Custom Stripe Receipts & Invoicing with React Email

import { headers } from 'next/headers';
import { NextResponse } from 'next/server';
import Stripe from 'stripe';
import { SadaSend } from 'sadasend';
import { render } from '@react-email/render';
import { ReceiptEmail } from '@/emails/ReceiptEmail';

const stripe = new Stripe(process.env.STRIPE_SECRET_KEY!, {
  apiVersion: '2024-12-18.acacia' as Stripe.LatestApiVersion,
});

const sadasend = new SadaSend({
  apiKey: process.env.SADASEND_API_KEY!,
});

export async function POST(req: Request) {
  const body = await req.text();
  const headersList = await headers();
  const signature = headersList.get('stripe-signature');

  if (!signature) {
    return NextResponse.json({ error: 'Missing signature' }, { status: 400 });
  }

  let event: Stripe.Event;

  try {
    event = stripe.webhooks.constructEvent(
      body,
      signature,
      process.env.STRIPE_WEBHOOK_SECRET!
    );
  } catch (err) {
    const message = err instanceof Error ? err.message : 'Unknown signature error';
    return NextResponse.json({ error: `Webhook signature verification failed: ${message}` }, { status: 400 });
  }

  if (event.type === 'invoice.payment_succeeded') {
    const invoice = event.data.object as Stripe.Invoice;
    const recipientEmail = invoice.customer_email;

    if (!recipientEmail) {
      return NextResponse.json({ received: true, note: 'No recipient email present' });
    }

    // Render branded React Email receipt component
    const emailHtml = await render(
      ReceiptEmail({
        customerName: invoice.customer_name || 'Valued Customer',
        invoiceNumber: invoice.number || invoice.id,
        amountFormatted: `$${(invoice.amount_paid / 100).toFixed(2)}`,
        items: invoice.lines.data.map((l) => ({
          description: l.description || 'Subscription',
          amount: `$${(l.amount / 100).toFixed(2)}`,
        })),
        pdfUrl: invoice.invoice_pdf || undefined,
        date: new Date(invoice.created * 1000).toLocaleDateString('en-US', {
          year: 'numeric',
          month: 'short',
          day: 'numeric',
        }),
      })
    );

    // Dispatch via SadaSend with custom domain DKIM and Idempotency key
    const result = await sadasend.emails.send({
      from: 'billing@yourdomain.com',
      to: recipientEmail,
      subject: `Your Receipt: ${invoice.number || 'Payment Confirmed'}`,
      html: emailHtml,
      idempotencyKey: `stripe_evt_${event.id}`,
    });

    if (!result.ok) {
      console.error('SadaSend receipt dispatch rejected:', result.error);
      return NextResponse.json({ error: 'Failed to send receipt email' }, { status: 500 });
    }
  }

  return NextResponse.json({ received: true });
}