// MQL5 Trading Automation Service Worker
// Version: 1.0.0

const CACHE_NAME = 'mql5-automation-v1';
const RUNTIME_CACHE = 'mql5-runtime-v1';

// Assets to cache on install
const PRECACHE_ASSETS = [
  '/',
  '/index.html',
  '/dashboard/index.html',
  '/manifest.json',
  '/sw-inspector.html',
  '/offline.html'
];

// Install event - cache essential assets
self.addEventListener('install', (event) => {
  console.log('[Service Worker] Installing...');
  
  event.waitUntil(
    caches.open(CACHE_NAME)
      .then((cache) => {
        console.log('[Service Worker] Precaching assets');
        return cache.addAll(PRECACHE_ASSETS);
      })
      .then(() => {
        console.log('[Service Worker] Installation complete');
        return self.skipWaiting();
      })
      .catch((error) => {
        console.error('[Service Worker] Installation failed:', error);
      })
  );
});

// Activate event - clean up old caches
self.addEventListener('activate', (event) => {
  console.log('[Service Worker] Activating...');
  
  event.waitUntil(
    caches.keys()
      .then((cacheNames) => {
        return Promise.all(
          cacheNames
            .filter((cacheName) => {
              return cacheName !== CACHE_NAME && cacheName !== RUNTIME_CACHE;
            })
            .map((cacheName) => {
              console.log('[Service Worker] Deleting old cache:', cacheName);
              return caches.delete(cacheName);
            })
        );
      })
      .then(() => {
        console.log('[Service Worker] Activation complete');
        return self.clients.claim();
      })
  );
});

// Fetch event - serve from cache, fallback to network
self.addEventListener('fetch', (event) => {
  // Skip cross-origin requests
  if (!event.request.url.startsWith(self.location.origin)) {
    return;
  }

  // Network-first strategy for API requests
  if (event.request.url.includes('/api/')) {
    event.respondWith(
      fetch(event.request)
        .then((response) => {
          // Clone the response before caching
          const responseClone = response.clone();
          caches.open(RUNTIME_CACHE).then((cache) => {
            cache.put(event.request, responseClone);
          });
          return response;
        })
        .catch(() => {
          return caches.match(event.request);
        })
    );
    return;
  }

  // Cache-first strategy for static assets
  event.respondWith(
    caches.match(event.request)
      .then((cachedResponse) => {
        if (cachedResponse) {
          // Return cached version and update cache in background
          fetch(event.request)
            .then((response) => {
              caches.open(RUNTIME_CACHE).then((cache) => {
                cache.put(event.request, response);
              });
            })
            .catch(() => {
              // Network request failed, but we have cache
            });
          return cachedResponse;
        }

        // Not in cache, fetch from network
        return fetch(event.request)
          .then((response) => {
            // Cache successful responses
            if (response.status === 200) {
              const responseClone = response.clone();
              caches.open(RUNTIME_CACHE).then((cache) => {
                cache.put(event.request, responseClone);
              });
            }
            return response;
          })
          .catch((error) => {
            console.error('[Service Worker] Fetch failed:', error);
            // Return offline page if available
            return caches.match('/offline.html') || new Response('Offline');
          });
      })
  );
});

// Message event - handle commands from clients
self.addEventListener('message', (event) => {
  console.log('[Service Worker] Message received:', event.data);
  
  if (event.data.type === 'SKIP_WAITING') {
    self.skipWaiting();
  }
  
  if (event.data.type === 'CACHE_STATS') {
    caches.keys().then((cacheNames) => {
      Promise.all(
        cacheNames.map((cacheName) => {
          return caches.open(cacheName).then((cache) => {
            return cache.keys().then((keys) => {
              return { name: cacheName, size: keys.length };
            });
          });
        })
      ).then((stats) => {
        event.ports[0].postMessage({
          type: 'CACHE_STATS_RESPONSE',
          data: stats
        });
      });
    });
  }
  
  if (event.data.type === 'CLEAR_CACHE') {
    caches.keys().then((cacheNames) => {
      Promise.all(
        cacheNames.map((cacheName) => caches.delete(cacheName))
      ).then(() => {
        event.ports[0].postMessage({
          type: 'CACHE_CLEARED',
          success: true
        });
      });
    });
  }
});

// Push notification event
self.addEventListener('push', (event) => {
  console.log('[Service Worker] Push received');
  
  const options = {
    body: event.data ? event.data.text() : 'New trading notification',
    icon: '/icons/icon-192x192.png',
    badge: '/icons/icon-72x72.png',
    vibrate: [200, 100, 200],
    tag: 'trading-notification',
    requireInteraction: false
  };
  
  event.waitUntil(
    self.registration.showNotification('MQL5 Trading Automation', options)
  );
});

// Notification click event
self.addEventListener('notificationclick', (event) => {
  console.log('[Service Worker] Notification clicked');
  event.notification.close();
  
  event.waitUntil(
    clients.openWindow('/')
  );
});