import type { PluginListenerHandle } from '@capacitor/core';
export interface TextToSpeechPlugin {
    /**
     * Starts the TTS engine and plays the desired text.
     */
    speak(options: TTSOptions): Promise<void>;
    /**
     * Stops the TTS engine.
     */
    stop(): Promise<void>;
    /**
     * Returns a list of supported BCP 47 language tags.
     */
    getSupportedLanguages(): Promise<{
        languages: string[];
    }>;
    /**
     * Returns a list of supported voices.
     */
    getSupportedVoices(): Promise<{
        voices: SpeechSynthesisVoice[];
    }>;
    /**
     * Checks if a specific BCP 47 language tag is supported.
     */
    isLanguageSupported(options: {
        lang: string;
    }): Promise<{
        supported: boolean;
    }>;
    /**
     * Verifies proper installation and availability of resource files on the system.
     *
     * Only available for Android.
     */
    openInstall(): Promise<void>;
    addListener(eventName: 'onRangeStart', listenerFunc: (info: {
        start: number;
        end: number;
        spokenWord: string;
    }) => void): Promise<PluginListenerHandle>;
}
export declare enum QueueStrategy {
    /**
     * Use `Flush` to stop the current request when a new request is sent.
     */
    Flush = 0,
    /**
     * Use `Add` to buffer the speech request. The request will be executed when all previous requests have been completed.
     */
    Add = 1
}
export interface TTSOptions {
    /**
     * The text that will be synthesised when the utterance is spoken.
     *
     * @example "Hello world"
     */
    text: string;
    /**
     * The language of the utterance.
     * Possible languages can be queried using `getSupportedLanguages`.
     *
     * @default "en-US"
     */
    lang?: string;
    /**
     * The speed at which the utterance will be spoken at.
     *
     * @default 1.0
     */
    rate?: number;
    /**
     * The pitch at which the utterance will be spoken at.
     *
     * @default 1.0
     */
    pitch?: number;
    /**
     * The volume that the utterance will be spoken at.
     *
     * @default 1.0
     */
    volume?: number;
    /**
     * The index of the selected voice that will be used to speak the utterance.
     * Possible voices can be queried using `getSupportedVoices`.
     */
    voice?: number;
    /**
     * Select the iOS Audio session category.
     * Possible values: `ambient` and `playback`.
     * Use `playback` to play audio even when the app is in the background.
     *
     * Only available for iOS.
     *
     * @default "ambient"
     */
    category?: string;
    /**
     * Select the strategy to adopt when several requests to speak overlap.
     *
     * @since 5.1.0
     * @default QueueStrategy.Flush
     */
    queueStrategy?: QueueStrategy;
}
/**
 * The SpeechSynthesisVoice interface represents a voice that the system supports.
 */
export interface SpeechSynthesisVoice {
    /**
     * Specifies whether the voice is the default voice for the current app (`true`) or not (`false`).
     *
     * @example false
     */
    default: boolean;
    /**
     * BCP 47 language tag indicating the language of the voice.
     *
     * @example "en-US"
     */
    lang: string;
    /**
     * Specifies whether the voice is supplied by a local (`true`) or remote (`false`) speech synthesizer service.
     *
     * @example true
     */
    localService: boolean;
    /**
     * Human-readable name that represents the voice.
     *
     * @example "Microsoft Zira Desktop - English (United States)"
     */
    name: string;
    /**
     * Type of URI and location of the speech synthesis service for this voice.
     *
     * @example "urn:moz-tts:sapi:Microsoft Zira Desktop - English (United States)?en-US"
     */
    voiceURI: string;
}