import OpenAI from "openai";
/**
 * Utility functions for the WhatsApp GPT bot
 */
export declare class Utils {
    /**
     * Downloads a media file from a URL to a temporary file
     *
     * @param url URL of the media file
     * @param extension Optional file extension (default: determined from URL)
     * @returns Path to the downloaded temporary file
     */
    static downloadMedia(url: string, extension?: string): Promise<string>;
    /**
     * Transcribes an audio file using OpenAI's Whisper API
     *
     * @param filePath Path to the audio file
     * @param openai OpenAI client instance
     * @returns Transcribed text
     */
    static transcribeAudio(filePath: string, openai: OpenAI): Promise<string>;
    /**
     * Trims conversation history to keep it within token limits
     *
     * @param messages Array of messages
     * @param maxMessages Maximum number of messages to keep
     * @param preserveSystem Whether to preserve the system message
     * @returns Trimmed message array
     */
    static trimConversationHistory(messages: any[], maxMessages: number, preserveSystem?: boolean): any[];
    /**
     * Estimates token usage for a conversation
     * Very rough estimate: ~4 chars per token
     *
     * @param messages Conversation messages
     * @returns Estimated token count
     */
    static estimateTokens(messages: any[]): number;
}