/*
 * @postId STRING: id do elemento da publicação (opcional)
 * @expand BOOL: opção de expandir todos os comentários antes de raspar
 */
var copyToClipboard = str => {
  const el = document.createElement('textarea')
  el.value = str
  document.body.appendChild(el)
  el.select()
  document.execCommand('copy')
  document.body.removeChild(el)
}

var copyResults = (str, len) => {
  if (str) {
    window.localStorage.setItem('fb-scrapper-results', str)
    const $el = `<div style="background-color: black; color: white; position: fixed; width: 100%; left: 0; bottom: 0; z-index: 10000; text-align: center; padding: 1em;" id="fb-scrapper-container">${len} comentários extraídos <button onClick="copyResults()">Copiar</button></div>`
    const node = new DOMParser().parseFromString($el, 'text/html').body.childNodes[0]
    document.body.appendChild(node)
  } else {
    const results = window.localStorage.getItem('fb-scrapper-results')
    copyToClipboard(results)
    alert('Comentários copiados')
    document.querySelector('#fb-scrapper-container').parentElement.removeChild(document.querySelector('#fb-scrapper-container'))
  }
}
function fetchComments(length) {

  let baseSelector = document.querySelector('#pagelet_timeline_main_column .permalinkPost')
    || document.querySelectorAll('.uiStreamStory')
  if (!baseSelector || (baseSelector instanceof window.NodeList && !baseSelector.length)) {
    baseSelector = document.querySelector('._wyj._20nr')
  } else {
    if (baseSelector.forEach) {
      baseSelector = baseSelector[baseSelector.length - 1]
    }
  }
  const allCommentsQuery = '[data-testid="UFI2Comment/root_depth_0"]'

  const getCommentsLength = () => baseSelector
    .querySelectorAll(allCommentsQuery).length

  const exportToCsv = (filename, rows) => {

    var processRow = function (row) {
      return row
      .map(col => {
        let innerValue = col === null ? '' : col.toString()
        if (col instanceof Date) innerValue = col.toLocaleString()
        return '"' + innerValue.replace(/"/g, '\"').replace(/\s+$/, '') + '"'
      })
      .join(';')
    }

    let csvFile = rows.map(processRow).join('\n')

    var blob = new Blob([csvFile], { type: 'text/csv;charset=utf-8;' })
    if (navigator.msSaveBlob) { // IE 10+
      navigator.msSaveBlob(blob, filename)
    } else {
      var link = document.createElement("a")
      if (link.download !== undefined) { // feature detection
        // Browsers that support HTML5 download attribute
        var url = URL.createObjectURL(blob)
        link.setAttribute("href", url)
        link.setAttribute("download", filename)
        link.style.visibility = 'hidden'
        document.body.appendChild(link)
        link.click()
        document.body.removeChild(link)
      }
    }
  }

  const scrapComments = () => {
    console.log('Raspando comentários...')
    const comments = []
    comments.push(['time', 'name', 'comment'])
    baseSelector
      .querySelectorAll(allCommentsQuery)
      .forEach((el) => {
        const $comment = el.querySelector('[data-testid="UFI2Comment/body"]')
        const $actions = el.querySelector('[data-testid="UFI2CommentActionLinks/root"]')
        if (!$comment) return
        const time = $actions.querySelector('abbr').getAttribute('title')
        const name = $comment.querySelector('a').innerText
        const textEl = $comment.querySelector('._3l3x')
        const text = textEl ? textEl.innerText
          .replace(/^[·:\d\s]+/, '')
          .replace(/\n+/g, ' ') : ''
        comments.push([time, name, text])
    })

    if (comments.length) {
      // const name = prompt('Digite o nome do arquivo CSV')
      // exportToCsv(name, comments)
      copyResults(comments.map(c => c.join('\t')).join('\n'), comments.length)
    } else {
      alert('Nenhum comentário encontrado')
    }
  }

  const expandComments = () => {
    const currentLength = getCommentsLength()
    if (currentLength >= length) {
      return Promise.resolve()
    }
    console.log(`Expandindo comentários ${(currentLength / length * 100).toFixed(2)}%`)
    baseSelector
      .querySelector('[data-testid="UFI2CommentsPagerRenderer/pager_depth_0"]')
      .click()
    return new Promise(function(resolve) {
      const interv = setInterval(() => {
        if (getCommentsLength() > currentLength) {
          clearInterval(interv)
          resolve(expandComments())
        }
      }, 100)
    })
  }

  // Initialize
  if (length) {
    return expandComments()
      .then(scrapComments)
  } else {
    return scrapComments()
  }

}