fix(api): stop counting one refund twice against the allowance (#3226)

fluxer_api/src/api/stripe/services/RefundAllowance.ts

@@ -0,0 +1,39 @@
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+import type {BillingRefundRow} from '@app/api/database/types/BillingTypes';
+import {getBillingRepository} from '@app/api/middleware/ServiceRegistry';
+import type {User} from '@app/api/models/User';
+import type {IUserRepository} from '@app/api/user/IUserRepository';
+
+export const REFUND_ALLOWANCE_BLOCK_THRESHOLD = 2;
+
+function isCountedAgainstAllowance(refund: BillingRefundRow): boolean {
+	if (refund.status !== 'succeeded') {
+		return false;
+	}
+	return (refund.metadata?.get('rejection_reason') ?? null) === null;
+}
+
+export async function listCountedRefundIds(user: User, userRepository: IUserRepository): Promise<Array<string>> {
+	const payments = await userRepository.findPaymentsByUserId(user.id);
+	const paymentIntentIds = [
+		...new Set(payments.map((payment) => payment.paymentIntentId).filter((id): id is string => id !== null)),
+	];
+	const counted = new Set<string>();
+	for (const paymentIntentId of paymentIntentIds) {
+		for (const refund of await getBillingRepository().refunds.listByPaymentIntent(paymentIntentId)) {
+			if (isCountedAgainstAllowance(refund)) {
+				counted.add(refund.provider_id);
+			}
+		}
+	}
+	return [...counted].sort();
+}
+
+export async function shouldBlockFurtherPurchases(
+	user: User,
+	userRepository: IUserRepository,
+): Promise<{blocked: boolean; countedRefundIds: Array<string>}> {
+	const countedRefundIds = await listCountedRefundIds(user, userRepository);
+	return {blocked: countedRefundIds.length >= REFUND_ALLOWANCE_BLOCK_THRESHOLD, countedRefundIds};
+}

fluxer_api/src/api/stripe/services/StripeDisputeWebhookHandler.ts

@@ -11,6 +11,7 @@ import {getBillingRepository} from '@app/api/middleware/ServiceRegistry';
 import type {GiftCode} from '@app/api/models/GiftCode';
 import type {User} from '@app/api/models/User';
 import {extractId} from '@app/api/stripe/StripeUtils';
+import {shouldBlockFurtherPurchases} from '@app/api/stripe/services/RefundAllowance';
 import type {StripeGiftReversalHandler} from '@app/api/stripe/services/StripeGiftReversalHandler';
 import type {StripePaymentFraudService} from '@app/api/stripe/services/StripePaymentFraudService';
 import type {IUserRepository} from '@app/api/user/IUserRepository';
@@ -236,9 +237,25 @@ export class StripeDisputeWebhookHandler {
 			return;
 		}
 		const isFirstRefund = !user.firstRefundAt;
-		const patch: Partial<UserRow> = isFirstRefund
+		let patch: Partial<UserRow>;
-			? {first_refund_at: new Date()}
+		let countedRefundIds: Array<string> = [];
-			: {premium_flags: user.premiumFlags | PremiumFlags.PURCHASE_DISABLED};
+		if (isFirstRefund) {
+			patch = {first_refund_at: new Date()};
+		} else {
+			const outcome = await shouldBlockFurtherPurchases(user, this.userRepository);
+			countedRefundIds = outcome.countedRefundIds;
+			if (!outcome.blocked) {
+				for (const claimKey of claimedKeys) {
+					await getBillingRepository().webhookEvents.markProcessed(claimKey);
+				}
+				Logger.info(
+					{userId: user.id, chargeId: charge.id, paymentIntentId, countedRefundIds},
+					'Refund redelivered after the allowance claim expired; not counting it twice',
+				);
+				return;
+			}
+			patch = {premium_flags: user.premiumFlags | PremiumFlags.PURCHASE_DISABLED};
+		}
 		let updatedUser: User;
 		try {
 			updatedUser = await this.userRepository.patchUpsert(user.id, patch, user.toRow());
@@ -253,7 +270,7 @@ export class StripeDisputeWebhookHandler {
 		}
 		await this.dispatchUser(updatedUser);
 		Logger.debug(
-			{userId: user.id, chargeId: charge.id, paymentIntentId},
+			{userId: user.id, chargeId: charge.id, paymentIntentId, countedRefundIds},
 			isFirstRefund
 				? 'First refund recorded - 30 day self-serve refund cooldown applied'
 				: 'Second refund recorded - permanent purchase block applied',

