// 古诗词智能解析器 - Service Worker
// 支持PWA功能，提供离线访问能力

const CACHE_NAME = 'poetry-ai-v1.0.0';
const urlsToCache = [
  '/',
  '/index.html',
  '/static/css/style.css',
  '/static/js/main.js',
  'https://cdnjs.cloudflare.com/ajax/libs/font-awesome/6.4.0/css/all.min.css',
  'https://fonts.googleapis.com/css2?family=Noto+Serif+SC:wght@400;700&family=Ma+Shan+Zheng&display=swap'
];

// 安装Service Worker
self.addEventListener('install', event => {
  console.log('Service Worker: 安装中...');
  
  event.waitUntil(
    caches.open(CACHE_NAME)
      .then(cache => {
        console.log('Service Worker: 缓存文件中...');
        return cache.addAll(urlsToCache);
      })
      .then(() => {
        console.log('Service Worker: 安装完成');
        return self.skipWaiting();
      })
  );
});

// 激活Service Worker
self.addEventListener('activate', event => {
  console.log('Service Worker: 激活中...');
  
  // 清理旧缓存
  event.waitUntil(
    caches.keys().then(cacheNames => {
      return Promise.all(
        cacheNames.map(cacheName => {
          if (cacheName !== CACHE_NAME) {
            console.log('Service Worker: 清理旧缓存:', cacheName);
            return caches.delete(cacheName);
          }
        })
      );
    }).then(() => {
      console.log('Service Worker: 激活完成');
      return self.clients.claim();
    })
  );
});

// 拦截网络请求
self.addEventListener('fetch', event => {
  // 只处理GET请求
  if (event.request.method !== 'GET') return;
  
  // 对于API请求，使用网络优先策略
  if (event.request.url.includes('/api/')) {
    event.respondWith(
      fetch(event.request)
        .then(response => {
          // 克隆响应以进行缓存
          const responseToCache = response.clone();
          
          caches.open(CACHE_NAME)
            .then(cache => {
              cache.put(event.request, responseToCache);
            });
            
          return response;
        })
        .catch(() => {
          // 网络失败时尝试从缓存获取
          return caches.match(event.request);
        })
    );
    return;
  }
  
  // 对于静态资源，使用缓存优先策略
  event.respondWith(
    caches.match(event.request)
      .then(cachedResponse => {
        if (cachedResponse) {
          console.log('Service Worker: 从缓存返回:', event.request.url);
          return cachedResponse;
        }
        
        // 缓存中没有，从网络获取
        return fetch(event.request)
          .then(response => {
            // 检查响应是否有效
            if (!response || response.status !== 200 || response.type !== 'basic') {
              return response;
            }
            
            // 克隆响应以进行缓存
            const responseToCache = response.clone();
            
            caches.open(CACHE_NAME)
              .then(cache => {
                cache.put(event.request, responseToCache);
              });
              
            return response;
          })
          .catch(error => {
            console.log('Service Worker: 获取失败:', error);
            
            // 对于HTML页面，返回离线页面
            if (event.request.headers.get('accept').includes('text/html')) {
              return caches.match('/index.html');
            }
            
            // 对于其他资源，可以返回一个占位符
            return new Response('网络连接失败，请检查网络设置。', {
              status: 408,
              headers: { 'Content-Type': 'text/plain' }
            });
          });
      })
  );
});

// 处理推送通知
self.addEventListener('push', event => {
  console.log('Service Worker: 收到推送通知');
  
  const options = {
    body: event.data ? event.data.text() : '古诗词智能解析器有新内容更新',
    icon: '/static/images/icon-192.png',
    badge: '/static/images/badge-72.png',
    vibrate: [100, 50, 100],
    data: {
      dateOfArrival: Date.now(),
      primaryKey: '1'
    },
    actions: [
      {
        action: 'explore',
        title: '探索诗词',
        icon: '/static/images/explore-icon.png'
      },
      {
        action: 'close',
        title: '关闭',
        icon: '/static/images/close-icon.png'
      }
    ]
  };
  
  event.waitUntil(
    self.registration.showNotification('古诗词智能解析器', options)
  );
});

// 处理通知点击
self.addEventListener('notificationclick', event => {
  console.log('Service Worker: 通知被点击');
  
  event.notification.close();
  
  if (event.action === 'explore') {
    // 用户点击了"探索诗词"按钮
    event.waitUntil(
      clients.openWindow('/')
    );
  } else {
    // 用户点击了通知主体
    event.waitUntil(
      clients.matchAll({
        type: 'window',
        includeUncontrolled: true
      }).then(clientList => {
        // 如果已经有打开的窗口，聚焦它
        for (const client of clientList) {
          if (client.url === '/' && 'focus' in client) {
            return client.focus();
          }
        }
        
        // 否则打开新窗口
        if (clients.openWindow) {
          return clients.openWindow('/');
        }
      })
    );
  }
});

// 处理后台同步
self.addEventListener('sync', event => {
  console.log('Service Worker: 后台同步:', event.tag);
  
  if (event.tag === 'sync-favorites') {
    event.waitUntil(syncFavorites());
  }
});

// 同步收藏数据
function syncFavorites() {
  console.log('Service Worker: 同步收藏数据');
  
  // 这里应该实现实际的同步逻辑
  // 暂时只是记录日志
  return Promise.resolve();
}

// 处理消息
self.addEventListener('message', event => {
  console.log('Service Worker: 收到消息:', event.data);
  
  if (event.data && event.data.type === 'SKIP_WAITING') {
    self.skipWaiting();
  }
});