// DungeonCraft service worker: makes the game installable and playable offline.
// Network first (updates arrive at once), the cache is the fallback when offline.
// The savegame service (/api/) is never cached.
const CACHE = "dungeoncraft-v2";
const CORE = [
  "./",
  "index.html",
  "mq_js_bundle.js",
  "dc_plugin.js",
  "dungeoncraft.wasm",
  "manifest.webmanifest",
  "icons/icon-192.png",
  "icons/icon-512.png",
];

self.addEventListener("install", (event) => {
  event.waitUntil(caches.open(CACHE).then((c) => c.addAll(CORE)).then(() => self.skipWaiting()));
});

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

self.addEventListener("fetch", (event) => {
  const req = event.request;
  const url = new URL(req.url);
  if (req.method !== "GET" || url.origin !== self.location.origin || url.pathname.includes("/api/") || url.pathname.includes("/standalone/")) {
    return;
  }
  event.respondWith(
    fetch(req)
      .then((res) => {
        if (res.ok) {
          const copy = res.clone();
          caches.open(CACHE).then((c) => c.put(req, copy));
        }
        return res;
      })
      .catch(() => caches.match(req).then((hit) => hit || caches.match("index.html")))
  );
});