/**
 * expand -t comma-separated tab stops
 */
import { readFile } from 'node:fs/promises'
import path from 'node:path'
import { fileURLToPath } from 'node:url'
import test from 'brittle'
import b4a from 'b4a'

const __dirname = path.dirname(fileURLToPath(import.meta.url))

const AsyncFunction = Object.getPrototypeOf(async function () {}).constructor

async function loadBin(name) {
  const runtime = await readFile(
    path.join(__dirname, '../lib/runtime.js'),
    'utf8'
  )
  const body = await readFile(
    path.join(__dirname, `../src/${name}.js`),
    'utf8'
  )
  return new AsyncFunction(
    'ctx',
    'argv',
    `${runtime}\n${body}\nif (typeof run === 'function') return await run(ctx, argv)\n`
  )
}

function createCtx() {
  const logs = []
  return {
    b4a,
    exitCode: 0,
    vfs: { async stat() { return null } },
    console: {
      log: (m) => logs.push(String(m)),
      error: (m) => logs.push(String(m))
    },
    _logs: logs
  }
}

test('expand -t 1,5 maps two leading tabs to five spaces before text', async (t) => {
  const run = await loadBin('expand')
  const ctx = createCtx()
  ctx.shellStdin = '\t\tfoo'
  await run(ctx, ['expand', '-t', '1,5'])
  t.is(ctx.exitCode, 0)
  t.is(ctx._logs.join('\n'), '     foo')
})

test('expand -t 8 uniform matches single-stop width', async (t) => {
  const run = await loadBin('expand')
  const ctx = createCtx()
  ctx.shellStdin = '\tx'
  await run(ctx, ['expand', '-t', '8'])
  t.is(ctx._logs.join('\n'), '        x')
})