FINERACT-2354: Introduce reaging preview API

fineract-provider/src/main/java/org/apache/fineract/portfolio/loanaccount/api/LoanTransactionsApiResource.java

@@ -27,6 +27,8 @@ import io.swagger.v3.oas.annotations.parameters.RequestBody;
 import io.swagger.v3.oas.annotations.responses.ApiResponse;
 import io.swagger.v3.oas.annotations.responses.ApiResponses;
 import io.swagger.v3.oas.annotations.tags.Tag;
+import jakarta.validation.Valid;
+import jakarta.ws.rs.BeanParam;
 import jakarta.ws.rs.Consumes;
 import jakarta.ws.rs.GET;
 import jakarta.ws.rs.POST;
@@ -63,14 +65,17 @@ import org.apache.fineract.infrastructure.core.service.CommandParameterUtil;
 import org.apache.fineract.infrastructure.core.service.DateUtils;
 import org.apache.fineract.infrastructure.core.service.ExternalIdFactory;
 import org.apache.fineract.infrastructure.security.service.PlatformSecurityContext;
+import org.apache.fineract.portfolio.loanaccount.api.request.ReAgePreviewRequest;
 import org.apache.fineract.portfolio.loanaccount.data.LoanRepaymentScheduleInstallmentData;
 import org.apache.fineract.portfolio.loanaccount.data.LoanTransactionData;
 import org.apache.fineract.portfolio.loanaccount.domain.LoanTransactionType;
 import org.apache.fineract.portfolio.loanaccount.exception.InvalidLoanTransactionTypeException;
 import org.apache.fineract.portfolio.loanaccount.exception.LoanNotFoundException;
 import org.apache.fineract.portfolio.loanaccount.exception.LoanTransactionNotFoundException;
+import org.apache.fineract.portfolio.loanaccount.loanschedule.data.LoanScheduleData;
 import org.apache.fineract.portfolio.loanaccount.service.LoanChargePaidByReadService;
 import org.apache.fineract.portfolio.loanaccount.service.LoanReadPlatformService;
+import org.apache.fineract.portfolio.loanaccount.service.reaging.LoanReAgingService;
 import org.apache.fineract.portfolio.paymenttype.data.PaymentTypeData;
 import org.apache.fineract.portfolio.paymenttype.service.PaymentTypeReadPlatformService;
 import org.springframework.data.domain.Page;
@@ -104,6 +109,7 @@ public class LoanTransactionsApiResource {
     private final PortfolioCommandSourceWritePlatformService commandsSourceWritePlatformService;
     private final PaymentTypeReadPlatformService paymentTypeReadPlatformService;
     private final LoanChargePaidByReadService loanChargePaidByReadService;
+    private final LoanReAgingService loanReAgingService;
 
     @GET
     @Path("{loanId}/transactions/template")
@@ -777,4 +783,26 @@ public class LoanTransactionsApiResource {
             throw new IllegalArgumentException("loanId and loanExternalId cannot be both null");
         }
     }
+
+    @GET
+    @Path("{loanId}/transactions/reage-preview")
+    @Produces({ MediaType.APPLICATION_JSON })
+    @Operation(summary = "Preview Re-Age Schedule", description = "Generates a preview of the re-aged loan schedule based on the provided parameters without creating any transactions or modifying the loan.")
+    public LoanScheduleData previewReAgeSchedule(@PathParam("loanId") @Parameter(description = "loanId", required = true) final Long loanId,
+            @Valid @BeanParam final ReAgePreviewRequest reAgePreviewRequest) {
+        this.context.authenticatedUser().validateHasReadPermission(RESOURCE_NAME_FOR_PERMISSIONS);
+        return loanReAgingService.previewReAge(loanId, null, reAgePreviewRequest);
+    }
+
+    @GET
+    @Path("external-id/{loanExternalId}/transactions/reage-preview")
+    @Produces({ MediaType.APPLICATION_JSON })
+    @Operation(summary = "Preview Re-Age Schedule", description = "Generates a preview of the re-aged loan schedule based on the provided parameters without creating any transactions or modifying the loan.")
+    public LoanScheduleData previewReAgeSchedule(
+            @PathParam("loanExternalId") @Parameter(description = "loanExternalId", required = true) final String loanExternalId,
+            @Valid @BeanParam final ReAgePreviewRequest reAgePreviewRequest) {
+        this.context.authenticatedUser().validateHasReadPermission(RESOURCE_NAME_FOR_PERMISSIONS);
+        return loanReAgingService.previewReAge(null, loanExternalId, reAgePreviewRequest);
+    }
+
 }

fineract-provider/src/main/java/org/apache/fineract/portfolio/loanaccount/api/request/ReAgePreviewRequest.java

