FINERACT-2210: fix previously refunded interest calculation during interest refund

fineract-loan/src/main/java/org/apache/fineract/portfolio/loanaccount/service/InterestRefundService.java

@@ -18,10 +18,8 @@
  */
 package org.apache.fineract.portfolio.loanaccount.service;
 
-import java.math.MathContext;
 import java.time.LocalDate;
 import java.util.List;
-import org.apache.fineract.organisation.monetary.domain.MonetaryCurrency;
 import org.apache.fineract.organisation.monetary.domain.Money;
 import org.apache.fineract.portfolio.loanaccount.domain.Loan;
 import org.apache.fineract.portfolio.loanaccount.domain.LoanTransaction;
@@ -36,6 +34,4 @@ public interface InterestRefundService {
     @Transactional(readOnly = true, propagation = Propagation.REQUIRES_NEW)
     Money totalInterestByTransactions(LoanRepaymentScheduleTransactionProcessor processor, Long loanId,
             LocalDate relatedRefundTransactionDate, List<LoanTransaction> newTransactions, List<Long> oldTransactionIds);
-
-    Money getTotalInterestRefunded(List<LoanTransaction> loanTransactions, MonetaryCurrency currency, MathContext mc);
 }

fineract-provider/src/main/java/org/apache/fineract/portfolio/loanaccount/domain/LoanAccountDomainServiceJpa.java

@@ -190,13 +190,10 @@ public class LoanAccountDomainServiceJpa implements LoanAccountDomainService {
 
         Money totalInterest = interestRefundService.totalInterestByTransactions(null, loan.getId(), refundTransaction.getTransactionDate(),
                 List.of(), loan.getLoanTransactions().stream().map(AbstractPersistableCustom::getId).toList());
-        Money previouslyRefundedInterests = interestRefundService.getTotalInterestRefunded(loan.getLoanTransactions(), loan.getCurrency(),
-                totalInterest.getMc());
-
         Money newTotalInterest = interestRefundService.totalInterestByTransactions(null, loan.getId(),
                 refundTransaction.getTransactionDate(), List.of(refundTransaction),
                 loan.getLoanTransactions().stream().map(AbstractPersistableCustom::getId).toList());
-        BigDecimal interestRefundAmount = totalInterest.minus(previouslyRefundedInterests).minus(newTotalInterest).getAmount();
+        BigDecimal interestRefundAmount = totalInterest.minus(newTotalInterest).getAmount();
 
         if (MathUtil.isZero(interestRefundAmount)) {
             return null;

fineract-provider/src/main/java/org/apache/fineract/portfolio/loanaccount/service/ProgressiveLoanInterestRefundServiceImpl.java

@@ -21,7 +21,6 @@ package org.apache.fineract.portfolio.loanaccount.service;
 import static org.apache.fineract.portfolio.loanaccount.domain.LoanTransactionType.REPAYMENT;
 
 import java.math.BigDecimal;
-import java.math.MathContext;
 import java.time.LocalDate;
 import java.util.ArrayList;
 import java.util.List;
@@ -31,7 +30,6 @@ import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
 import org.apache.commons.lang3.tuple.Pair;
 import org.apache.fineract.infrastructure.core.service.MathUtil;
-import org.apache.fineract.organisation.monetary.domain.MonetaryCurrency;
 import org.apache.fineract.organisation.monetary.domain.Money;
 import org.apache.fineract.portfolio.loanaccount.data.ScheduleGeneratorDTO;
 import org.apache.fineract.portfolio.loanaccount.data.TransactionChangeData;
@@ -145,15 +143,4 @@ public class ProgressiveLoanInterestRefundServiceImpl implements InterestRefundS
         return recalculateTotalInterest((AdvancedPaymentScheduleTransactionProcessor) processor, loan, relatedRefundTransactionDate,
                 transactionsToReprocess);
     }
-
-    @Override
-    public Money getTotalInterestRefunded(List<LoanTransaction> loanTransactions, MonetaryCurrency currency, MathContext mc) {
-        final BigDecimal totalInterestRefunded = loanTransactions.stream() //
-                .filter(LoanTransaction::isNotReversed) //
-                .filter(LoanTransaction::isInterestRefund) //
-                .map(LoanTransaction::getAmount) //
-                .reduce(BigDecimal.ZERO, BigDecimal::add); //
-        return Money.of(currency, totalInterestRefunded, mc);
-    }
-
 }

integration-tests/src/test/java/org/apache/fineract/integrationtests/LoanRefundTransactionTest.java

@@ -71,7 +71,7 @@ public class LoanRefundTransactionTest extends BaseLoanIntegrationTest {
     public void testMerchantIssuedRefundCreatesAndReversesInterestRefund() {
         runAt("01 July 2024", () -> {
             Long clientId = clientHelper.createClient(ClientHelper.defaultClientCreationRequest()).getClientId();
-            final Long loanId = createLoanForMerchantIssuedRefundWithInterestRefund(clientId);
+            final Long loanId = createAndDisburseLoanForMerchantIssuedRefundWithInterestRefund(clientId);
             final PostLoansLoanIdTransactionsResponse merchantIssuedRefundResponse = loanTransactionHelper.makeMerchantIssuedRefund(loanId,
                     new PostLoansLoanIdTransactionsRequest().dateFormat("dd MMMM yyyy").transactionDate("01 July 2024").locale("en")
                             .transactionAmount(100.0));
@@ -103,7 +103,7 @@ public class LoanRefundTransactionTest extends BaseLoanIntegrationTest {
     public void testPayoutRefundCreatesAndReversesInterestRefund() {
         runAt("01 July 2024", () -> {
             Long clientId = clientHelper.createClient(ClientHelper.defaultClientCreationRequest()).getClientId();
-            final Long loanId = createLoanForPayoutRefundWithInterestRefund(clientId);
+            final Long loanId = createAndDisburseLoanForPayoutRefundWithInterestRefund(clientId);
             final PostLoansLoanIdTransactionsResponse payoutRefundResponse = loanTransactionHelper.makePayoutRefund(loanId,
                     new PostLoansLoanIdTransactionsRequest().dateFormat("dd MMMM yyyy").transactionDate("01 July 2024").locale("en")
                             .transactionAmount(100.0));
@@ -129,22 +129,52 @@ public class LoanRefundTransactionTest extends BaseLoanIntegrationTest {
         });
     }
 
