// Minimal service worker — enables PWA install + an offline fallback for
// navigations. Live market data is never cached (always hits the network).
const SHELL = "yz-shell-v1";

self.addEventListener("install", (e) => {
  e.waitUntil(
    caches
      .open(SHELL)
      .then((c) => c.add("/"))
      .catch(() => {}),
  );
  self.skipWaiting();
});

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

self.addEventListener("fetch", (e) => {
  const req = e.request;
  // Only handle top-level navigations; let everything else (API, assets) pass through.
  if (req.mode !== "navigate") return;
  e.respondWith(
    fetch(req).catch(() => caches.match("/").then((r) => r || Response.error())),
  );
});