@@ -0,0 +1,81 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.fineract.portfolio.loanaccount.api.request;
+
+import io.swagger.v3.oas.annotations.Parameter;
+import jakarta.validation.constraints.Min;
+import jakarta.validation.constraints.NotBlank;
+import jakarta.validation.constraints.NotNull;
+import jakarta.ws.rs.QueryParam;
+import java.io.Serial;
+import java.io.Serializable;
+import lombok.AllArgsConstructor;
+import lombok.Builder;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+import org.apache.fineract.portfolio.common.domain.PeriodFrequencyType;
+import org.apache.fineract.validation.constraints.EnumValue;
+import org.apache.fineract.validation.constraints.LocalDate;
+import org.apache.fineract.validation.constraints.Locale;
+
+@Builder
+@Data
+@NoArgsConstructor
+@AllArgsConstructor
+@LocalDate(dateField = "startDate", formatField = "dateFormat", localeField = "locale")
+public class ReAgePreviewRequest implements Serializable {
+
+    @Serial
+    private static final long serialVersionUID = 1L;
+
+    @QueryParam("frequencyNumber")
+    @Parameter(description = "The frequency number for the re-aging schedule", required = true)
+    @NotNull(message = "{org.apache.fineract.reage.frequency-number.not-blank}")
+    @Min(value = 1, message = "{org.apache.fineract.reage.frequency-number.min}")
+    private Integer frequencyNumber;
+
+    @QueryParam("frequencyType")
+    @Parameter(description = "The frequency type (DAYS, WEEKS, MONTHS, YEARS)", required = true)
+    @NotBlank(message = "{org.apache.fineract.reage.frequency-type.not-blank}")
+    @EnumValue(enumClass = PeriodFrequencyType.class, message = "{org.apache.fineract.frequency-type.invalid}")
+    private String frequencyType;
+
+    @QueryParam("startDate")
+    @Parameter(description = "The start date for the re-aging schedule", required = true)
+    @NotBlank(message = "{org.apache.fineract.reage.start-date.not-blank}")
+    private String startDate;
+
+    @QueryParam("numberOfInstallments")
+    @Parameter(description = "The number of installments for the re-aged loan", required = true)
+    @NotNull(message = "{org.apache.fineract.reage.number-of-installments.not-blank}")
+    @Min(value = 1, message = "{org.apache.fineract.reage.number-of-installments.min}")
+    private Integer numberOfInstallments;
+
+    @QueryParam("dateFormat")
+    @Parameter(description = "The date format used for the startDate parameter", required = true)
+    @NotBlank(message = "{org.apache.fineract.businessdate.date-format.not-blank}")
+    private String dateFormat;
+
+    @QueryParam("locale")
+    @Parameter(description = "The locale to use for formatting", required = true)
+    @NotBlank(message = "{org.apache.fineract.businessdate.locale.not-blank}")
+    @Locale
+    private String locale;
+
+}

fineract-provider/src/main/java/org/apache/fineract/portfolio/loanaccount/handler/loan/reaging/LoanReAgingCommandHandler.java

@@ -24,7 +24,7 @@ import org.apache.fineract.commands.handler.NewCommandSourceHandler;
 import org.apache.fineract.infrastructure.DataIntegrityErrorHandler;
 import org.apache.fineract.infrastructure.core.api.JsonCommand;
 import org.apache.fineract.infrastructure.core.data.CommandProcessingResult;
-import org.apache.fineract.portfolio.loanaccount.service.reaging.LoanReAgingServiceImpl;
+import org.apache.fineract.portfolio.loanaccount.service.reaging.LoanReAgingService;
 import org.springframework.dao.DataIntegrityViolationException;
 import org.springframework.orm.jpa.JpaSystemException;
 import org.springframework.stereotype.Service;
@@ -34,7 +34,7 @@ import org.springframework.stereotype.Service;
 @CommandType(entity = "LOAN", action = "REAGE")
 public class LoanReAgingCommandHandler implements NewCommandSourceHandler {
 
