/** Shared helpers for drive-resident /bin scripts (prepended before each command). */
function bareStdin(ctx) {
  return typeof ctx.shellStdin === 'string' ? ctx.shellStdin : ''
}

async function evalTest(ctx, args) {
  if (!args.length) return false
  if (args[0] === '!') {
    const inner = await evalTest(ctx, args.slice(1))
    return !inner
  }
  if (args.length === 3) {
    const [a, op, b] = args
    if (op === '=') return a === b
    if (op === '!=') return a !== b
    return false
  }
  if (args.length === 2) {
    const op = args[0]
    const p = args[1]
    const st = await ctx.vfs.stat(p)
    if (op === '-e' || op === '-a') return st != null
    if (op === '-f') return st != null && st.type === 'file'
    if (op === '-d') return st != null && st.type === 'directory'
    if (op === '-z') return p.length === 0
    if (op === '-n') return p.length > 0
    return false
  }
  if (args.length === 1) return args[0] !== ''
  return false
}

async function run(ctx, argv) {
  ctx.exitCode = (await evalTest(ctx, argv.slice(1))) ? 0 : 1
}