const TR_CLASS = {
  '[:alnum:]':
    'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789',
  '[:alpha:]': 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ',
  '[:blank:]': ' \t',
  '[:cntrl:]': [...Array(32).keys()].map((i) => String.fromCharCode(i)).join('') + '\x7f',
  '[:digit:]': '0123456789',
  '[:lower:]': 'abcdefghijklmnopqrstuvwxyz',
  '[:print:]': [...Array(95).keys()].map((i) => String.fromCharCode(i + 32)).join(''),
  '[:punct:]': '!"#$%&\'()*+,-./:;<=>?@[\\]^_`{|}~',
  '[:space:]': ' \t\n\r\v\f',
  '[:upper:]': 'ABCDEFGHIJKLMNOPQRSTUVWXYZ',
  '[:xdigit:]': '0123456789abcdefABCDEF'
}

/** @param {string} s */
function trExpandClasses(s) {
  let out = s
  for (const [name, chars] of Object.entries(TR_CLASS)) {
    out = out.split(name).join(chars)
  }
  return out
}

async function run(ctx, argv) {
  let del = false
  const sets = []
  for (let i = 1; i < argv.length; i++) {
    if (argv[i] === '-d' || argv[i] === '--delete') del = true
    else if (argv[i] !== '--') sets.push(argv[i])
  }
  if (!sets.length || (!del && sets.length < 2)) {
    ctx.console.error('usage: tr [-d] SET1 [SET2]')
    ctx.exitCode = 1
    return
  }
  const s = bareStdin(ctx)
  if (del) {
    const kill = new Set(trExpandClasses(sets[0]).split(''))
    let o = ''
    for (const ch of s) if (!kill.has(ch)) o += ch
    ctx.console.log(o)
    return
  }
  const from = trExpandClasses(sets[0])
  const to = trExpandClasses(sets[1])
  const map = Object.create(null)
  const n = Math.max(from.length, to.length)
  for (let i = 0; i < n; i++) {
    const fc = from[i] || from[from.length - 1]
    const tc = to[i] != null ? to[i] : to[to.length - 1] || ''
    map[fc] = tc
  }
  let o = ''
  for (const ch of s) o += map[ch] != null ? map[ch] : ch
  ctx.console.log(o)
}