checkout: Allow fully discounted carts to be placed.

CHANGELOG.md

@@ -91,6 +91,24 @@ the cart has been adjusted and written back to cache
 **search**
 * Extend `Suggestion` struct with `Type` and `AdditionalAttributes` to be able to distinguish between product/category suggestions
 
-## v3.1.1 [upcoming]
+## v3.2.X [upcoming]
 **w3cdatalayer**
-* Fixed a bug that causes the datalayer to panic if it failed to build an absolute url
+* Fixed a bug that causes the datalayer to panic if it failed to build an absolute url
+
+**checkout**
+* Controller
+  * Allow checkout for fully discounted carts without payment processing. Previously all checkouts needed a valid payment to continue.
+    In case there is nothing to pay this can be skipped.
+    * Order ID will be reserved as soon as the user hits the checkout previously it was done before starting the payment
+* GraphQL
+  * Update place order process to also allow zero carts which don't need payment, this leads to a state flow that lacks the payment steps.
+    See module readme for further details.
+
+**cart**
+* inMemoryBehaviour: Allow custom logic for GiftCard / Voucher handling
+  * We introduced two new interfaces `GiftCardHandler` + `VoucherHandler`
+  * This enables users of the in-memory cart to add project specific gift card and voucher handling 
+
+**price**
+* IsZero() now uses LikelyEqual() instead of Equal() to avoid issues occurring due to floating-point arithmetic
+

cart/Readme.md

@@ -326,7 +326,11 @@ injector.Bind((*cart.CustomerCartService)(nil)).To(infrastructure.YourAdapter{})
 Most of the cart modification methods are part of the `ModifyBehaviour` interface - if you look at the secondary ports you will see, that they need to return an (initialized) implementation of the
 `ModifyBehaviour` interface - so in fact this interface needs to be implemented when writing an adapter as well.
 
-There is a "InMemoryAdapter" implementation as part of the package.
+**in-memory cart adapter**
+There is a "InMemoryAdapter" implementation as part of the package. It allows basic cart operations with a cart that is stored in memory.
+Since the cart storage is not persisted in any way we currently recommend the usage only for demo / testing.
+
+The in memory adapter supports custom gift card / voucher logic by implementing the `GiftCardHandler` and `VoucherHandler` interfaces.
 
 **PlaceOrderService**
 

cart/application/cartService_test.go

@@ -793,6 +793,8 @@ func (m *MockGuestCartServiceWithModifyBehaviour) GetModifyBehaviour(context.Con
 		},
 		nil,
 		nil,
+		nil,
+		nil,
 	)
 
 	return cob, nil

cart/infrastructure/InMemoryBehaviour.go

@@ -7,10 +7,9 @@ import (
 	"math/rand"
 	"strconv"
 
+	domaincart "flamingo.me/flamingo-commerce/v3/cart/domain/cart"
 	"flamingo.me/flamingo-commerce/v3/cart/domain/events"
 	priceDomain "flamingo.me/flamingo-commerce/v3/price/domain"
-
-	domaincart "flamingo.me/flamingo-commerce/v3/cart/domain/cart"
 	"flamingo.me/flamingo-commerce/v3/product/domain"
 	"flamingo.me/flamingo/v3/framework/flamingo"
 	"github.com/pkg/errors"
@@ -25,22 +24,44 @@ type (
 		itemBuilderProvider     domaincart.ItemBuilderProvider
 		deliveryBuilderProvider domaincart.DeliveryBuilderProvider
 		cartBuilderProvider     domaincart.BuilderProvider
+		giftCardHandler         GiftCardHandler
+		voucherHandler          VoucherHandler
 		defaultTaxRate          float64
 	}
 
