const CACHE_NAME = 'bitfielder-v2';
const STATIC_CACHE = 'bitfielder-static-v2';
const DYNAMIC_CACHE = 'bitfielder-dynamic-v2';

// Core app files that should always be cached
const CORE_ASSETS = [
  '/',
  '/index.html',
  '/manifest.json',
  '/icon-192.png',
  '/icon-512.png'
];

// Assets that can be cached dynamically
const DYNAMIC_ASSETS_PATTERNS = [
  /\/src\/.+\.(ts|tsx|js|jsx)$/,
  /\/src\/.+\.css$/,
  /fonts\.googleapis\.com/,
  /fonts\.gstatic\.com/
];

// Install event - cache core resources
self.addEventListener('install', event => {
  console.log('Service Worker installing...');
  event.waitUntil(
    Promise.all([
      caches.open(STATIC_CACHE).then(cache => {
        console.log('Caching core assets');
        return cache.addAll(CORE_ASSETS);
      }),
      caches.open(DYNAMIC_CACHE).then(cache => {
        console.log('Dynamic cache initialized');
      })
    ]).then(() => {
      console.log('Service Worker installed successfully');
      return self.skipWaiting();
    })
  );
});

// Activate event - clean up old caches and take control
self.addEventListener('activate', event => {
  console.log('Service Worker activating...');
  event.waitUntil(
    caches.keys().then(cacheNames => {
      return Promise.all([
        ...cacheNames.map(cacheName => {
          if (cacheName !== STATIC_CACHE && cacheName !== DYNAMIC_CACHE) {
            console.log('Deleting old cache:', cacheName);
            return caches.delete(cacheName);
          }
        }),
        self.clients.claim()
      ]);
    }).then(() => {
      console.log('Service Worker activated successfully');
    })
  );
});

// Fetch event - sophisticated caching strategy
self.addEventListener('fetch', event => {
  const { request } = event;
  const url = new URL(request.url);

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

  // Skip external APIs and chrome-extension
  if (!url.origin.includes(self.location.origin) && !url.hostname.includes('googleapis') && !url.hostname.includes('gstatic')) {
    return;
  }

  event.respondWith(handleFetch(request));
});

async function handleFetch(request) {
  const url = new URL(request.url);
  
  try {
    // Strategy 1: Core assets - Cache First
    if (CORE_ASSETS.some(asset => url.pathname === asset || url.pathname.endsWith(asset))) {
      return await cacheFirst(request, STATIC_CACHE);
    }

    // Strategy 2: Dynamic assets - Stale While Revalidate
    if (DYNAMIC_ASSETS_PATTERNS.some(pattern => pattern.test(url.pathname))) {
      return await staleWhileRevalidate(request, DYNAMIC_CACHE);
    }

    // Strategy 3: Fonts - Cache First with longer TTL
    if (url.hostname.includes('googleapis') || url.hostname.includes('gstatic')) {
      return await cacheFirst(request, DYNAMIC_CACHE);
    }

    // Strategy 4: Everything else - Network First
    return await networkFirst(request, DYNAMIC_CACHE);

  } catch (error) {
    console.error('Fetch error:', error);
    
    // Fallback for navigation requests
    if (request.mode === 'navigate') {
      const cache = await caches.open(STATIC_CACHE);
      return await cache.match('/index.html') || new Response('App offline', { status: 503 });
    }
    
    return new Response('Resource not available offline', { status: 503 });
  }
}

// Cache First strategy
async function cacheFirst(request, cacheName) {
  const cache = await caches.open(cacheName);
  const cached = await cache.match(request);
  
  if (cached) {
    return cached;
  }
  
  const response = await fetch(request);
  if (response.status === 200) {
    cache.put(request, response.clone());
  }
  return response;
}

// Network First strategy
async function networkFirst(request, cacheName) {
  const cache = await caches.open(cacheName);
  
  try {
    const response = await fetch(request);
    if (response.status === 200) {
      cache.put(request, response.clone());
    }
    return response;
  } catch (error) {
    const cached = await cache.match(request);
    if (cached) {
      return cached;
    }
    throw error;
  }
}

// Stale While Revalidate strategy
async function staleWhileRevalidate(request, cacheName) {
  const cache = await caches.open(cacheName);
  const cached = await cache.match(request);
  
  // Always try to fetch and update cache in background
  const fetchPromise = fetch(request).then(response => {
    if (response.status === 200) {
      cache.put(request, response.clone());
    }
    return response;
  }).catch(() => null);
  
  // Return cached version immediately if available, otherwise wait for network
  return cached || await fetchPromise;
}

// Handle background sync for offline actions
self.addEventListener('sync', event => {
  console.log('Background sync triggered:', event.tag);
  
  if (event.tag === 'shader-save') {
    event.waitUntil(syncShaderData());
  }
});

async function syncShaderData() {
  // This would handle syncing shader data when coming back online
  // For now, just log that sync is available
  console.log('Shader data sync available for future implementation');
}

// Handle push notifications (for future features)
self.addEventListener('push', event => {
  if (event.data) {
    const data = event.data.json();
    console.log('Push notification received:', data);
    
    // Could be used for shader sharing notifications, etc.
  }
});

// Provide offline status
self.addEventListener('message', event => {
  if (event.data && event.data.type === 'GET_VERSION') {
    event.ports[0].postMessage({ version: CACHE_NAME });
  }
});