feat: use customer id when present whilst creating a premium order

services/skus/model/model.go

@@ -413,6 +413,7 @@ type OrderItemRequest struct {
 // CreateOrderRequestNew includes information needed to create an order.
 type CreateOrderRequestNew struct {
 	Email          string                `json:"email" validate:"required,email"`
+	CustomerID     string                `json:"customer_id"` // Optional.
 	Currency       string                `json:"currency" validate:"required,iso4217"`
 	StripeMetadata *OrderStripeMetadata  `json:"stripe_metadata"`
 	RadomMetadata  *OrderRadomMetadata   `json:"radom_metadata"`

services/skus/service.go

@@ -2021,6 +2021,7 @@ func (s *Service) createStripeSession(ctx context.Context, req *model.CreateOrde
 	sreq := createStripeSessionRequest{
 		orderID:    oid,
 		email:      req.Email,
+		customerID: req.CustomerID,
 		successURL: surl,
 		cancelURL:  curl,
 		trialDays:  order.GetTrialDays(),
@@ -2572,6 +2573,7 @@ func (s *Service) recreateStripeSession(ctx context.Context, dbi sqlx.ExecerCont
 	req := createStripeSessionRequest{
 		orderID:    ord.ID.String(),
 		email:      email,
+		customerID: xstripe.CustomerIDFromSession(oldSess),
 		successURL: oldSess.SuccessURL,
 		cancelURL:  oldSess.CancelURL,
 		trialDays:  ord.GetTrialDays(),
@@ -2798,6 +2800,7 @@ func chooseStripeSessID(ord *model.Order, canBeNewSessID string) (string, bool)
 type createStripeSessionRequest struct {
 	orderID    string
 	email      string
+	customerID string
 	successURL string
 	cancelURL  string
 	trialDays  int64
@@ -2815,9 +2818,17 @@ func createStripeSession(ctx context.Context, cl stripeClient, req createStripeS
 		LineItems:          req.items,
 	}
 
-	// Email might not be given.
-	// This could happen while recreating a session, and the email was not extracted from the old one.
-	if req.email != "" {
+	// Different processes can supply different info about customer:
+	// - when customerID is present, it takes precedence;
+	// - when email is present:
+	//    - first, search for customer;
+	//    - fallback to using the email directly.
+	// Based on the rules above, if both are present, customerID wins.
+	switch {
+	case req.customerID != "":
+		params.Customer = &req.customerID
+
+	case req.customerID == "" && req.email != "":
 		if cust, ok := cl.FindCustomer(ctx, req.email); ok && cust.Email != "" {
 			params.Customer = &cust.ID
 		} else {

services/skus/service_nonint_test.go

@@ -4388,7 +4388,7 @@ func TestService_recreateStripeSession(t *testing.T) {
 		},
 
 		{
-			name: "success_email_from_session",
+			name: "success_email_cust_from_session",
 			given: tcGiven{
 				ordRepo: &repository.MockOrder{
 					FnAppendMetadata: func(ctx context.Context, dbi sqlx.ExecerContext, id uuid.UUID, key, val string) error {
@@ -4405,7 +4405,7 @@ func TestService_recreateStripeSession(t *testing.T) {
 							ID:         "cs_test_id_old",
 							SuccessURL: "https://example.com/success",
 							CancelURL:  "https://example.com/cancel",
-							Customer:   &stripe.Customer{Email: "[email protected]"},
+							Customer:   &stripe.Customer{ID: "cus_id", Email: "[email protected]"},
 						}
 
 						return result, nil
@@ -4455,6 +4455,79 @@ func TestService_recreateStripeSession(t *testing.T) {
 			},
 		},
 
