/**
 * Composable to track online/offline status
 * 
 * Usage:
 * const { isOnline, wasOffline } = useOnlineStatus()
 * 
 * watch(isOnline, (online) => {
 *   if (online && wasOffline.value) {
 *     // User came back online, sync data
 *   }
 * })
 */
export function useOnlineStatus() {
  const isOnline = ref(true)
  const wasOffline = ref(false)

  if (process.client) {
    // Initial state
    isOnline.value = navigator.onLine

    // Listen for online/offline events
    const updateOnlineStatus = () => {
      const online = navigator.onLine
      
      if (!online && isOnline.value) {
        // Just went offline
        wasOffline.value = true
      }
      
      isOnline.value = online
    }

    window.addEventListener('online', updateOnlineStatus)
    window.addEventListener('offline', updateOnlineStatus)

    // Cleanup on unmount
    onUnmounted(() => {
      window.removeEventListener('online', updateOnlineStatus)
      window.removeEventListener('offline', updateOnlineStatus)
    })
  }

  return {
    isOnline: readonly(isOnline),
    wasOffline: readonly(wasOffline)
  }
}