// Service Worker for Talk2Me PWA

const CACHE_NAME = 'voice-translator-v1';
const ASSETS_TO_CACHE = [
  '/',
  '/static/css/styles.css',
  '/static/js/dist/app.js',
  '/static/icons/icon-192x192.png',
  '/static/icons/icon-512x512.png',
  '/static/icons/favicon.ico',
  'https://cdn.jsdelivr.net/npm/bootstrap@5.3.0-alpha1/dist/css/bootstrap.min.css',
  'https://cdnjs.cloudflare.com/ajax/libs/font-awesome/6.0.0/css/all.min.css'
];

// Install event - cache essential assets
self.addEventListener('install', (event) => {
  event.waitUntil(
    caches.open(CACHE_NAME)
      .then((cache) => {
        console.log('Service Worker: Caching files');
        return cache.addAll(ASSETS_TO_CACHE);
      })
      .then(() => self.skipWaiting())
  );
});

// Activate event - clean up old caches
self.addEventListener('activate', (event) => {
  event.waitUntil(
    caches.keys().then((cacheNames) => {
      return Promise.all(
        cacheNames.map((name) => {
          if (name !== CACHE_NAME) {
            console.log('Service Worker: Clearing old cache');
            return caches.delete(name);
          }
        })
      );
    })
  );
});

// Fetch event - serve cached content when offline
self.addEventListener('fetch', (event) => {
  // Skip cross-origin requests
  if (!event.request.url.startsWith(self.location.origin)) {
    return;
  }

  // Skip API calls - we don't want to cache those
  if (event.request.url.includes('/transcribe') || 
      event.request.url.includes('/translate') || 
      event.request.url.includes('/speak') ||
      event.request.url.includes('/get_audio/')) {
    return;
  }

  event.respondWith(
    caches.match(event.request)
      .then((cachedResponse) => {
        // Return cached response if available
        if (cachedResponse) {
          return cachedResponse;
        }

        // Otherwise fetch from network
        return fetch(event.request)
          .then((response) => {
            // Don't cache if response is not valid
            if (!response || response.status !== 200 || response.type !== 'basic') {
              return response;
            }

            // Clone the response since it can only be consumed once
            const responseToCache = response.clone();
            caches.open(CACHE_NAME)
              .then((cache) => {
                cache.put(event.request, responseToCache);
              });

            return response;
          })
          .catch(() => {
            // If network fetch fails and it's a document request, return fallback
            if (event.request.mode === 'navigate') {
              return caches.match('/');
            }
          });
      })
  );
});

// Handle push notifications
self.addEventListener('push', (event) => {
  if (!event.data) {
    return;
  }
  
  const data = event.data.json();
  const options = {
    body: data.body || 'New translation available',
    icon: data.icon || '/static/icons/icon-192x192.png',
    badge: data.badge || '/static/icons/icon-192x192.png',
    vibrate: [100, 50, 100],
    tag: data.tag || 'talk2me-notification',
    requireInteraction: false,
    silent: false,
    data: {
      url: data.url || '/',
      ...data.data
    },
    actions: [
      {
        action: 'view',
        title: 'View',
        icon: '/static/icons/icon-192x192.png'
      },
      {
        action: 'close',
        title: 'Close'
      }
    ]
  };

  event.waitUntil(
    self.registration.showNotification(data.title || 'Voice Translator', options)
  );
});

// Handle notification click
self.addEventListener('notificationclick', (event) => {
  event.notification.close();
  
  if (event.action === 'close') {
    return;
  }
  
  const urlToOpen = event.notification.data.url || '/';
  
  event.waitUntil(
    clients.matchAll({
      type: 'window',
      includeUncontrolled: true
    }).then((windowClients) => {
      // Check if there's already a window/tab with the app open
      for (let client of windowClients) {
        if (client.url === urlToOpen && 'focus' in client) {
          return client.focus();
        }
      }
      // If not, open a new window/tab
      if (clients.openWindow) {
        return clients.openWindow(urlToOpen);
      }
    })
  );
});

// Handle periodic background sync
self.addEventListener('periodicsync', (event) => {
  if (event.tag === 'translation-updates') {
    event.waitUntil(checkForUpdates());
  }
});

async function checkForUpdates() {
  // Check for app updates or send usage statistics
  try {
    const response = await fetch('/api/check-updates');
    if (response.ok) {
      const data = await response.json();
      if (data.hasUpdate) {
        self.registration.showNotification('Update Available', {
          body: 'A new version of Voice Translator is available!',
          icon: '/static/icons/icon-192x192.png',
          badge: '/static/icons/icon-192x192.png',
          tag: 'update-notification'
        });
      }
    }
  } catch (error) {
    console.error('Failed to check for updates:', error);
  }
}