-    private final LoanReAgingServiceImpl loanReAgingService;
+    private final LoanReAgingService loanReAgingService;
     private final DataIntegrityErrorHandler dataIntegrityErrorHandler;
 
     @Override

fineract-provider/src/main/java/org/apache/fineract/portfolio/loanaccount/handler/loan/reaging/LoanUndoReAgingCommandHandler.java

@@ -24,7 +24,7 @@ import org.apache.fineract.commands.handler.NewCommandSourceHandler;
 import org.apache.fineract.infrastructure.DataIntegrityErrorHandler;
 import org.apache.fineract.infrastructure.core.api.JsonCommand;
 import org.apache.fineract.infrastructure.core.data.CommandProcessingResult;
-import org.apache.fineract.portfolio.loanaccount.service.reaging.LoanReAgingServiceImpl;
+import org.apache.fineract.portfolio.loanaccount.service.reaging.LoanReAgingService;
 import org.springframework.dao.DataIntegrityViolationException;
 import org.springframework.orm.jpa.JpaSystemException;
 import org.springframework.stereotype.Service;
@@ -34,7 +34,7 @@ import org.springframework.stereotype.Service;
 @CommandType(entity = "LOAN", action = "UNDO_REAGE")
 public class LoanUndoReAgingCommandHandler implements NewCommandSourceHandler {
 
-    private final LoanReAgingServiceImpl loanReAgingService;
+    private final LoanReAgingService loanReAgingService;
     private final DataIntegrityErrorHandler dataIntegrityErrorHandler;
 
     @Override

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

@@ -31,8 +31,6 @@ import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
-import java.util.HashMap;
-import java.util.HashSet;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
@@ -103,7 +101,6 @@ import org.apache.fineract.portfolio.loanaccount.data.LoanApprovalData;
 import org.apache.fineract.portfolio.loanaccount.data.LoanChargePaidByData;
 import org.apache.fineract.portfolio.loanaccount.data.LoanInterestRecalculationData;
 import org.apache.fineract.portfolio.loanaccount.data.LoanRepaymentScheduleInstallmentData;
-import org.apache.fineract.portfolio.loanaccount.data.LoanSchedulePeriodDataWrapper;
 import org.apache.fineract.portfolio.loanaccount.data.LoanStatusEnumData;
 import org.apache.fineract.portfolio.loanaccount.data.LoanSummaryData;
 import org.apache.fineract.portfolio.loanaccount.data.LoanTransactionData;
@@ -136,7 +133,6 @@ import org.apache.fineract.portfolio.loanaccount.domain.reamortization.LoanReAmo
 import org.apache.fineract.portfolio.loanaccount.exception.LoanNotFoundException;
 import org.apache.fineract.portfolio.loanaccount.exception.LoanTransactionNotFoundException;
 import org.apache.fineract.portfolio.loanaccount.loanschedule.data.LoanScheduleData;
-import org.apache.fineract.portfolio.loanaccount.loanschedule.data.LoanSchedulePeriodData;
 import org.apache.fineract.portfolio.loanaccount.loanschedule.data.OverdueLoanScheduleData;
 import org.apache.fineract.portfolio.loanaccount.loanschedule.domain.LoanScheduleProcessingType;
 import org.apache.fineract.portfolio.loanaccount.loanschedule.domain.LoanScheduleType;
@@ -158,9 +154,7 @@ import org.springframework.dao.DataAccessException;
 import org.springframework.dao.EmptyResultDataAccessException;
 import org.springframework.data.domain.Pageable;
 import org.springframework.jdbc.core.JdbcTemplate;
-import org.springframework.jdbc.core.ResultSetExtractor;
 import org.springframework.jdbc.core.RowMapper;
-import org.springframework.lang.NonNull;
 import org.springframework.transaction.annotation.Transactional;
 import org.springframework.util.CollectionUtils;
 
