const { test } = require('node:test')
const assert = require('node:assert/strict')
const fs = require('node:fs')
const os = require('node:os')
const path = require('node:path')
const { mergeAssets } = require('./preserve_frontend_assets.cjs')

test('keeps old lazy chunks without replacing current build files', () => {
  const dir = fs.mkdtempSync(path.join(os.tmpdir(), 'assets-test-'))
  try {
    const old = path.join(dir, 'old'), current = path.join(dir, 'current')
    fs.mkdirSync(old); fs.mkdirSync(current)
    fs.writeFileSync(path.join(old, 'Agent-oldhash.js'), 'old import')
    fs.writeFileSync(path.join(old, 'shared.css'), 'old style')
    fs.writeFileSync(path.join(current, 'shared.css'), 'current style')
    assert.equal(mergeAssets(old, current), 1)
    assert.equal(fs.readFileSync(path.join(current, 'Agent-oldhash.js'), 'utf8'), 'old import')
    assert.equal(fs.readFileSync(path.join(current, 'shared.css'), 'utf8'), 'current style')
    assert.equal(mergeAssets(old, current), 0)
  } finally { fs.rmSync(dir, { recursive: true, force: true }) }
})