/* 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 parseTouchDate(s) {
  const t = String(s || '').trim()
  if (t.startsWith('@')) {
    const sec = Number(t.slice(1))
    if (Number.isFinite(sec)) return Math.round(sec * 1000)
    return null
  }
  const ms = Date.parse(t)
  return Number.isFinite(ms) ? ms : null
}

function parseTouchArgv(argv) {
  let onlyA = false
  let onlyM = false
  /** @type {{ kind: 'd', s: string } | { kind: 'r', path: string } | null} */
  let timeSpec = null
  const files = []
  let i = 1
  while (i < argv.length) {
    const a = argv[i]
    if (a === '--') {
      files.push(...argv.slice(i + 1))
      return { onlyA, onlyM, timeSpec, files }
    }
    if (a === '-a') {
      onlyA = true
      i++
      continue
    }
    if (a === '-m') {
      onlyM = true
      i++
      continue
    }
    if (a === '-d' || a === '--date') {
      i++
      if (i >= argv.length) {
        return { err: 'touch: option requires an argument -- ' + a.slice(1) }
      }
      timeSpec = { kind: 'd', s: argv[i] }
      i++
      continue
    }
    if (a === '-r' || a === '--reference') {
      i++
      if (i >= argv.length) {
        return { err: 'touch: option requires an argument -- reference' }
      }
      timeSpec = { kind: 'r', path: argv[i] }
      i++
      continue
    }
    if (a.startsWith('-')) {
      return { err: 'touch: unsupported option ' + a }
    }
    files.push(a)
    i++
  }
  return { onlyA, onlyM, timeSpec, files }
}

async function run(ctx, argv) {
  const p = parseTouchArgv(argv)
  if (p.err) {
    ctx.console.error(p.err)
    ctx.exitCode = 1
    return
  }
  const { onlyA, onlyM, timeSpec, files } = p
  if (!files.length) {
    ctx.console.error('touch: missing file operand')
    ctx.exitCode = 1
    return
  }

  /** @type {number | null} */
  let T = null
  if (timeSpec) {
    if (timeSpec.kind === 'd') {
      const ms = parseTouchDate(timeSpec.s)
      if (ms == null) {
        ctx.console.error('touch: invalid date ' + JSON.stringify(timeSpec.s))
        ctx.exitCode = 1
        return
      }
      T = ms
    } else {
      try {
        const st = await ctx.vfs.lstat(timeSpec.path)
        if (!st) {
          ctx.console.error(
            'touch: failed to get attributes of ' +
              timeSpec.path +
              ': No such file'
          )
          ctx.exitCode = 1
          return
        }
        T =
          typeof st.mtimeMs === 'number' && Number.isFinite(st.mtimeMs)
            ? st.mtimeMs
            : null
      } catch (e) {
        ctx.console.error(
          'touch: ' + timeSpec.path + ': ' + ((e && e.message) || String(e))
        )
        ctx.exitCode = 1
        return
      }
    }
  }
  if (T == null) T = Date.now()
  let changeMtime = true
  let changeCtime = true
  if (onlyA && !onlyM) {
    changeMtime = false
    changeCtime = true
  } else if (onlyM && !onlyA) {
    changeMtime = true
    changeCtime = false
  }

  const vfs = ctx.vfs
  for (const f of files) {
    try {
      const existingBuf = await vfs.readFile(f)
      let st = null
      try {
        st = await vfs.lstat(f)
      } catch {
        st = null
      }
      const buf = existingBuf || ctx.b4a.from('')
      let newM
      let newC
      if (!st) {
        newM = T
        newC = T
      } else {
        const pm =
          typeof st.mtimeMs === 'number' && Number.isFinite(st.mtimeMs)
            ? st.mtimeMs
            : T
        const pc =
          typeof st.ctimeMs === 'number' && Number.isFinite(st.ctimeMs)
            ? st.ctimeMs
            : T
        newM = changeMtime ? T : pm
        newC = changeCtime ? T : pc
      }
      await vfs.writeFile(f, buf, {
        bumpMtime: false,
        touchCtime: false,
        mtimeMs: newM,
        ctimeMs: newC
      })
    } catch (e) {
      ctx.console.error('touch: ' + f + ': ' + (e.message || e))
      ctx.exitCode = 1
    }
  }
}