SaaS billing

async function chargePlan(customer: { id: string; email: string }, planNgn: number) {
  const res = await fetch("https://pesarc.xyz/api/v1/payments", {
    method: "POST",
    headers: {
      Authorization: `Bearer ${process.env.PESARC_SECRET_KEY}`,
      "Content-Type": "application/json",
    },
    body: JSON.stringify({
      amount: planNgn,
      currency: "NGN",
      reference: `sub_${customer.id}`,
      merchant_name: "Your SaaS",
      description: "Pro plan — monthly",
      redirect_url: `https://app.your-saas.com/billing/return`,
      webhook_url: `https://app.your-saas.com/api/pesarc/webhook`,
      metadata: { customerId: customer.id, plan: "pro" },
    }),
  });
  const { checkout_url } = await res.json();
  return checkout_url; // redirect the customer here
}

// POST /api/pesarc/webhook
export async function POST(req: Request) {
  const event = await req.json();
  if (event.type === "payment.settled") {
    const { reference, metadata } = event.data;
    await activateSubscription(metadata.customerId, metadata.plan);
  }
  return new Response("ok");
}