import { Observable } from 'rxjs';
import { EngineAction, EngineConfig } from './types';
import { ChatEngineResponse } from './client';
type ReceiveMessage = {
    text: string;
    source: string;
    invitationNo?: string;
    alias?: string;
    timestamp?: number;
};
export declare class Engine {
    config: EngineConfig;
    private readonly client;
    private readonly messageSubject$;
    private readonly actionsSubject$;
    messages: () => Observable<ReceiveMessage>;
    actions: () => Observable<EngineAction>;
    private readonly sessionId;
    private lastObjectId;
    /**
     * Tracks when the page was last hidden/visible. On iOS Safari, switching to
     * another tab (e.g. for authentication) freezes the page and aborts
     * in-flight fetch requests. We use timestamps to distinguish recoverable
     * fetch interruptions (page was recently frozen) from genuine failures.
     */
    private lastPageHiddenAt;
    private lastPageVisibleAt;
    constructor(config: EngineConfig, sessionId: string | null);
    private setupVisibilityTracking;
    /**
     * Returns true if the error is a fetch interruption that likely occurred
     * because iOS Safari froze/resumed the page (e.g. when a new tab opened for
     * authentication). We allow a grace window after the page was hidden or
     * recently became visible again.
     */
    private isRecoverableFetchInterruption;
    chatJoin(payload: {
        customerName: string;
        invitationUid: string;
    }): Observable<ChatEngineResponse>;
    chatRequest(payload: {
        customerName?: string;
        customerEmailAddress: string;
        visitorQuestion: string;
        customData: Record<string, any>;
        errand: string;
        authToken?: string;
    }): Observable<ChatEngineResponse>;
    reconnect(): Observable<ChatEngineResponse>;
    poll(): Observable<ChatEngineResponse>;
    chatWrite(message: string): Promise<void>;
    sendPenStatusOn(key: string): void;
    videoPrepared(result: string): Promise<void>;
    chatAuthentication(authToken: string): Promise<void>;
    chatQuit(): Promise<void>;
    chatEmailSession(emailAddress: string): Promise<void>;
    isOpenEntrance(entrance: string): Promise<boolean>;
    private processMessages;
    getChatStatus(): Promise<"finished" | "noSession" | "active">;
    rehydrate(): Promise<ChatEngineResponse | null>;
}
export {};