@@ -188,7 +182,7 @@ public class LoanReadPlatformServiceImpl implements LoanReadPlatformService, Loa
     private final ConfigurationDomainService configurationDomainService;
     private final AccountDetailsReadPlatformService accountDetailsReadPlatformService;
     private final ColumnValidator columnValidator;
-    protected final DatabaseSpecificSQLGenerator sqlGenerator;
+    private final DatabaseSpecificSQLGenerator sqlGenerator;
     private final DelinquencyReadPlatformService delinquencyReadPlatformService;
     private final LoanTransactionRepository loanTransactionRepository;
     private final LoanChargePaidByReadService loanChargePaidByReadService;
@@ -201,6 +195,7 @@ public class LoanReadPlatformServiceImpl implements LoanReadPlatformService, Loa
     private final LoanBuyDownFeeBalanceRepository loanBuyDownFeeBalanceRepository;
     private final InterestRefundServiceDelegate interestRefundServiceDelegate;
     private final LoanMaximumAmountCalculator loanMaximumAmountCalculator;
+    private final LoanRepaymentScheduleService loanRepaymentScheduleService;
 
     @Override
     public LoanAccountData retrieveOne(final Long loanId) {
@@ -280,19 +275,9 @@ public class LoanReadPlatformServiceImpl implements LoanReadPlatformService, Loa
             final RepaymentScheduleRelatedLoanData repaymentScheduleRelatedLoanData, Collection<DisbursementData> disbursementData,
             Collection<LoanTransactionRepaymentPeriodData> capitalizedIncomeData, boolean isInterestRecalculationEnabled,
             LoanScheduleType loanScheduleType) {
-
-        try {
-            this.context.authenticatedUser();
-
-            final LoanScheduleResultSetExtractor fullResultsetExtractor = new LoanScheduleResultSetExtractor(
-                    repaymentScheduleRelatedLoanData, disbursementData, capitalizedIncomeData, isInterestRecalculationEnabled,
-                    loanScheduleType);
-            final String sql = "select " + fullResultsetExtractor.schema() + " where ls.loan_id = ? order by ls.loan_id, ls.installment";
-
-            return this.jdbcTemplate.query(sql, fullResultsetExtractor, loanId); // NOSONAR
-        } catch (final EmptyResultDataAccessException e) {
-            throw new LoanNotFoundException(loanId, e);
-        }
+        this.context.authenticatedUser();
+        return loanRepaymentScheduleService.findLoanScheduleData(loanId, repaymentScheduleRelatedLoanData, disbursementData,
+                capitalizedIncomeData, isInterestRecalculationEnabled, loanScheduleType);
     }
 
     @Override
@@ -1339,373 +1324,6 @@ public class LoanReadPlatformServiceImpl implements LoanReadPlatformService, Loa
         }
     }
 
