// This is the "Offline page" service worker

importScripts(
    'https://storage.googleapis.com/workbox-cdn/releases/5.1.2/workbox-sw.js'
)
const offlineFallbackPage = 'offline.html'

const PRECACHE_ASSETS = [offlineFallbackPage]

const CACHE = 'voucher-app'

self.addEventListener('message', (event) => {
    if (event.data && event.data.type === 'SKIP_WAITING') {
        self.skipWaiting()
    }
})

self.addEventListener('install', async (event) => {
    event.waitUntil(
        caches.open(CACHE).then((cache) => {
            cache.addAll(PRECACHE_ASSETS)
        })
    )
})

if (workbox.navigationPreload.isSupported()) {
    workbox.navigationPreload.enable()
}

self.addEventListener('fetch', (event) => {
    if (event.request.mode === 'navigate') {
        event.respondWith(
            (async () => {
                try {
                    const preloadResp = await event.preloadResponse

                    if (preloadResp) {
                        return preloadResp
                    }

                    const networkResp = await fetch(event.request)
                    return networkResp
                } catch (error) {
                    const cache = await caches.open(CACHE)
                    const cachedResp = await cache.match(offlineFallbackPage)
                    return cachedResp
                }
            })()
        )
    }
})