-	//CartStorage Interface - might be implemented by other persistence types later as well
+	// CartStorage Interface - might be implemented by other persistence types later as well
 	CartStorage interface {
 		GetCart(id string) (*domaincart.Cart, error)
 		HasCart(id string) bool
 		StoreCart(cart *domaincart.Cart) error
 		RemoveCart(cart *domaincart.Cart) error
 	}
+
+	// GiftCardHandler enables the projects to have specific GiftCard handling within the in-memory cart
+	GiftCardHandler interface {
+		ApplyGiftCard(ctx context.Context, cart *domaincart.Cart, giftCardCode string) (*domaincart.Cart, error)
+		RemoveGiftCard(ctx context.Context, cart *domaincart.Cart, giftCardCode string) (*domaincart.Cart, error)
+	}
+
+	// VoucherHandler enables the projects to have specific Voucher handling within the in-memory cart
+	VoucherHandler interface {
+		ApplyVoucher(ctx context.Context, cart *domaincart.Cart, couponCode string) (*domaincart.Cart, error)
+		RemoveVoucher(ctx context.Context, cart *domaincart.Cart, couponCode string) (*domaincart.Cart, error)
+	}
+
+	// DefaultGiftCardHandler implements a basic gift card handler
+	DefaultGiftCardHandler struct{}
+
+	// DefaultVoucherHandler implements a basic voucher handler
+	DefaultVoucherHandler struct{}
 )
 
 var (
 	_ domaincart.ModifyBehaviour             = (*InMemoryBehaviour)(nil)
 	_ domaincart.GiftCardAndVoucherBehaviour = (*InMemoryBehaviour)(nil)
 	_ domaincart.CompleteBehaviour           = (*InMemoryBehaviour)(nil)
+	_ GiftCardHandler                        = (*DefaultGiftCardHandler)(nil)
+	_ VoucherHandler                         = (*DefaultVoucherHandler)(nil)
 )
 
 // Inject dependencies
@@ -52,6 +73,8 @@ func (cob *InMemoryBehaviour) Inject(
 	deliveryBuilderProvider domaincart.DeliveryBuilderProvider,
 	cartBuilderProvider domaincart.BuilderProvider,
 	eventPublisher events.EventPublisher,
+	voucherHandler VoucherHandler,
+	giftCardHandler GiftCardHandler,
 	config *struct {
 		DefaultTaxRate float64 `inject:"config:commerce.cart.inMemoryCartServiceAdapter.defaultTaxRate,optional"`
 	},
@@ -62,6 +85,8 @@ func (cob *InMemoryBehaviour) Inject(
 	cob.itemBuilderProvider = itemBuilderProvider
 	cob.deliveryBuilderProvider = deliveryBuilderProvider
 	cob.cartBuilderProvider = cartBuilderProvider
+	cob.voucherHandler = voucherHandler
+	cob.giftCardHandler = giftCardHandler
 	if config != nil {
 		cob.defaultTaxRate = config.DefaultTaxRate
 	}
@@ -429,16 +454,13 @@ func (cob *InMemoryBehaviour) storeCart(cart *domaincart.Cart) error {
 
 // ApplyVoucher applies a voucher to the cart
 func (cob *InMemoryBehaviour) ApplyVoucher(ctx context.Context, cart *domaincart.Cart, couponCode string) (*domaincart.Cart, domaincart.DeferEvents, error) {
-	if couponCode != "valid_voucher" && couponCode != "valid" {
-		err := errors.New("Code invalid")
+	cart, err := cob.voucherHandler.ApplyVoucher(ctx, cart, couponCode)
+
+	if err != nil {
 		return nil, nil, err
 	}
 
-	coupon := domaincart.CouponCode{
-		Code: couponCode,
-	}
-	cart.AppliedCouponCodes = append(cart.AppliedCouponCodes, coupon)
-	err := cob.cartStorage.StoreCart(cart)
+	err = cob.cartStorage.StoreCart(cart)
 	if err != nil {
 		return nil, nil, err
 	}
@@ -460,16 +482,12 @@ func (cob *InMemoryBehaviour) ApplyAny(ctx context.Context, cart *domaincart.Car
 
