/* 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 B32 = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ234567'

function bareHexEncode(u8) {
  let s = ''
  for (let i = 0; i < u8.length; i++) {
    s += u8[i].toString(16).padStart(2, '0')
  }
  return s
}

function bareHexDecode(s) {
  const t = String(s).replace(/\s+/g, '')
  if (t.length % 2 !== 0) throw new Error('odd hex length')
  const out = new Uint8Array(t.length / 2)
  for (let i = 0; i < out.length; i++) {
    out[i] = parseInt(t.slice(i * 2, i * 2 + 2), 16)
    if (!Number.isFinite(out[i])) throw new Error('invalid hex')
  }
  return out
}

function bareB32EncodeBytes(u8) {
  let out = ''
  let i = 0
  let buf = 0
  let bits = 0
  for (; i < u8.length; i++) {
    buf = (buf << 8) | u8[i]
    bits += 8
    while (bits >= 5) {
      bits -= 5
      out += B32[(buf >> bits) & 31]
    }
  }
  if (bits > 0) out += B32[(buf << (5 - bits)) & 31]
  while (out.length % 8 !== 0) out += '='
  return out
}

function bareB32DecodeToU8(s) {
  const t = String(s).replace(/\s+/g, '').replace(/=+$/, '')
  let buf = 0
  let bits = 0
  const bytes = []
  for (let i = 0; i < t.length; i++) {
    const c = t[i]
    const v = B32.indexOf(c)
    if (v < 0) throw new Error('invalid base32 character')
    buf = (buf << 5) | v
    bits += 5
    if (bits >= 8) {
      bits -= 8
      bytes.push((buf >> bits) & 255)
    }
  }
  return new Uint8Array(bytes)
}

function bareB64EncodeBytes(u8) {
  const B =
    'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'
  let out = ''
  let i = 0
  for (; i + 2 < u8.length; i += 3) {
    const n = (u8[i] << 16) | (u8[i + 1] << 8) | u8[i + 2]
    out += B[(n >> 18) & 63] + B[(n >> 12) & 63] + B[(n >> 6) & 63] + B[n & 63]
  }
  const rest = u8.length - i
  if (rest === 1) {
    const n = u8[i] << 16
    out += B[(n >> 18) & 63] + B[(n >> 12) & 63] + '=='
  } else if (rest === 2) {
    const n = (u8[i] << 16) | (u8[i + 1] << 8)
    out += B[(n >> 18) & 63] + B[(n >> 12) & 63] + B[(n >> 6) & 63] + '='
  }
  return out
}

function bareB64DecodeToU8(s) {
  const t = String(s).replace(/\s+/g, '')
  if (typeof globalThis.Buffer !== 'undefined') {
    return new Uint8Array(globalThis.Buffer.from(t, 'base64'))
  }
  if (typeof globalThis.atob === 'function') {
    const bin = globalThis.atob(t)
    const out = new Uint8Array(bin.length)
    for (let i = 0; i < bin.length; i++) out[i] = bin.charCodeAt(i) & 255
    return out
  }
  throw new Error('base64 decode requires Buffer or atob')
}

async function run(ctx, argv) {
  let decode = false
  let base16 = false
  let base32 = false
  let base64 = false
  let wrap = 0
  const paths = []
  for (let i = 1; i < argv.length; i++) {
    const a = argv[i]
    if (a === '-h' || a === '--help') {
      ctx.console.log(
        'usage: basenc [--base16 | --base32 | --base64] [-d] [-w COLS] [FILE]\n' +
          '  --base16   hex (default when no base flag)\n' +
          '  --base32   RFC 4648 Base32\n' +
          '  --base64   RFC 4648 Base64\n' +
          '  -d         decode from text to raw bytes (stdout)\n' +
          '  -w COLS    wrap encoded output (base64/base32 only; 0 = no wrap)'
      )
      ctx.exitCode = 0
      return
    }
    if (a === '-d' || a === '--decode') {
      decode = true
      continue
    }
    if (a === '--base16') {
      base16 = true
      continue
    }
    if (a === '--base32') {
      base32 = true
      continue
    }
    if (a === '--base64') {
      base64 = true
      continue
    }
    if ((a === '-w' || a === '--wrap') && argv[i + 1]) {
      wrap = Number.parseInt(argv[++i], 10)
      if (!Number.isFinite(wrap) || wrap < 0) wrap = 0
      continue
    }
    if (a.startsWith('-')) {
      ctx.console.error('basenc: unsupported option ' + a)
      ctx.exitCode = 1
      return
    }
    paths.push(a)
  }

