import { Controller, Get, Query, Res, Logger } from '@nestjs/common'; import * as express from 'express'; @Controller('payments/checkout') export class CheckoutController { private readonly logger = new Logger(CheckoutController.name); @Get() serveCheckout( @Query('reference') reference: string, @Query('amount') amount: string, @Query('currency') currency: string, @Query('orderId') orderId: string, @Query('email') email: string, @Res() res: express.Response, ) { this.logger.log(`Checkout page requested: ref=${reference}, amount=${amount}, currency=${currency}`); const safeRef = this.esc(reference || ''); const safeAmount = this.esc(amount || '0.00'); const safeCurrency = this.esc(currency || 'USD'); const safeEmail = this.esc(email || ''); const safeOrderId = this.esc(orderId || ''); // The backend's own public URL (ngrok URL). Used to call the webhook from the browser. const backendPublicUrl = process.env.PUBLIC_URL || ''; const html = ` Secure Payment – WhatsApp Commerce Hub

Payment Confirmed!

Your payment of ${safeCurrency} $${safeAmount} has been successfully processed.

💬 A confirmation has been sent to your WhatsApp. You can now close this tab and return to the chat.

Secure Payment Checkout

Ref: ${safeRef}
Total Amount Due ${safeCurrency} $${parseFloat(safeAmount || '0').toFixed(2)}
Payment Details
Email: ${safeEmail || 'N/A'}
Order: #${safeOrderId || 'N/A'}
Gateway: WhatsApp Commerce Hub (Sandbox)
`; res.setHeader('Content-Type', 'text/html; charset=utf-8'); res.setHeader('Cache-Control', 'no-store'); res.send(html); } private esc(str: string): string { return str .replace(/&/g, '&') .replace(//g, '>') .replace(/"/g, '"') .replace(/'/g, '''); } }