/**
 * Service for monitoring network status
 * Provides methods to check if the user is online and to register listeners for network status changes
 */
class NetworkService {
    private online: boolean = navigator.onLine
    private listeners: Set<(online: boolean) => void> = new Set()

    constructor() {
        // Initialize with current online status
        this.online = navigator.onLine

        // Add event listeners for online/offline events
        if (typeof window !== 'undefined') {
            window.addEventListener('online', this.handleOnline.bind(this))
            window.addEventListener('offline', this.handleOffline.bind(this))
        }
    }

    /**
     * Check if the user is currently online
     * @returns boolean - True if online, false if offline
     */
    isOnline(): boolean {
        return this.online
    }

    /**
     * Add a listener for network status changes
     * @param listener - Function to call when network status changes
     * @returns Function - Function to remove the listener
     */
    addStatusChangeListener(listener: (online: boolean) => void): () => void {
        this.listeners.add(listener)

        // Return function to remove listener
        return () => {
            this.listeners.delete(listener)
        }
    }

    /**
     * Handle online event
     */
    private handleOnline(): void {
        this.online = true
        this.notifyListeners()
    }

    /**
     * Handle offline event
     */
    private handleOffline(): void {
        this.online = false
        this.notifyListeners()
    }

    /**
     * Notify all listeners of network status change
     */
    private notifyListeners(): void {
        for (const listener of this.listeners) {
            listener(this.online)
        }
    }
}

// Create a singleton instance
export const networkService = new NetworkService()