+		{
+			name: "success_email_from_request_cust_without_email",
+			given: tcGiven{
+				ordRepo: &repository.MockOrder{
+					FnAppendMetadata: func(ctx context.Context, dbi sqlx.ExecerContext, id uuid.UUID, key, val string) error {
+						if key == "stripeCheckoutSessionId" && val == "cs_test_id" {
+							return nil
+						}
+
+						return model.Error("unexpected")
+					},
+				},
+				cl: &xstripe.MockClient{
+					FnSession: func(ctx context.Context, id string, params *stripe.CheckoutSessionParams) (*stripe.CheckoutSession, error) {
+						result := &stripe.CheckoutSession{
+							ID:         "cs_test_id_old",
+							SuccessURL: "https://example.com/success",
+							CancelURL:  "https://example.com/cancel",
+							Customer:   &stripe.Customer{ID: "cus_id"},
+						}
+
+						return result, nil
+					},
+
+					FnFindCustomer: func(ctx context.Context, email string) (*stripe.Customer, bool) {
+						return nil, false
+					},
+
+					FnCreateSession: func(ctx context.Context, params *stripe.CheckoutSessionParams) (*stripe.CheckoutSession, error) {
+						if params.Customer != nil {
+							return nil, model.Error("unexpected_customer")
+						}
+
+						if *params.CustomerEmail != "[email protected]" {
+							return nil, model.Error("unexpected_customer_email")
+						}
+
+						result := &stripe.CheckoutSession{
+							ID:                 "cs_test_id",
+							PaymentMethodTypes: []string{"card"},
+							Mode:               stripe.CheckoutSessionModeSubscription,
+							SuccessURL:         *params.SuccessURL,
+							CancelURL:          *params.CancelURL,
+							ClientReferenceID:  *params.ClientReferenceID,
+							Subscription: &stripe.Subscription{
+								ID: "sub_id",
+								Metadata: map[string]string{
+									"orderID": *params.ClientReferenceID,
+								},
+							},
+							AllowPromotionCodes: true,
+						}
+
+						return result, nil
+					},
+				},
+				ord: &model.Order{
+					ID: uuid.Must(uuid.FromString("facade00-0000-4000-a000-000000000000")),
+					Items: []model.OrderItem{
+						{
+							Quantity: 1,
+							Metadata: datastore.Metadata{"stripe_item_id": "stripe_item_id"},
+						},
+					},
+				},
+				oldSessID: "cs_test_id_old",
+				email:     "[email protected]",
+			},
+			exp: tcExpected{
+				val: "cs_test_id",
+			},
+		},
+
 		{
 			name: "success_email_from_request",
 			given: tcGiven{
@@ -4473,7 +4546,6 @@ func TestService_recreateStripeSession(t *testing.T) {
 							ID:         "cs_test_id_old",
 							SuccessURL: "https://example.com/success",
 							CancelURL:  "https://example.com/cancel",
-							Customer:   &stripe.Customer{Email: "[email protected]"},
 						}
 
 						return result, nil
@@ -4564,7 +4636,84 @@ func TestCreateStripeSession(t *testing.T) {
 
 	tests := []testCase{
 		{
-			name: "success_found_customer",
+			name: "success_cust_id",
+			given: tcGiven{
+				cl: &xstripe.MockClient{
+					FnCreateSession: func(ctx context.Context, params *stripe.CheckoutSessionParams) (*stripe.CheckoutSession, error) {
+						if params.Customer == nil || *params.Customer != "cus_id" {
+							return nil, model.Error("unexpected")
+						}
+
+						result := &stripe.CheckoutSession{ID: "cs_test_id"}
+
+						return result, nil
+					},
+
+					FnFindCustomer: func(ctx context.Context, email string) (*stripe.Customer, bool) {
+						panic("unexpected_find_customer")
+					},
+				},
+
+				req: createStripeSessionRequest{
+					orderID:    "facade00-0000-4000-a000-000000000000",
+					customerID: "cus_id",
+					successURL: "https://example.com/success",
+					cancelURL:  "https://example.com/cancel",
+					trialDays:  7,
+					items: []*stripe.CheckoutSessionLineItemParams{
+						{
+							Quantity: ptrTo[int64](1),
+							Price:    ptrTo("stripe_item_id"),
+						},
+					},
+				},
+			},
+			exp: tcExpected{
+				val: "cs_test_id",
+			},
+		},
+
+		{
+			name: "success_cust_id_email",
+			given: tcGiven{
+				cl: &xstripe.MockClient{
+					FnCreateSession: func(ctx context.Context, params *stripe.CheckoutSessionParams) (*stripe.CheckoutSession, error) {
+						if params.Customer == nil || *params.Customer != "cus_id" {
+							return nil, model.Error("unexpected")
+						}
+
+						result := &stripe.CheckoutSession{ID: "cs_test_id"}
+
+						return result, nil
+					},
+
+					FnFindCustomer: func(ctx context.Context, email string) (*stripe.Customer, bool) {
+						panic("unexpected_find_customer")
+					},
+				},
+
+				req: createStripeSessionRequest{
+					orderID:    "facade00-0000-4000-a000-000000000000",
+					customerID: "cus_id",
+					email:      "[email protected]",
+					successURL: "https://example.com/success",
+					cancelURL:  "https://example.com/cancel",
+					trialDays:  7,
+					items: []*stripe.CheckoutSessionLineItemParams{
+						{
+							Quantity: ptrTo[int64](1),
+							Price:    ptrTo("stripe_item_id"),
+						},
+					},
+				},
+			},
+			exp: tcExpected{
+				val: "cs_test_id",
+			},
+		},
+
+		{
+			name: "success_email_found_customer",
 			given: tcGiven{
 				cl: &xstripe.MockClient{
 					FnCreateSession: func(ctx context.Context, params *stripe.CheckoutSessionParams) (*stripe.CheckoutSession, error) {
@@ -4598,7 +4747,7 @@ func TestCreateStripeSession(t *testing.T) {
 		},
 
