import { ReadiumSpeechPlaybackEngine } from '../engine';
import { ReadiumSpeechPlaybackEvent, ReadiumSpeechPlaybackState } from '../navigator';
import { ReadiumSpeechUtterance } from '../utterance';
import { ReadiumSpeechVoice } from '../voices/types';
export declare class WebSpeechEngine implements ReadiumSpeechPlaybackEngine {
    private speechSynthesis;
    private speechSynthesisUtterance;
    private currentVoice;
    private currentUtterances;
    private currentUtteranceIndex;
    private playbackState;
    private readonly events;
    private voiceManager;
    private voices;
    private defaultVoice;
    private speakInContentLanguage;
    private languageVoiceCache;
    private warmingLanguages;
    private speakGeneration;
    private resumeInfinityTimer?;
    private isSpeakingInternal;
    private restartPending;
    private isPausedInternal;
    private isAndroidPaused;
    private pausedAtUtteranceIndex;
    private initialized;
    private maxLengthExceeded;
    private utterancesBeingCancelled;
    private rate;
    private pitch;
    private volume;
    private features;
    private patches;
    constructor();
    private shouldUseResumeInfinity;
    private createUtterance;
    initialize(options?: {
        languages?: string[];
        maxTimeout?: number;
        interval?: number;
        maxLengthExceeded?: "error" | "none" | "warn";
    }): Promise<boolean>;
    private validateText;
    private getCurrentVoiceForUtterance;
    private voiceMatchesLanguage;
    private voiceForUtteranceSync;
    private voiceForUtterance;
    private warmLanguageVoiceCache;
    getCurrentVoice(): ReadiumSpeechVoice | null;
    setSpeakInContentLanguage(enabled: boolean): void;
    getSpeakInContentLanguage(): boolean;
    private toPlainText;
    loadUtterances(contents: ReadiumSpeechUtterance[], startIndex?: number): void;
    setVoice(voice: ReadiumSpeechVoice | string): Promise<void>;
    getAvailableVoices(): Promise<ReadiumSpeechVoice[]>;
    speak(utteranceIndex?: number): void;
    private cancelCurrentSpeech;
    private speakCurrentUtterance;
    private startResumeInfinity;
    private stopResumeInfinity;
    pause(): void;
    resume(): void;
    stop(): void;
    setRate(rate: number): void;
    getRate(): number;
    setPitch(pitch: number): void;
    getPitch(): number;
    setVolume(volume: number): void;
    getVolume(): number;
    private scheduleRestartIfSpeaking;
    getState(): ReadiumSpeechPlaybackState;
    getCurrentUtteranceIndex(): number;
    setCurrentUtteranceIndex(index: number, onComplete?: (success: boolean) => void): void;
    getUtteranceCount(): number;
    on(event: ReadiumSpeechPlaybackEvent["type"], callback: (event: ReadiumSpeechPlaybackEvent) => void): () => void;
    private emitEvent;
    private setState;
    destroy(): Promise<void>;
}