/* 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
}

/**
 * date — print current date/time; optional +FORMAT (strftime-like subset).
 */

/**
 * @param {string} fmt
 * @param {Date} d
 * @param {boolean} utc
 */
function bareDateFormat(fmt, d, utc) {
  const pad2 = (n) => String(n).padStart(2, '0')
  const pad3 = (n) => String(n).padStart(3, '0')
  const Y = utc ? d.getUTCFullYear() : d.getFullYear()
  const m = utc ? d.getUTCMonth() + 1 : d.getMonth() + 1
  const day = utc ? d.getUTCDate() : d.getDate()
  const H = utc ? d.getUTCHours() : d.getHours()
  const M = utc ? d.getUTCMinutes() : d.getMinutes()
  const S = utc ? d.getUTCSeconds() : d.getSeconds()
  const ms = utc ? d.getUTCMilliseconds() : d.getMilliseconds()

  let o = ''
  for (let i = 0; i < fmt.length; i++) {
    if (fmt[i] !== '%') {
      o += fmt[i]
      continue
    }
    if (fmt[i + 1] === '%') {
      o += '%'
      i++
      continue
    }
    const spec = fmt[i + 1] || ''
    i++
    switch (spec) {
      case 'Y':
        o += String(Y).padStart(4, '0')
        break
      case 'm':
        o += pad2(m)
        break
      case 'd':
        o += pad2(day)
        break
      case 'H':
        o += pad2(H)
        break
      case 'M':
        o += pad2(M)
        break
      case 'S':
        o += pad2(S)
        break
      case 's':
        o += String(Math.floor(d.getTime() / 1000))
        break
      case '3N':
        o += pad3(ms)
        break
      case 'z': {
        if (utc) {
          o += '+0000'
          break
        }
        const offMin = -d.getTimezoneOffset()
        const sign = offMin >= 0 ? '+' : '-'
        const abs = Math.abs(offMin)
        const oh = Math.floor(abs / 60)
        const om = abs % 60
        o += sign + pad2(oh) + pad2(om)
        break
      }
      case 'a': {
        const days = ['Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat']
        o += days[utc ? d.getUTCDay() : d.getDay()]
        break
      }
      case 'b': {
        const mons = [
          'Jan',
          'Feb',
          'Mar',
          'Apr',
          'May',
          'Jun',
          'Jul',
          'Aug',
          'Sep',
          'Oct',
          'Nov',
          'Dec'
        ]
        o += mons[(utc ? d.getUTCMonth() : d.getMonth()) || 0]
        break
      }
      default:
        o += '%' + spec
    }
  }
  return o
}

async function run(ctx, argv) {
  const utc = argv.includes('-u') || argv.includes('--utc')
  const rest = argv.filter((a) => a !== '-u' && a !== '--utc')
  const plus = rest.find((a) => a.startsWith('+') && a.length > 1)
  const d = new Date()
  if (plus) {
    ctx.console.log(bareDateFormat(plus.slice(1), d, utc))
    return
  }
  ctx.console.log(
    utc
      ? d
          .toISOString()
          .replace('T', ' ')
          .replace(/\.\d{3}Z$/, ' UTC')
      : d.toString()
  )
}