 // RemoveVoucher removes a voucher from the cart
 func (cob *InMemoryBehaviour) RemoveVoucher(ctx context.Context, cart *domaincart.Cart, couponCode string) (*domaincart.Cart, domaincart.DeferEvents, error) {
-	for i, coupon := range cart.AppliedCouponCodes {
-		if coupon.Code == couponCode {
-			cart.AppliedCouponCodes[i] = cart.AppliedCouponCodes[len(cart.AppliedCouponCodes)-1]
-			cart.AppliedCouponCodes[len(cart.AppliedCouponCodes)-1] = domaincart.CouponCode{}
-			cart.AppliedCouponCodes = cart.AppliedCouponCodes[:len(cart.AppliedCouponCodes)-1]
-			break
-		}
+	cart, err := cob.voucherHandler.RemoveVoucher(ctx, cart, couponCode)
+	if err != nil {
+		return nil, nil, err
 	}
 
-	err := cob.cartStorage.StoreCart(cart)
+	err = cob.cartStorage.StoreCart(cart)
 	if err != nil {
 		return nil, nil, err
 	}
@@ -480,18 +498,12 @@ func (cob *InMemoryBehaviour) RemoveVoucher(ctx context.Context, cart *domaincar
 // ApplyGiftCard applies a gift card to the cart
 // if a GiftCard is applied, it will be added to the array AppliedGiftCards on the cart
 func (cob *InMemoryBehaviour) ApplyGiftCard(ctx context.Context, cart *domaincart.Cart, giftCardCode string) (*domaincart.Cart, domaincart.DeferEvents, error) {
-	if giftCardCode != "valid_giftcard" && giftCardCode != "valid" {
-		err := errors.New("Code invalid")
+	cart, err := cob.giftCardHandler.ApplyGiftCard(ctx, cart, giftCardCode)
+	if err != nil {
 		return nil, nil, err
 	}
 
-	giftCard := domaincart.AppliedGiftCard{
-		Code:      giftCardCode,
-		Applied:   priceDomain.NewFromInt(10, 100, "$"),
-		Remaining: priceDomain.NewFromInt(0, 100, "$"),
-	}
-	cart.AppliedGiftCards = append(cart.AppliedGiftCards, giftCard)
-	err := cob.cartStorage.StoreCart(cart)
+	err = cob.cartStorage.StoreCart(cart)
 	if err != nil {
 		return nil, nil, err
 	}
@@ -501,16 +513,12 @@ func (cob *InMemoryBehaviour) ApplyGiftCard(ctx context.Context, cart *domaincar
 // RemoveGiftCard removes a gift card from the cart
 // if a GiftCard is removed, it will be removed from the array AppliedGiftCards on the cart
 func (cob *InMemoryBehaviour) RemoveGiftCard(ctx context.Context, cart *domaincart.Cart, giftCardCode string) (*domaincart.Cart, domaincart.DeferEvents, error) {
-	for i, giftcard := range cart.AppliedGiftCards {
-		if giftcard.Code == giftCardCode {
-			cart.AppliedGiftCards[i] = cart.AppliedGiftCards[len(cart.AppliedGiftCards)-1]
-			cart.AppliedGiftCards[len(cart.AppliedGiftCards)-1] = domaincart.AppliedGiftCard{}
-			cart.AppliedGiftCards = cart.AppliedGiftCards[:len(cart.AppliedGiftCards)-1]
-			break
-		}
+	cart, err := cob.giftCardHandler.RemoveGiftCard(ctx, cart, giftCardCode)
+	if err != nil {
+		return nil, nil, err
 	}
 
-	err := cob.cartStorage.StoreCart(cart)
+	err = cob.cartStorage.StoreCart(cart)
 	if err != nil {
 		return nil, nil, err
 	}
@@ -529,7 +537,7 @@ func (cob *InMemoryBehaviour) checkPaymentSelection(ctx context.Context, cart *d
 	}
 	paymentSelectionTotal := paymentSelection.TotalValue()
 