fluxer_api/src/api/stripe/services/StripeRefundService.ts

@@ -7,6 +7,7 @@ import {Logger} from '@app/api/Logger';
 import {getBillingRepository} from '@app/api/middleware/ServiceRegistry';
 import type {User} from '@app/api/models/User';
 import {extractId} from '@app/api/stripe/StripeUtils';
+import {shouldBlockFurtherPurchases} from '@app/api/stripe/services/RefundAllowance';
 import {REFUND_ALLOWANCE_CLAIM_PREFIX} from '@app/api/stripe/services/StripeDisputeWebhookHandler';
 import type {StripeSubscriptionService} from '@app/api/stripe/services/StripeSubscriptionService';
 import type {IUserRepository} from '@app/api/user/IUserRepository';
@@ -271,17 +272,31 @@ export class StripeRefundService {
 		}
 		const claimKey = `${REFUND_ALLOWANCE_CLAIM_PREFIX}:${refund.id}`;
 		const claim = await getBillingRepository().webhookEvents.tryClaim(claimKey);
-		if (claim !== 'claimed') {
+		if (claim === 'in_flight') {
 			Logger.debug(
 				{userId: user.id.toString(), refundId: refund.id, claim},
-				'Self-serve refund already counted against the user refund allowance',
+				'Self-serve refund allowance is being counted by another delivery',
 			);
 			return;
 		}
 		const isFirstRefund = !user.firstRefundAt;
-		const patch: Partial<UserRow> = isFirstRefund
+		let patch: Partial<UserRow>;
-			? {first_refund_at: new Date()}
+		let countedRefundIds: Array<string> = [];
-			: {premium_flags: user.premiumFlags | PremiumFlags.PURCHASE_DISABLED};
+		if (isFirstRefund) {
+			patch = {first_refund_at: new Date()};
+		} else {
+			const outcome = await shouldBlockFurtherPurchases(user, this.userRepository);
+			countedRefundIds = outcome.countedRefundIds;
+			if (!outcome.blocked) {
+				await getBillingRepository().webhookEvents.markProcessed(claimKey);
+				Logger.info(
+					{userId: user.id.toString(), refundId: refund.id, countedRefundIds},
+					'Self-serve refund redelivered after the allowance claim expired; not counting it twice',
+				);
+				return;
+			}
+			patch = {premium_flags: user.premiumFlags | PremiumFlags.PURCHASE_DISABLED};
+		}
 		try {
 			await this.userRepository.patchUpsert(user.id, patch, user.toRow());
 		} catch (error) {
@@ -290,7 +305,13 @@ export class StripeRefundService {
 		}
 		await getBillingRepository().webhookEvents.markProcessed(claimKey);
 		Logger.info(
-			{userId: user.id.toString(), refundId: refund.id, subscriptionId: subscriptionId || null, isFirstRefund},
+			{
+				userId: user.id.toString(),
+				refundId: refund.id,
+				subscriptionId: subscriptionId || null,
+				isFirstRefund,
+				countedRefundIds,
+			},
 			'Self-serve refund confirmed succeeded; refund allowance and cancellation finalized',
 		);
 	}

