sw.js

/**
 * PROJECT 417 // SERVICE WORKER (OFFLINE FIRST PWA ENGINE)
 * Caches core app shell, static assets, and enables offline training in basement gyms.
 * Strict Zero-Emoji compliance.
 */

const CACHE_NAME = 'project-417-v2.1';
const CORE_PRECACHE_URLS = [
  '/',
  '/index.html',
  '/manifest.json',
  '/favicon.svg',
  '/favicon-32x32.png',
  '/favicon-16x16.png',
  '/logo-417.svg',
  '/apple-touch-icon.png',
  '/telegram-web-app.js',
];

self.addEventListener('install', (event) => {
  event.waitUntil(
    caches.open(CACHE_NAME).then((cache) => {
      return cache.addAll(CORE_PRECACHE_URLS).catch(() => {
        // Continue even if some individual icons fail
      });
    }).then(() => self.skipWaiting())
  );
});

self.addEventListener('activate', (event) => {
  event.waitUntil(
    caches.keys().then((cacheNames) => {
      return Promise.all(
        cacheNames.map((name) => {
          if (name !== CACHE_NAME) {
            return caches.delete(name);
          }
          return Promise.resolve();
        })
      );
    }).then(() => self.clients.claim())
  );
});

self.addEventListener('fetch', (event) => {
  const request = event.request;
  if (request.method !== 'GET') return;

  const url = new URL(request.url);

  // Skip API or Telegram external calls
  if (url.pathname.startsWith('/api/') || url.hostname.includes('telegram.org')) {
    return;
  }

  // Navigation requests: Network first, fall back to cached index.html
  if (request.mode === 'navigate') {
    event.respondWith(
      fetch(request)
        .then((response) => {
          if (response && response.status === 200) {
            const copy = response.clone();
            caches.open(CACHE_NAME).then((cache) => cache.put(request, copy));
          }
          return response;
        })
        .catch(async () => {
          const cached = await caches.match('/index.html');
          return cached || (await caches.match('/'));
        })
    );
    return;
  }

  // Static Assets (JS, CSS, SVGs, Fonts, Images): Cache First with background update
  if (
    url.pathname.startsWith('/assets/') ||
    url.pathname.endsWith('.js') ||
    url.pathname.endsWith('.css') ||
    url.pathname.endsWith('.svg') ||
    url.pathname.endsWith('.png') ||
    url.pathname.endsWith('.woff2')
  ) {
    event.respondWith(
      caches.match(request).then((cachedResponse) => {
        if (cachedResponse) {
          // Fetch update in background
          fetch(request).then((networkResponse) => {
            if (networkResponse && networkResponse.status === 200) {
              caches.open(CACHE_NAME).then((cache) => cache.put(request, networkResponse));
            }
          }).catch(() => {});
          return cachedResponse;
        }

        return fetch(request).then((networkResponse) => {
          if (networkResponse && networkResponse.status === 200) {
            const copy = networkResponse.clone();
            caches.open(CACHE_NAME).then((cache) => cache.put(request, copy));
          }
          return networkResponse;
        });
      })
    );
    return;
  }

  // Default fallback
  event.respondWith(
    caches.match(request).then((cached) => cached || fetch(request))
  );
});