From 89e98a144a1c1db2a6d860e459b4cfd57ece1e81 Mon Sep 17 00:00:00 2001
From: Lisa Chan <lchan@mozilla.com>
Date: Fri, 10 Apr 2026 11:47:04 -0400
Subject: [PATCH] fix(payments-next): Show pre-discount tax

---
 .../customer/src/lib/invoice.manager.spec.ts  | 41 ++++++++++++++++++-
 .../customer/src/lib/invoice.manager.ts       |  3 ++
 .../src/lib/subscriptionManagement.service.ts |  6 ++-
 3 files changed, 48 insertions(+), 2 deletions(-)

diff --git a/libs/payments/customer/src/lib/invoice.manager.spec.ts b/libs/payments/customer/src/lib/invoice.manager.spec.ts
index 7a1d62c7b4b..1e6a8f86ac1 100644
--- a/libs/payments/customer/src/lib/invoice.manager.spec.ts
+++ b/libs/payments/customer/src/lib/invoice.manager.spec.ts
@@ -307,7 +307,37 @@ describe('InvoiceManager', () => {
       );
       const mockPreviewUpcomingInvoice = InvoicePreviewFactory();
 
-      jest
+      const spy = jest
+        .spyOn(stripeClient, 'invoicesRetrieveUpcoming')
+        .mockResolvedValue(mockUpcomingInvoice);
+
+      mockedStripeInvoiceToFirstInvoicePreviewDTO.mockReturnValue(
+        mockPreviewUpcomingInvoice
+      );
+
+      const result = await invoiceManager.previewUpcomingSubscription({
+        customer: mockCustomer,
+        subscription: mockSubscription,
+      });
+      expect(result).toEqual(mockPreviewUpcomingInvoice);
+      expect(spy).toHaveBeenCalledWith({
+        customer: mockCustomer.id,
+        subscription: mockSubscription.id,
+        subscription_details: {
+          cancel_at_period_end: false,
+        },
+      });
+    });
+
+    it('passes empty string discounts when excludeDiscounts is true', async () => {
+      const mockCustomer = StripeCustomerFactory({ currency: 'usd' });
+      const mockSubscription = StripeSubscriptionFactory();
+      const mockUpcomingInvoice = StripeResponseFactory(
+        StripeUpcomingInvoiceFactory()
+      );
+      const mockPreviewUpcomingInvoice = InvoicePreviewFactory();
+
+      const spy = jest
         .spyOn(stripeClient, 'invoicesRetrieveUpcoming')
         .mockResolvedValue(mockUpcomingInvoice);
 
@@ -318,8 +348,17 @@ describe('InvoiceManager', () => {
       const result = await invoiceManager.previewUpcomingSubscription({
         customer: mockCustomer,
         subscription: mockSubscription,
+        excludeDiscounts: true,
       });
       expect(result).toEqual(mockPreviewUpcomingInvoice);
+      expect(spy).toHaveBeenCalledWith({
+        customer: mockCustomer.id,
+        subscription: mockSubscription.id,
+        subscription_details: {
+          cancel_at_period_end: false,
+        },
+        discounts: '',
+      });
     });
   });
 
diff --git a/libs/payments/customer/src/lib/invoice.manager.ts b/libs/payments/customer/src/lib/invoice.manager.ts
index 5be07ab641f..7fb94a8e494 100644
--- a/libs/payments/customer/src/lib/invoice.manager.ts
+++ b/libs/payments/customer/src/lib/invoice.manager.ts
@@ -187,9 +187,11 @@ export class InvoiceManager {
   async previewUpcomingSubscription({
     customer,
     subscription,
+    excludeDiscounts,
   }: {
     customer: StripeCustomer;
     subscription: StripeSubscription;
+    excludeDiscounts?: boolean;
   }): Promise<InvoicePreview> {
     const upcomingInvoice = await this.stripeClient.invoicesRetrieveUpcoming({
       customer: customer.id,
@@ -197,6 +199,7 @@ export class InvoiceManager {
       subscription_details: {
         cancel_at_period_end: false,
       },
+      ...(excludeDiscounts ? { discounts: '' } : {}),
     });
 
     return stripeInvoiceToInvoicePreviewDTO(upcomingInvoice);
diff --git a/libs/payments/management/src/lib/subscriptionManagement.service.ts b/libs/payments/management/src/lib/subscriptionManagement.service.ts
index 34a0a0652bf..c8c52d11392 100644
--- a/libs/payments/management/src/lib/subscriptionManagement.service.ts
+++ b/libs/payments/management/src/lib/subscriptionManagement.service.ts
@@ -459,6 +459,7 @@ export class SubscriptionManagementService {
       this.invoiceManager.previewUpcomingSubscription({
         customer,
         subscription,
+        excludeDiscounts: true,
       }),
       this.churnInterventionService.determineStaySubscribedEligibility(
         uid,
@@ -501,12 +502,13 @@ export class SubscriptionManagementService {
 
     const {
       nextInvoiceDate,
-      promotionName: nextPromotionName,
       subsequentAmount,
       subsequentAmountExcludingTax,
       subsequentTax,
     } = upcomingInvoice;
 
+    const nextPromotionName = subscription.discount?.coupon.name ?? null;
+
     const totalExclusiveTax = taxAmounts
       .filter((tax) => !tax.inclusive)
       .reduce((sum, tax) => sum + tax.amount, 0);
@@ -791,6 +793,7 @@ export class SubscriptionManagementService {
         await this.invoiceManager.previewUpcomingSubscription({
           customer: stripeCustomer,
           subscription,
+          excludeDiscounts: true,
         });
 
       if (!upcomingInvoice) {
@@ -912,6 +915,7 @@ export class SubscriptionManagementService {
         await this.invoiceManager.previewUpcomingSubscription({
           customer: stripeCustomer,
           subscription,
+          excludeDiscounts: true,
         });
 
       if (!upcomingInvoice) {