more

pkg/checkout/checkout-grain.go

@@ -101,6 +101,7 @@ type CheckoutGrain struct {
 	OrderId                *string             `json:"orderId"`
 	Deliveries             []*CheckoutDelivery `json:"deliveries,omitempty"`
 	PaymentInProgress      uint16              `json:"paymentInProgress"`
+	AmountInCentsRemaining int64               `json:"amountRemaining"`
 	InventoryReserved      bool                `json:"inventoryReserved"`
 	Confirmation           *ConfirmationStatus `json:"confirmationViewed,omitempty"`
 	Payments               []*Payment          `json:"payments,omitempty"`

pkg/checkout/mutation_initialize_checkout.go

@@ -47,6 +47,7 @@ func HandleInitializeCheckout(g *CheckoutGrain, m *messages.InitializeCheckout)
 	}
 
 	g.CartTotalPrice = g.CartState.TotalPrice
+	g.AmountInCentsRemaining = g.CartTotalPrice.IncVat
 
 	return nil
 }

pkg/checkout/mutation_payment_completed.go

@@ -36,6 +36,12 @@ func HandlePaymentCompleted(g *CheckoutGrain, m *messages.PaymentCompleted) erro
 
 	// Update checkout status
 	g.PaymentInProgress--
+	sum := g.CartState.TotalPrice.IncVat
+
+	for _, payment := range g.SettledPayments() {
+		sum -= payment.Amount
+	}
+	g.AmountInCentsRemaining = sum
 
 	return nil
 }