/* 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
}

async function duBytes(ctx, path, followSymlinks) {
  const st = followSymlinks
    ? await ctx.vfs.stat(path)
    : await ctx.vfs.lstat(path)
  if (!st) return 0
  if (st.type === 'file' || st.type === 'symlink') {
    return st.size || 0
  }
  let total = st.size || 0
  let names = []
  try {
    names = await ctx.vfs.readdir(path)
  } catch {
    return total
  }
  for (const n of names) {
    if (n === '.bareos_empty') continue
    const sub = path.replace(/\/+$/, '') + '/' + n
    total += await duBytes(ctx, sub, followSymlinks)
  }
  return total
}

async function duPath(ctx, path, blockSize, followSymlinks) {
  const st = followSymlinks
    ? await ctx.vfs.stat(path)
    : await ctx.vfs.lstat(path)
  if (!st) return 0
  if (st.type === 'file' || st.type === 'symlink') {
    return Math.ceil((st.size || 0) / blockSize) || 1
  }
  let total = Math.ceil((st.size || 0) / blockSize) || 1
  let names = []
  try {
    names = await ctx.vfs.readdir(path)
  } catch {
    return total
  }
  for (const n of names) {
    if (n === '.bareos_empty') continue
    const sub = path.replace(/\/+$/, '') + '/' + n
    total += await duPath(ctx, sub, blockSize, followSymlinks)
  }
  return total
}

/** @param {number} bytes */
function duHuman(bytes) {
  if (!Number.isFinite(bytes) || bytes < 0) bytes = 0
  const units = ['K', 'M', 'G', 'T', 'P']
  if (bytes < 1024) return String(bytes)
  let u = -1
  let v = bytes
  while (v >= 1024 && u < units.length - 1) {
    v /= 1024
    u++
  }
  const rounded = v >= 10 ? Math.round(v) : Math.round(v * 10) / 10
  const s = String(rounded).replace(/\.0$/, '')
  return s + units[u]
}

async function duPrintAll(ctx, path, human, blockSize, followSymlinks) {
  const st = followSymlinks
    ? await ctx.vfs.stat(path)
    : await ctx.vfs.lstat(path)
  if (!st) return
  const bytes = st.size || 0
  const blocks =
    human || blockSize <= 0
      ? null
      : Math.ceil(bytes / blockSize) || (bytes === 0 ? 0 : 1)
  const label = human ? duHuman(bytes) : String(blocks)
  ctx.console.log(label + '\t' + path)
  if (st.type !== 'directory') return
  let names = []
  try {
    names = await ctx.vfs.readdir(path)
  } catch {
    return
  }
  for (const n of names) {
    if (n === '.bareos_empty') continue
    const sub = path.replace(/\/+$/, '') + '/' + n
    await duPrintAll(ctx, sub, human, blockSize, followSymlinks)
  }
}

async function run(ctx, argv) {
  let blockSize = 512
  let human = false
  let allFiles = false
  let followSymlinks = false
  const paths = []
  for (let i = 1; i < argv.length; i++) {
    if (argv[i] === '-k') blockSize = 1024
    else if (argv[i] === '-h' || argv[i] === '--human-readable') human = true
    else if (argv[i] === '-a' || argv[i] === '--all') allFiles = true
    else if (argv[i] === '-L' || argv[i] === '--dereference') followSymlinks = true
    else if (argv[i] === '-s' || argv[i] === '--summarize') {
      /* Bare du already prints one total per path (GNU -s default for us). */
    } else if (argv[i] !== '--') paths.push(argv[i])
  }
  const targets = paths.length ? paths : ['.']
  for (const p of targets) {
    try {
      const abs = ctx.vfs.resolveLogical(p)
      if (allFiles) {
        await duPrintAll(ctx, abs, human, blockSize, followSymlinks)
        continue
      }
      if (human) {
        const b = await duBytes(ctx, abs, followSymlinks)
        ctx.console.log(duHuman(b) + '\t' + p)
      } else {
        const kb = await duPath(ctx, abs, blockSize, followSymlinks)
        ctx.console.log(String(kb) + '\t' + p)
      }
    } catch (e) {
      ctx.console.error('du: ' + p + ': ' + ((e && e.message) || e))
      ctx.exitCode = 1
    }
  }
}