/* 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
}

/**
 * chgrp — change file group (Hyperdrive metadata on writable paths).
 */

/**
 * @param {string} spec
 * @param {Record<string, string>} env
 * @returns {number | null}
 */
function parseGroupSpec(spec, env) {
  const s = String(spec).trim()
  if (!s) return null
  if (/^\d+$/.test(s)) {
    const n = Number.parseInt(s, 10)
    return Number.isFinite(n) ? n : null
  }
  const g = (env.GROUP || env.USER || 'guest').trim()
  if (s === 'root') return 0
  if (s === 'guest' || s === 'nobody') return 65534
  if (g && s === g) {
    const gid = Number.parseInt(String(env.GID ?? '65534'), 10)
    return Number.isFinite(gid) ? gid : 65534
  }
  return null
}

async function run(ctx, argv) {
  let i = 1
  const files = []
  for (; i < argv.length; i++) {
    const a = argv[i]
    if (a === '-h' || a === '--help') {
      ctx.console.log(
        'usage: chgrp [-h] GROUP FILE...\n' +
          'GROUP may be a numeric gid or root/guest/nobody/current GROUP name.'
      )
      ctx.exitCode = 0
      return
    }
    if (!a.startsWith('-')) break
    ctx.console.error('chgrp: unsupported option: ' + a)
    ctx.exitCode = 1
    return
  }
  const groupSpec = argv[i++]
  if (!groupSpec || i >= argv.length) {
    ctx.console.error('usage: chgrp GROUP FILE...')
    ctx.exitCode = 1
    return
  }
  for (; i < argv.length; i++) files.push(argv[i])
  const gid = parseGroupSpec(groupSpec, ctx.vfs.env)
  if (gid == null) {
    ctx.console.error('chgrp: invalid group: ' + groupSpec)
    ctx.exitCode = 1
    return
  }
  const gname = /^\d+$/.test(groupSpec.trim())
    ? undefined
    : groupSpec.trim() || undefined
  for (const f of files) {
    try {
      const st = await ctx.vfs.stat(f)
      if (!st) {
        ctx.console.error('chgrp: ' + f + ': No such file')
        ctx.exitCode = 1
        continue
      }
      if (typeof ctx.vfs.chown !== 'function') {
        ctx.console.error('chgrp: not supported by this VFS')
        ctx.exitCode = 1
        return
      }
      await ctx.vfs.chown(f, {
        uid: st.uid,
        gid,
        uname: st.user,
        gname
      })
    } catch (e) {
      ctx.console.error('chgrp: ' + f + ': ' + (e.message || e))
      ctx.exitCode = 1
    }
  }
}