/* BARE_OS_BIN_API 1.0.0 — bump when staged /bin script semantics change (see developer guide). */
/** Shared helpers for drive-resident /bin scripts (prepended before each command). */
function bareStdin(ctx) {
  return typeof ctx.shellStdin === 'string' ? ctx.shellStdin : ''
}

/** @param {number} mode @param {'file' | 'directory' | 'symlink'} type */
function bareFormatModeString(mode, type) {
  const typeChar = type === 'directory' ? 'd' : type === 'symlink' ? 'l' : '-'
  const perm = mode & 0o777
  const r = (bit) => (perm & bit ? 'r' : '-')
  const w = (bit) => (perm & bit ? 'w' : '-')
  const x = (bit) => (perm & bit ? 'x' : '-')
  return (
    typeChar +
    r(0o400) +
    w(0o200) +
    x(0o100) +
    r(0o040) +
    w(0o020) +
    x(0o010) +
    r(0o004) +
    w(0o002) +
    x(0o001)
  )
}

/** @param {number} mtimeMs @param {number} [nowMs] */
function bareFormatLsMtime(mtimeMs, nowMs) {
  const now = nowMs != null ? nowMs : Date.now()
  const d = new Date(mtimeMs)
  const months = [
    'Jan',
    'Feb',
    'Mar',
    'Apr',
    'May',
    'Jun',
    'Jul',
    'Aug',
    'Sep',
    'Oct',
    'Nov',
    'Dec'
  ]
  const mon = months[d.getMonth()]
  const day = String(d.getDate()).padStart(2, ' ')
  const sixMo = 180 * 24 * 3600 * 1000
  if (Math.abs(now - mtimeMs) > sixMo) {
    const yr = String(d.getFullYear()).padStart(4, ' ')
    return mon + ' ' + day + '  ' + yr
  }
  const hh = String(d.getHours()).padStart(2, '0')
  const mm = String(d.getMinutes()).padStart(2, '0')
  return mon + ' ' + day + ' ' + hh + ':' + mm
}

/** @param {number} size */
function barePosixBlocks(size) {
  return Math.ceil(Number(size) / 512) || 0
}

/**
 * Raw stdout for NUL/binary when **`process.stdout.write`** is missing.
 * If **`ctx.bareOsBinWrite(Uint8Array|string)`** is set (tests / host), use it.
 * @param {Record<string, unknown>} ctx
 * @param {string | Uint8Array} chunk
 * @returns {boolean}
 */
function bareOsEmitRaw(ctx, chunk) {
  if (typeof ctx.bareOsBinWrite === 'function') {
    const b4 = ctx.b4a
    const u8 =
      typeof chunk === 'string'
        ? b4 && typeof b4.from === 'function'
          ? b4.from(chunk)
          : new TextEncoder().encode(chunk)
        : chunk
    ctx.bareOsBinWrite(u8 instanceof Uint8Array ? u8 : new Uint8Array(u8))
    return true
  }
  const w = globalThis.process?.stdout?.write
  if (typeof w === 'function') {
    w.call(globalThis.process.stdout, chunk)
    return true
  }
  return false
}

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)
}