function normalizeBaseUrl(value) {
  const raw = String(value || '').trim()
  if (!raw) return ''
  return raw.replace(/\/+$/, '')
}

export default defineEventHandler((event) => {
  const runtimeConfig = useRuntimeConfig(event)
  const requestUrl = getRequestURL(event)

  const baseUrl = normalizeBaseUrl(runtimeConfig.public?.baseUrl) || `${requestUrl.protocol}//${requestUrl.host}`

  const lines = [
    'User-agent: *',
    'Allow: /',
    'Disallow: /cms',
    'Disallow: /cms/',
    'Disallow: /mitgliederbereich',
    'Disallow: /mitgliederbereich/',
    'Disallow: /api/',
    'Disallow: /login',
    'Disallow: /registrieren',
    'Disallow: /passwort-vergessen',
    'Disallow: /konto-loeschen',
    `Sitemap: ${baseUrl}/sitemap.xml`
  ]

  setHeader(event, 'Content-Type', 'text/plain; charset=utf-8')
  return `${lines.join('\n')}\n`
})