// Service worker for SvelteMUD Client PWA
const CACHE_NAME = 'svelte-mud-v1';
const ASSETS_TO_CACHE = [
  '/',
  '/index.html',
  '/manifest.json',
  '/favicon.ico',
  '/global.css',
  '/build/bundle.css',
  '/build/bundle.js'
];

// Install event - cache critical assets
self.addEventListener('install', (event) => {
  event.waitUntil(
    caches.open(CACHE_NAME)
      .then((cache) => {
        return cache.addAll(ASSETS_TO_CACHE);
      })
      .then(() => {
        return 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(() => {
      return self.clients.claim();
    })
  );
});

// Fetch event - serve from cache if available, otherwise fetch from network
self.addEventListener('fetch', (event) => {
  // Skip cross-origin requests
  if (!event.request.url.startsWith(self.location.origin) || 
      event.request.method !== 'GET') {
    return;
  }

  // For navigation requests (HTML pages), use a network-first strategy
  if (event.request.mode === 'navigate') {
    event.respondWith(
      fetch(event.request)
        .catch(() => {
          return caches.match(event.request);
        })
    );
    return;
  }

  // For all other requests, use a cache-first strategy
  event.respondWith(
    caches.match(event.request)
      .then((response) => {
        if (response) {
          return response;
        }
        
        // Clone the request because it's a one-time use stream
        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 because it's a one-time use stream
          const responseToCache = response.clone();
          
          caches.open(CACHE_NAME)
            .then((cache) => {
              cache.put(event.request, responseToCache);
            });
            
          return response;
        });
      })
  );
});

// Listen for messages from clients
self.addEventListener('message', (event) => {
  if (event.data && event.data.type === 'SKIP_WAITING') {
    self.skipWaiting();
  }
});