sw.js

const CACHE_NAME = 'swiftqr-v3';
const ASSETS_TO_CACHE = [
    './',
    './index.html',
    './app.js',
    './style.css',
    './manifest.json',
    './icon.svg'
];

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

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

self.addEventListener('fetch', (event) => {
    // Network-first for CDN scripts, cache-first for local assets
    const url = new URL(event.request.url);
    if (url.origin !== location.origin) {
        event.respondWith(fetch(event.request).catch(() => caches.match(event.request)));
        return;
    }
    event.respondWith(
        caches.match(event.request).then((cached) => cached || fetch(event.request))
    );
});