const CACHE_NAME = 'pantryhub-v2';
const urlsToCache = [
    '/',
    '/css/style.css',
    '/js/app.js',
    '/manifest.json',
    '/icons/icon.svg'
];

// Install event
self.addEventListener('install', (event) => {
    event.waitUntil(
        caches.open(CACHE_NAME).then((cache) => {
            return cache.addAll(urlsToCache).catch(err => {
                console.log('Cache addAll error:', err);
            });
        })
    );
});

// Activate event
self.addEventListener('activate', (event) => {
    event.waitUntil(
        caches.keys().then((cacheNames) => {
            return Promise.all(
                cacheNames.map((cacheName) => {
                    if (cacheName !== CACHE_NAME) {
                        return caches.delete(cacheName);
                    }
                })
            );
        })
    );
});

// Fetch event
self.addEventListener('fetch', (event) => {
    // Skip non-GET requests
    if (event.request.method !== 'GET') {
        return;
    }

    // Browser extensions and third-party resources cannot be stored by Cache API.
    // Only handle same-origin HTTP(S) requests belonging to PantryHub.
    const url = new URL(event.request.url);
    if (!['http:', 'https:'].includes(url.protocol) || url.origin !== self.location.origin) {
        return;
    }

    // For API calls, use network-first strategy
    if (event.request.url.includes('/api/')) {
        event.respondWith(
            fetch(event.request)
                .then(response => {
                    const responseClone = response.clone();
                    caches.open(CACHE_NAME).then(cache => {
                        cache.put(event.request, responseClone);
                    });
                    return response;
                })
                .catch(() => {
                    return caches.match(event.request);
                })
        );
        return;
    }

    // For other requests, use cache-first strategy
    event.respondWith(
        caches.match(event.request)
            .then(response => {
                if (response) {
                    return response;
                }
                return fetch(event.request).then(response => {
                    if (!response || response.status !== 200 || response.type !== 'basic') {
                        return response;
                    }
                    const responseClone = response.clone();
                    caches.open(CACHE_NAME)
                        .then(cache => {
                            cache.put(event.request, responseClone);
                        });
                    return response;
                });
            })
            .catch(() => {
                // Return offline page or empty response
                return new Response('Offline - pagina niet beschikbaar', {
                    status: 503,
                    statusText: 'Service Unavailable',
                    headers: new Headers({
                        'Content-Type': 'text/plain'
                    })
                });
            })
    );
});