// Service Worker for ROA2WEB PWA
// Network-first strategy to always show fresh content

const CACHE_VERSION = 'v2';
const CACHE_NAME = `roa2web-${CACHE_VERSION}`;

// Install event - skip waiting to activate immediately
self.addEventListener('install', (event) => {
  console.log('[SW] Installing service worker...');
  self.skipWaiting();
});

// Activate event - clear old caches and claim clients
self.addEventListener('activate', (event) => {
  console.log('[SW] Service worker activated');
  event.waitUntil(
    Promise.all([
      // Clear all old caches
      caches.keys().then(cacheNames => {
        return Promise.all(
          cacheNames.map(cacheName => {
            if (cacheName !== CACHE_NAME) {
              console.log('[SW] Deleting old cache:', cacheName);
              return caches.delete(cacheName);
            }
          })
        );
      }),
      // Take control of all clients immediately
      clients.claim()
    ]).then(() => {
      // Notify all clients that a new SW version is active
      return clients.matchAll({ includeUncontrolled: true }).then(allClients => {
        allClients.forEach(client => {
          client.postMessage({ type: 'SW_UPDATED' });
        });
      });
    })
  );
});

// Message handler - allows pages to trigger SW actions
self.addEventListener('message', (event) => {
  if (event.data && event.data.type === 'SKIP_WAITING') {
    self.skipWaiting();
  }
});

// Fetch event - ALWAYS network first, no caching for HTML/JS/CSS
self.addEventListener('fetch', (event) => {
  const url = new URL(event.request.url);

  // Skip non-GET requests
  if (event.request.method !== 'GET') {
    return;
  }

  // API calls - always network, no cache
  if (url.pathname.includes('/api/')) {
    event.respondWith(fetch(event.request));
    return;
  }

  // index.html - bypass HTTP cache entirely to always get fresh app shell
  if (
    url.pathname.endsWith('index.html') ||
    url.pathname === '/roa2web/' ||
    url.pathname === '/roa2web'
  ) {
    event.respondWith(
      fetch(event.request, { cache: 'no-cache' })
        .catch(() => caches.match(event.request))
    );
    return;
  }

  // HTML, JS, CSS - always fetch fresh from network
  // This ensures PWA always loads latest version
  event.respondWith(
    fetch(event.request)
      .then(response => {
        return response;
      })
      .catch(() => {
        // Only fallback to cache if network fails
        return caches.match(event.request);
      })
  );
});