// HurkiCorgi MC — minimal service worker
// Strategy: network-first for HTML/data, stale-while-revalidate for assets,
// offline fallback to the cached shell.

const VERSION = "v1";
const SHELL_CACHE = `shell-${VERSION}`;
const ASSET_CACHE = `assets-${VERSION}`;
const SHELL_URLS = ["/", "/icon.svg", "/manifest.json"];

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

self.addEventListener("activate", (event) => {
  event.waitUntil(
    (async () => {
      const keys = await caches.keys();
      await Promise.all(
        keys
          .filter((k) => k !== SHELL_CACHE && k !== ASSET_CACHE)
          .map((k) => caches.delete(k))
      );
      await self.clients.claim();
    })()
  );
});

function isAsset(url) {
  return (
    url.pathname.startsWith("/_next/static/") ||
    url.pathname.endsWith(".svg") ||
    url.pathname.endsWith(".woff2") ||
    url.pathname.endsWith(".png") ||
    url.pathname.endsWith(".ico")
  );
}

self.addEventListener("fetch", (event) => {
  const req = event.request;
  if (req.method !== "GET") return;

  const url = new URL(req.url);
  if (url.origin !== self.location.origin) return;

  // Never intercept API, auth, SSE, or anything under /api
  if (url.pathname.startsWith("/api/")) return;
  if (req.headers.get("accept")?.includes("text/event-stream")) return;

  // Assets: stale-while-revalidate
  if (isAsset(url)) {
    event.respondWith(
      caches.open(ASSET_CACHE).then(async (cache) => {
        const cached = await cache.match(req);
        const fetchPromise = fetch(req)
          .then((res) => {
            if (res.ok) cache.put(req, res.clone());
            return res;
          })
          .catch(() => cached || Response.error());
        return cached || fetchPromise;
      })
    );
    return;
  }

  // HTML / navigations: network-first with cache fallback
  if (req.mode === "navigate" || req.headers.get("accept")?.includes("text/html")) {
    event.respondWith(
      fetch(req)
        .then((res) => {
          if (res.ok) {
            const clone = res.clone();
            caches.open(SHELL_CACHE).then((c) => c.put(req, clone));
          }
          return res;
        })
        .catch(async () => {
          const cached = await caches.match(req);
          return cached || caches.match("/");
        })
    );
  }
});