import { AbstractTTSClient } from "../core/abstract-tts";
import type { SpeakOptions, TTSCredentials, UnifiedVoice } from "../types";
/**
 * IBM Watson TTS Client Credentials
 */
export interface WatsonTTSCredentials extends TTSCredentials {
    apiKey: string;
    region: string;
    instanceId: string;
    disableSSLVerification?: boolean;
}
/**
 * IBM Watson TTS Client
 */
export declare class WatsonTTSClient extends AbstractTTSClient {
    private apiKey;
    private region;
    private instanceId;
    protected wordBoundaries: Array<{
        text: string;
        offset: number;
        duration: number;
    }>;
    private iamToken;
    private wsUrl;
    /**
     * Create a new IBM Watson TTS client
     * @param credentials Watson credentials object with apiKey, region, and instanceId
     */
    constructor(credentials: WatsonTTSCredentials);
    /**
     * Get raw voices from Watson
     * @returns Promise resolving to an array of unified voice objects
     */
    protected _getVoices(): Promise<any[]>;
    /**
     * Map Watson voice objects to unified format
     * @param rawVoices Array of Watson voice objects
     * @returns Promise resolving to an array of unified voice objects
     */
    protected _mapVoicesToUnified(rawVoices: any[]): Promise<UnifiedVoice[]>;
    /**
     * Refresh the IAM token for Watson API
     * @returns Promise resolving when token is refreshed
     */
    private _refreshIAMToken;
    /**
     * Prepare SSML for synthesis
     * @param text Text or SSML to prepare
     * @param options Synthesis options
     * @returns SSML string ready for synthesis
     */
    private prepareSSML;
    /**
     * Check if credentials are valid
     * @returns Promise resolving to true if credentials are valid
     */
    checkCredentials(): Promise<boolean>;
    /**
     * Get the list of required credential types for this engine
     * @returns Array of required credential field names
     */
    protected getRequiredCredentials(): string[];
    /**
     * Synthesize text to audio bytes
     * @param text Text or SSML to synthesize
     * @param options Synthesis options
     * @returns Promise resolving to audio bytes
     */
    synthToBytes(text: string, options?: SpeakOptions): Promise<Uint8Array>;
    /**
     * Synthesize text to a byte stream with word boundary information
     * @param text Text or SSML to synthesize
     * @param options Synthesis options
     * @returns Promise resolving to an object containing the audio stream and word boundary information
     */
    synthToBytestream(text: string, options?: SpeakOptions): Promise<{
        audioStream: ReadableStream<Uint8Array>;
        wordBoundaries: Array<{
            text: string;
            offset: number;
            duration: number;
        }>;
    }>;
    /**
     * Synthesize text to a byte stream using the WebSocket API in browser
     * @param ssml SSML to synthesize
     * @param voice Voice to use
     * @returns Promise resolving to an object containing the audio stream and word boundary information
     */
    private _synthToBytestreamWithBrowserWebSocket;
    /**
     * Synthesize text to a byte stream using the REST API
     * @param ssml SSML to synthesize
     * @param options Synthesis options
     * @returns Promise resolving to an object containing the audio stream and word boundary information
     */
    private _synthToBytestreamWithREST;
    /**
     * Set the voice to use for synthesis
     * @param voiceId Voice ID to use
     * @param lang Language code (not used in Watson)
     */
    setVoice(voiceId: string, lang?: string): void;
}
/**
 * Extended options for Watson TTS
 */
export interface WatsonTTSOptions extends SpeakOptions {
    format?: "mp3" | "wav";
}