Send PDF email attachments with Resend

import type { NextApiRequest, NextApiResponse } from 'next';
import { Resend } from 'resend';
import { pdfn } from '@pdfn/react';
import Invoice from '@/pdfn-templates/invoice';
import { InvoiceEmail } from '@/emails/invoice-email';

const resend = new Resend(process.env.RESEND_API_KEY);
const client = pdfn();

export default async function handler(req: NextApiRequest, res: NextApiResponse) {
  const { invoiceNumber, customerName, customerEmail, total } = req.body;

  // Generate PDF
  const { data: pdf, error: pdfError } = await client.generate({
    react: <Invoice number={invoiceNumber} customer={customerName} total={total} />,
  });

  if (pdfError) {
    return res.status(500).json({ error: pdfError.message });
  }

  // Send email with attachment
  const { data: email, error: emailError } = await resend.emails.send({
    from: 'Billing <billing@yourdomain.com>',
    to: customerEmail,
    subject: `Invoice ${invoiceNumber}`,
    react: <InvoiceEmail customerName={customerName} invoiceNumber={invoiceNumber} />,
    attachments: [
      {
        filename: `invoice-${invoiceNumber}.pdf`,
        content: pdf.buffer,
      },
    ],
  });

  if (emailError) {
    return res.status(500).json({ error: emailError.message });
  }

  return res.json({ id: email.id });
}