// Service worker for the /rep visit-logging PWA.
//
// Unlike the boss-phone SW, this one exists primarily so the app SHELL
// loads with no signal. A rep at a mine shaft has GPS but often no
// data, and the whole check-in flow is built to complete offline: the
// customer list is cached in localStorage, matching runs on the phone,
// and the submission sits in an outbox until there's a connection.
//
// So the shell must open from cache, every time, or none of that is
// reachable.
const CACHE_NAME = "wfdash-rep-v1";
const OFFLINE_URL = "/offline";

const PRECACHE_ASSETS = [
  "/rep",
  "/manifest-rep.json",
  "/offline",
  "/android-chrome-192x192.png",
  "/android-chrome-512x512.png",
  "/apple-touch-icon.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;

  const url = new URL(request.url);

  // Never cache API traffic. Serving a stale customer snapshot would
  // hide newly-added customers from a rep standing in front of one,
  // and the app maintains its own snapshot cache in localStorage where
  // it can reason about the age of the data.
  if (url.pathname.startsWith("/api/")) return;

  // Navigations: cache-first for the shell. The opposite of the boss
  // dashboard's network-first, and deliberately so — the boss wants
  // fresh numbers, the rep wants the app to open at all. Freshness
  // comes from the snapshot refresh once there's signal.
  if (request.mode === "navigate") {
    event.respondWith(
      caches
        .match(request)
        .then((cached) => {
          if (cached) {
            // Refresh in the background for the next launch.
            event.waitUntil(
              fetch(request)
                .then((response) =>
                  caches
                    .open(CACHE_NAME)
                    .then((cache) => cache.put(request, response.clone()))
                )
                .catch(() => {})
            );
            return cached;
          }
          return fetch(request).then((response) => {
            const clone = response.clone();
            caches.open(CACHE_NAME).then((cache) => cache.put(request, clone));
            return response;
          });
        })
        .catch(async () => {
          const shell = await caches.match("/rep");
          return shell || 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;
    })
  );
});