import { defineMiddleware } from 'astro/middleware';
import { getRedirectUrl, getRedirectStatus } from './utils/redirects';

export const onRequest = defineMiddleware(async (context, next) => {
  const { url } = context;
  const { pathname } = url;
  
  // 1. Prüfe zuerst die Redirect-Map für alte URLs
  const redirectUrl = getRedirectUrl(pathname);
  if (redirectUrl) {
    const status = getRedirectStatus(pathname);
    return context.redirect(redirectUrl, status);
  }
  
  // 2. Handle root path - redirect to /de
  if (pathname === '/') {
    return context.redirect('/de', 301);
  }
  
  // 3. Handle paths without language prefix (except special paths)
  const segments = pathname.split('/').filter(Boolean);
  const firstSegment = segments[0];
  const validLanguages = ['de', 'en'];
  const specialPaths = ['admin', 'api', '_astro', 'images', 'favicon', '404'];
  
  // If no language prefix and not a special path, redirect to /de/...
  if (!validLanguages.includes(firstSegment) && !specialPaths.includes(firstSegment) && !pathname.includes('.')) {
    return context.redirect(`/de${pathname}`, 301);
  }
  
  // 4. Lasse alle anderen Requests durch
  const response = await next();
  
  // 5. Log 404 errors für Monitoring (nur in Production)
  if (response.status === 404 && import.meta.env.PROD) {
    console.warn(`404 Error: ${pathname} | Referrer: ${context.request.headers.get('referer') || 'direct'}`);
  }
  
  return response;
});