const CACHE_NAME = "wfdash-counter-v1";
const OFFLINE_URL = "/offline";

const PRECACHE_ASSETS = [
  "/new-order",
  "/manifest-counter.json",
  "/offline",
  "/android-chrome-192x192.png",
  "/android-chrome-512x512.png",
];

self.addEventListener("install", (event) => {
  event.waitUntil(
    caches.open(CACHE_NAME).then((cache) => cache.addAll(PRECACHE_ASSETS))
  );
  self.skipWaiting();
});

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

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

  // Never cache API or admin/upload traffic — every submit must hit
  // the server live so the order lands on the board immediately.
  const url = new URL(request.url);
  if (url.pathname.startsWith("/api/")) return;

  // Navigation requests: network-first, fall back to cached
  // /new-order, then /offline.
  if (request.mode === "navigate") {
    event.respondWith(
      fetch(request)
        .then((response) => {
          const clone = response.clone();
          caches.open(CACHE_NAME).then((cache) => cache.put(request, clone));
          return response;
        })
        .catch(async () => {
          const cached = await caches.match(request);
          if (cached) return cached;
          const newOrder = await caches.match("/new-order");
          if (newOrder) return newOrder;
          return caches.match(OFFLINE_URL);
        })
    );
    return;
  }

  // Static assets: stale-while-revalidate.
  event.respondWith(
    caches.match(request).then((cached) => {
      const networkFetch = fetch(request)
        .then((response) => {
          const clone = response.clone();
          caches.open(CACHE_NAME).then((cache) => cache.put(request, clone));
          return response;
        })
        .catch(() => cached);
      return cached || networkFetch;
    })
  );
});