-	if !cart.GrandTotal().Equal(paymentSelectionTotal) {
+	if !cart.GrandTotal().LikelyEqual(paymentSelectionTotal) {
 		return errors.New("Payment Total does not match with Grandtotal")
 	}
 	return nil
@@ -549,3 +557,63 @@ func (cob *InMemoryBehaviour) resetPaymentSelectionIfInvalid(ctx context.Context
 
 	return cart, nil, nil
 }
+
+// ApplyVoucher checks the voucher and adds the voucher to the supplied cart if valid
+func (DefaultVoucherHandler) ApplyVoucher(_ context.Context, cart *domaincart.Cart, couponCode string) (*domaincart.Cart, error) {
+	if couponCode != "valid_voucher" && couponCode != "valid" {
+		err := errors.New("Code invalid")
+		return nil, err
+	}
+
+	coupon := domaincart.CouponCode{
+		Code: couponCode,
+	}
+
+	cart.AppliedCouponCodes = append(cart.AppliedCouponCodes, coupon)
+	return cart, nil
+}
+
+// RemoveVoucher removes the voucher from the cart if possible
+func (DefaultVoucherHandler) RemoveVoucher(_ context.Context, cart *domaincart.Cart, couponCode string) (*domaincart.Cart, error) {
+	for i, coupon := range cart.AppliedCouponCodes {
+		if coupon.Code == couponCode {
+			cart.AppliedCouponCodes[i] = cart.AppliedCouponCodes[len(cart.AppliedCouponCodes)-1]
+			cart.AppliedCouponCodes[len(cart.AppliedCouponCodes)-1] = domaincart.CouponCode{}
+			cart.AppliedCouponCodes = cart.AppliedCouponCodes[:len(cart.AppliedCouponCodes)-1]
+			return cart, nil
+		}
+	}
+
+	return cart, nil
+}
+
+// ApplyGiftCard checks the gift card and adds it to the supplied cart if valid
+func (DefaultGiftCardHandler) ApplyGiftCard(_ context.Context, cart *domaincart.Cart, giftCardCode string) (*domaincart.Cart, error) {
+	if giftCardCode != "valid_giftcard" && giftCardCode != "valid" {
+		err := errors.New("Code invalid")
+		return nil, err
+	}
+
+	giftCard := domaincart.AppliedGiftCard{
+		Code:      giftCardCode,
+		Applied:   priceDomain.NewFromInt(10, 100, "$"),
+		Remaining: priceDomain.NewFromInt(0, 100, "$"),
+	}
+	cart.AppliedGiftCards = append(cart.AppliedGiftCards, giftCard)
+
+	return cart, nil
+}
+
+// RemoveGiftCard removes the gift card from the cart if possible
+func (DefaultGiftCardHandler) RemoveGiftCard(_ context.Context, cart *domaincart.Cart, giftCardCode string) (*domaincart.Cart, error) {
+	for i, giftcard := range cart.AppliedGiftCards {
+		if giftcard.Code == giftCardCode {
+			cart.AppliedGiftCards[i] = cart.AppliedGiftCards[len(cart.AppliedGiftCards)-1]
+			cart.AppliedGiftCards[len(cart.AppliedGiftCards)-1] = domaincart.AppliedGiftCard{}
+			cart.AppliedGiftCards = cart.AppliedGiftCards[:len(cart.AppliedGiftCards)-1]
+			return cart, nil
+		}
+	}
+
+	return cart, nil
+}

