import { OnModuleDestroy, OnModuleInit } from '@nestjs/common';
import { ConfigService } from '../../config/services/config.service';
import { TtsProviderRegistryService } from './tts-provider-registry.service';
export declare class TtsProviderService implements OnModuleInit, OnModuleDestroy {
    private readonly configService;
    private readonly ttsProviderRegistry;
    private readonly logger;
    private readonly audioCache;
    private readonly inflightRequests;
    private cacheBytes;
    private cleanupTimer;
    constructor(configService: ConfigService, ttsProviderRegistry: TtsProviderRegistryService);
    onModuleInit(): void;
    onModuleDestroy(): void;
    synthesize(text: string, messageId: string): Promise<{
        buffer: Buffer;
        contentType: string;
    }>;
    private synthesizeAndCache;
    isConfigured(): boolean;
    private handleProviderError;
    private getConfig;
    private getSystemLanguage;
    private buildCacheKey;
    private cleanExpiredCache;
}