/* 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
}

/**
 * @param {string} line
 * @param {string | null} delim
 * @param {number} start1
 * @param {number | null} end1
 */
function sortKeySlice(line, delim, start1, end1) {
  /** @type {string[]} */
  let fields
  if (delim != null) {
    if (delim === '') fields = line.split('')
    else fields = line.split(delim)
  } else {
    const t = line.trim()
    fields = t.length ? t.split(/\s+/) : []
  }
  const i0 = Math.max(0, start1 - 1)
  const i1 = end1 != null ? end1 : fields.length
  const slice = fields.slice(i0, i1)
  if (delim != null) return slice.join(delim)
  return slice.join(' ')
}

async function run(ctx, argv) {
  const vfs = ctx.vfs
  let numeric = false
  let reverse = false
  let uniq = false
  let fold = false
  /** @type {string | undefined} */
  let delim
  /** @type {number | null} */
  let keyStart = null
  /** @type {number | null} */
  let keyEnd = null
  let i = 1
  while (i < argv.length) {
    const a = argv[i]
    if (a === '--') {
      i++
      break
    }
    if (a === '-n' || a === '--numeric-sort' || a === '-g') {
      numeric = true
      i++
      continue
    }
    if (a === '-r' || a === '--reverse') {
      reverse = true
      i++
      continue
    }
    if (a === '-u' || a === '--unique') {
      uniq = true
      i++
      continue
    }
    if (a === '-f' || a === '--ignore-case') {
      fold = true
      i++
      continue
    }
    if (a === '-t' || a === '--field-separator') {
      const d = argv[++i]
      if (d === undefined) {
        ctx.console.error('sort: option requires an argument -- t')
        ctx.exitCode = 1
        return
      }
      delim = d === '\\t' ? '\t' : d
      i++
      continue
    }
    if (a.startsWith('-t') && a.length > 2) {
      delim = a.slice(2) === 't' ? '\t' : a.slice(2)
      i++
      continue
    }
    if (a === '-k' || a === '--key') {
      const spec = argv[++i]
      if (spec === undefined) {
        ctx.console.error('sort: option requires an argument -- k')
        ctx.exitCode = 1
        return
      }
      const parts = String(spec).split(',')
      keyStart = Number.parseInt(parts[0], 10)
      keyEnd =
        parts[1] !== undefined && parts[1] !== ''
          ? Number.parseInt(parts[1], 10)
          : null
      if (!Number.isFinite(keyStart) || keyStart < 1) {
        ctx.console.error('sort: invalid key specification')
        ctx.exitCode = 1
        return
      }
      if (
        keyEnd != null &&
        (!Number.isFinite(keyEnd) || keyEnd < keyStart)
      ) {
        ctx.console.error('sort: invalid key specification')
        ctx.exitCode = 1
        return
      }
      i++
      continue
    }
    if (/^-k\d/.test(a)) {
      const spec = a.slice(2)
      const parts = String(spec).split(',')
      keyStart = Number.parseInt(parts[0], 10)
      keyEnd =
        parts[1] !== undefined && parts[1] !== ''
          ? Number.parseInt(parts[1], 10)
          : null
      if (!Number.isFinite(keyStart) || keyStart < 1) {
        ctx.console.error('sort: invalid key specification')
        ctx.exitCode = 1
        return
      }
      i++
      continue
    }
    if (a.startsWith('-') && a.length > 1) {
      let j = 1
      let ok = true
      while (j < a.length) {
        const c = a[j++]
        if (c === 'n') numeric = true
        else if (c === 'r') reverse = true
        else if (c === 'u') uniq = true
        else if (c === 'f') fold = true
        else {
          ok = false
          break
        }
      }
      if (ok) {
        i++
        continue
      }
    }
    break
  }

  const files = argv.slice(i).filter((x) => x !== '--')
  /** @type {string[]} */
  let lines = []
  if (!files.length) {
    const s = bareStdin(ctx)
    lines = s.length ? s.split('\n') : []
    if (lines.length && lines[lines.length - 1] === '') lines.pop()
  } else {
    for (const f of files) {
      if (f === '-') {
        const s = bareStdin(ctx)
        const part = s.length ? s.split('\n') : []
        if (part.length && part[part.length - 1] === '') part.pop()
        lines.push(...part)
        continue
      }
      const buf = await vfs.readFile(f)
      if (!buf) {
        ctx.console.error('sort: ' + f + ': No such file')
        ctx.exitCode = 1
        continue
      }
      const part = ctx.b4a.toString(buf).split('\n')
      if (part.length && part[part.length - 1] === '') part.pop()
      lines.push(...part)
    }
  }

  const dForKey = delim === undefined ? null : delim

  /** @param {string} s */
  function sortKey(s) {
    const keyText =
      keyStart != null
        ? sortKeySlice(s, dForKey, keyStart, keyEnd)
        : s
    if (numeric) {
      const m = String(keyText).match(
        /^\s*(-?(?:\d+(?:\.\d*)?|\.\d+)(?:[eE][+-]?\d+)?)/
      )
      if (m) return { n: Number(m[1]), raw: keyText }
      return { n: Number.POSITIVE_INFINITY, raw: keyText }
    }
    if (fold) return { n: 0, raw: keyText.toLowerCase() }
    return { n: 0, raw: keyText }
  }

  lines.sort((x, y) => {
    const kx = sortKey(x)
    const ky = sortKey(y)
    if (numeric) {
      if (kx.n !== ky.n) {
        const ord = kx.n < ky.n ? -1 : 1
        return reverse ? -ord : ord
      }
    }
    const cmp =
      kx.raw < ky.raw ? -1 : kx.raw > ky.raw ? 1 : x < y ? -1 : x > y ? 1 : 0
    return reverse ? -cmp : cmp
  })

  if (uniq) {
    const out = []
    let prev = null
    for (const ln of lines) {
      if (ln !== prev) out.push(ln)
      prev = ln
    }
    lines = out
  }

  if (lines.length) ctx.console.log(lines.join('\n'))
}