const CACHE_NAME = 'inknote-v7';

// Install — don't precache, just activate immediately
self.addEventListener('install', () => {
  self.skipWaiting();
});

// Activate — clean old caches, take control
self.addEventListener('activate', (e) => {
  e.waitUntil(
    caches.keys().then(keys =>
      Promise.all(keys.filter(k => k !== CACHE_NAME).map(k => caches.delete(k)))
    ).then(() => self.clients.claim())
  );
});

// Fetch — runtime caching strategy
self.addEventListener('fetch', (e) => {
  const url = new URL(e.request.url);

  // Never intercept API or WebSocket
  if (url.pathname.startsWith('/api/') || url.pathname.startsWith('/ws')) return;

  // Only handle GET requests
  if (e.request.method !== 'GET') return;

  // Navigation (HTML) — network-first with cache fallback
  if (e.request.mode === 'navigate') {
    e.respondWith(
      fetch(e.request).then(r => {
        const clone = r.clone();
        caches.open(CACHE_NAME).then(c => c.put(e.request, clone));
        return r;
      }).catch(() => caches.match(e.request).then(r => r || caches.match('/')))
    );
    return;
  }

  // Static assets — stale-while-revalidate
  e.respondWith(
    caches.open(CACHE_NAME).then(cache =>
      cache.match(e.request).then(cached => {
        const fetchP = fetch(e.request).then(r => {
          if (r.ok) cache.put(e.request, r.clone());
          return r;
        }).catch(() => cached);
        return cached || fetchP;
      })
    )
  );
});

// Background sync trigger
self.addEventListener('sync', (e) => {
  if (e.tag === 'sync-changes') {
    e.waitUntil(
      self.clients.matchAll().then(clients =>
        clients.forEach(c => c.postMessage({ type: 'FLUSH_QUEUE' }))
      )
    );
  }
});