const CACHE_NAME = 'bagg-v1';
const STATIC_ASSETS = [
  '/login.html',
  '/style.css',
  '/app.js',
  '/manifest.json',
];

// ── Install: cache static assets ─────────────────────────────────────────────
self.addEventListener('install', e => {
  e.waitUntil(
    caches.open(CACHE_NAME).then(cache => cache.addAll(STATIC_ASSETS))
  );
  self.skipWaiting();
});

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

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

  // Skip non-GET and cross-origin requests
  if (request.method !== 'GET' || url.origin !== location.origin) return;

  // API requests: network-first, no cache
  if (url.pathname.startsWith('/web/api/') || url.pathname.startsWith('/api/')) {
    e.respondWith(fetch(request).catch(() => new Response('{"error":"offline"}', {
      headers: { 'Content-Type': 'application/json' }
    })));
    return;
  }

  // Static assets: cache-first
  if (STATIC_ASSETS.includes(url.pathname) || url.pathname.startsWith('/icons/')) {
    e.respondWith(
      caches.match(request).then(cached => cached || fetch(request).then(res => {
        if (res.ok) {
          const clone = res.clone();
          caches.open(CACHE_NAME).then(c => c.put(request, clone));
        }
        return res;
      }))
    );
    return;
  }

  // Navigation (HTML pages): network-first, fallback to cache
  if (request.mode === 'navigate') {
    e.respondWith(
      fetch(request)
        .then(res => {
          if (res.ok) {
            const clone = res.clone();
            caches.open(CACHE_NAME).then(c => c.put(request, clone));
          }
          return res;
        })
        .catch(() => caches.match(request).then(cached => cached || caches.match('/login.html')))
    );
    return;
  }
});