-    private static final class LoanScheduleResultSetExtractor implements ResultSetExtractor<LoanScheduleData> {
-
-        private final CurrencyData currency;
-        private final DisbursementData disbursement;
-        private final BigDecimal totalFeeChargesDueAtDisbursement;
-        private final Collection<DisbursementData> disbursementData;
-        private final Collection<LoanTransactionRepaymentPeriodData> capitalizedIncomeData;
-        private final LoanScheduleType loanScheduleType;
-        private LocalDate lastDueDate;
-        private BigDecimal outstandingLoanPrincipalBalance;
-        private boolean excludePastUnDisbursed;
-
-        LoanScheduleResultSetExtractor(final RepaymentScheduleRelatedLoanData repaymentScheduleRelatedLoanData,
-                Collection<DisbursementData> disbursementData, Collection<LoanTransactionRepaymentPeriodData> capitalizedIncomeData,
-                boolean isInterestRecalculationEnabled, LoanScheduleType loanScheduleType) {
-            this.currency = repaymentScheduleRelatedLoanData.getCurrency();
-            this.disbursement = repaymentScheduleRelatedLoanData.disbursementData();
-            this.capitalizedIncomeData = capitalizedIncomeData;
-            this.totalFeeChargesDueAtDisbursement = repaymentScheduleRelatedLoanData.getTotalFeeChargesAtDisbursement();
-            this.lastDueDate = this.disbursement.disbursementDate();
-            this.outstandingLoanPrincipalBalance = this.disbursement.getPrincipal();
-            this.disbursementData = disbursementData;
-            this.excludePastUnDisbursed = isInterestRecalculationEnabled;
-            this.loanScheduleType = loanScheduleType;
-        }
-
-        public String schema() {
-
-            return " ls.loan_id as loanId, ls.installment as period, ls.fromdate as fromDate, ls.duedate as dueDate, ls.obligations_met_on_date as obligationsMetOnDate, ls.completed_derived as complete,"
-                    + " ls.principal_amount as principalDue, ls.principal_completed_derived as principalPaid, ls.principal_writtenoff_derived as principalWrittenOff, ls.is_additional as isAdditional, "
-                    + " ls.interest_amount as interestDue, ls.interest_completed_derived as interestPaid, ls.interest_waived_derived as interestWaived, ls.interest_writtenoff_derived as interestWrittenOff, "
-                    + " ls.fee_charges_amount as feeChargesDue, ls.fee_charges_completed_derived as feeChargesPaid, ls.fee_charges_waived_derived as feeChargesWaived, ls.fee_charges_writtenoff_derived as feeChargesWrittenOff, "
-                    + " ls.penalty_charges_amount as penaltyChargesDue, ls.penalty_charges_completed_derived as penaltyChargesPaid, ls.penalty_charges_waived_derived as penaltyChargesWaived, "
-                    + " ls.penalty_charges_writtenoff_derived as penaltyChargesWrittenOff, ls.total_paid_in_advance_derived as totalPaidInAdvanceForPeriod, "
-                    + " ls.total_paid_late_derived as totalPaidLateForPeriod, ls.credits_amount as principalCredits, ls.credited_fee as feeCredits, ls.credited_penalty as penaltyCredits, ls.is_down_payment isDownPayment, "
-                    + " ls.accrual_interest_derived as accrualInterest " + " from m_loan_repayment_schedule ls ";
-        }
-
-        @Override
-        public LoanScheduleData extractData(@NonNull final ResultSet rs) throws SQLException, DataAccessException {
-            BigDecimal waivedChargeAmount = BigDecimal.ZERO;
-            for (DisbursementData disbursementDetail : disbursementData) {
-                waivedChargeAmount = waivedChargeAmount.add(disbursementDetail.getWaivedChargeAmount());
-            }
-            final LoanSchedulePeriodData disbursementPeriod = LoanSchedulePeriodData.disbursementOnlyPeriod(
-                    this.disbursement.disbursementDate(), this.disbursement.getPrincipal(), this.totalFeeChargesDueAtDisbursement,
-                    this.disbursement.isDisbursed());
-
-            final List<LoanSchedulePeriodData> periods = new ArrayList<>();
-            final MonetaryCurrency monCurrency = new MonetaryCurrency(this.currency.getCode(), this.currency.getDecimalPlaces(),
-                    this.currency.getInMultiplesOf());
