// PWA Service Worker v2
// - 页面导航：网络优先（构建更新后强制拿到新 index.html），离线才回落缓存
// - 静态资源：缓存优先
// - /api：直连不缓存
const CACHE = 'fp-static-v2';
const CORE = ['/', '/manifest.webmanifest', '/icons/pwa-192.png', '/icons/pwa-512.png'];

self.addEventListener('install', (e) => {
  self.skipWaiting();
  e.waitUntil(caches.open(CACHE).then((c) => c.addAll(CORE)));
});

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

self.addEventListener('fetch', (e) => {
  const url = new URL(e.request.url);
  if (e.request.method !== 'GET' || url.pathname.startsWith('/api')) return;

  if (e.request.mode === 'navigate') {
    e.respondWith(
      fetch(e.request).then((res) => {
        const copy = res.clone();
        caches.open(CACHE).then((c) => c.put('/index.html', copy));
        return res;
      }).catch(() => caches.match('/index.html').then((h) => h || caches.match('/')))
    );
    return;
  }

  e.respondWith(
    caches.match(e.request).then((hit) => hit || fetch(e.request).then((res) => {
      if (res.ok && url.origin === location.origin) {
        const copy = res.clone();
        caches.open(CACHE).then((c) => c.put(e.request, copy));
      }
      return res;
    }))
  );
});