// Copyright (c) 2020-2021 Drew Lemmy
// This file is part of TenebraWeb 2 under AGPL-3.0.
// Full details: https://github.com/tmpim/TenebraWeb2/blob/master/LICENSE.txt
/// <reference lib="webworker" />
/* eslint-disable no-restricted-globals */

// This service worker can be customized!
// See https://developers.google.com/web/tools/workbox/modules
// for the list of available Workbox modules, or add any other
// code you'd like.
// You can also remove this file if you'd prefer not to use a
// service worker, and the Workbox build step will be skipped.

import { clientsClaim } from "workbox-core";
import { precacheAndRoute, createHandlerBoundToURL } from "workbox-precaching";
import { registerRoute } from "workbox-routing";
import { StaleWhileRevalidate } from "workbox-strategies";

declare const self: ServiceWorkerGlobalScope;

clientsClaim();

// Precache all of the assets generated by your build process.
// Their URLs are injected into the manifest variable below.
// This variable must be present somewhere in your service worker file,
// even if you decide not to use precaching. See https://cra.link/PWA

// Filter out all locale files from the precache. There's usually a few hundred
// of these, so we definitely don't want to download them all on install!
const filteredManifest = self.__WB_MANIFEST
  .filter(u => !(typeof u === "string" ? u : u.url).includes("locale-"));
precacheAndRoute(filteredManifest);

// Cache the locale files (currently the only preloading step)
registerRoute(
  ({ url }) => (
    url.pathname.startsWith("/locales/")
    || url.pathname.startsWith("/static/js/locale-")
  ),
  new StaleWhileRevalidate({})
);

// Set up App Shell-style routing, so that all navigation requests
// are fulfilled with your index.html shell. Learn more at
// https://developers.google.com/web/fundamentals/architecture/app-shell
const fileExtensionRegexp = new RegExp("/[^/?]+\\.[^/]+$");
registerRoute(
  // Return false to exempt requests from being fulfilled by index.html.
  ({ request, url }: { request: Request; url: URL }) => {
    // If this isn't a navigation, skip.
    if (request.mode !== "navigate") {
      return false;
    }

    // If this is a URL that starts with /_, skip.
    if (url.pathname.startsWith("/_")) {
      return false;
    }

    // If this looks like a URL for a resource, because it contains
    // a file extension, skip.
    if (url.pathname.match(fileExtensionRegexp)) {
      return false;
    }

    // Return true to signal that we want to use the handler.
    return true;
  },
  createHandlerBoundToURL(process.env.PUBLIC_URL + "/index.html")
);

// This allows the web app to trigger skipWaiting via
// registration.waiting.postMessage({type: 'SKIP_WAITING'})
self.addEventListener("message", (event) => {
  if (event.data && event.data.type === "SKIP_WAITING") {
    self.skipWaiting();
  }
});
