export default {
  commatize,
  privacyDot,
  shortMonths,
  verboseDate,
  carbonDate,
  hushViews,
  hushSize,
  hushNull,
  courtesyS,
  getRevision,
  getAge,
  tidyURLs,
  getDomain,
}

function commatize (n) {
  var nums = [], i, counter = 0, r = Math.floor
  if (n > 1024) {
    n /= 1024
    nums.unshift(r((n * 10) % 10))
    nums.unshift(".")
  }
  do {
    i = n % 10
    n = r(n / 10)
    if (n && ! (++counter % 3))
      { i = ' ' + r(i) }
    nums.unshift(r(i))
  }
  while (n)
  return nums.join("")
}

function privacyDot (p) {
  if (! p) return "·"
  else return "·:"
}

const shortMonths = "Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec".split(" ")
function verboseDate (dateStr, pad_hours) {
  const dateObj = new Date(dateStr)
	let d = dateObj.getDate()
	let m = dateObj.getMinutes()
  let h = dateObj.getHours()
  let meridian

	if (h == 0) {
	  h = 12
		meridian = " am"
  }
	else if (h == 12) {
	  meridian = " pm"
	}
	else if (h > 12) {
	  h -= 12
	  meridian = " pm"
	}
	else {
	  meridian = " am"
	}

	if (d < 10) d = "0" + d
	if (m < 10) m = "0" + m
	if (pad_hours && h < 10) h = "0" + h
  
  const date = d + '-' + shortMonths[dateObj.getMonth()] + '-' + dateObj.getFullYear()
  const time = h + ':' + m + meridian
  
  return { date, time }
}
function carbonDate (date, no_bold) {
  const span = (+new Date() - new Date(date)) / 1000
  if (! no_bold && span < 86400) // modified today
    { color = "new" }
  else if (span < 604800) // modifed this week
    { color = "recent" }
  else if (span < 1209600) // modifed 2 weeks ago
    { color = "med" }
  else if (span < 3024000) // modifed 5 weeks ago
    { color = "old" }
  else if (span < 12315200) // modifed 6 months ago
    { color = "older" }
  else
    { color = "quiet" }
  return color
}

function hushViews (n, bias, no_bold) {
  const txt = commatize(n)
  bias = bias || 1
  n = n || 0
  if (n < 30) { return["quiet", n + "&nbsp;v."] }
  if (n < 200) { return ["quiet", txt + "&nbsp;v."] }
  else if (n < 500) { return ["quiet", txt + "&nbsp;v."] }
  else if (n < 1000) { return ["old", txt + "&nbsp;v."] }
  else if (n < 5000) { return ["med", txt + "&nbsp;kv."] }
  else if (nobold || n < 10000) { return ["recent", txt + "&nbsp;kv."] }
  else { return ["new", txt + "&nbsp;kv."] }
}

function hushSize (n, bias, nobold) {
  const txt = commatize(Math.floor(n / 1024))
  bias = 1 || bias
  n = n || 0
  if (n < 1024) {
    return ["quiet", n + "&nbsp;b."]
  }
  if (n < 1024*1024) {
    return ["quiet", txt + "&nbsp;kb."]
  }
  else if (n < (20000000/bias)) {
    return ["quiet", txt + "&nbsp;mb."]
  }
  else if (n < (50000000/bias)) {
    return ["old", txt + "&nbsp;mb."]
  }
  else if (n < (80000000/bias)) {
    return ["med", txt + "&nbsp;mb."]
  }
  else if (nobold || n < (170000000/bias)) {
    return ["recent", txt + "&nbsp;mb."]
  }
  else {
    return ["new", txt + "&nbsp;mb."]
  }
}

function hushNull (n, unit, no_bold) {
  const s = unit ? n + "&nbsp;" + unit + "." : n
  if (n < 3) {
    return ["quiet", s]
  }
  else if (n < 6) {
    return ["older", s]
  }
  else if (n < 10) {
    return ["old", s]
  }
  else if (n < 16) {
    return ["med", s]
  }
  else if (no_bold || n < 21) {
    return ["recent", s]
  }
  else {
    return ["new", s]
  }
}

function courtesyS (n, s) { return v == 1 ? "" : (s || "s") }

const revisionLetters = "z a b c d f g h j k l m n p q r s t v w x y".split(" ")
function getRevision (thread) {
  if (! thread.revision) return ""
  let rev = thread.revision
  let n = 0
  let digits = ""
  do {
    n = rev % 21
    rev = Math.floor(rev / 21)
    digits = revisionLetters[n] + digits
  }
  while (rev !== 0)
  return digits
}

function getAge (t) {
  let age = Math.abs( Date.now() - new Date(t)) / 1000
  const r = Math.floor
  let m
  if (age < 5) { return "now" }
  if (age < 60) { return r(age) + "s" }
  age /= 60
  if (age < 60) { return r(age) + "m" }
  m = r(age % 60)
  age /= 60
  if (m > 0 && age < 2) { return r(age) + "h" + m + "m" }
  if (age < 24) { return r(age) + "h" }
  age /= 24
  if (age < 7) { return r(age) + "d" }
  age /= 7
  if (age < 12) { return r(age) + "w" }
  age /= 4
  if (age < 12) { return r(age) + "m" }
  age /= 12
  return r(age) + "y"
}

function tidyURLs (s, short_urls) {
  return s.split("\n").map(function(line){
    if (line.indexOf("<") !== -1) {
      return line
    }
    return line.replace(/https?:\/\/[^ ]+/g, function(url){
      if (is_image(url)) {
        return '<a href="' + url + '" target="_blank"><img src="' + url + '"></a>'
      }
      else if (short_urls) {
        return '<a href="' + url + '" target="_blank">[' + get_domain(url) + ']</a>'
      }
      else {
        return '<a href="' + url + '" target="_blank">' + url + '</a>'
      }
    })
  }).join("<br>\n")
}
function getDomain(url){
  return url.replace(/https?:\/\//,"").replace(/\/.*/,"").replace(/www\./, "")
}