/* ObsiGate Service Worker - PWA v2 with IndexedDB offline support */

const CACHE_VERSION = 'obsigate-v2-pwa';
const STATIC_CACHE = CACHE_VERSION + '-static';
const DYNAMIC_CACHE = CACHE_VERSION + '-dynamic';
const MAX_DYNAMIC_CACHE_SIZE = 100;

const STATIC_ASSETS = [
  '/',
  '/static/index.html',
  '/static/app.js',
  '/static/style.css',
  '/static/manifest.json'
];

/* ── Install ── */
self.addEventListener('install', (event) => {
  console.log('[SW] Installing v' + CACHE_VERSION);
  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] Cache error:', err))
      .then(() => self.skipWaiting())
  );
});

/* ── Activate ── */
self.addEventListener('activate', (event) => {
  console.log('[SW] Activating...');
  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 ── */
self.addEventListener('fetch', (event) => {
  const { request } = event;
  const url = new URL(request.url);

  if (request.method !== 'GET') return;
  if (url.pathname === '/api/events') return;
  if (url.pathname.startsWith('/api/auth/')) return;

  // API requests: Network first, tell client to use IndexedDB if offline
  if (url.pathname.startsWith('/api/')) {
    event.respondWith(networkFirstAPI(request));
    return;
  }

  // Static assets: Cache first
  event.respondWith(cacheFirstStatic(request, url));
});

/* ── Network First for API ── */
async function networkFirstAPI(request) {
  try {
    const response = await fetch(request);

    // Cache successful GETs in dynamic cache
    if (response && response.status === 200) {
      const cache = await caches.open(DYNAMIC_CACHE);
      cache.put(request, response.clone());
      limitCacheSize(DYNAMIC_CACHE, MAX_DYNAMIC_CACHE_SIZE);
    }
    return response;
  } catch (error) {
    console.log('[SW] Offline — checking cache for:', request.url);

    // Try dynamic cache first
    const cached = await caches.match(request);
    if (cached) {
      // Add offline header so the page can detect
      const headers = new Headers(cached.headers);
      headers.set('X-ObsiGate-Offline', 'true');
      return new Response(cached.body, { status: cached.status, statusText: cached.statusText, headers });
    }

    // Fallback: tell the page to use IndexedDB
    return new Response(JSON.stringify({
      offline: true,
      endpoint: new URL(request.url).pathname,
      message: 'Vous etes hors-ligne. Les donnees locales sont utilisees.'
    }), {
      status: 200,
      headers: { 'Content-Type': 'application/json', 'X-ObsiGate-Offline': 'true' }
    });
  }
}

/* ── Cache First for Static ── */
async function cacheFirstStatic(request, url) {
  const cached = await caches.match(request);
  if (cached) return cached;

  try {
    const response = await fetch(request);
    if (response && response.status === 200) {
      const cache = await caches.open(STATIC_CACHE);
      cache.put(request, response.clone());
    }
    return response;
  } catch {
    // Offline fallback for HTML navigation
    if (request.mode === 'navigate' || url.pathname === '/' || url.pathname.endsWith('/')) {
      const offlinePage = await caches.match('/static/index.html');
      if (offlinePage) return offlinePage;
    }
    return new Response('Offline', { status: 503 });
  }
}

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

/* ── Messages ── */
self.addEventListener('message', (event) => {
  const data = event.data;
  if (!data || !data.type) return;

  switch (data.type) {
    case 'SKIP_WAITING':
      self.skipWaiting();
      break;
    case 'CLEAR_CACHE':
      event.waitUntil(
        caches.keys().then(names => Promise.all(names.map(n => caches.delete(n))))
      );
      break;
    case 'CLAIM_CLIENTS':
      event.waitUntil(self.clients.claim());
      break;
  }
});

/* ── Sync ── */
self.addEventListener('sync', (event) => {
  console.log('[SW] Background sync:', event.tag);
  if (event.tag === 'obsigate-sync') {
    event.waitUntil(
      self.clients.matchAll().then(clients => {
        clients.forEach(client => {
          client.postMessage({ type: 'SYNC_TRIGGERED' });
        });
      })
    );
  }
});

/* ── Push ── */
self.addEventListener('push', (event) => {
  const options = {
    body: event.data ? event.data.text() : 'Nouvelle mise a jour',
    icon: '/static/icons/icon-192x192.svg',
    badge: '/static/icons/icon-72x72.svg',
    vibrate: [200, 100, 200],
    actions: [
      { action: 'open', title: 'Ouvrir ObsiGate' },
      { action: 'close', title: 'Fermer' }
    ]
  };
  event.waitUntil(self.registration.showNotification('ObsiGate', options));
});

self.addEventListener('notificationclick', (event) => {
  event.notification.close();
  if (event.action === 'open') {
    event.waitUntil(clients.openWindow('/'));
  }
});