const CACHE_NAME = 'opulent-pos-cache-v2';
const urlsToCache = [
    '/',
    '/index.php',
    '/dashboard.php',
    '/dashboard.php?view=cashier_checkout',
    '/manifest.json',
    '/assets/css/custom.css',
    '/assets/js/main.js',
    'https://cdn.jsdelivr.net/npm/bootstrap@5.1.3/dist/css/bootstrap.min.css',
    'https://cdn.jsdelivr.net/npm/bootstrap-icons@1.8.1/font/bootstrap-icons.css'
];

self.addEventListener('install', event => {
    self.skipWaiting(); // Activate worker immediately
    event.waitUntil(
        caches.open(CACHE_NAME)
            .then(cache => {
                console.log('Opened cache and caching assets');
                return cache.addAll(urlsToCache);
            })
    );
});

self.addEventListener('activate', event => {
    const cacheWhitelist = [CACHE_NAME];
    event.waitUntil(
        caches.keys().then(cacheNames => {
            return Promise.all(
                cacheNames.map(cacheName => {
                    if (cacheWhitelist.indexOf(cacheName) === -1) {
                        console.log('Deleting old cache:', cacheName);
                        return caches.delete(cacheName);
                    }
                })
            );
        })
        .then(() => self.clients.claim()) // Take control of all clients
    );
});

self.addEventListener('fetch', event => {
    // We only want to cache GET requests
    if (event.request.method !== 'GET') {
        return;
    }

    event.respondWith(
        caches.open(CACHE_NAME).then(async (cache) => {
            // Try to get the response from the cache
            const cachedResponse = await cache.match(event.request);
            
            // Return the cached response if found
            if (cachedResponse) {
                // Re-fetch in the background to update the cache for next time
                fetch(event.request).then(response => {
                    if (response.ok) {
                        cache.put(event.request, response.clone());
                    }
                });
                return cachedResponse;
            }

            // If not in cache, fetch from the network
            try {
                const networkResponse = await fetch(event.request);
                // If the fetch is successful, clone it and store it in the cache
                if (networkResponse.ok) {
                    cache.put(event.request, networkResponse.clone());
                }
                return networkResponse;
            } catch (error) {
                // If the fetch fails (e.g., offline), return a fallback or an error
                console.log('Fetch failed; returning offline page instead.', error);
                // You could return a generic offline page here if you had one
                // For now, just let the browser handle the error
            }
        })
    );
});