// famapp service worker — app-shell pattern
// Caches a minimal offline fallback on install.
// Navigation requests: network-first with offline fallback.
// Next.js static chunks: cache-first.
// API routes: network-only (pass through).

const CACHE = "famapp-shell-v1";
const OFFLINE = "/offline.html";

// --- install: precache offline shell ---

self.addEventListener("install", (event) => {
  event.waitUntil(
    caches.open(CACHE).then((cache) => cache.add(OFFLINE))
  );
  self.skipWaiting();
});

// --- activate: evict old caches ---

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

// --- fetch ---

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

  const url = new URL(request.url);

  // API routes — always go to network, never cache.
  if (url.pathname.startsWith("/api/")) return;

  // NextAuth — network-only.
  if (url.pathname.startsWith("/api/auth/")) return;

  // Next.js immutable static assets — cache-first.
  if (url.pathname.startsWith("/_next/static/")) {
    event.respondWith(
      caches.match(request).then(
        (cached) =>
          cached ??
          fetch(request).then((res) => {
            const clone = res.clone();
            caches.open(CACHE).then((c) => c.put(request, clone));
            return res;
          })
      )
    );
    return;
  }

  // Navigation requests — network-first, serve offline shell if unreachable.
  if (request.mode === "navigate") {
    event.respondWith(
      fetch(request).catch(() => caches.match(OFFLINE))
    );
    return;
  }
});