const CACHE_NAME = "nexus-v1";
const PRECACHE_URLS = ["/", "/index.html"];
const STATIC_EXTENSION_RE = /\.(js|css|woff2?|png|svg|ico|webmanifest)$/;

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

// ── Activate ─────────────────────────────────────────────────────────────────
// Delete all caches except nexus-v1 (removes any stale caches from prior versions).
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())
  );
});

// ── Fetch ─────────────────────────────────────────────────────────────────────
self.addEventListener("fetch", (event) => {
  const { request } = event;
  const url = new URL(request.url);

  // API calls — network only, no interception
  if (url.pathname.startsWith("/api")) {
    return;
  }

  // Navigation requests — cache-first: serve shell from cache, fall back to network
  if (request.mode === "navigate") {
    event.respondWith(
      caches.match("/").then((cached) => cached || fetch(request))
    );
    return;
  }

  // Static assets — cache-first: serve from cache, on miss fetch and cache
  if (STATIC_EXTENSION_RE.test(url.pathname)) {
    event.respondWith(
      caches.match(request).then((cached) => {
        if (cached) return cached;
        return fetch(request).then((response) => {
          if (response.ok) {
            const clone = response.clone();
            caches.open(CACHE_NAME).then((cache) => cache.put(request, clone));
          }
          return response;
        });
      })
    );
    return;
  }

  // All other requests — pass through, no interception
});

// ── Push Notifications ────────────────────────────────────────────────────────
self.addEventListener("push", (event) => {
  const data = event.data ? event.data.json() : {};
  const { title = "Nexus", body = "", icon, data: notifData } = data;

  event.waitUntil(
    self.registration.showNotification(title, {
      body,
      icon: icon || "/android-chrome-192x192.png",
      badge: "/favicon-32x32.png",
      data: notifData,
    })
  );
});

// ── Notification Click ────────────────────────────────────────────────────────
self.addEventListener("notificationclick", (event) => {
  event.notification.close();
  const targetUrl = event.notification.data?.url || "/";
  event.waitUntil(clients.openWindow(targetUrl));
});