From 6320cb14e502f752f0603a09484eaf7d651823f7 Mon Sep 17 00:00:00 2001
From: robin <robin@fluffigewolke.de>
Date: Mon, 19 Jan 2026 11:39:40 +0100
Subject: [PATCH] fix: Service Worker always returns valid Response

- Fixed fetch handler that could return undefined instead of Response
- Changed from stale-while-revalidate to network-first with cache fallback
- Always return proper 503 Response when offline and no cache available
- Bump cache version to v21 to force SW update
---
 public/sw.js | 41 ++++++++++++++++++++++++++---------------
 1 file changed, 26 insertions(+), 15 deletions(-)

diff --git a/public/sw.js b/public/sw.js
index 485787a..d7a7cd5 100644
--- a/public/sw.js
+++ b/public/sw.js
@@ -1,4 +1,4 @@
-const CACHE_NAME = 'whisky-vault-v20-offline';
+const CACHE_NAME = 'whisky-vault-v21-offline';
 
 // CONFIG: Assets - Only essential files, no heavy OCR (~2MB instead of ~50MB)
 const STATIC_ASSETS = [
@@ -189,22 +189,33 @@ self.addEventListener('fetch', (event) => {
     if (isNavigation || isAsset) {
         event.respondWith(
             caches.match(event.request).then(async (cachedResponse) => {
-                const fetchPromise = fetchWithTimeout(event.request, 10000)
-                    .then(async (networkResponse) => {
-                        if (networkResponse && networkResponse.status === 200) {
-                            const cache = await caches.open(CACHE_NAME);
-                            cache.put(event.request, networkResponse.clone());
-                        }
-                        return networkResponse;
-                    }).catch(() => { });
+                // Try network first
+                try {
+                    const networkResponse = await fetchWithTimeout(event.request, 10000);
+                    if (networkResponse && networkResponse.status === 200) {
+                        const cache = await caches.open(CACHE_NAME);
+                        cache.put(event.request, networkResponse.clone());
+                    }
+                    return networkResponse;
+                } catch (networkError) {
+                    // Network failed, fall back to cache
+                    if (cachedResponse) {
+                        return cachedResponse;
+                    }
 
-                if (isNavigation) {
-                    if (cachedResponse) return cachedResponse;
-                    const shell = await caches.match('/');
-                    if (shell) return shell;
+                    // For navigation, try to serve the app shell
+                    if (isNavigation) {
+                        const shell = await caches.match('/');
+                        if (shell) return shell;
+                    }
+
+                    // Last resort: return a proper error response
+                    return new Response('Offline - Resource not available', {
+                        status: 503,
+                        statusText: 'Service Unavailable',
+                        headers: { 'Content-Type': 'text/plain' }
+                    });
                 }
-
-                return cachedResponse || fetchPromise || fetch(event.request);
             })
         );
     }