import { WsListenerService, WsListenerServiceConfig, Message, Template } from './ws-listener.service';
interface PingConfig {
    /**
     * Send ping request every `heartbeatMs` (null - disabled).
     */
    heartbeatMs?: number;
    /**
     * Send ping request if there are no incoming messages for more than `checkAliveMs` (null - disabled).
     */
    checkAliveMs?: number;
    /**
     * May be a string, an object or a function.
     */
    request: Message | (() => Message | Promise<Message>);
    /**
     * May be a template or a matcher function.
     */
    response: Template;
    /**
     * A timeout to await for the response.
     */
    timeoutMs?: number;
}
interface ReconnectConfig {
    /**
     * Delay before auto reconnect (null - disabled).
     */
    delayMs?: number;
    /**
     * Resubscribe simultaneously to all subscriptions.
     */
    parallelResubscribe?: boolean;
}
export declare type Subscribe = () => void | Promise<void>;
export declare type WsServiceConfig = WsListenerServiceConfig & {
    ping?: PingConfig;
    reconnect?: ReconnectConfig;
};
export declare class WsService extends WsListenerService {
    protected pingConf: PingConfig;
    protected reconnectConf: ReconnectConfig;
    protected isReconnectConfigured: boolean;
    protected heartbeatTimeoutId: ReturnType<typeof setTimeout>;
    protected checkAliveTimeoutId: ReturnType<typeof setTimeout>;
    protected subs: any[];
    /**
     * Set to `true` on open if reconnect is configured.
     * Set to `false` on `close`
     * Check on `close` event handler
     */
    protected shouldReconnect: boolean;
    constructor({ ping, reconnect, ...conf }: WsServiceConfig);
    protected _init(): void;
    open(): Promise<void>;
    protected _handleMessage(event: any): Promise<void>;
    protected _reconnectableClose(...args: Parameters<WsListenerService['_reconnectableClose']>): ReturnType<WsListenerService['_reconnectableClose']>;
    close(...args: Parameters<WsListenerService['close']>): ReturnType<WsListenerService['close']>;
    /**
     * Return `true` if successfully received pong, otherwise return `false`.
     * Throw if ping request or response in not configured.
     */
    ping(): Promise<boolean>;
    protected _heartbeatLoop(): void;
    protected _scheduleCheckAlive(): void;
    protected _configureAutoReconnect(): void;
    /**
     * Reopen the connection.
     * Restore all subscriptions (call functions previously passed to `subscribe` method).
     */
    reconnect(): Promise<void>;
    /**
     * Accept a function that performs a sequence of actions required to subscribe.
     * Call the accepted function once to subscribe.
     * Add the function to a list of functions to be called on `reconnect`.
     * Return subscribe function passed as an argument (can be used to `unsubscribe` later).
     */
    subscribe(fn: Subscribe): Promise<Subscribe>;
    /**
     * Remove a function from a list of functions to be called on reconnect.
     * A sequence of actions required to unsubscribe should be performed elsewhere.
     */
    unsubscribe(fn: Subscribe): Promise<void>;
}
export {};