// Veza Platform Service Worker
// Version 1.0.0

const CACHE_NAME = 'veza-platform-v1';
const STATIC_CACHE_NAME = 'veza-static-v1';
const DYNAMIC_CACHE_NAME = 'veza-dynamic-v1';

// Files to cache on install
const STATIC_ASSETS = [
  '/',
  '/dashboard',
  '/chat',
  '/library',
  '/profile',
  '/settings',
  '/manifest.json',
  '/icons/icon-192x192.png',
  '/icons/icon-512x512.png'
];

// API endpoints to cache with network-first strategy
const API_CACHE_PATTERNS = [
  /^https?:\/\/.*\/api\/v1\/user\/profile$/,
  /^https?:\/\/.*\/api\/v1\/library\/files$/,
  /^https?:\/\/.*\/api\/v1\/dashboard\/stats$/
];

// Install event - cache static assets
self.addEventListener('install', (event) => {
  console.log('[SW] Installing service worker...');
  
  event.waitUntil(
    caches.open(STATIC_CACHE_NAME)
      .then((cache) => {
        console.log('[SW] Caching static assets');
        return cache.addAll(STATIC_ASSETS);
      })
      .then(() => {
        console.log('[SW] Static assets cached successfully');
        return self.skipWaiting();
      })
      .catch((error) => {
        console.error('[SW] Failed to cache static assets:', error);
      })
  );
});

// Activate event - clean old caches
self.addEventListener('activate', (event) => {
  console.log('[SW] Activating service worker...');
  
  event.waitUntil(
    caches.keys()
      .then((cacheNames) => {
        return Promise.all(
          cacheNames.map((cacheName) => {
            if (cacheName !== STATIC_CACHE_NAME && cacheName !== DYNAMIC_CACHE_NAME) {
              console.log('[SW] Deleting old cache:', cacheName);
              return caches.delete(cacheName);
            }
          })
        );
      })
      .then(() => {
        console.log('[SW] Service worker activated');
        return self.clients.claim();
      })
  );
});

// Fetch event - handle requests with appropriate 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 WebSocket connections
  if (request.headers.get('upgrade') === 'websocket') {
    return;
  }

  // Skip external requests (except API)
  if (!url.origin.includes(self.location.origin) && !isApiRequest(request.url)) {
    return;
  }

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

// Handle different types of requests with appropriate strategies
async function handleRequest(request) {
  try {
    // Strategy 1: Cache First for static assets
    if (isStaticAsset(request.url)) {
      return await cacheFirst(request, STATIC_CACHE_NAME);
    }
    
    // Strategy 2: Network First for API requests
    if (isApiRequest(request.url)) {
      return await networkFirst(request, DYNAMIC_CACHE_NAME);
    }
    
    // Strategy 3: Stale While Revalidate for pages
    if (isPageRequest(request.url)) {
      return await staleWhileRevalidate(request, DYNAMIC_CACHE_NAME);
    }
    
    // Default: Network only
    return await fetch(request);
    
  } catch (error) {
    console.error('[SW] Request failed:', error);
    
    // Return offline page for navigation requests
    if (isPageRequest(request.url)) {
      return await getOfflinePage();
    }
    
    // Return cached version if available
    const cachedResponse = await caches.match(request);
    if (cachedResponse) {
      return cachedResponse;
    }
    
    // Return generic offline response
    return new Response('Offline', { 
      status: 503, 
      statusText: 'Service Unavailable' 
    });
  }
}

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

// Network First strategy
async function networkFirst(request, cacheName) {
  try {
    const networkResponse = await fetch(request);
    
    if (networkResponse.ok) {
      const cache = await caches.open(cacheName);
      cache.put(request, networkResponse.clone());
    }
    
    return networkResponse;
  } catch (error) {
    const cachedResponse = await caches.match(request);
    
    if (cachedResponse) {
      console.log('[SW] Serving cached API response');
      return cachedResponse;
    }
    
    throw error;
  }
}

// Stale While Revalidate strategy
// CORRECTION DURABLE: Clone la réponse IMMÉDIATEMENT pour éviter "Response body is already used"
async function staleWhileRevalidate(request, cacheName) {
  const cachedResponse = await caches.match(request);
  
  const networkResponsePromise = fetch(request)
    .then((networkResponse) => {
      if (networkResponse.ok) {
        // ✅ Cloner IMMÉDIATEMENT la réponse avant toute autre opération
        const responseToCache = networkResponse.clone();
        
