function assertRouter(api) {
  if (!api || typeof api.get !== 'function') {
    throw new Error('attachPortalSeoDiscoveryRoutes requires an Express-compatible router');
  }
}

export function attachPortalSeoDiscoveryRoutes(
  app,
  {
    getAuthPool = () => null,
    getMindSpaceConfig = async () => ({ seoGeo: { enabled: false } }),
    getSeoDiscoveryService = () => null,
    resolveRequestOrigin = () => '',
  } = {},
) {
  assertRouter(app);

  app.get('/robots.txt', async (req, res) => {
    const config = await getMindSpaceConfig();
    const seoGeo = config?.seoGeo ?? {};
    if (!seoGeo.enabled || !seoGeo.seo?.robotsTxt) {
      return res.type('text/plain; charset=utf-8').send('User-agent: *\nDisallow: /\n');
    }
    const service = getSeoDiscoveryService();
    if (!service) {
      return res.status(503).type('text/plain; charset=utf-8').send('SEO discovery unavailable\n');
    }
    const origin = resolveRequestOrigin(req);
    return res
      .type('text/plain; charset=utf-8')
      .set('Cache-Control', 'public, max-age=300')
      .send(
        service.renderRobotsTxt({
          origin,
          sitemapEnabled: Boolean(seoGeo.seo?.sitemap),
          llmsTxtEnabled: Boolean(seoGeo.geo?.llmsTxt),
        }),
      );
  });

  app.get('/sitemap.xml', async (req, res) => {
    const config = await getMindSpaceConfig();
    const seoGeo = config?.seoGeo ?? {};
    if (!seoGeo.enabled || !seoGeo.seo?.enabled || !seoGeo.seo?.sitemap) {
      return res.status(404).type('text/plain; charset=utf-8').send('Not Found\n');
    }
    const pool = getAuthPool();
    const service = getSeoDiscoveryService();
    if (!pool || !service) {
      return res.status(503).type('text/plain; charset=utf-8').send('SEO discovery unavailable\n');
    }
    const origin = resolveRequestOrigin(req);
    const entries = await service.listIndexablePublications(pool, {
      limit: req.query.limit,
      offset: req.query.offset,
    });
    return res
      .type('application/xml; charset=utf-8')
      .set('Cache-Control', 'public, max-age=300')
      .send(service.renderSitemapXml(entries, { origin }));
  });

  app.get('/llms.txt', async (req, res) => {
    const config = await getMindSpaceConfig();
    const seoGeo = config?.seoGeo ?? {};
    if (!seoGeo.enabled || !seoGeo.geo?.enabled || !seoGeo.geo?.llmsTxt) {
      return res.status(404).type('text/plain; charset=utf-8').send('Not Found\n');
    }
    const pool = getAuthPool();
    const service = getSeoDiscoveryService();
    if (!pool || !service) {
      return res.status(503).type('text/plain; charset=utf-8').send('GEO discovery unavailable\n');
    }
    const origin = resolveRequestOrigin(req);
    const entries = await service.listIndexablePublications(pool, {
      limit: req.query.limit,
      offset: req.query.offset,
    });
    return res
      .type('text/plain; charset=utf-8')
      .set('Cache-Control', 'public, max-age=300')
      .send(service.renderLlmsTxt(entries, { origin }));
  });
}