/* 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
}

/**
 * Walk a home directory on the VFS and emit a bounded manifest (no archive bytes).
 */
async function run(ctx, argv) {
  let json = false
  let maxFiles = 8000
  let maxDepth = 12
  /** @type {string[]} */
  const roots = []
  for (let i = 1; i < argv.length; i++) {
    if (argv[i] === '--json') json = true
    else if (argv[i] === '--max' && argv[i + 1]) {
      maxFiles = Number.parseInt(argv[++i], 10) || maxFiles
    } else if (argv[i] === '--depth' && argv[i + 1]) {
      maxDepth = Number.parseInt(argv[++i], 10) || maxDepth
    } else if (!argv[i].startsWith('-')) roots.push(argv[i])
  }
  const vfs = ctx.vfs
  const b4 = ctx.b4a
  if (!vfs || !b4 || typeof vfs.readdir !== 'function') {
    ctx.console.error('kernel-home-snapshot: vfs unavailable')
    ctx.exitCode = 1
    return
  }
  const home =
    roots.length > 0
      ? roots[0]
      : String(vfs.env?.HOME || vfs.env?.USERPROFILE || '/').trim() || '/'
  let absRoot
  try {
    absRoot = vfs.resolveLogical(home)
  } catch {
    ctx.console.error('kernel-home-snapshot: bad home path')
    ctx.exitCode = 1
    return
  }

  /** @type {{ path: string, kind: string, size?: number }[]} */
  const entries = []
  let truncated = false

  /**
   * @param {string} abs
   * @param {string} display
   * @param {number} depth
   */
  async function walk(abs, display, depth) {
    if (entries.length >= maxFiles) {
      truncated = true
      return
    }
    if (depth > maxDepth) return
    /** @type {string[]} */
    const sub = []
    try {
      for await (const n of vfs.readdir(abs)) sub.push(n)
    } catch {
      return
    }
    sub.sort()
    for (const name of sub) {
      if (entries.length >= maxFiles) {
        truncated = true
        return
      }
      const childAbs = abs.replace(/\/$/, '') + '/' + name
      const childDisp = display.replace(/\/$/, '') + '/' + name
      try {
        for await (const _ of vfs.readdir(childAbs)) {
          void _
          break
        }
      } catch {
        let size = 0
        try {
          const buf = await vfs.readFile(childAbs)
          size = buf ? buf.byteLength || buf.length || 0 : 0
        } catch {
          size = -1
        }
        entries.push({ path: childDisp, kind: 'file', size })
        continue
      }
      entries.push({ path: childDisp, kind: 'dir' })
      await walk(childAbs, childDisp, depth + 1)
    }
  }

  entries.push({ path: home, kind: 'root' })
  await walk(absRoot, home, 0)

  const out = {
    schema: 2,
    ok: true,
    root: home,
    entryCount: entries.length,
    truncated,
    maxFiles,
    maxDepth,
    entries,
    atMs: Date.now(),
    note: 'VFS manifest only; use host backup for full byte streams.'
  }
  if (json) {
    ctx.console.log(JSON.stringify(out, null, 2))
  } else {
    ctx.console.log(
      'kernel-home-snapshot: ' +
        entries.length +
        ' entries under ' +
        home +
        (truncated ? ' (truncated)' : '')
    )
  }
  ctx.exitCode = 0
}