const SHELL_CACHE='fixfin-shell-v3.19';
const DATA_CACHE='fixfin-data-v1';
const APP_SHELL=['/','/manifest.webmanifest','/icons/icon-192.png','/icons/icon-512.png','/icons/apple-touch-icon.png'];

self.addEventListener('install',event=>{
  event.waitUntil(caches.open(SHELL_CACHE).then(cache=>cache.addAll(APP_SHELL)).then(()=>self.skipWaiting()));
});

self.addEventListener('activate',event=>{
  event.waitUntil(Promise.all([
    caches.keys().then(keys=>Promise.all(keys.filter(key=>key.startsWith('fixfin-shell-')&&key!==SHELL_CACHE).map(key=>caches.delete(key)))),
    self.clients.claim(),
  ]));
});

self.addEventListener('fetch',event=>{
  const request=event.request;
  if(request.method!=='GET') return;
  const url=new URL(request.url);
  if(url.origin!==self.location.origin) return;

  if(url.pathname==='/api/data') {
    event.respondWith(fetch(request).then(response=>{
      if(response.ok) caches.open(DATA_CACHE).then(cache=>cache.put(request,response.clone()));
      return response;
    }).catch(()=>caches.match(request).then(cached=>cached||new Response(JSON.stringify({error:'Offline und keine zwischengespeicherten Daten verfügbar.'}),{status:503,headers:{'Content-Type':'application/json'}}))));
    return;
  }
  if(url.pathname.startsWith('/api/')) return;

  if(request.mode==='navigate') {
    event.respondWith(fetch(request).then(response=>{
      caches.open(SHELL_CACHE).then(cache=>cache.put('/',response.clone()));
      return response;
    }).catch(()=>caches.match('/')));
    return;
  }

  event.respondWith(caches.match(request).then(cached=>{
    const network=fetch(request).then(response=>{
      if(response.ok) caches.open(SHELL_CACHE).then(cache=>cache.put(request,response.clone()));
      return response;
    }).catch(()=>cached);
    return cached||network;
  }));
});