add bitcoin support to storefront invoice view

Refactor invoice view building to share logic across XMR and BTC, including BIP21 QR codes and payment detail validation.

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/src/utils/invoice/toStorefrontInvoiceView.spec.ts

@@ -1,15 +1,19 @@
 import { InternalServerErrorException } from '@nestjs/common';
 import { XMR_ATOMIC_PER_XMR } from '../../consts/xmrAtomicPerXmr';
+import { BTC_ATOMIC_PER_BTC } from '../../consts/btcAtomicPerBtc';
 import type { Invoice } from '../../modules/payment/entities/Invoice';
+import type { InvoiceBtcDetails } from '../../modules/payment/entities/InvoiceBtcDetails';
 import type { InvoiceMoneroDetails } from '../../modules/payment/entities/InvoiceMoneroDetails';
 import type { InvoicePayment } from '../../modules/payment/entities/InvoicePayment';
 import { PaymentMethod } from '../../modules/payment/types/PaymentMethod';
 import { InvoiceReason } from '../../modules/payment/types/InvoiceReason';
+import type { BtcDetailsOverrides, MoneroDetailsOverrides } from './types/ToStorefrontInvoiceViewTestTypes';
 import * as formatRelativeTimeAgoModule from '../formatRelativeTimeAgo';
 import * as generateQrCodeDataUrlModule from '../generateQrCodeDataUrl';
 import { toStorefrontInvoiceView } from './toStorefrontInvoiceView';
 
 const oneXmrAtomic = XMR_ATOMIC_PER_XMR.toString();
+const oneBtcAtomic = BTC_ATOMIC_PER_BTC.toString();
 const paymentAddress = '4StorefrontInvoiceViewTestAddress';
 
 const buildPayment = (overrides: Partial<InvoicePayment> = {}): InvoicePayment =>
@@ -21,10 +25,6 @@ const buildPayment = (overrides: Partial<InvoicePayment> = {}): InvoicePayment =
         ...overrides
     }) as InvoicePayment;
 
-type MoneroDetailsOverrides = Partial<
-    Pick<InvoiceMoneroDetails, 'paymentAddressIndex' | 'fiatPerXmrAtCreation' | 'requiredConfirmations'>
->;
-
 const buildMoneroDetails = (overrides: MoneroDetailsOverrides = {}): InvoiceMoneroDetails =>
     ({
         paymentAddressIndex: 1,
@@ -33,6 +33,13 @@ const buildMoneroDetails = (overrides: MoneroDetailsOverrides = {}): InvoiceMone
         ...overrides
     }) as InvoiceMoneroDetails;
 
+const buildBtcDetails = (overrides: BtcDetailsOverrides = {}): InvoiceBtcDetails =>
+    ({
+        fiatPerBtcAtCreation: 60_000,
+        requiredConfirmations: 1,
+        ...overrides
+    }) as InvoiceBtcDetails;
+
 const buildInvoice = (overrides: Partial<Invoice> = {}): Invoice =>
     ({
         reason: InvoiceReason.Checkout,
@@ -77,10 +84,21 @@ describe('toStorefrontInvoiceView', () => {
             await expect(toStorefrontInvoiceView(invoice)).rejects.toBeInstanceOf(InternalServerErrorException);
         });
 
-        it('throws for unsupported payment methods', async () => {
-            const invoice = buildInvoice({ paymentMethod: 'btc' as PaymentMethod });
+        it('throws when bitcoin details are missing', async () => {
+            const invoice = buildInvoice({
+                paymentMethod: PaymentMethod.Btc,
+                moneroDetails: null,
+                btcDetails: null,
+                expectedTotalAtomic: oneBtcAtomic
+            });
 
-            await expect(toStorefrontInvoiceView(invoice)).rejects.toThrow('Unsupported payment method: btc');
+            await expect(toStorefrontInvoiceView(invoice)).rejects.toThrow('Invoice is missing Bitcoin payment details');
+        });
+
+        it('throws for unsupported payment methods', async () => {
+            const invoice = buildInvoice({ paymentMethod: 'eth' as PaymentMethod, moneroDetails: null });
+
+            await expect(toStorefrontInvoiceView(invoice)).rejects.toThrow('Unsupported payment method: eth');
         });
     });
 
@@ -124,6 +142,27 @@ describe('toStorefrontInvoiceView', () => {
             expect(generateQrCodeDataUrlSpy).toHaveBeenCalledWith(`monero:${paymentAddress}?tx_amount=1.00000000`);
         });
 
+        it('maps bitcoin invoices and builds a bip21 qr code', async () => {
+            const invoice = buildInvoice({
+                paymentMethod: PaymentMethod.Btc,
+                moneroDetails: null,
+                btcDetails: buildBtcDetails(),
+                expectedTotalAtomic: oneBtcAtomic,
+                paymentAddress: 'bc1qstorefronttest'
+            });
+
+            const view = await toStorefrontInvoiceView(invoice);
+
+            expect(view).toMatchObject({
+                cryptoCurrency: 'BTC',
+                expectedTotalCrypto: '1.00000000',
+                paymentAddress: 'bc1qstorefronttest'
+            });
+            expect(generateQrCodeDataUrlSpy).toHaveBeenCalledWith(
+                'bitcoin:bc1qstorefronttest?amount=1.00000000'
+            );
+        });
+
         it('formats expiry as seconds only when under one minute remains', async () => {
             const invoice = buildInvoice({
                 expiresAt: new Date('2026-06-01T12:00:45.000Z')