import type { TInvoice } from '../../interfaces/common.js';
/**
 * Base decoder class that defines common decoding functionality
 * for all invoice format decoders
 */
export declare abstract class BaseDecoder {
    protected xml: string;
    constructor(xml: string);
    /**
     * Decodes XML into a TInvoice object
     * @returns Promise resolving to a TInvoice object
     */
    abstract decode(): Promise<TInvoice>;
    /**
     * Gets letter data in the standard format
     * @returns Promise resolving to a TInvoice object
     */
    getLetterData(): Promise<TInvoice>;
    /**
     * Gets the raw XML content
     * @returns XML string
     */
    getXml(): string;
}