FINERACT-2107: Interest Refund - Transaction Amount Recalculation

fineract-progressive-loan/src/main/java/org/apache/fineract/portfolio/loanaccount/domain/transactionprocessor/impl/AdvancedPaymentScheduleTransactionProcessor.java

@@ -57,6 +57,7 @@ import lombok.extern.slf4j.Slf4j;
 import org.apache.commons.lang3.NotImplementedException;
 import org.apache.commons.lang3.ObjectUtils;
 import org.apache.commons.lang3.tuple.Pair;
+import org.apache.fineract.infrastructure.core.domain.AbstractPersistableCustom;
 import org.apache.fineract.infrastructure.core.service.DateUtils;
 import org.apache.fineract.infrastructure.core.service.MathUtil;
 import org.apache.fineract.organisation.monetary.domain.MonetaryCurrency;
@@ -85,6 +86,7 @@ import org.apache.fineract.portfolio.loanaccount.domain.transactionprocessor.Tra
 import org.apache.fineract.portfolio.loanaccount.loanschedule.data.PeriodDueDetails;
 import org.apache.fineract.portfolio.loanaccount.loanschedule.data.ProgressiveLoanInterestScheduleModel;
 import org.apache.fineract.portfolio.loanaccount.loanschedule.domain.LoanScheduleProcessingType;
+import org.apache.fineract.portfolio.loanaccount.service.InterestRefundService;
 import org.apache.fineract.portfolio.loanproduct.calc.EMICalculator;
 import org.apache.fineract.portfolio.loanproduct.domain.AllocationType;
 import org.apache.fineract.portfolio.loanproduct.domain.CreditAllocationTransactionType;
@@ -102,6 +104,7 @@ public class AdvancedPaymentScheduleTransactionProcessor extends AbstractLoanRep
     public static final String ADVANCED_PAYMENT_ALLOCATION_STRATEGY_NAME = "Advanced payment allocation strategy";
 
     public final EMICalculator emiCalculator;
+    public final InterestRefundService interestRefundService;
 
     @Override
     public String getCode() {
@@ -196,6 +199,7 @@ public class AdvancedPaymentScheduleTransactionProcessor extends AbstractLoanRep
                 LoanTransaction transaction = changeOperation.getLoanTransaction().get();
                 processSingleTransaction(transaction, ctx);
                 transaction = getProcessedTransaction(changedTransactionDetail, transaction);
+                ctx.getAlreadyProcessedTransactions().add(transaction);
                 if (transaction.isOverPaid() && transaction.isRepaymentLikeType()) { // TODO CREDIT, DEBIT
                     overpaidTransactions.add(transaction);
                 }
@@ -268,9 +272,10 @@ public class AdvancedPaymentScheduleTransactionProcessor extends AbstractLoanRep
             case CHARGEBACK -> handleChargeback(loanTransaction, ctx);
             case CREDIT_BALANCE_REFUND ->
                 handleCreditBalanceRefund(loanTransaction, ctx.getCurrency(), ctx.getInstallments(), ctx.getOverpaymentHolder());
-            case INTEREST_REFUND, REPAYMENT, MERCHANT_ISSUED_REFUND, PAYOUT_REFUND, GOODWILL_CREDIT, CHARGE_REFUND, CHARGE_ADJUSTMENT,
-                    DOWN_PAYMENT, WAIVE_INTEREST, RECOVERY_REPAYMENT, INTEREST_PAYMENT_WAIVER ->
+            case REPAYMENT, MERCHANT_ISSUED_REFUND, PAYOUT_REFUND, GOODWILL_CREDIT, CHARGE_REFUND, CHARGE_ADJUSTMENT, DOWN_PAYMENT,
+                    WAIVE_INTEREST, RECOVERY_REPAYMENT, INTEREST_PAYMENT_WAIVER ->
                 handleRepayment(loanTransaction, ctx);
+            case INTEREST_REFUND -> handleInterestRefund(loanTransaction, ctx);
             case CHARGE_OFF -> handleChargeOff(loanTransaction, ctx);
             case CHARGE_PAYMENT -> handleChargePayment(loanTransaction, ctx);
             case WAIVE_CHARGES -> log.debug("WAIVE_CHARGES transaction will not be processed.");
@@ -284,6 +289,25 @@ public class AdvancedPaymentScheduleTransactionProcessor extends AbstractLoanRep
         }
     }
 
+    private void handleInterestRefund(LoanTransaction loanTransaction, TransactionCtx ctx) {
+
+        if (ctx instanceof ProgressiveTransactionCtx progCtx) {
+            Money interestBeforeRefund = emiCalculator.getSumOfDueInterestsOnDate(progCtx.getModel(), loanTransaction.getDateOf());
+            List<Long> unmodifiedTransactionIds = progCtx.getAlreadyProcessedTransactions().stream().filter(LoanTransaction::isNotReversed)
+                    .map(AbstractPersistableCustom::getId).toList();
+            List<LoanTransaction> modifiedTransactions = new ArrayList<>(progCtx.getAlreadyProcessedTransactions().stream()
+                    .filter(LoanTransaction::isNotReversed).filter(tr -> tr.getId() == null).toList());
+            if (!modifiedTransactions.isEmpty()) {
+                Money interestAfterRefund = interestRefundService.totalInterestByTransactions(this, loanTransaction.getLoan().getId(),
+                        loanTransaction.getDateOf(), modifiedTransactions, unmodifiedTransactionIds);
+                Money newAmount = interestBeforeRefund.minus(progCtx.getSumOfInterestRefundAmount()).minus(interestAfterRefund);
+                loanTransaction.updateAmount(newAmount.getAmount());
+            }
+            progCtx.setSumOfInterestRefundAmount(progCtx.getSumOfInterestRefundAmount().add(loanTransaction.getAmount()));
+        }
+        handleRepayment(loanTransaction, ctx);
+    }
+
     private void handleReAmortization(LoanTransaction loanTransaction, TransactionCtx transactionCtx) {
         LocalDate transactionDate = loanTransaction.getTransactionDate();
         List<LoanRepaymentScheduleInstallment> previousInstallments = transactionCtx.getInstallments().stream() //

