import { Request, Response, NextFunction } from 'express';
/**
 * Express middleware for standardizing success response formatting across the API.
 *
 * Provides consistent success response formatting by intercepting and transforming
 * JSON responses. Ensures all successful API responses follow a standardized structure
 * with proper metadata, request correlation, and optional success messages.
 *
 * @class ResponseMiddleware
 *
 * @example
 * ```typescript
 * // Application setup with response middleware
 * const responseMiddleware = new ResponseMiddleware();
 *
 * const app = express();
 *
 * // Apply middleware after routes but before error handlers
 * app.use(responseMiddleware.successHandler());
 *
 * // Example route responses:
 *
 * // GET /api/users returns array of users
 * // Original: [{ id: 1, name: 'John' }, { id: 2, name: 'Jane' }]
 * // Formatted: {
 * //   success: true,
 * //   data: [{ id: 1, name: 'John' }, { id: 2, name: 'Jane' }],
 * //   timestamp: '2023-10-05T12:00:00.000Z',
 * //   requestId: 'req_123'
 * // }
 *
 * // POST /api/users returns created user with 201 status
 * // Formatted: {
 * //   success: true,
 * //   data: { id: 3, name: 'New User' },
 * //   message: 'Resource created successfully',
 * //   timestamp: '2023-10-05T12:00:00.000Z',
 * //   requestId: 'req_123'
 * // }
 * ```
 */
export declare class ResponseMiddleware {
    /**
     * Success response formatting middleware for Express applications.
     *
     * Intercepts all JSON responses and applies consistent formatting to successful
     * responses. Preserves existing formatted responses, adds request correlation IDs,
     * and provides appropriate success messages for common status codes like 201 Created.
     *
     * @returns {function} Express middleware function
     *
     * @example
     * ```typescript
     * // Route handlers work normally - formatting is automatic
     *
     * app.get('/api/users', (req: Request, res: Response) => {
     *   const users = userService.getAll();
     *   res.json(users); // Automatically formatted
     * });
     *
     * app.post('/api/users', (req: Request, res: Response) => {
     *   const newUser = userService.create(req.body);
     *   res.status(201).json(newUser); // Gets "Resource created successfully" message
     * });
     *
     * app.get('/api/users/:id', (req: Request, res: Response) => {
     *   const user = userService.getById(req.params.id);
     *   res.json(user); // Single object formatted consistently
     * });
     *
     * // Already formatted responses are preserved
     * app.get('/api/custom', (req: Request, res: Response) => {
     *   const customResponse = {
     *     success: true,
     *     data: { custom: 'data' },
     *     customField: 'preserved'
     *   };
     *   res.json(customResponse); // Left unchanged due to existing 'success' field
     * });
     * ```
     */
    successHandler(): (req: Request, res: Response, next: NextFunction) => void;
}