fluxer_api/src/api/stripe/tests/StripeWebhookRefund.test.ts

@@ -105,23 +105,14 @@ describe('Stripe Webhook Refund', () => {
 			expect(updatedPayment).not.toBeNull();
 			expect(updatedPayment!.status).toBe('refunded');
 		});
-		test('applies permanent purchase block on second refund', async () => {
+		async function seedRefundedPayment(
-			const account = await createTestAccount(harness);
+			userId: ReturnType<typeof createUserID>,
-			const userId = createUserID(BigInt(account.userId));
+			suffix: string,
-			const {UserRepository} = await import('@app/api/user/repositories/UserRepository');
+		): Promise<{paymentIntentId: string; chargeId: string}> {
-			const userRepository = new UserRepository();
-			const firstRefundDate = new Date('2024-01-01');
-			await userRepository.patchUpsert(
-				userId,
-				{
-					first_refund_at: firstRefundDate,
-				},
-				(await userRepository.findUnique(userId))!.toRow(),
-			);
 			const {PaymentRepository} = await import('@app/api/user/repositories/PaymentRepository');
 			const paymentRepository = new PaymentRepository();
-			const paymentIntentId = 'pi_test_refund_second_456';
+			const paymentIntentId = `pi_test_refund_${suffix}`;
-			const checkoutSessionId = 'cs_test_refund_second_456';
+			const checkoutSessionId = `cs_test_refund_${suffix}`;
 			await paymentRepository.createPayment({
 				checkout_session_id: checkoutSessionId,
 				user_id: userId,
@@ -136,14 +127,41 @@ describe('Stripe Webhook Refund', () => {
 				payment_intent_id: paymentIntentId,
 				completed_at: new Date(),
 			});
-			useRefundListHandler('ch_test_refund_456');
+			return {paymentIntentId, chargeId: `ch_test_refund_${suffix}`};
+		}
+		test('applies permanent purchase block when a second distinct refund exists', async () => {
+			const account = await createTestAccount(harness);
+			const userId = createUserID(BigInt(account.userId));
+			const {UserRepository} = await import('@app/api/user/repositories/UserRepository');
+			const userRepository = new UserRepository();
+			const firstRefundDate = new Date('2024-01-01');
+			await userRepository.patchUpsert(
+				userId,
+				{first_refund_at: firstRefundDate},
+				(await userRepository.findUnique(userId))!.toRow(),
+			);
+			const {paymentIntentId, chargeId} = await seedRefundedPayment(userId, 'second_456');
+			const nowSeconds = Math.floor(Date.now() / 1000);
+			const earlier = {
+				id: 're_test_refund_second_456_1',
+				object: 'refund',
+				charge: chargeId,
+				payment_intent: paymentIntentId,
+				amount: 1200,
+				currency: 'usd',
+				status: 'succeeded',
+				created: nowSeconds - 600,
+				metadata: {},
+			};
+			const latest = {...earlier, id: 're_test_refund_second_456_2', amount: 1300, created: nowSeconds};
 			await sendWebhook({
 				type: 'charge.refunded',
 				data: {
 					object: {
-						id: 'ch_test_refund_456',
+						id: chargeId,
 						payment_intent: paymentIntentId,
 						amount_refunded: 2500,
+						refunds: {object: 'list', has_more: false, url: `/v1/charges/${chargeId}/refunds`, data: [earlier, latest]},
 					},
 				},
 			});
@@ -155,6 +173,45 @@ describe('Stripe Webhook Refund', () => {
 			expect(updatedPayment).not.toBeNull();
 			expect(updatedPayment!.status).toBe('refunded');
 		});
+		test('does not block purchases when one refund is redelivered after the allowance claim expired', async () => {
+			const account = await createTestAccount(harness);
+			const userId = createUserID(BigInt(account.userId));
+			const {UserRepository} = await import('@app/api/user/repositories/UserRepository');
+			const userRepository = new UserRepository();
+			const firstRefundDate = new Date('2024-01-01');
+			await userRepository.patchUpsert(
+				userId,
+				{first_refund_at: firstRefundDate},
+				(await userRepository.findUnique(userId))!.toRow(),
+			);
+			const {paymentIntentId, chargeId} = await seedRefundedPayment(userId, 'replay_789');
+			const onlyRefund = {
+				id: 're_test_refund_replay_789',
+				object: 'refund',
+				charge: chargeId,
+				payment_intent: paymentIntentId,
+				amount: 2500,
+				currency: 'usd',
+				status: 'succeeded',
+				created: Math.floor(Date.now() / 1000),
+				metadata: {},
+			};
+			await sendWebhook({
+				type: 'charge.refunded',
+				data: {
+					object: {
+						id: chargeId,
+						payment_intent: paymentIntentId,
+						amount_refunded: 2500,
+						refunds: {object: 'list', has_more: false, url: `/v1/charges/${chargeId}/refunds`, data: [onlyRefund]},
+					},
+				},
+			});
+			const updatedUser = await userRepository.findUnique(userId);
+			expect(updatedUser).not.toBeNull();
+			expect(updatedUser!.firstRefundAt).toEqual(firstRefundDate);
+			expect(updatedUser!.premiumFlags & PremiumFlags.PURCHASE_DISABLED).toBe(0);
+		});
 		test('counts a refund once when the same charge.refunded event is redelivered', async () => {
 			const account = await createTestAccount(harness);
 			const userId = createUserID(BigInt(account.userId));

fluxer_api/src/api/user/repositories/IUserContentRepository.ts

@@ -74,6 +74,7 @@ export interface IUserContentRepository {
 			checkout_session_id: string;
 		},
 	): Promise<void>;
+	findPaymentsByUserId(userId: UserID): Promise<Array<Payment>>;
 	getPaymentByCheckoutSession(checkoutSessionId: string): Promise<Payment | null>;
 	getPaymentByPaymentIntent(paymentIntentId: string): Promise<Payment | null>;
 	getSubscriptionInfo(subscriptionId: string): Promise<PaymentBySubscriptionRow | null>;

fluxer_api/src/api/user/repositories/UserContentRepository.ts

@@ -116,6 +116,10 @@ export class UserContentRepository implements IUserContentRepository {
 		return this.paymentRepository.getPaymentByCheckoutSession(checkoutSessionId);
 	}
 
+	async findPaymentsByUserId(userId: UserID): Promise<Array<Payment>> {
+		return this.paymentRepository.findPaymentsByUserId(userId);
+	}
+
 	async getPaymentByPaymentIntent(paymentIntentId: string): Promise<Payment | null> {
 		return this.paymentRepository.getPaymentByPaymentIntent(paymentIntentId);
 	}

fluxer_api/src/api/user/repositories/UserRepository.ts

@@ -740,6 +740,10 @@ export class UserRepository implements IUserRepositoryAggregate {
 		return this.contentRepo.getPaymentByCheckoutSession(checkoutSessionId);
 	}
 
+	async findPaymentsByUserId(userId: UserID): Promise<Array<Payment>> {
+		return this.contentRepo.findPaymentsByUserId(userId);
+	}
+
 	async getPaymentByPaymentIntent(paymentIntentId: string): Promise<Payment | null> {
 		return this.contentRepo.getPaymentByPaymentIntent(paymentIntentId);
 	}