fineract-progressive-loan/src/main/java/org/apache/fineract/portfolio/loanaccount/domain/transactionprocessor/impl/ProgressiveTransactionCtx.java

@@ -19,14 +19,17 @@
 package org.apache.fineract.portfolio.loanaccount.domain.transactionprocessor.impl;
 
 import java.time.LocalDate;
+import java.util.ArrayList;
 import java.util.List;
 import java.util.Set;
 import lombok.Getter;
 import lombok.Setter;
 import org.apache.fineract.organisation.monetary.domain.MonetaryCurrency;
+import org.apache.fineract.organisation.monetary.domain.Money;
 import org.apache.fineract.portfolio.loanaccount.domain.ChangedTransactionDetail;
 import org.apache.fineract.portfolio.loanaccount.domain.LoanCharge;
 import org.apache.fineract.portfolio.loanaccount.domain.LoanRepaymentScheduleInstallment;
+import org.apache.fineract.portfolio.loanaccount.domain.LoanTransaction;
 import org.apache.fineract.portfolio.loanaccount.domain.transactionprocessor.MoneyHolder;
 import org.apache.fineract.portfolio.loanaccount.domain.transactionprocessor.TransactionCtx;
 import org.apache.fineract.portfolio.loanaccount.loanschedule.data.ProgressiveLoanInterestScheduleModel;
@@ -37,11 +40,15 @@ public class ProgressiveTransactionCtx extends TransactionCtx {
     private final ProgressiveLoanInterestScheduleModel model;
     @Setter
     private LocalDate lastOverdueBalanceChange = null;
+    private List<LoanTransaction> alreadyProcessedTransactions = new ArrayList<>();
+    @Setter
+    private Money sumOfInterestRefundAmount;
 
     public ProgressiveTransactionCtx(MonetaryCurrency currency, List<LoanRepaymentScheduleInstallment> installments,
             Set<LoanCharge> charges, MoneyHolder overpaymentHolder, ChangedTransactionDetail changedTransactionDetail,
             ProgressiveLoanInterestScheduleModel model) {
         super(currency, installments, charges, overpaymentHolder, changedTransactionDetail);
+        sumOfInterestRefundAmount = model.getZero();
         this.model = model;
     }
 }

fineract-progressive-loan/src/main/java/org/apache/fineract/portfolio/loanproduct/calc/EMICalculator.java

@@ -62,4 +62,6 @@ public interface EMICalculator {
             LocalDate targetDate);
 
     OutstandingDetails getOutstandingAmountsTillDate(ProgressiveLoanInterestScheduleModel model, LocalDate targetDate);
+
+    Money getSumOfDueInterestsOnDate(ProgressiveLoanInterestScheduleModel scheduleModel, LocalDate subjectDate);
 }

fineract-progressive-loan/src/main/java/org/apache/fineract/portfolio/loanproduct/calc/ProgressiveEMICalculator.java

@@ -716,4 +716,22 @@ public final class ProgressiveEMICalculator implements EMICalculator {
 
         return new ProgressiveLoanInterestScheduleModel(repaymentModels, loanProductRelatedDetail, installmentAmountInMultiplesOf, mc);
     }
+
+    /**
+     * Calculates the sum of due interests on interest periods.
+     *
+     * @param scheduleModel
+     *            schedule model
+     * @param subjectDate
+     *            the date to calculate the interest for.
+     * @return sum of due interests
+     */
+    @Override
+    public Money getSumOfDueInterestsOnDate(ProgressiveLoanInterestScheduleModel scheduleModel, LocalDate subjectDate) {
+        return scheduleModel.repaymentPeriods().stream().map(RepaymentPeriod::getDueDate) //
+                .map(repaymentPeriodDueDate -> getDueAmounts(scheduleModel, repaymentPeriodDueDate, subjectDate) //
+                        .getDueInterest()) //
+                .reduce(scheduleModel.getZero(), Money::add); //
+    }
+
 }

fineract-progressive-loan/src/test/java/org/apache/fineract/portfolio/loanaccount/domain/transactionprocessor/impl/AdvancedPaymentScheduleTransactionProcessorTest.java

@@ -109,7 +109,7 @@ class AdvancedPaymentScheduleTransactionProcessorTest {
 
     @BeforeEach
     public void setUp() {
-        underTest = new AdvancedPaymentScheduleTransactionProcessor(emiCalculator);
+        underTest = new AdvancedPaymentScheduleTransactionProcessor(emiCalculator, null);
 
         ThreadLocalContextUtil.setTenant(new FineractPlatformTenant(1L, "default", "Default", "Asia/Kolkata", null));
         ThreadLocalContextUtil.setActionContext(ActionContext.DEFAULT);