-            BigDecimal totalPrincipalDisbursed = BigDecimal.ZERO;
-            BigDecimal disbursementChargeAmount = this.totalFeeChargesDueAtDisbursement;
-            if (disbursementData.isEmpty()) {
-                periods.add(disbursementPeriod);
-                totalPrincipalDisbursed = Money.of(monCurrency, this.disbursement.getPrincipal()).getAmount();
-            } else {
-                if (!this.disbursement.isDisbursed()) {
-                    excludePastUnDisbursed = false;
-                }
-                for (DisbursementData data : disbursementData) {
-                    if (data.getChargeAmount() != null) {
-                        disbursementChargeAmount = disbursementChargeAmount.subtract(data.getChargeAmount());
-                    }
-                }
-                this.outstandingLoanPrincipalBalance = BigDecimal.ZERO;
-            }
-
-            Money totalPrincipalExpected = Money.zero(monCurrency);
-            Money totalPrincipalPaid = Money.zero(monCurrency);
-            Money totalInterestCharged = Money.zero(monCurrency);
-            Money totalFeeChargesCharged = Money.zero(monCurrency);
-            Money totalPenaltyChargesCharged = Money.zero(monCurrency);
-            Money totalWaived = Money.zero(monCurrency);
-            Money totalWrittenOff = Money.zero(monCurrency);
-            Money totalRepaymentExpected = Money.zero(monCurrency);
-            Money totalRepayment = Money.zero(monCurrency);
-            Money totalPaidInAdvance = Money.zero(monCurrency);
-            Money totalPaidLate = Money.zero(monCurrency);
-            Money totalOutstanding = Money.zero(monCurrency);
-            Money totalCredits = Money.zero(monCurrency);
-
-            // update totals with details of fees charged during disbursement
-            totalFeeChargesCharged = totalFeeChargesCharged.plus(disbursementPeriod.getFeeChargesDue().subtract(waivedChargeAmount));
-            totalRepaymentExpected = totalRepaymentExpected.plus(disbursementPeriod.getFeeChargesDue()).minus(waivedChargeAmount);
-            totalRepayment = totalRepayment.plus(disbursementPeriod.getFeeChargesPaid()).minus(waivedChargeAmount);
-            totalOutstanding = totalOutstanding.plus(disbursementPeriod.getFeeChargesDue()).minus(disbursementPeriod.getFeeChargesPaid());
-
-            Integer loanTermInDays = 0;
-            Set<Long> disbursementPeriodIds = new HashSet<>();
-            while (rs.next()) {
-                final Integer period = JdbcSupport.getInteger(rs, "period");
-                LocalDate fromDate = JdbcSupport.getLocalDate(rs, "fromDate");
-                final LocalDate dueDate = JdbcSupport.getLocalDate(rs, "dueDate");
-                final LocalDate obligationsMetOnDate = JdbcSupport.getLocalDate(rs, "obligationsMetOnDate");
-                final boolean complete = rs.getBoolean("complete");
-
-                List<LoanSchedulePeriodDataWrapper> combinedDataList = new ArrayList<>();
-                combinedDataList.addAll(
-                        collectEligibleDisbursementData(loanScheduleType, disbursementData, fromDate, dueDate, disbursementPeriodIds));
-                combinedDataList.addAll(collectEligibleCapitalizedIncomeData(fromDate, dueDate, disbursementPeriodIds));
-                combinedDataList.sort(this::sortPeriodDataHolders);
-                fillLoanSchedulePeriodData(periods, combinedDataList, disbursementChargeAmount, waivedChargeAmount);
-
-                BigDecimal disbursedAmount = calculateDisbursedAmount(combinedDataList);
-
-                // Add the Charge back or Credits to the initial amount to avoid negative balance
-                final BigDecimal principalCredits = JdbcSupport.getBigDecimalDefaultToZeroIfNull(rs, "principalCredits");
-                final BigDecimal feeCredits = JdbcSupport.getBigDecimalDefaultToZeroIfNull(rs, "feeCredits");
-                final BigDecimal penaltyCredits = JdbcSupport.getBigDecimalDefaultToZeroIfNull(rs, "penaltyCredits");
-                final BigDecimal credits = principalCredits.add(feeCredits).add(penaltyCredits);
-                this.outstandingLoanPrincipalBalance = this.outstandingLoanPrincipalBalance.add(principalCredits);
-