        // Mettre en cache de manière asynchrone (sans bloquer)
        caches.open(cacheName).then((cache) => {
          cache.put(request, responseToCache).catch((err) => {
            console.warn('[SW] Failed to cache response:', err);
          });
        });
      }
      return networkResponse;
    })
    .catch(() => null);
  
  return cachedResponse || await networkResponsePromise;
}

// Get offline page
async function getOfflinePage() {
  const cache = await caches.open(STATIC_CACHE_NAME);
  const offlineResponse = await cache.match('/');
  
  if (offlineResponse) {
    return offlineResponse;
  }
  
  return new Response(`
    <!DOCTYPE html>
    <html>
      <head>
        <title>Veza - Hors ligne</title>
        <meta charset="utf-8">
        <meta name="viewport" content="width=device-width, initial-scale=1">
        <style>
          body { 
            font-family: system-ui, sans-serif; 
            text-align: center; 
            padding: 2rem; 
            background: #1a1a1a; 
            color: white;
          }
          .offline-container {
            max-width: 400px;
            margin: 0 auto;
            padding: 2rem;
            border-radius: 8px;
            background: #2a2a2a;
          }
          .offline-icon {
            font-size: 4rem;
            margin-bottom: 1rem;
          }
        </style>
      </head>
      <body>
        <div class="offline-container">
          <div class="offline-icon">📱</div>
          <h1>Veza - Mode Hors Ligne</h1>
          <p>Vous êtes actuellement hors ligne. Certaines fonctionnalités peuvent être limitées.</p>
          <button onclick="window.location.reload()">Réessayer</button>
        </div>
      </body>
    </html>
  `, {
    headers: { 'Content-Type': 'text/html' }
  });
}

// Helper functions
function isStaticAsset(url) {
  return /\.(js|css|png|jpg|jpeg|gif|svg|woff|woff2|ttf|eot|ico)(\?.*)?$/.test(url);
}

function isApiRequest(url) {
  return url.includes('/api/') || API_CACHE_PATTERNS.some(pattern => pattern.test(url));
}

function isPageRequest(url) {
  const urlObj = new URL(url);
  return urlObj.pathname.match(/^\/[^.]*$/) && !isApiRequest(url);
}

// Message handling for communication with the main thread
self.addEventListener('message', (event) => {
  const { type } = event.data;
  
  switch (type) {
    case 'SKIP_WAITING':
      self.skipWaiting();
      break;
      
    case 'GET_VERSION':
      event.ports[0].postMessage({
        type: 'VERSION',
        payload: { version: CACHE_NAME }
      });
      break;
      
    case 'CLEAR_CACHE':
      caches.keys().then((cacheNames) => {
        return Promise.all(
          cacheNames.map((cacheName) => caches.delete(cacheName))
        );
      }).then(() => {
        event.ports[0].postMessage({
          type: 'CACHE_CLEARED',
          payload: { success: true }
        });
      });
      break;
      
    default:
      console.log('[SW] Unknown message type:', type);
  }
});

// Background sync for offline actions
self.addEventListener('sync', (event) => {
  if (event.tag === 'background-sync') {
    event.waitUntil(doBackgroundSync());
  }
});

async function doBackgroundSync() {
  console.log('[SW] Performing background sync...');
  // Implement background sync logic here
  // For example: sync offline messages, upload queued files, etc.
}

// Push notifications
self.addEventListener('push', (event) => {
  if (!event.data) {
    return;
  }

  const data = event.data.json();
  const options = {
    body: data.body,
    icon: '/icons/icon-192x192.png',
    badge: '/icons/badge-72x72.png',
    vibrate: [100, 50, 100],
    data: {
      dateOfArrival: Date.now(),
      primaryKey: data.primaryKey || 1,
      url: data.url || '/'
    },
    actions: [
      {
        action: 'explore',
        title: 'Ouvrir',
        icon: '/icons/checkmark.png'
      },
      {
        action: 'close',
        title: 'Fermer',
        icon: '/icons/xmark.png'
      }
    ]
  };

  event.waitUntil(
    self.registration.showNotification(data.title, options)
  );
});

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

  if (event.action === 'close') {
    return;
  }

  const urlToOpen = event.notification.data?.url || '/';

  event.waitUntil(
    self.clients.matchAll({ type: 'window' }).then((clientList) => {
      // Check if a window is already open
      for (const client of clientList) {
        if (client.url === urlToOpen && 'focus' in client) {
          return client.focus();
        }
      }
      
      // Open a new window
      if (self.clients.openWindow) {
        return self.clients.openWindow(urlToOpen);
      }
    })
  );
});

console.log('[SW] Veza Platform Service Worker loaded');