const CACHE_NAME = 'ttmqms-enterprise-v2.3-offline';
const STATIC_ASSETS = [
  '/',
  '/assets/css/index.css',
  '/assets/css/bootstrap-icons.min.css',
  '/assets/css/flatpickr.min.css',
  '/assets/js/app.js',
  '/assets/js/tailwindcss.min.js',
  '/assets/js/alpine.min.js',
  '/assets/js/chart.umd.min.js',
  '/assets/js/sweetalert2.all.min.js',
  '/assets/js/flatpickr.min.js'
];

// Install Event - Precache static resources
self.addEventListener('install', (event) => {
  event.waitUntil(
    caches.open(CACHE_NAME).then((cache) => {
      console.log('[ServiceWorker] Caching App Shell & Static Assets');
      return cache.addAll(STATIC_ASSETS.map(url => new Request(url, { mode: 'no-cors' }))).catch(err => {
        console.warn('[ServiceWorker] Some CDN assets failed to precache in offline mode', err);
      });
    }).then(() => self.skipWaiting())
  );
});

// Activate Event - Clean up old caches
self.addEventListener('activate', (event) => {
  event.waitUntil(
    caches.keys().then((keyList) => {
      return Promise.all(
        keyList.map((key) => {
          if (key !== CACHE_NAME) {
            console.log('[ServiceWorker] Removing old cache:', key);
            return caches.delete(key);
          }
        })
      );
    }).then(() => self.clients.claim())
  );
});

// Fetch Event - Cache-first for CDN/static, Network-first for API & Views
self.addEventListener('fetch', (event) => {
  const url = new URL(event.request.url);

  // ห้ามแคชคำขอ REST API (/api/v1/ หรือ ?api=/api/v1/) และคำขอ POST/PUT/DELETE
  if (url.pathname.startsWith('/api/') || url.pathname.includes('/api/v1/') || url.search.includes('api=') || url.search.includes('endpoint=') || event.request.method !== 'GET') {
    event.respondWith(
      fetch(event.request).catch((err) => {
        return new Response(
          JSON.stringify({
            success: false,
            error: 'ออฟไลน์ (Offline Mode): ไม่สามารถเชื่อมต่อกับเซิร์ฟเวอร์โรงพยาบาลได้ในขณะนี้',
            offline: true
          }),
          { status: 503, headers: { 'Content-Type': 'application/json; charset=utf-8' } }
        );
      })
    );
    return;
  }

  // Stale-While-Revalidate Strategy for HTML and assets
  event.respondWith(
    caches.match(event.request).then((cachedResponse) => {
      const fetchPromise = fetch(event.request).then((networkResponse) => {
        if (networkResponse && networkResponse.status === 200) {
          const responseToCache = networkResponse.clone();
          caches.open(CACHE_NAME).then((cache) => {
            cache.put(event.request, responseToCache);
          });
        }
        return networkResponse;
      }).catch((err) => {
        console.warn('[ServiceWorker] Network request failed, serving from cache if available');
      });

      return cachedResponse || fetchPromise;
    })
  );
});