// Service Worker for ECHO TUTOR PRO
const CACHE_NAME = 'echo-tutor-cache-v4';
const STATIC_CACHE_PREFIX = 'echo-tutor-cache-';
const STATIC_ASSETS = [
  '/',
  '/app',
  '/static/css/style.css',
  '/static/js/script.js',
  '/static/js/features.js',
  '/static/manifest.json',
  '/static/icons/icon-192.png',
  '/static/icons/icon-512.png',
  '/static/icons/Echo.png',
];

function isApiRequest(url) {
  return (
    url.pathname.startsWith('/chat') ||
    url.pathname.startsWith('/topics') ||
    url.pathname.startsWith('/health') ||
    url.pathname.startsWith('/transcribe') ||
    url.pathname.startsWith('/auth')
  );
}

self.addEventListener('install', (event) => {
  self.skipWaiting();
  event.waitUntil(
    caches
      .open(CACHE_NAME)
      .then((cache) => cache.addAll(STATIC_ASSETS))
      .catch(() => {}),
  );
});

self.addEventListener('activate', (event) => {
  event.waitUntil(
    caches
      .keys()
      .then((keys) =>
        Promise.all(
          keys
            .filter(
              (key) =>
                key.startsWith(STATIC_CACHE_PREFIX) && key !== CACHE_NAME,
            )
            .map((key) => caches.delete(key)),
        ),
      )
      .then(() => self.clients.claim()),
  );
});

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

  const requestUrl = new URL(event.request.url);

  if (requestUrl.origin !== self.location.origin || isApiRequest(requestUrl)) {
    return;
  }

  const isNavigation = event.request.mode === 'navigate';
  if (isNavigation) {
    event.respondWith(
      fetch(event.request)
        .then((networkResponse) => {
          const cloned = networkResponse.clone();
          caches
            .open(CACHE_NAME)
            .then((cache) => cache.put(event.request, cloned));
          return networkResponse;
        })
        .catch(() =>
          caches
            .match(event.request)
            .then((cached) => cached || caches.match('/')),
        ),
    );
    return;
  }

  event.respondWith(
    caches.match(event.request).then((cached) => {
      const fetchPromise = fetch(event.request)
        .then((networkResponse) => {
          if (networkResponse && networkResponse.status === 200) {
            const cloned = networkResponse.clone();
            caches
              .open(CACHE_NAME)
              .then((cache) => cache.put(event.request, cloned));
          }
          return networkResponse;
        })
        .catch(() => cached);

      return cached || fetchPromise;
    }),
  );
});