import { DataSourceAdapter } from "../models/dataSourceAdapter.model";
import { Readable } from "stream";
import { Response } from 'express';
type DownloadParameters = Parameters<DataSourceAdapter['getTableRecordsStream']>;
interface ExportOperation {
    parameters: DownloadParameters;
    dataSourceName: string;
    format: keyof typeof ExportFormat;
}
export declare enum ExportFormat {
    json = "json",
    csv = "csv",
    xlsx = "xlsx"
}
/**
 * Service for exporting files into various formats
 */
export declare class Exporter {
    private readonly operations;
    createOperation({ parameters, dataSourceName, format }: ExportOperation): string;
    getOperation(id: string): ExportOperation | undefined;
    getHeadersByFormat(format: keyof typeof ExportFormat, filename: string): {
        [key: string]: string;
    };
    /**
     * Flattens a nested object/array structure into a single-level object
     * @example { name: "John", address: { city: "NY" } } => { name: "John", address__city: "NY" }
     */
    private flattenObject;
    /**
     * Formats a Date object into a string "YYYY-MM-DD HH:mm:ss"
     * @example new Date("2023-08-15T14:30:00Z") => "2023-08-15 14:30:00"
     */
    private formatDate;
    private sortHeaders;
    convertToJSON(stream: Readable, res: Response): void;
    convertToCSV(stream: Readable, res: Response): void;
    private escapeValueForCSV;
    convertToXLSX(stream: Readable, res: Response): Promise<void>;
}
export {};