const CACHE_NAME = 'clinicpro-admin-v1';
const BUILD_CACHE = 'clinicpro-build-v1';

const SHELL_URLS = [
  '/admin',
  '/manifest.json',
  '/icons/icon-192.png',
  '/icons/icon-512.png',
];

// ── Install: cache the app shell ──────────────────────────────────────────────
self.addEventListener('install', (event) => {
  event.waitUntil(
    caches.open(CACHE_NAME).then((cache) => cache.addAll(SHELL_URLS))
  );
  self.skipWaiting();
});

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

// ── Fetch ─────────────────────────────────────────────────────────────────────
self.addEventListener('fetch', (event) => {
  const { request } = event;
  const url = new URL(request.url);

  // Only handle same-origin requests
  if (url.origin !== self.location.origin) return;

  // API calls → Network only, never cache
  if (url.pathname.startsWith('/api/')) {
    return;
  }

  // Build assets (/build/) → Cache First
  if (url.pathname.startsWith('/build/')) {
    event.respondWith(
      caches.open(BUILD_CACHE).then(async (cache) => {
        const cached = await cache.match(request);
        if (cached) return cached;
        const response = await fetch(request);
        if (response.ok) cache.put(request, response.clone());
        return response;
      })
    );
    return;
  }

  // Navigation to /admin/* → Network First, fallback to cached shell
  if (request.mode === 'navigate' && url.pathname.startsWith('/admin')) {
    event.respondWith(
      fetch(request)
        .then((response) => {
          const clone = response.clone();
          caches.open(CACHE_NAME).then((cache) => cache.put(request, clone));
          return response;
        })
        // Offline: fall back to the cached shell. If it was never cached, return a
        // real offline Response — respondWith(undefined) throws "Failed to convert
        // value to 'Response'" and surfaces as a network error in the console.
        .catch(async () =>
          (await caches.match('/admin')) ||
          new Response('آفلاین هستید', {
            status: 503,
            headers: { 'Content-Type': 'text/plain; charset=utf-8' },
          })
        )
    );
    return;
  }

  // Everything else → Network First with cache fallback
  event.respondWith(
    fetch(request).catch(async () =>
      (await caches.match(request)) || Response.error()
    )
  );
});