Phương thức thanh toán tại India

const session = await client.checkoutSessions.create({
  product_cart: [{ product_id: 'prod_123', quantity: 1 }],
  allowed_payment_method_types: [
    'upi_collect',
    'credit',
    'debit'
  ],
  billing_currency: 'INR',
  customer: {
    email: 'customer@example.in',
    name: 'Priya Sharma',
    phone_number: '+919876543210'
  },
  billing_address: {
    country: 'IN',
    zipcode: '560001'
  },
  return_url: 'https://example.com/success'
});

// Per-checkout override
const session = await client.checkoutSessions.create({
  product_cart: [{ product_id: 'prod_inr_monthly', quantity: 1 }],
  mandate_min_amount_inr_paise: 2_000_000, // ₹20,000 ceiling
  return_url: 'https://yoursite.com/return'
});

// Per-subscription override
const subscription = await client.subscriptions.create({
  product_id: 'pdt_inr_monthly',
  quantity: 1,
  customer: { email: 'customer@example.in' },
  billing: { country: 'IN', /* ... */ },
  mandate_min_amount_inr_paise: 2_000_000
});

// DON'T do this:
async function handleSubscriptionRenewal(subscription) {
  // ❌ Bad: Granting access immediately when charge is initiated
  grantPremiumAccess(subscription.customer_id);
}

// DO this:
async function handlePaymentWebhook(event) {
  if (event.type === 'payment.succeeded') {
    // ✅ Good: Only grant access after payment is confirmed
    grantPremiumAccess(event.data.customer_id);
  }
  
  if (event.type === 'payment.failed') {
    // Handle failed payment (mandate cancelled, insufficient funds)
    revokePremiumAccess(event.data.customer_id);
  }
}