 		{
-			name: "success_customer_not_found",
+			name: "success_email_customer_not_found",
 			given: tcGiven{
 				cl: &xstripe.MockClient{
 					FnFindCustomer: func(ctx context.Context, email string) (*stripe.Customer, bool) {
@@ -4636,7 +4785,7 @@ func TestCreateStripeSession(t *testing.T) {
 		},
 
 		{
-			name: "success_no_customer_email",
+			name: "success_email_no_customer_email",
 			given: tcGiven{
 				cl: &xstripe.MockClient{
 					FnFindCustomer: func(ctx context.Context, email string) (*stripe.Customer, bool) {
@@ -4663,7 +4812,7 @@ func TestCreateStripeSession(t *testing.T) {
 		},
 
 		{
-			name: "success_no_trial_days",
+			name: "success_email_no_trial_days",
 			given: tcGiven{
 				cl: &xstripe.MockClient{},
 

services/skus/xstripe/mock.go

@@ -15,7 +15,10 @@ type MockClient struct {
 
 func (c *MockClient) Session(ctx context.Context, id string, params *stripe.CheckoutSessionParams) (*stripe.CheckoutSession, error) {
 	if c.FnSession == nil {
-		result := &stripe.CheckoutSession{ID: id}
+		result := &stripe.CheckoutSession{
+			ID:       id,
+			Customer: &stripe.Customer{ID: "cus_id", Email: "[email protected]"},
+		}
 
 		return result, nil
 	}

services/skus/xstripe/xstripe.go

@@ -56,3 +56,13 @@ func CustomerEmailFromSession(sess *stripe.CheckoutSession) string {
 	// Default to empty, Stripe will ask the customer.
 	return ""
 }
+
+func CustomerIDFromSession(sess *stripe.CheckoutSession) string {
+	// Return the customer id only if the customer is present AND it has email set.
+	// Without the email, the customer record is not fully formed, and does not suit the use case.
+	if sess.Customer != nil && sess.Customer.Email != "" {
+		return sess.Customer.ID
+	}
+
+	return ""
+}

services/skus/xstripe/xstripe_test.go

@@ -65,3 +65,52 @@ func TestCustomerEmailFromSession(t *testing.T) {
 		})
 	}
 }
+
+func TestCustomerIDFromSession(t *testing.T) {
+	tests := []struct {
+		name  string
+		exp   string
+		given *stripe.CheckoutSession
+	}{
+		{
+			name:  "nil_customer_no_email",
+			given: &stripe.CheckoutSession{},
+		},
+
+		{
+			name: "customer_empty_email",
+			given: &stripe.CheckoutSession{
+				Customer: &stripe.Customer{},
+			},
+		},
+
+		{
+			name: "customer_email_no_id",
+			given: &stripe.CheckoutSession{
+				Customer: &stripe.Customer{
+					Email: "[email protected]",
+				},
+			},
+		},
+
+		{
+			name: "customer_email_id",
+			given: &stripe.CheckoutSession{
+				Customer: &stripe.Customer{
+					ID:    "cus_id",
+					Email: "[email protected]",
+				},
+			},
+			exp: "cus_id",
+		},
+	}
+
+	for i := range tests {
+		tc := tests[i]
+
+		t.Run(tc.name, func(t *testing.T) {
+			actual := CustomerIDFromSession(tc.given)
+			should.Equal(t, tc.exp, actual)
+		})
+	}
+}