  const modeCount = (base16 ? 1 : 0) + (base32 ? 1 : 0) + (base64 ? 1 : 0)
  if (modeCount > 1) {
    ctx.console.error('basenc: specify at most one of --base16, --base32, --base64')
    ctx.exitCode = 1
    return
  }
  if (modeCount === 0) base16 = true

  const b4 = ctx.b4a
  let buf
  if (!paths.length || paths[0] === '-') {
    buf = b4.from(bareStdin(ctx))
  } else {
    const b = await ctx.vfs.readFile(paths[0])
    if (!b) {
      ctx.console.error('basenc: cannot read ' + paths[0])
      ctx.exitCode = 1
      return
    }
    buf = b instanceof Uint8Array ? b : new Uint8Array(b)
  }

  if (base16) {
    if (decode) {
      const text = b4.toString(buf)
      let raw
      try {
        raw = bareHexDecode(text)
      } catch (e) {
        ctx.console.error('basenc: ' + (e.message || e))
        ctx.exitCode = 1
        return
      }
      if (!bareOsEmitRaw(ctx, raw)) {
        ctx.console.error(
          'basenc: decode output requires process.stdout.write or ctx.bareOsBinWrite'
        )
        ctx.exitCode = 1
      }
      return
    }
    ctx.console.log(bareHexEncode(buf))
    return
  }

  if (base32) {
    if (decode) {
      const text = b4.toString(buf)
      let raw
      try {
        raw = bareB32DecodeToU8(text)
      } catch (e) {
        ctx.console.error('basenc: ' + (e.message || e))
        ctx.exitCode = 1
        return
      }
      if (!bareOsEmitRaw(ctx, raw)) {
        ctx.console.error(
          'basenc: decode output requires process.stdout.write or ctx.bareOsBinWrite'
        )
        ctx.exitCode = 1
      }
      return
    }
    let enc = bareB32EncodeBytes(buf)
    if (wrap > 0) {
      const lines = []
      for (let i = 0; i < enc.length; i += wrap) {
        lines.push(enc.slice(i, i + wrap))
      }
      enc = lines.join('\n')
    }
    ctx.console.log(enc)
    return
  }

  if (base64) {
    if (decode) {
      const text = new TextDecoder().decode(buf)
      let raw
      try {
        raw = bareB64DecodeToU8(text)
      } catch (e) {
        ctx.console.error('basenc: ' + (e.message || e))
        ctx.exitCode = 1
        return
      }
      if (!bareOsEmitRaw(ctx, raw)) {
        ctx.console.error(
          'basenc: decode output requires process.stdout.write or ctx.bareOsBinWrite'
        )
        ctx.exitCode = 1
      }
      return
    }
    let enc
    if (typeof globalThis.btoa === 'function') {
      let s = ''
      const step = 0x8000
      for (let i = 0; i < buf.length; i += step) {
        const chunk = buf.subarray(i, i + step)
        s += String.fromCharCode.apply(null, chunk)
      }
      enc = globalThis.btoa(s)
    } else {
      enc = bareB64EncodeBytes(buf)
    }
    if (wrap > 0) {
      const lines = []
      for (let i = 0; i < enc.length; i += wrap) {
        lines.push(enc.slice(i, i + wrap))
      }
      enc = lines.join('\n')
    }
    ctx.console.log(enc)
  }
}