/* ObsiGate — Service Worker (Push notifications + Offline cache)
 * Version: 1.0.0
 * Scope: /
 */
const CACHE_NAME = 'obsigate-v1';
const OFFLINE_CACHE = 'obsigate-offline-v1';

// Files to cache for offline access
const PRECACHE_URLS = [
  '/',
  '/index.html',
  '/manifest.json',
  '/frontend/js/app.js',
  '/frontend/js/state.js',
  '/frontend/js/auth.js',
  '/frontend/js/ui.js',
  '/frontend/js/sidebar.js',
  '/frontend/js/viewer.js',
  '/frontend/js/search.js',
  '/frontend/js/config.js',
  '/frontend/js/utils.js',
  '/frontend/js/i18n.js',
  '/frontend/js/offline.js',
  '/frontend/js/offline-db.js',
  '/frontend/style.css',
  '/static/lucide.min.js'
];

// ── Install: precache static assets ────────────────────────────────────────
self.addEventListener('install', (event) => {
  event.waitUntil(
    caches.open(CACHE_NAME).then((cache) => {
      console.log('[SW] Precaching static assets');
      return cache.addAll(PRECACHE_URLS);
    }).then(() => self.skipWaiting())
  );
});

// ── Activate: clean old caches ─────────────────────────────────────────────
self.addEventListener('activate', (event) => {
  event.waitUntil(
    caches.keys().then((cacheNames) => {
      return Promise.all(
        cacheNames
          .filter((name) => name !== CACHE_NAME && name !== OFFLINE_CACHE)
          .map((name) => caches.delete(name))
      );
    }).then(() => self.clients.claim())
  );
});

// ── Fetch: Network-first for API, Cache-first for static ───────────────────
self.addEventListener('fetch', (event) => {
  const url = new URL(event.request.url);
  
  // Skip non-GET
  if (event.request.method !== 'GET') return;
  
  // Skip cross-origin
  if (url.origin !== location.origin) return;
  
  // API requests: Network-first with offline fallback
  if (url.pathname.startsWith('/api/')) {
    event.respondWith(networkFirstStrategy(event.request));
    return;
  }
  
  // Static assets: Cache-first
  event.respondWith(cacheFirstStrategy(event.request));
});

// Network-first strategy (for API)
async function networkFirstStrategy(request) {
  try {
    const response = await fetch(request);
    if (response.ok) {
      const cache = await caches.open(OFFLINE_CACHE);
      cache.put(request, response.clone());
    }
    return response;
  } catch (error) {
    const cached = await caches.match(request);
    if (cached) return cached;
    return new Response(JSON.stringify({ error: 'Offline' }), {
      status: 503,
      headers: { 'Content-Type': 'application/json' }
    });
  }
}

// Cache-first strategy (for static assets)
async function cacheFirstStrategy(request) {
  const cached = await caches.match(request);
  if (cached) {
    // Stale-while-revalidate: update cache in background
    fetch(request).then((response) => {
      if (response.ok) {
        caches.open(CACHE_NAME).then((cache) => cache.put(request, response));
      }
    }).catch(() => {});
    return cached;
  }
  
  try {
    const response = await fetch(request);
    if (response.ok) {
      const cache = await caches.open(CACHE_NAME);
      cache.put(request, response.clone());
    }
    return response;
  } catch (error) {
    // Return offline page for navigation requests
    if (request.mode === 'navigate') {
      return caches.match('/index.html');
    }
    return new Response('Offline', { status: 503 });
  }
}

// ── Push Event: Display notification ───────────────────────────────────────
self.addEventListener('push', (event) => {
  if (!event.data) return;
  
  const data = event.data.json();
  const options = {
    body: data.body || data.message || 'Nouvelle notification',
    icon: '/static/icon-192.png',
    badge: '/static/badge-72.png',
    vibrate: [200, 100, 200],
    tag: data.tag || 'obsigate-notification',
    renotify: true,
    data: data.data || {},
    actions: [
      { action: 'open', title: 'Ouvrir' },
      { action: 'dismiss', title: 'Ignorer' }
    ],
    requireInteraction: false
  };
  
  event.waitUntil(
    self.registration.showNotification(data.title || 'ObsiGate', options)
  );
});

// ── Notification Click: Open the app ───────────────────────────────────────
self.addEventListener('notificationclick', (event) => {
  event.notification.close();
  
  if (event.action === 'dismiss') return;
  
  // Default action or 'open' action: navigate to the file
  const urlToOpen = event.notification.data?.url || '/';
  
  event.waitUntil(
    clients.matchAll({ type: 'window', includeUncontrolled: true }).then((clientList) => {
      // Try to focus existing window
      for (const client of clientList) {
        if (client.url.includes(urlToOpen) && 'focus' in client) {
          return client.focus();
        }
      }
      // Open new window
      if (clients.openWindow) {
        return clients.openWindow(urlToOpen);
      }
    })
  );
});

// ── Notification Close ─────────────────────────────────────────────────────
self.addEventListener('notificationclose', (event) => {
  console.log('[SW] Notification closed:', event.notification.tag);
});

// ── Background Sync: Periodic index sync ──────────────────────────────────
self.addEventListener('sync', (event) => {
  if (event.tag === 'sync-file-index') {
    event.waitUntil(syncFileIndex());
  }
});

async function syncFileIndex() {
  try {
    const resp = await fetch('/api/search/advanced?q=**&vault=all&limit=200');
    if (resp.ok) {
      const data = await resp.json();
      const files = (data.results || []).map(r => ({
        vault: r.vault,
        path: r.path,
        title: r.title,
        tags: r.tags || [],
        snippet: r.snippet || '',
        modified: r.modified || ''
      }));
      
      // Send to main thread for IndexedDB storage
      const clients = await self.clients.matchAll();
      clients.forEach(client => client.postMessage({
        type: 'OFFLINE_INDEX_SYNC',
        files
      }));
    }
  } catch (e) {
    console.warn('[SW] Background sync failed:', e);
  }
}

// ── Periodic Background Sync (if supported) ────────────────────────────────
self.addEventListener('periodicsync', (event) => {
  if (event.tag === 'periodic-index-sync') {
    event.waitUntil(syncFileIndex());
  }
});

// ── Message from main thread ───────────────────────────────────────────────
self.addEventListener('message', (event) => {
  if (event.data?.type === 'SKIP_WAITING') {
    self.skipWaiting();
  }
});