cart/infrastructure/InMemoryBehaviour_test.go

@@ -48,6 +48,8 @@ func TestInMemoryBehaviour_CleanCart(t *testing.T) {
 				},
 				nil,
 				nil,
+				nil,
+				nil,
 			)
 			cart := &domaincart.Cart{
 				ID: "17",
@@ -174,6 +176,8 @@ func TestInMemoryBehaviour_CleanDelivery(t *testing.T) {
 				},
 				nil,
 				nil,
+				nil,
+				nil,
 			)
 			if err := cob.cartStorage.StoreCart(tt.args.cart); err != nil {
 				t.Fatalf("cart could not be initialized")
@@ -241,6 +245,8 @@ func TestInMemoryBehaviour_ApplyVoucher(t *testing.T) {
 				nil,
 				nil,
 				nil,
+				&DefaultVoucherHandler{},
+				&DefaultGiftCardHandler{},
 				nil,
 			)
 			got, _, err := cob.ApplyVoucher(context.Background(), tt.args.cart, tt.args.voucherCode)
@@ -334,6 +340,8 @@ func TestInMemoryBehaviour_RemoveVoucher(t *testing.T) {
 					return &domaincart.Builder{}
 				},
 				nil,
+				&DefaultVoucherHandler{},
+				&DefaultGiftCardHandler{},
 				nil,
 			)
 
@@ -399,6 +407,8 @@ func TestInMemoryBehaviour_ApplyGiftCard(t *testing.T) {
 				nil,
 				nil,
 				nil,
+				&DefaultVoucherHandler{},
+				&DefaultGiftCardHandler{},
 				nil,
 			)
 			got, _, err := cob.ApplyGiftCard(context.Background(), tt.args.cart, tt.args.giftCardCode)
@@ -466,6 +476,8 @@ func TestInMemoryBehaviour_RemoveGiftCard(t *testing.T) {
 				nil,
 				nil,
 				nil,
+				&DefaultVoucherHandler{},
+				&DefaultGiftCardHandler{},
 				nil,
 			)
 			got, _, err := cob.RemoveGiftCard(context.Background(), tt.args.cart, tt.args.giftCardCode)
@@ -492,6 +504,8 @@ func TestInMemoryBehaviour_Complete(t *testing.T) {
 			nil,
 			nil,
 			nil,
+			nil,
+			nil,
 		)
 		cart := &domaincart.Cart{ID: "test-id"}
 		require.NoError(t, cob.storeCart(cart))
@@ -517,6 +531,8 @@ func TestInMemoryBehaviour_Restore(t *testing.T) {
 			nil,
 			nil,
 			nil,
+			nil,
+			nil,
 		)
 		cart := &domaincart.Cart{ID: "1234"}
 

cart/infrastructure/inMemoryStorage.go

@@ -15,7 +15,7 @@ type (
 	}
 )
 
-/** Implementation fo the storage **/
+var _ CartStorage = &InMemoryCartStorage{}
 
 func (s *InMemoryCartStorage) init() {
 	if s.guestCarts == nil {

cart/module.go

@@ -60,6 +60,8 @@ func (m *Module) Inject(
 func (m *Module) Configure(injector *dingo.Injector) {
 	if m.useInMemoryCart {
 		injector.Bind((*infrastructure.CartStorage)(nil)).To(infrastructure.InMemoryCartStorage{}).AsEagerSingleton()
+		injector.Bind((*infrastructure.GiftCardHandler)(nil)).To(infrastructure.DefaultGiftCardHandler{})
+		injector.Bind((*infrastructure.VoucherHandler)(nil)).To(infrastructure.DefaultVoucherHandler{})
 		injector.Bind((*cart.GuestCartService)(nil)).To(infrastructure.InMemoryGuestCartService{})
 		injector.Bind((*cart.CustomerCartService)(nil)).To(infrastructure.InMemoryCustomerCartService{})
 	}

checkout/Readme.md

@@ -139,10 +139,14 @@ The start and failed states are defined by an annotated binding with annotations
 Exposed states implement the interface `checkout/interfaces/graphql/dto.State`. To map internal states to exposed states, 
 we use a map binding on the `dto.State` interface with the internal state names as keys and the exposed state as target.
 
-The default implementation defines the state flow as follows: 
+The default implementation defines the state flow as follows (for an cart that needs payment): 
 
 ![](domain/placeorder/states/transitions.png)
 
+Fully discounted carts don't need a payment, therefore the state flow is similar but lacks the payment creation/validation:
+
+![](domain/placeorder/states/transitions_zeropay.png)
+
 ### Context store
 
 The place order context must be stored aside of the session, since it is manipulated by a background process.