redirecting to homepage when user not logged in (#421)

* redirecting to homepage when user not logged in

* linting

frontend/src/App.tsx

@@ -35,6 +35,7 @@ const router = createBrowserRouter(
     >
       <Route index element={<HomePages />} loader={fetchProjectPage} />
       <Route path=":lang" element={<LanguagePath />}>
+        <Route index element={<HomePages />} loader={fetchProjectPage} />
         <Route path="home" element={<HomePages />} loader={fetchProjectPage} />
         <Route path="courses">
           <Route

frontend/src/components/Header/Layout.tsx

@@ -1,13 +1,35 @@
-import { Outlet, useLoaderData } from "react-router-dom";
+import {
+  Outlet,
+  useLoaderData,
+  useLocation,
+  useNavigate,
+} from "react-router-dom";
 import { Header } from "./Header.tsx";
 import { Me } from "../../types/me.ts";
+import { useEffect } from "react";
+import i18next from "i18next";
 
 /**
  * Basic layout component that will be used on all routes.
  * @returns The Layout component
  */
 export default function Layout(): JSX.Element {
   const meData: Me = useLoaderData() as Me;
+  useEnsureLangCodeInPath();
+  const navigate = useNavigate();
+  const location = useLocation();
+
+  useEffect(() => {
+    if (
+      !meData.loggedIn &&
+      !(
+        location.pathname === "/" ||
+        /\/([a-z]{2})?\/home/.test(location.pathname)
+      )
+    ) {
+      navigate("/");
+    }
+  }, [meData.loggedIn, location.pathname, navigate]);
 
   return (
     <>
@@ -16,3 +38,20 @@ export default function Layout(): JSX.Element {
     </>
   );
 }
+
+const useEnsureLangCodeInPath = () => {
+  const location = useLocation();
+  const navigate = useNavigate();
+
+  useEffect(() => {
+    const pathParts = location.pathname.split("/").filter(Boolean);
+    const langCode = i18next.resolvedLanguage;
+
+    // Check if the URL starts with the lang code
+    if (pathParts[0] !== langCode) {
+      // Prepend the lang code to the path
+      const newPath = `/${langCode}/${pathParts.join("/")}`;
+      navigate(newPath);
+    }
+  }, [location, navigate]);
+};