import { AbstractTTSClient } from "../core/abstract-tts.js";
import type { SpeakOptions, TTSCredentials, UnifiedVoice } from "../types.js";
/**
 * ModelsLab TTS Client Credentials
 */
export interface ModelsLabTTSCredentials extends TTSCredentials {
    /** ModelsLab API key (also reads MODELSLAB_API_KEY env var) */
    apiKey?: string;
}
/**
 * Extended speak options for ModelsLab TTS
 */
export interface ModelsLabTTSOptions extends SpeakOptions {
    /** Language descriptor e.g. "american english", "british english" */
    language?: string;
    /** Speed multiplier (default 1.0) */
    speed?: number;
    /** Enable emotion tags in the prompt (English only) */
    emotion?: boolean;
}
/**
 * ModelsLab TTS Client
 *
 * Provides text-to-speech via the ModelsLab Voice API.
 * API docs: https://docs.modelslab.com/voice-cloning/text-to-speech
 *
 * @example
 * ```ts
 * const client = new ModelsLabTTSClient({ apiKey: "your-api-key" });
 * await client.synthToFile("Hello world!", "output.mp3");
 * ```
 */
export declare class ModelsLabTTSClient extends AbstractTTSClient {
    private apiKey;
    private defaultLanguage;
    private defaultSpeed;
    protected sampleRate: number;
    constructor(credentials?: ModelsLabTTSCredentials);
    /** Check if credentials are present */
    checkCredentials(): Promise<boolean>;
    protected getRequiredCredentials(): string[];
    protected _getVoices(): Promise<UnifiedVoice[]>;
    /**
     * Synthesize text to audio bytes (Uint8Array).
     * Handles async generation — polls until audio is ready.
     */
    synthToBytes(text: string, options?: ModelsLabTTSOptions): Promise<Uint8Array>;
    /**
     * Synthesize text to a ReadableStream of audio chunks.
     */
    synthToBytestream(text: string, options?: ModelsLabTTSOptions): Promise<{
        audioStream: ReadableStream<Uint8Array>;
        wordBoundaries: Array<{
            text: string;
            offset: number;
            duration: number;
        }>;
    }>;
    /** Internal: call ModelsLab API and return audio bytes. */
    private _synthesize;
    /** Poll the fetch_result URL until audio is ready. */
    private _poll;
    /** Download audio from URL and return as Uint8Array. */
    private _downloadAudio;
    private _sleep;
}
export default ModelsLabTTSClient;