/* ObsiGate Service Worker - PWA Support */

const CACHE_VERSION = 'obsigate-v1.4.0';
const STATIC_CACHE = `${CACHE_VERSION}-static`;
const DYNAMIC_CACHE = `${CACHE_VERSION}-dynamic`;
const MAX_DYNAMIC_CACHE_SIZE = 50;

// Assets to cache on install
const STATIC_ASSETS = [
  '/',
  '/static/index.html',
  '/static/app.js',
  '/static/style.css',
  '/static/manifest.json'
];

// Install event - cache static assets
self.addEventListener('install', (event) => {
  console.log('[SW] Installing service worker...');
  event.waitUntil(
    caches.open(STATIC_CACHE)
      .then((cache) => {
        console.log('[SW] Caching static assets');
        return cache.addAll(STATIC_ASSETS.map(url => new Request(url, { cache: 'reload' })));
      })
      .catch((err) => {
        console.error('[SW] Failed to cache static assets:', err);
      })
      .then(() => self.skipWaiting())
  );
});

// Activate event - clean up old caches
self.addEventListener('activate', (event) => {
  console.log('[SW] Activating service worker...');
  event.waitUntil(
    caches.keys()
      .then((cacheNames) => {
        return Promise.all(
          cacheNames
            .filter((name) => name.startsWith('obsigate-') && name !== STATIC_CACHE && name !== DYNAMIC_CACHE)
            .map((name) => {
              console.log('[SW] Deleting old cache:', name);
              return caches.delete(name);
            })
        );
      })
      .then(() => self.clients.claim())
  );
});

// Fetch event - serve from cache, fallback to network
self.addEventListener('fetch', (event) => {
  const { request } = event;
  const url = new URL(request.url);

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

  // Skip SSE connections
  if (url.pathname === '/api/events') {
    return;
  }

  // Skip authentication endpoints
  if (url.pathname.startsWith('/api/auth/')) {
    return;
  }

  // API requests - Network first, cache fallback
  if (url.pathname.startsWith('/api/')) {
    event.respondWith(networkFirstStrategy(request));
    return;
  }

  // Static assets - Cache first, network fallback
  event.respondWith(cacheFirstStrategy(request));
});

// Cache first strategy (for static assets)
async function cacheFirstStrategy(request) {
  try {
    const cachedResponse = await caches.match(request);
    if (cachedResponse) {
      return cachedResponse;
    }

    const networkResponse = await fetch(request);
    
    // Cache successful responses
    if (networkResponse && networkResponse.status === 200) {
      const cache = await caches.open(STATIC_CACHE);
      cache.put(request, networkResponse.clone());
    }
    
    return networkResponse;
  } catch (error) {
    console.error('[SW] Cache first strategy failed:', error);
    
    // Return offline page if available
    const offlinePage = await caches.match('/static/index.html');
    if (offlinePage) {
      return offlinePage;
    }
    
    return new Response('Offline - Unable to fetch resource', {
      status: 503,
      statusText: 'Service Unavailable',
      headers: new Headers({
        'Content-Type': 'text/plain'
      })
    });
  }
}

// Network first strategy (for API calls)
async function networkFirstStrategy(request) {
  try {
    const networkResponse = await fetch(request);
    
    // Cache successful GET responses
    if (networkResponse && networkResponse.status === 200 && request.method === 'GET') {
      const cache = await caches.open(DYNAMIC_CACHE);
      cache.put(request, networkResponse.clone());
      
      // Limit dynamic cache size
      limitCacheSize(DYNAMIC_CACHE, MAX_DYNAMIC_CACHE_SIZE);
    }
    
    return networkResponse;
  } catch (error) {
    console.log('[SW] Network failed, trying cache:', request.url);
    
    const cachedResponse = await caches.match(request);
    if (cachedResponse) {
      return cachedResponse;
    }
    
    // Return offline response
    return new Response(JSON.stringify({
      error: 'Offline',
      message: 'Unable to fetch data. Please check your connection.'
    }), {
      status: 503,
      statusText: 'Service Unavailable',
      headers: new Headers({
        'Content-Type': 'application/json'
      })
    });
  }
}

// Limit cache size
async function limitCacheSize(cacheName, maxSize) {
  const cache = await caches.open(cacheName);
  const keys = await cache.keys();
  
  if (keys.length > maxSize) {
    // Delete oldest entries
    const deleteCount = keys.length - maxSize;
    for (let i = 0; i < deleteCount; i++) {
      await cache.delete(keys[i]);
    }
  }
}

// Message event - handle messages from clients
self.addEventListener('message', (event) => {
  if (event.data && event.data.type === 'SKIP_WAITING') {
    self.skipWaiting();
  }
  
  if (event.data && event.data.type === 'CLEAR_CACHE') {
    event.waitUntil(
      caches.keys().then((cacheNames) => {
        return Promise.all(
          cacheNames.map((name) => caches.delete(name))
        );
      })
    );
  }
});

// Sync event - background sync for offline actions
self.addEventListener('sync', (event) => {
  console.log('[SW] Background sync:', event.tag);
  
  if (event.tag === 'sync-data') {
    event.waitUntil(syncData());
  }
});

async function syncData() {
  // Placeholder for background sync logic
  console.log('[SW] Syncing data...');
}

// Push notification event
self.addEventListener('push', (event) => {
  const options = {
    body: event.data ? event.data.text() : 'New update available',
    icon: '/static/icons/icon-192x192.png',
    badge: '/static/icons/icon-72x72.png',
    vibrate: [200, 100, 200],
    data: {
      dateOfArrival: Date.now(),
      primaryKey: 1
    },
    actions: [
      {
        action: 'explore',
        title: 'Ouvrir ObsiGate'
      },
      {
        action: 'close',
        title: 'Fermer'
      }
    ]
  };

  event.waitUntil(
    self.registration.showNotification('ObsiGate', options)
  );
});

// Notification click event
self.addEventListener('notificationclick', (event) => {
  event.notification.close();

  if (event.action === 'explore') {
    event.waitUntil(
      clients.openWindow('/')
    );
  }
});