/* 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
}

/** RFC 1321 MD5 — no Web Crypto; used by md5sum. */
function bareMd5DigestBytes(u8) {
  const n = u8.length
  const bitLen = (BigInt(n) * 8n) & 0xffffffffffffffffn
  const padLen = (56 - ((n + 1) % 64) + 64) % 64
  const total = n + 1 + padLen + 8
  const buf = new Uint8Array(total)
  buf.set(u8)
  buf[n] = 0x80
  const view = new DataView(buf.buffer)
  view.setUint32(total - 8, Number(bitLen & 0xffffffffn), true)
  view.setUint32(total - 4, Number((bitLen >> 32n) & 0xffffffffn), true)

  let a0 = 0x67452301
  let b0 = 0xefcdab89
  let c0 = 0x98badcfe
  let d0 = 0x10325476
  const s = [
    7, 12, 17, 22, 7, 12, 17, 22, 7, 12, 17, 22, 7, 12, 17, 22, 5, 9, 14, 20, 5, 9,
    14, 20, 5, 9, 14, 20, 5, 9, 14, 20, 4, 11, 16, 23, 4, 11, 16, 23, 4, 11, 16, 23,
    4, 11, 16, 23, 6, 10, 15, 21, 6, 10, 15, 21, 6, 10, 15, 21, 6, 10, 15, 21
  ]
  const K = new Uint32Array(64)
  for (let i = 0; i < 64; i++) K[i] = Math.floor(Math.abs(Math.sin(i + 1)) * 0x100000000) >>> 0

  const leftRotate = (x, c) => ((x << c) | (x >>> (32 - c))) >>> 0
  for (let off = 0; off < total; off += 64) {
    const M = new Uint32Array(16)
    for (let i = 0; i < 16; i++) {
      M[i] = view.getUint32(off + i * 4, true)
    }
    let A = a0
    let B = b0
    let C = c0
    let D = d0
    for (let i = 0; i < 64; i++) {
      let F, g
      if (i < 16) {
        F = (B & C) | (~B & D)
        g = i
      } else if (i < 32) {
        F = (D & B) | (~D & C)
        g = (5 * i + 1) % 16
      } else if (i < 48) {
        F = B ^ C ^ D
        g = (3 * i + 5) % 16
      } else {
        F = C ^ (B | ~D)
        g = (7 * i) % 16
      }
      F = (F + A + K[i] + M[g]) >>> 0
      A = D
      D = C
      C = B
      B = (B + leftRotate(F, s[i])) >>> 0
    }
    a0 = (a0 + A) >>> 0
    b0 = (b0 + B) >>> 0
    c0 = (c0 + C) >>> 0
    d0 = (d0 + D) >>> 0
  }
  const out = new Uint8Array(16)
  const dv = new DataView(out.buffer)
  dv.setUint32(0, a0, true)
  dv.setUint32(4, b0, true)
  dv.setUint32(8, c0, true)
  dv.setUint32(12, d0, true)
  return [...out].map((b) => b.toString(16).padStart(2, '0')).join('')
}

async function run(ctx, argv) {
  const paths = []
  for (let i = 1; i < argv.length; i++) {
    const a = argv[i]
    if (a === '-h' || a === '--help') {
      ctx.console.log(
        'usage: md5sum [FILE]...\n' +
          'With no FILE, or when FILE is -, read standard input. Uses bundled MD5 (no Web Crypto MD5).'
      )
      ctx.exitCode = 0
      return
    }
    if (a.startsWith('-') && a !== '-') {
      ctx.console.error('md5sum: unsupported option ' + a)
      ctx.exitCode = 1
      return
    }
    paths.push(a)
  }
  const b4 = ctx.b4a
  function one(name, buf) {
    const u8 = buf instanceof Uint8Array ? buf : new Uint8Array(buf)
    try {
      const hex = bareMd5DigestBytes(u8)
      ctx.console.log(hex + '  ' + name)
    } catch (e) {
      ctx.console.error('md5sum: ' + (e.message || e))
      ctx.exitCode = 1
    }
  }
  if (!paths.length || (paths.length === 1 && paths[0] === '-')) {
    one('-', b4.from(bareStdin(ctx)))
    return
  }
  for (const p of paths) {
    if (p === '-') {
      one('-', b4.from(bareStdin(ctx)))
      continue
    }
    const b = await ctx.vfs.readFile(p)
    if (!b) {
      ctx.console.error('md5sum: ' + p + ': No such file')
      ctx.exitCode = 1
      continue
    }
    one(p, b)
  }
}