const CACHE_NAME = 'cyrene-v1';
const ASSETS_TO_CACHE = [
  '/',
  '/index.html',
];

// Install: 缓存核心资源
self.addEventListener('install', (event) => {
  event.waitUntil(
    caches.open(CACHE_NAME).then((cache) => {
      return cache.addAll(ASSETS_TO_CACHE);
    })
  );
  self.skipWaiting();
});

// Activate: 清理旧缓存
self.addEventListener('activate', (event) => {
  event.waitUntil(
    caches.keys().then((keys) => {
      return Promise.all(
        keys.filter(key => key !== CACHE_NAME).map(key => caches.delete(key))
      );
    })
  );
  self.clients.claim();
});

// Fetch: 缓存优先策略（对 API 请求使用网络优先）
self.addEventListener('fetch', (event) => {
  const url = new URL(event.request.url);

  // API 请求：网络优先，失败时返回离线 JSON
  if (url.pathname.startsWith('/api/')) {
    event.respondWith(networkFirst(event.request));
  } else if (url.pathname.startsWith('/ws')) {
    // WebSocket 连接不缓存
    event.respondWith(fetch(event.request));
  } else {
    // 静态资源：缓存优先
    event.respondWith(cacheFirst(event.request));
  }
});

async function cacheFirst(request) {
  const cached = await caches.match(request);
  if (cached) return cached;
  try {
    const response = await fetch(request);
    if (response.ok) {
      const cache = await caches.open(CACHE_NAME);
      cache.put(request, response.clone());
    }
    return response;
  } catch (e) {
    // 返回离线页面（HTML 请求）
    if (request.headers.get('Accept')?.includes('text/html')) {
      return caches.match('/offline.html');
    }
    throw e;
  }
}

async function networkFirst(request) {
  try {
    const response = await fetch(request);
    const cache = await caches.open(CACHE_NAME);
    cache.put(request, response.clone());
    return response;
  } catch (e) {
    const cached = await caches.match(request);
    if (cached) return cached;
    return new Response(JSON.stringify({ error: '离线状态，请检查网络连接' }), {
      status: 503,
      headers: { 'Content-Type': 'application/json' }
    });
  }
}

// Push 通知
self.addEventListener('push', (event) => {
  const data = event.data?.json() || { title: 'Cyrene', body: '新消息' };
  event.waitUntil(
    self.registration.showNotification(data.title, {
      body: data.body,
      icon: '/images/Cyrene_Avatar/2nd_Form/Cyrene-2F-N-Happy-1.png',
      badge: '/images/Cyrene_Avatar/2nd_Form/Cyrene-2F-N-Happy-1.png',
      data: data.data || {},
    })
  );
});

self.addEventListener('notificationclick', (event) => {
  event.notification.close();
  const sessionId = event.notification.data?.session_id;
  const targetUrl = sessionId ? `/#/session/${sessionId}` : '/';
  event.waitUntil(
    clients.matchAll({ type: 'window' }).then((clientList) => {
      for (const client of clientList) {
        if (client.url.includes(targetUrl) && 'focus' in client) {
          return client.focus();
        }
      }
      if (clients.openWindow) return clients.openWindow(targetUrl);
    })
  );
});