/* 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
}

function bareParentLogical(p) {
  const t = p.replace(/\/+$/, '') || '/'
  if (t === '/') return '/'
  const i = t.lastIndexOf('/')
  return i <= 0 ? '/' : t.slice(0, i) || '/'
}

function bareJoinUnder(parent, rel) {
  if (rel.startsWith('/')) return rel
  const base = parent.replace(/\/+$/, '') || '/'
  if (base === '/') return '/' + rel.replace(/^\/+/, '')
  return base + '/' + rel.replace(/^\/+/, '')
}

function bareRelativeLogical(fromDirAbs, toAbs) {
  const from = fromDirAbs.replace(/\/+$/, '').split('/').filter(Boolean)
  const to = toAbs.replace(/\/+$/, '').split('/').filter(Boolean)
  let i = 0
  while (i < from.length && i < to.length && from[i] === to[i]) i++
  const up = from.length - i
  const parts = []
  for (let k = 0; k < up; k++) parts.push('..')
  parts.push(...to.slice(i))
  return parts.length ? parts.join('/') : '.'
}

async function run(ctx, argv) {
  let sym = false
  let force = false
  let relative = false
  const rest = []
  for (let i = 1; i < argv.length; i++) {
    const a = argv[i]
    if (a === '-s' || a === '--symbolic') {
      sym = true
      continue
    }
    if (a === '-f' || a === '--force') {
      force = true
      continue
    }
    if (a === '-r' || a === '--relative') {
      relative = true
      continue
    }
    if (a === '--') {
      rest.push(...argv.slice(i + 1))
      break
    }
    if (a.startsWith('-')) {
      ctx.console.error('ln: unsupported option ' + a)
      ctx.exitCode = 1
      return
    }
    rest.push(a)
  }
  if (!sym) {
    ctx.console.error('ln: only symbolic links (-s) are supported on Bare OS')
    ctx.exitCode = 1
    return
  }
  if (rest.length !== 2) {
    ctx.console.error('usage: ln -s [-f] [-r] TARGET LINK_NAME')
    ctx.exitCode = 1
    return
  }
  let target = rest[0]
  const linkName = rest[1]
  try {
    if (relative) {
      const linkAbs = ctx.vfs.resolveLogical(linkName)
      const linkDir = bareParentLogical(linkAbs)
      const tgtAbs = ctx.vfs.resolveLogical(target)
      target = bareRelativeLogical(linkDir, tgtAbs)
    }
    if (force) {
      try {
        await ctx.vfs.unlink(linkName)
      } catch {
        /* ignore */
      }
    }
    await ctx.vfs.symlink(target, linkName)
  } catch (e) {
    ctx.console.error('ln: ' + ((e && e.message) || e))
    ctx.exitCode = 1
  }
}