/**
 * @file WebSocket Client
 * @description Low-level WebSocket connection manager with retries
 */
/**
 * WebSocket connection state
 */
export type WebSocketState = 'connecting' | 'connected' | 'disconnected' | 'reconnecting';
/**
 * WebSocket message handler
 */
export type MessageHandler = (data: unknown) => void;
/**
 * WebSocket error handler
 */
export type ErrorHandler = (error: Event) => void;
/**
 * WebSocket state change handler
 */
export type StateChangeHandler = (state: WebSocketState) => void;
/**
 * WebSocket client configuration
 */
export interface WebSocketClientConfig {
    url: string;
    reconnect?: boolean;
    reconnectInterval?: number;
    maxReconnectAttempts?: number;
    heartbeatInterval?: number;
    protocols?: string[];
}
/**
 * WebSocket client class
 */
export declare class WebSocketClient {
    private socket;
    private config;
    private state;
    private reconnectAttempts;
    private reconnectTimeout;
    private heartbeatInterval;
    private messageHandlers;
    private errorHandlers;
    private stateChangeHandlers;
    private channelHandlers;
    constructor(config: WebSocketClientConfig);
    /**
     * Get current connection state
     */
    getState(): WebSocketState;
    /**
     * Check if connected
     */
    isConnected(): boolean;
    /**
     * Connect to WebSocket server
     */
    connect(): void;
    /**
     * Disconnect from WebSocket server
     */
    disconnect(): void;
    /**
     * Send message to server
     */
    send(data: unknown): void;
    /**
     * Send message to specific channel
     */
    sendToChannel(channel: string, data: unknown): void;
    /**
     * Subscribe to all messages
     */
    onMessage(handler: MessageHandler): () => void;
    /**
     * Subscribe to specific channel
     */
    subscribe(channel: string, handler: MessageHandler): () => void;
    /**
     * Subscribe to errors
     */
    onError(handler: ErrorHandler): () => void;
    /**
     * Subscribe to state changes
     */
    onStateChange(handler: StateChangeHandler): () => void;
    /**
     * Setup WebSocket event listeners
     */
    private setupEventListeners;
    /**
     * Handle disconnection
     */
    private handleDisconnect;
    /**
     * Schedule reconnection
     */
    private scheduleReconnect;
    /**
     * Calculate exponential backoff delay
     */
    private calculateBackoff;
    /**
     * Start heartbeat interval
     */
    private startHeartbeat;
    /**
     * Clear heartbeat interval
     */
    private clearHeartbeat;
    /**
     * Clear reconnect timeout
     */
    private clearReconnectTimeout;
    /**
     * Update and broadcast state
     */
    private setState;
}
/**
 * Create WebSocket client with default configuration
 */
export declare function createWebSocketClient(path?: string, config?: Partial<WebSocketClientConfig>): WebSocketClient;