/**
 * SherpaOnnx WebAssembly TTS Client
 *
 * This client uses the WebAssembly build of SherpaOnnx for browser environments
 * where native modules cannot be used.
 */
import { AbstractTTSClient } from "../core/abstract-tts";
import type { SpeakOptions, TTSCredentials, UnifiedVoice, WordBoundaryCallback } from "../types";
/**
 * SherpaOnnx WebAssembly TTS Client
 *
 * This client uses the WebAssembly build of SherpaOnnx for browser environments
 * where native modules cannot be used.
 */
export declare class SherpaOnnxWasmTTSClient extends AbstractTTSClient {
    private wasmModule;
    private tts;
    private sampleRate;
    private baseDir;
    private wasmPath;
    private wasmLoaded;
    /**
     * Create a new SherpaOnnx WebAssembly TTS client
     * @param credentials Optional credentials object
     */
    constructor(credentials?: TTSCredentials);
    /**
     * Get the default models directory
     * @returns Path to the default models directory
     */
    private _getDefaultModelsDir;
    /**
     * Check if the credentials are valid
     * @returns Promise resolving to true if credentials are valid
     */
    checkCredentials(): Promise<boolean>;
    /**
     * Get available voices
     * @returns Promise resolving to an array of unified voice objects
     */
    protected _getVoices(): Promise<UnifiedVoice[]>;
    /**
     * Initialize the WebAssembly module
     * @param wasmUrl URL to the WebAssembly file
     * @returns Promise resolving when the module is initialized
     */
    initializeWasm(_wasmUrl: string): Promise<void>;
    /**
     * Synthesize text to speech and return the audio as a byte array
     * @param text Text to synthesize
     * @param options Options for synthesis
     * @returns Promise resolving to a byte array of audio data
     */
    synthToBytes(text: string, _options?: SpeakOptions): Promise<Uint8Array>;
    /**
     * Convert audio samples to the requested format
     * @param samples Float32Array of audio samples
     * @returns Uint8Array of audio data in the requested format
     */
    private _convertAudioFormat;
    /**
     * Mock implementation for synthToBytes
     * @returns Promise resolving to a byte array of audio data
     */
    private _mockSynthToBytes;
    /**
     * Synthesize text to speech and stream the audio
     * @param text Text to synthesize
     * @param onAudioBuffer Callback for audio buffers
     * @param onStart Callback for when synthesis starts
     * @param onEnd Callback for when synthesis ends
     * @param onWord Callback for word boundary events
     * @param options Options for synthesis
     * @returns Promise resolving when synthesis is complete
     */
    synthToStream(text: string, onAudioBuffer: (audioBuffer: Uint8Array) => void, onStart?: () => void, onEnd?: () => void, onWord?: WordBoundaryCallback, options?: SpeakOptions): Promise<void>;
    /**
     * Synthesize text to speech and save to a file
     * @param text Text to synthesize
     * @param filename Filename to save as
     * @param format Audio format (mp3 or wav)
     * @param options Options for synthesis
     * @returns Promise resolving when synthesis is complete
     */
    synthToFile(text: string, filename: string, format?: "mp3" | "wav", options?: SpeakOptions): Promise<void>;
    /**
     * Get a property value
     * @param property Property name
     * @returns Property value
     */
    getProperty(property: string): any;
    /**
     * Set a property value
     * @param property Property name
     * @param value Property value
     */
    setProperty(property: string, value: any): void;
    /**
     * Clean up resources
     */
    dispose(): void;
    /**
     * Synthesize text to a byte stream
     * @param text Text to synthesize
     * @param options Options for synthesis
     * @returns Promise resolving to a readable stream of audio bytes
     */
    synthToBytestream(text: string, options?: SpeakOptions): Promise<ReadableStream<Uint8Array>>;
}