const CACHE_NAME = 'offline-cache-v1'
const ASSETS = [
    '/',
    '/index.html',
    '/styles.css',
    '/styles3.css',
    '/tempo.md',
    '/bell.png',
    '/bell.svg',
    '/by-sa.png',
    '/cc-by-sa-legalcode.txt',
    '/symbols.txt'
]

self.addEventListener('install', e => {
    console.log('installing sw')
    e.waitUntil(caches.open(CACHE_NAME).then(cache => cache.addAll(ASSETS)))
    self.skipWaiting()
})

self.addEventListener('activate', e => {
    console.log('sw activated')
    e.waitUntil(self.clients.claim())
})

self.addEventListener('fetch', e => {
    const url = new URL(e.request.url)
    const isTarget = ASSETS.includes(url.pathname) || url.pathname.startsWith('/fonts/')

    if (!isTarget) return

    e.respondWith(
        caches.open(CACHE_NAME).then(async cache => {
            const cachedResponse = await cache.match(e.request)

            if (cachedResponse) console.log(`cache ${url.pathname}`)
            else console.log(`fetch ${url.pathname}`)

            const networkFetch = fetch(e.request).then(networkResponse => {
                if (networkResponse.ok) {
                    console.log(`updating ${url.pathname}`)
                    cache.put(e.request, networkResponse.clone())
                }
                return networkResponse
            }).catch(err => {
                console.error(`failed ${url.pathname}:`, err)
            })

            return cachedResponse || networkFetch
        })
    )
})