bare-operating-system/packages/bare-os-coreutils/lib/summon-layout.js

/** Flow HTML to wrapped lines + link/form hit targets. */

var BARE_SUMMON_BLOCK = {
  address: 1,
  article: 1,
  aside: 1,
  blockquote: 1,
  body: 1,
  div: 1,
  dl: 1,
  dt: 1,
  dd: 1,
  fieldset: 1,
  figcaption: 1,
  figure: 1,
  footer: 1,
  form: 1,
  h1: 1,
  h2: 1,
  h3: 1,
  h4: 1,
  h5: 1,
  h6: 1,
  header: 1,
  hr: 1,
  li: 1,
  main: 1,
  nav: 1,
  ol: 1,
  p: 1,
  pre: 1,
  section: 1,
  table: 1,
  tr: 1,
  ul: 1
}

function bareSummonIsBlock(name, style) {
  var d = bareSummonDisplay(style)
  if (d === 'none') return false
  if (d === 'inline') return false
  if (d === 'block') return true
  return !!BARE_SUMMON_BLOCK[name]
}

function bareSummonLayout(doc, opts) {
  opts = opts || {}
  var cols = Math.max(20, opts.cols || 80)
  var sheets = opts.sheets || []
  var numbers = opts.numbers !== false
  var lines = []
  var links = []
  var forms = []
  var cur = ''
  var curMarks = []

  function flush() {
    if (cur === '' && !curMarks.length) return
    lines.push({ text: cur, marks: curMarks })
    cur = ''
    curMarks = []
  }

  function emitNl() {
    flush()
  }

  function emitText(s, mark) {
    s = String(s || '')
    if (!s) return
    var i = 0
    while (i < s.length) {
      var ch = s.charAt(i)
      if (ch === '\n') {
        emitNl()
        i++
        continue
      }
      if (ch === '\r') {
        i++
        continue
      }
      if (cur.length >= cols) emitNl()
      if (mark) {
        curMarks.push({
          col: cur.length,
          ch: ch,
          link: mark.link,
          form: mark.form,
          bold: mark.bold,
          dim: mark.dim
        })
      }
      cur += ch
      i++
    }
  }

  function emitSpace() {
    if (cur && cur.charAt(cur.length - 1) !== ' ') emitText(' ')
  }

  function walk(node, mark) {
    if (!node) return
    if (node.type === 'text') {
      var t = node.text || ''
      if (!mark || !mark.pre) t = t.replace(/\s+/g, ' ')
      if (t === ' ' || t === '') {
        if (t === ' ') emitSpace()
        return
      }
      emitText(t, mark)
      return
    }
    if (node.type !== 'element') return
    var st = bareSummonComputedStyle(node, sheets)
    if (bareSummonDisplay(st) === 'none') return
    var name = node.name
    var nextMark = {
      link: mark && mark.link,
      form: mark && mark.form,
      bold: mark && mark.bold,
      dim: mark && mark.dim,
      pre: mark && mark.pre
    }
    if (
      st['font-weight'] === 'bold' ||
      name === 'b' ||
      name === 'strong' ||
      /^h[1-6]$/.test(name)
    )
      nextMark.bold = true
    if (name === 'pre' || name === 'code' || st['font-family'] === 'monospace')
      nextMark.dim = true
    if (name === 'pre' || st['white-space'] === 'pre') nextMark.pre = true

    if (name === 'a' && node.attrs.href) {
      var id = links.length
      links.push({
        id: id,
        href: node.attrs.href,
        text: bareSummonTextContent(node).replace(/\s+/g, ' ').trim()
      })
      nextMark.link = id
      if (numbers) emitText('[' + (id + 1) + ']', nextMark)
    }
    if (name === 'br') {
      emitNl()
      return
    }
    if (name === 'hr') {
      emitNl()
      emitText('\u2500'.repeat(Math.min(cols, 40)))
      emitNl()
      return
    }
    if (name === 'img') {
      var alt = node.attrs.alt || node.attrs.src || 'img'
      emitText('[IMG ' + alt + ']')
      return
    }
    if (
      name === 'input' ||
      name === 'textarea' ||
      name === 'select' ||
      name === 'button'
    ) {
      var fid = forms.length
      forms.push({
        id: fid,
        name: node.attrs.name || '',
        type: (node.attrs.type || name).toLowerCase(),
        value: node.attrs.value || '',
        node: node
      })
      nextMark.form = fid
      emitText('[' + (node.attrs.type || name) + ']')
      if (name === 'input' && BARE_SUMMON_VOID[name]) return
    }
    if (name === 'iframe' || name === 'video' || name === 'audio') {
      emitText(
        '[' +
          name.toUpperCase() +
          (node.attrs.src ? ' ' + node.attrs.src : '') +
          ']'
      )
      return
    }

    var block = bareSummonIsBlock(name, st)
    if (block) emitNl()
    if (name === 'li') emitText('\u2022 ')
    var ch = node.children || []
    for (var i = 0; i < ch.length; i++) walk(ch[i], nextMark)
    if (block) emitNl()
  }

  walk(doc.body, {})
  flush()
  while (lines.length && !String(lines[0].text || '').trim()) lines.shift()
  while (lines.length && !String(lines[lines.length - 1].text || '').trim())
    lines.pop()

  var plain = lines.map(function (l) {
    return l.text
  })
  return {
    cols: cols,
    lines: lines,
    plain: plain,
    links: links,
    forms: forms,
    title: doc.title || ''
  }
}

function bareSummonReaderText(doc) {
  var bits = []
  function keep(n) {
    return (
      n &&
      n.type === 'element' &&
      (n.name === 'p' ||
        n.name === 'h1' ||
        n.name === 'h2' ||
        n.name === 'h3' ||
        n.name === 'li' ||
        n.name === 'pre' ||
        n.name === 'blockquote' ||
        n.name === 'article')
    )
  }
  function walk(n) {
    if (!n) return
    if (keep(n)) {
      var t = bareSummonTextContent(n).replace(/\s+/g, ' ').trim()
      if (t) bits.push(t)
      return
    }
    var ch = n.children || []
    for (var i = 0; i < ch.length; i++) walk(ch[i])
  }
  walk(doc.body)
  return bits.join('\n\n')
}