-                totalPrincipalDisbursed = totalPrincipalDisbursed.add(disbursedAmount);
-
-                Integer daysInPeriod = 0;
-                if (fromDate != null) {
-                    daysInPeriod = DateUtils.getExactDifferenceInDays(fromDate, dueDate);
-                    loanTermInDays = loanTermInDays + daysInPeriod;
-                }
-
-                final BigDecimal principalDue = JdbcSupport.getBigDecimalDefaultToZeroIfNull(rs, "principalDue");
-                totalPrincipalExpected = totalPrincipalExpected.plus(principalDue);
-                final BigDecimal principalPaid = JdbcSupport.getBigDecimalDefaultToZeroIfNull(rs, "principalPaid");
-                totalPrincipalPaid = totalPrincipalPaid.plus(principalPaid);
-                final BigDecimal principalWrittenOff = JdbcSupport.getBigDecimalDefaultToZeroIfNull(rs, "principalWrittenOff");
-
-                final BigDecimal principalOutstanding = principalDue.subtract(principalPaid).subtract(principalWrittenOff);
-
-                final BigDecimal interestExpectedDue = JdbcSupport.getBigDecimalDefaultToZeroIfNull(rs, "interestDue");
-                totalInterestCharged = totalInterestCharged.plus(interestExpectedDue);
-                final BigDecimal interestPaid = JdbcSupport.getBigDecimalDefaultToZeroIfNull(rs, "interestPaid");
-                final BigDecimal interestWaived = JdbcSupport.getBigDecimalDefaultToZeroIfNull(rs, "interestWaived");
-                final BigDecimal interestWrittenOff = JdbcSupport.getBigDecimalDefaultToZeroIfNull(rs, "interestWrittenOff");
-                final BigDecimal accrualInterest = JdbcSupport.getBigDecimalDefaultToZeroIfNull(rs, "accrualInterest");
-
-                final BigDecimal interestActualDue = interestExpectedDue.subtract(interestWaived).subtract(interestWrittenOff);
-                final BigDecimal interestOutstanding = interestActualDue.subtract(interestPaid);
-
-                final BigDecimal feeChargesExpectedDue = JdbcSupport.getBigDecimalDefaultToZeroIfNull(rs, "feeChargesDue");
-                totalFeeChargesCharged = totalFeeChargesCharged.plus(feeChargesExpectedDue);
-                final BigDecimal feeChargesPaid = JdbcSupport.getBigDecimalDefaultToZeroIfNull(rs, "feeChargesPaid");
-                final BigDecimal feeChargesWaived = JdbcSupport.getBigDecimalDefaultToZeroIfNull(rs, "feeChargesWaived");
-                final BigDecimal feeChargesWrittenOff = JdbcSupport.getBigDecimalDefaultToZeroIfNull(rs, "feeChargesWrittenOff");
-
-                final BigDecimal feeChargesActualDue = feeChargesExpectedDue.subtract(feeChargesWaived).subtract(feeChargesWrittenOff);
-                final BigDecimal feeChargesOutstanding = feeChargesActualDue.subtract(feeChargesPaid);
-
-                final BigDecimal penaltyChargesExpectedDue = JdbcSupport.getBigDecimalDefaultToZeroIfNull(rs, "penaltyChargesDue");
-                totalPenaltyChargesCharged = totalPenaltyChargesCharged.plus(penaltyChargesExpectedDue);
-                final BigDecimal penaltyChargesPaid = JdbcSupport.getBigDecimalDefaultToZeroIfNull(rs, "penaltyChargesPaid");
-                final BigDecimal penaltyChargesWaived = JdbcSupport.getBigDecimalDefaultToZeroIfNull(rs, "penaltyChargesWaived");
-                final BigDecimal penaltyChargesWrittenOff = JdbcSupport.getBigDecimalDefaultToZeroIfNull(rs, "penaltyChargesWrittenOff");
-
-                final BigDecimal totalPaidInAdvanceForPeriod = JdbcSupport.getBigDecimalDefaultToZeroIfNull(rs,
-                        "totalPaidInAdvanceForPeriod");
-                final BigDecimal totalPaidLateForPeriod = JdbcSupport.getBigDecimalDefaultToZeroIfNull(rs, "totalPaidLateForPeriod");
-
-                final BigDecimal penaltyChargesActualDue = penaltyChargesExpectedDue.subtract(penaltyChargesWaived)
-                        .subtract(penaltyChargesWrittenOff);
-                final BigDecimal penaltyChargesOutstanding = penaltyChargesActualDue.subtract(penaltyChargesPaid);
-
-                final BigDecimal totalExpectedCostOfLoanForPeriod = interestExpectedDue.add(feeChargesExpectedDue)
-                        .add(penaltyChargesExpectedDue);
-
-                final BigDecimal totalDueForPeriod = principalDue.add(totalExpectedCostOfLoanForPeriod);
