sw.js

// Linux Mastery Course - Service Worker
const CACHE_NAME = 'linux-mastery-v1';
const OFFLINE_URL = '/index.html';

// Assets to cache on install
const PRECACHE_ASSETS = [
    '/',
    '/index.html',
    '/site.webmanifest',
    '/android-chrome-192x192.png',
    '/android-chrome-512x512.png',
    '/apple-touch-icon.png',
    '/favicon-32x32.png',
    '/favicon-16x16.png',
    '/favicon.ico',
    'https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800&family=JetBrains+Mono:wght@400;500;600;700&display=swap',
    'https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.9.0/styles/base16/tomorrow-night.min.css',
    'https://cdn.jsdelivr.net/npm/marked/marked.min.js',
    'https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.9.0/highlight.min.js',
    'https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.9.0/languages/bash.min.js'
];

// Install event - cache assets
self.addEventListener('install', (event) => {
    event.waitUntil(
        caches.open(CACHE_NAME)
            .then((cache) => {
                console.log('📦 Caching app assets...');
                return cache.addAll(PRECACHE_ASSETS);
            })
            .then(() => {
                console.log('✅ Assets cached successfully');
                return self.skipWaiting();
            })
            .catch((error) => {
                console.error('❌ Cache failed:', error);
            })
    );
});

// Activate event - clean old caches
self.addEventListener('activate', (event) => {
    event.waitUntil(
        caches.keys()
            .then((cacheNames) => {
                return Promise.all(
                    cacheNames
                        .filter((name) => name !== CACHE_NAME)
                        .map((name) => {
                            console.log('🗑️ Deleting old cache:', name);
                            return caches.delete(name);
                        })
                );
            })
            .then(() => {
                console.log('🚀 Service Worker activated');
                return self.clients.claim();
            })
    );
});

// Fetch event - serve from cache, fallback to network
self.addEventListener('fetch', (event) => {
    // Skip non-GET requests
    if (event.request.method !== 'GET') return;

    // Skip chrome-extension and other non-http requests
    if (!event.request.url.startsWith('http')) return;

    event.respondWith(
        caches.match(event.request)
            .then((cachedResponse) => {
                if (cachedResponse) {
                    // Return cached version
                    return cachedResponse;
                }

                // Not in cache, fetch from network
                return fetch(event.request)
                    .then((networkResponse) => {
                        // Check if valid response
                        if (!networkResponse || networkResponse.status !== 200 || networkResponse.type !== 'basic') {
                            return networkResponse;
                        }

                        // Clone and cache the response
                        const responseToCache = networkResponse.clone();
                        caches.open(CACHE_NAME)
                            .then((cache) => {
                                cache.put(event.request, responseToCache);
                            });

                        return networkResponse;
                    })
                    .catch(() => {
                        // Network failed, try to return offline page for navigation requests
                        if (event.request.mode === 'navigate') {
                            return caches.match(OFFLINE_URL);
                        }
                        return new Response('Offline', { status: 503, statusText: 'Service Unavailable' });
                    });
            })
    );
});

// Handle messages from the client
self.addEventListener('message', (event) => {
    if (event.data && event.data.type === 'SKIP_WAITING') {
        self.skipWaiting();
    }
});