import * as plugins from '../plugins.js';
import { BaseDecoder } from './base.decoder.js';
/**
 * A decoder specifically for XInvoice/XRechnung format.
 * XRechnung is the German implementation of the European standard EN16931
 * for electronic invoices to the German public sector.
 */
export declare class XInvoiceDecoder extends BaseDecoder {
    private xmlDoc;
    private namespaces;
    constructor(xmlString: string);
    /**
     * Set up namespaces from the document
     */
    private setupNamespaces;
    /**
     * Extract element text by tag name with namespace awareness
     */
    private getElementText;
    /**
     * Converts XInvoice/XRechnung XML to a structured letter object
     */
    getLetterData(): Promise<plugins.tsclass.business.ILetter>;
    /**
     * Extracts invoice items from XInvoice document
     */
    private extractInvoiceItems;
}