-    private Long createLoanForMerchantIssuedRefundWithInterestRefund(Long clientId) {
-        return createLoanForRefundWithInterestRefund(clientId, "MERCHANT_ISSUED_REFUND");
+    @Test
+    public void testMerchantIssuedRefundDoesNotCreateInterestRefundWithLessThanOrEqualToZeroInterest() {
+        runAt("20 April 2025", () -> {
+            Long clientId = clientHelper.createClient(ClientHelper.defaultClientCreationRequest()).getClientId();
+            Long loanId = createLoanForRefundWithInterestRefund(clientId, "MERCHANT_ISSUED_REFUND", "05 April 2025", 500.0, 20.99, 6);
+            disburseLoan(loanId, BigDecimal.valueOf(265.91), "05 April 2025");
+            disburseLoan(loanId, BigDecimal.valueOf(1.99), "05 April 2025");
+            disburseLoan(loanId, BigDecimal.valueOf(20.00), "05 April 2025");
+
+            final PostLoansLoanIdTransactionsResponse merchantIssuedRefundResponse1 = loanTransactionHelper.makeMerchantIssuedRefund(loanId,
+                    new PostLoansLoanIdTransactionsRequest().dateFormat("dd MMMM yyyy").transactionDate("06 April 2025").locale("en")
+                            .transactionAmount(6.29));
+
+            final PostLoansLoanIdTransactionsResponse merchantIssuedRefundResponse2 = loanTransactionHelper.makeMerchantIssuedRefund(loanId,
+                    new PostLoansLoanIdTransactionsRequest().dateFormat("dd MMMM yyyy").transactionDate("07 April 2025").locale("en")
+                            .transactionAmount(1.99));
+
+            GetLoansLoanIdResponse loanDetails = loanTransactionHelper.getLoanDetails(loanId);
+            Assertions.assertTrue(loanDetails.getTransactions().stream()
+                    .filter(transaction -> transaction.getType().getCode().equals("loanTransactionType.interestRefund"))
+                    .allMatch(transaction -> transaction.getAmount().compareTo(0.0) > 0));
+        });
     }
 
-    private Long createLoanForPayoutRefundWithInterestRefund(Long clientId) {
-        return createLoanForRefundWithInterestRefund(clientId, "PAYOUT_REFUND");
+    private Long createAndDisburseLoanForMerchantIssuedRefundWithInterestRefund(Long clientId) {
+        return createAndDisburseLoanForRefundWithInterestRefund(clientId, "MERCHANT_ISSUED_REFUND");
     }
 
-    private Long createLoanForRefundWithInterestRefund(Long clientId, String refundType) {
-        final PostLoanProductsResponse loanProductsResponse = loanProductHelper.createLoanProduct(
-                create4IProgressive().supportedInterestRefundTypes(new ArrayList<>()).addSupportedInterestRefundTypesItem(refundType));
-        PostLoansResponse postLoansResponse = loanTransactionHelper.applyLoan(
-                applyLP2ProgressiveLoanRequest(clientId, loanProductsResponse.getResourceId(), "01 June 2024", 1000.0, 10.0, 4, null));
-        Long loanId = postLoansResponse.getLoanId();
-        loanTransactionHelper.approveLoan(loanId, approveLoanRequest(1000.0, "01 June 2024"));
+    private Long createAndDisburseLoanForPayoutRefundWithInterestRefund(Long clientId) {
+        return createAndDisburseLoanForRefundWithInterestRefund(clientId, "PAYOUT_REFUND");
+    }
+
+    private Long createAndDisburseLoanForRefundWithInterestRefund(Long clientId, String refundType) {
+        Long loanId = createLoanForRefundWithInterestRefund(clientId, refundType, "01 June 2024", 1000.0, 10.0, 4);
         disburseLoan(loanId, BigDecimal.valueOf(1000.0), "01 June 2024");
         return loanId;
     }
+
+    private Long createLoanForRefundWithInterestRefund(Long clientId, String refundType, String date, double amount, double interestRate,
+            int numRepayments) {
+        final PostLoanProductsResponse loanProductsResponse = loanProductHelper.createLoanProduct(
+                create4IProgressive().supportedInterestRefundTypes(new ArrayList<>()).addSupportedInterestRefundTypesItem(refundType));
+        PostLoansResponse postLoansResponse = loanTransactionHelper.applyLoan(applyLP2ProgressiveLoanRequest(clientId,
+                loanProductsResponse.getResourceId(), date, amount, interestRate, numRepayments, null));
+        Long loanId = postLoansResponse.getLoanId();
+        loanTransactionHelper.approveLoan(loanId, approveLoanRequest(amount, date));
+        return loanId;
+    }
 }