const VERSION = "faang-prep-v1";
const CACHE_NAME = `${VERSION}-shell`;

const APP_SHELL = [
  "/",
  "/roadmap",
  "/dashboard",
  "/favicon.svg",
  "/favicon.ico",
  "/site.webmanifest",
  "/og-image.png",
  "/android-chrome-192x192.png",
  "/android-chrome-512x512.png",
];

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

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

self.addEventListener("fetch", (event) => {
  const request = event.request;

  if (request.method !== "GET") return;

  const url = new URL(request.url);

  // Same-origin only
  if (url.origin !== self.location.origin) return;

  // Never cache the service worker itself
  if (url.pathname === "/sw.js") return;

  // API-ish / non-HTML JSON that changes (search index, leetcode db)
  if (url.pathname.endsWith(".json")) {
    event.respondWith(
      fetch(request).then((response) => {
        const copy = response.clone();
        caches.open(CACHE_NAME).then((cache) => cache.put(request, copy));
        return response;
      }).catch(() => caches.match(request)),
    );
    return;
  }

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

  // Static assets (hashed /_astro/*, images, css, js): cache-first
  event.respondWith(
    caches.match(request).then(
      (cached) =>
        cached ||
        fetch(request).then((response) => {
          if (response.ok && response.status === 200) {
            const copy = response.clone();
            caches.open(CACHE_NAME).then((cache) => cache.put(request, copy));
          }
          return response;
        }),
    ),
  );
});