Initial commit: RhetorikMaster PWA Trainer & Klausur-Spickzettel

www/sw.js

@@ -0,0 +1,80 @@
+const CACHE_NAME = 'rhetorikmaster-v5';
+const STATIC_ASSETS = [
+  '/',
+  '/index.html',
+  '/rhetorik_trainer_quiz.html',
+  '/favicon.svg',
+  '/manifest.json',
+  '/icon-192.png',
+  '/icon-512.png',
+  'https://cdn.tailwindcss.com',
+  'https://cdnjs.cloudflare.com/ajax/libs/font-awesome/6.4.0/css/all.min.css',
+  'https://fonts.googleapis.com/css2?family=Plus+Jakarta+Sans:wght@400;500;600;700;800&display=swap'
+];
+
+self.addEventListener('install', (event) => {
+  event.waitUntil(
+    caches.open(CACHE_NAME).then((cache) => {
+      return cache.addAll(STATIC_ASSETS).catch((err) => {
+        console.warn('Precache partial failure:', err);
+      });
+    })
+  );
+  self.skipWaiting();
+});
+
+self.addEventListener('activate', (event) => {
+  event.waitUntil(
+    caches.keys().then((cacheNames) => {
+      return Promise.all(
+        cacheNames.map((name) => {
+          if (name !== CACHE_NAME) {
+            console.log('Cleaning old cache:', name);
+            return caches.delete(name);
+          }
+        })
+      );
+    }).then(() => self.clients.claim())
+  );
+});
+
+self.addEventListener('fetch', (event) => {
+  const request = event.request;
+  const isHtmlNavigation = request.mode === 'navigate' || 
+    (request.method === 'GET' && request.headers.get('accept') && request.headers.get('accept').includes('text/html'));
+
+  if (isHtmlNavigation) {
+    // Network-First for HTML/Navigation: Always fetch fresh HTML from server, fallback to cache if offline
+    event.respondWith(
+      fetch(request)
+        .then((networkResponse) => {
+          if (networkResponse && networkResponse.status === 200) {
+            const copy = networkResponse.clone();
+            caches.open(CACHE_NAME).then((cache) => cache.put(request, copy));
+          }
+          return networkResponse;
+        })
+        .catch(() => {
+          return caches.match(request).then((cached) => cached || caches.match('/rhetorik_trainer_quiz.html') || caches.match('/'));
+        })
+    );
+    return;
+  }
+
+  // Stale-While-Revalidate for other static assets (CSS, fonts, images)
+  event.respondWith(
+    caches.match(request).then((cachedResponse) => {
+      const fetchPromise = fetch(request).then((networkResponse) => {
+        if (networkResponse && networkResponse.status === 200) {
+          const responseToCache = networkResponse.clone();
+          caches.open(CACHE_NAME).then((cache) => {
+            cache.put(request, responseToCache);
+          });
+        }
+        return networkResponse;
+      }).catch(() => cachedResponse);
+
+      return cachedResponse || fetchPromise;
+    })
+  );
+});