const CACHE_NAME = 'brew-journal-v2';

// Static assets to cache immediately
const PRECACHE_ASSETS = [
  '/',
  '/index.html',
  '/manifest.json',
  '/favicon.svg',
  '/icon-192.png',
  '/icon-512.png'
];

// Install Event
self.addEventListener('install', (e) => {
  e.waitUntil(
    caches.open(CACHE_NAME).then((cache) => {
      return cache.addAll(PRECACHE_ASSETS);
    })
  );
  self.skipWaiting();
});

// Activate Event — clean old caches and notify clients of update
self.addEventListener('activate', (e) => {
  e.waitUntil(
    caches.keys().then((keys) => {
      return Promise.all(
        keys.map((key) => {
          if (key !== CACHE_NAME) {
            return caches.delete(key);
          }
        })
      );
    }).then(() => {
      // Take control of all open clients immediately
      return self.clients.claim();
    }).then(() => {
      // Notify all clients that a new version is now active
      return self.clients.matchAll({ type: 'window' }).then((clients) => {
        clients.forEach((client) => {
          client.postMessage({ type: 'SW_UPDATED' });
        });
      });
    })
  );
});

// Fetch Event
self.addEventListener('fetch', (e) => {
  const url = new URL(e.request.url);

  // Bypass API requests - always network-only for backend API calls
  if (url.pathname.startsWith('/api/')) {
    e.respondWith(fetch(e.request));
    return;
  }

  // Network-first for HTML documents so users always get fresh markup
  if (e.request.mode === 'navigate') {
    e.respondWith(
      fetch(e.request).then((networkResponse) => {
        const responseToCache = networkResponse.clone();
        caches.open(CACHE_NAME).then((cache) => {
          cache.put(e.request, responseToCache);
        });
        return networkResponse;
      }).catch(() => {
        return caches.match(e.request);
      })
    );
    return;
  }

  // Stale-while-revalidate for other static assets
  e.respondWith(
    caches.match(e.request).then((cachedResponse) => {
      if (cachedResponse) {
        // Fetch new version in background to update cache
        fetch(e.request).then((networkResponse) => {
          if (networkResponse.status === 200) {
            caches.open(CACHE_NAME).then((cache) => {
              cache.put(e.request, networkResponse.clone());
            });
          }
        }).catch(() => {/* Ignore network errors offline */});

        return cachedResponse;
      }

      // Network fallback
      return fetch(e.request).then((networkResponse) => {
        if (!networkResponse || networkResponse.status !== 200 || networkResponse.type !== 'basic') {
          return networkResponse;
        }

        const responseToCache = networkResponse.clone();
        caches.open(CACHE_NAME).then((cache) => {
          cache.put(e.request, responseToCache);
        });

        return networkResponse;
      });
    })
  );
});