    img.src = config.prefix + srcParams[1]
    return true
  }
  return false
}

const MathQueue = function(elementId, callback) {
  _ensureMathjaxInit()
  const docEle = document.getElementById(elementId)
  if (!docEle) return
  _transferTikuQuestionImageUrls(docEle)

  if (!window.MathJax) {
    return
  }
  window.MathJax.Hub.Queue(['Typeset', window.MathJax.Hub, docEle])
  if (typeof callback === 'function') window.MathJax.Hub.Queue(callback)
}