Refactor for i18n, CMS integration, and project slugs; enhance admin & analytics

Co-authored-by: dennis <dennis@konkol.net>

middleware.ts

@@ -1,21 +1,82 @@
 import { NextResponse } from "next/server";
 import type { NextRequest } from "next/server";
 
+const SUPPORTED_LOCALES = ["en", "de"] as const;
+type SupportedLocale = (typeof SUPPORTED_LOCALES)[number];
+
+function pickLocaleFromHeader(acceptLanguage: string | null): SupportedLocale {
+  if (!acceptLanguage) return "en";
+  const lower = acceptLanguage.toLowerCase();
+  // Very small parser: prefer de, then en
+  if (lower.includes("de")) return "de";
+  if (lower.includes("en")) return "en";
+  return "en";
+}
+
+function hasLocalePrefix(pathname: string): boolean {
+  return SUPPORTED_LOCALES.some((l) => pathname === `/${l}` || pathname.startsWith(`/${l}/`));
+}
+
 export function middleware(request: NextRequest) {
-  // For /manage and /editor routes, the pages handle their own authentication
-  // No middleware redirect needed - let the pages show login forms
+  const { pathname, search } = request.nextUrl;
+
+  // Keep admin + APIs unlocalized for simplicity
+  const isAdminOrApi =
+    pathname.startsWith("/api/") ||
+    pathname === "/api" ||
+    pathname.startsWith("/manage") ||
+    pathname.startsWith("/editor");
+
+  // Locale routing for public site pages
+  const responseUrl = request.nextUrl.clone();
+
+  if (!isAdminOrApi) {
+    if (hasLocalePrefix(pathname)) {
+      // Persist locale preference
+      const locale = pathname.split("/")[1] as SupportedLocale;
+      const res = NextResponse.next();
+      res.cookies.set("NEXT_LOCALE", locale, { path: "/" });
+
+      // Continue below to add security headers
+      // eslint-disable-next-line no-use-before-define
+      return addHeaders(request, res);
+    }
+
+    // Redirect bare routes to locale-prefixed ones
+    const preferred = pickLocaleFromHeader(request.headers.get("accept-language"));
+    const redirectTarget =
+      pathname === "/" ? `/${preferred}` : `/${preferred}${pathname}${search || ""}`;
+    responseUrl.pathname = redirectTarget;
+    const res = NextResponse.redirect(responseUrl);
+    res.cookies.set("NEXT_LOCALE", preferred, { path: "/" });
+    // eslint-disable-next-line no-use-before-define
+    return addHeaders(request, res);
+  }
 
   // Fix for 421 Misdirected Request with Nginx Proxy Manager
   // Ensure proper host header handling for reverse proxy
-  const hostname = request.headers.get('host') || request.headers.get('x-forwarded-host') || '';
+  const hostname = request.headers.get("host") || request.headers.get("x-forwarded-host") || "";
   
   // Add security headers to all responses
   const response = NextResponse.next();
   
+  return addHeaders(request, response, hostname);
+}
+
+function addHeaders(request: NextRequest, response: NextResponse, hostnameOverride?: string) {
+  const hostname =
+    hostnameOverride ??
+    request.headers.get("host") ??
+    request.headers.get("x-forwarded-host") ??
+    "";
+
   // Set proper headers for Nginx Proxy Manager
   if (hostname) {
-    response.headers.set('X-Forwarded-Host', hostname);
-    response.headers.set('X-Real-IP', request.headers.get('x-real-ip') || request.headers.get('x-forwarded-for') || '');
+    response.headers.set("X-Forwarded-Host", hostname);
+    response.headers.set(
+      "X-Real-IP",
+      request.headers.get("x-real-ip") || request.headers.get("x-forwarded-for") || "",
+    );
   }
 
   // Security headers (complementing next.config.ts headers)
@@ -42,13 +103,11 @@ export const config = {
   matcher: [
     /*
      * Match all request paths except for the ones starting with:
-     * - api/email (email API routes)
-     * - api/health (health check)
+     * - api (all API routes)
      * - _next/static (static files)
      * - _next/image (image optimization files)
      * - favicon.ico (favicon file)
-     * - api/auth (auth API routes - need to be processed)
      */
-    "/((?!api/email|api/health|_next/static|_next/image|favicon.ico|api/auth).*)",
+    "/((?!api|_next/static|_next/image|favicon.ico).*)",
   ],
 };