const CACHE_NAME = 'fina-v1';
const urlsToCache = [
  '/',
  '/static/js/app.js',
  '/static/js/pwa.js',
  '/static/manifest.json',
  'https://cdn.tailwindcss.com',
  'https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&display=swap',
  'https://fonts.googleapis.com/css2?family=Material+Symbols+Outlined:wght,FILL@100..700,0..1&display=swap'
];

// Install event - cache resources
self.addEventListener('install', event => {
  event.waitUntil(
    caches.open(CACHE_NAME)
      .then(cache => cache.addAll(urlsToCache))
      .then(() => self.skipWaiting())
  );
});

// Activate event - clean up old caches
self.addEventListener('activate', event => {
  event.waitUntil(
    caches.keys().then(cacheNames => {
      return Promise.all(
        cacheNames.map(cacheName => {
          if (cacheName !== CACHE_NAME) {
            return caches.delete(cacheName);
          }
        })
      );
    }).then(() => self.clients.claim())
  );
});

// Fetch event - serve from cache, fallback to network
self.addEventListener('fetch', event => {
  // Skip non-GET requests
  if (event.request.method !== 'GET') {
    return;
  }

  event.respondWith(
    caches.match(event.request)
      .then(response => {
        // Cache hit - return response
        if (response) {
          return response;
        }

        // Clone the request
        const fetchRequest = event.request.clone();

        return fetch(fetchRequest).then(response => {
          // Check if valid response
          if (!response || response.status !== 200 || response.type !== 'basic') {
            return response;
          }

          // Clone the response
          const responseToCache = response.clone();

          caches.open(CACHE_NAME)
            .then(cache => {
              cache.put(event.request, responseToCache);
            });

          return response;
        }).catch(() => {
          // Return offline page or fallback
          return new Response('You are offline', {
            headers: { 'Content-Type': 'text/plain' }
          });
        });
      })
  );
});

// Background sync for offline expense creation
self.addEventListener('sync', event => {
  if (event.tag === 'sync-expenses') {
    event.waitUntil(syncExpenses());
  }
});

async function syncExpenses() {
  // Implement offline expense sync logic
  console.log('Syncing expenses...');
}