-                final BigDecimal totalPaidForPeriod = principalPaid.add(interestPaid).add(feeChargesPaid).add(penaltyChargesPaid);
-                final BigDecimal totalWaivedForPeriod = interestWaived.add(feeChargesWaived).add(penaltyChargesWaived);
-                totalWaived = totalWaived.plus(totalWaivedForPeriod);
-                final BigDecimal totalWrittenOffForPeriod = principalWrittenOff.add(interestWrittenOff).add(feeChargesWrittenOff)
-                        .add(penaltyChargesWrittenOff);
-                totalWrittenOff = totalWrittenOff.plus(totalWrittenOffForPeriod);
-
-                final BigDecimal totalOutstandingForPeriod = principalOutstanding.add(interestOutstanding).add(feeChargesOutstanding)
-                        .add(penaltyChargesOutstanding);
-
-                totalRepaymentExpected = totalRepaymentExpected.plus(totalDueForPeriod);
-                totalRepayment = totalRepayment.plus(totalPaidForPeriod);
-                totalPaidInAdvance = totalPaidInAdvance.plus(totalPaidInAdvanceForPeriod);
-                totalPaidLate = totalPaidLate.plus(totalPaidLateForPeriod);
-                totalOutstanding = totalOutstanding.plus(totalOutstandingForPeriod);
-                totalCredits = totalCredits.add(credits);
-
-                if (fromDate == null) {
-                    fromDate = this.lastDueDate;
-                }
-
-                BigDecimal outstandingPrincipalBalanceOfLoan = this.outstandingLoanPrincipalBalance.subtract(principalDue);
-
-                // update based on current period values
-                this.lastDueDate = dueDate;
-                this.outstandingLoanPrincipalBalance = this.outstandingLoanPrincipalBalance.subtract(principalDue);
-
-                final boolean isDownPayment = rs.getBoolean("isDownPayment");
-
-                LoanSchedulePeriodData periodData;
-
-                periodData = LoanSchedulePeriodData.periodWithPayments(period, fromDate, dueDate, obligationsMetOnDate, complete,
-                        principalDue, principalPaid, principalWrittenOff, principalOutstanding, outstandingPrincipalBalanceOfLoan,
-                        interestExpectedDue, interestPaid, interestWaived, interestWrittenOff, interestOutstanding, feeChargesExpectedDue,
-                        feeChargesPaid, feeChargesWaived, feeChargesWrittenOff, feeChargesOutstanding, penaltyChargesExpectedDue,
-                        penaltyChargesPaid, penaltyChargesWaived, penaltyChargesWrittenOff, penaltyChargesOutstanding, totalPaidForPeriod,
-                        totalPaidInAdvanceForPeriod, totalPaidLateForPeriod, totalWaivedForPeriod, totalWrittenOffForPeriod, credits,
-                        isDownPayment, accrualInterest);
-
-                periods.add(periodData);
-            }
-
-            return new LoanScheduleData(this.currency, periods, loanTermInDays, totalPrincipalDisbursed, totalPrincipalExpected.getAmount(),
-                    totalPrincipalPaid.getAmount(), totalInterestCharged.getAmount(), totalFeeChargesCharged.getAmount(),
-                    totalPenaltyChargesCharged.getAmount(), totalWaived.getAmount(), totalWrittenOff.getAmount(),
-                    totalRepaymentExpected.getAmount(), totalRepayment.getAmount(), totalPaidInAdvance.getAmount(),
-                    totalPaidLate.getAmount(), totalOutstanding.getAmount(), totalCredits.getAmount());
-        }
-
-        private List<LoanSchedulePeriodDataWrapper> collectEligibleDisbursementData(LoanScheduleType loanScheduleType,
-                Collection<DisbursementData> disbursementData, LocalDate fromDate, LocalDate dueDate, Set<Long> disbursementPeriodIds) {
-            List<LoanSchedulePeriodDataWrapper> disbursementDataList = new ArrayList<>();
-
-            boolean hasMultipleTranchesOnSameDate = hasMultipleTranchesOnSameDate(disbursementData);
-
-            if (hasMultipleTranchesOnSameDate) {
-                Map<LocalDate, List<DisbursementData>> disbursementsByDate = new HashMap<>();
-
-                for (final DisbursementData data : disbursementData) {
-                    boolean isDueForDisbursement = data.isDueForDisbursement(loanScheduleType, fromDate, dueDate);
-                    boolean isEligible = ((fromDate.equals(this.disbursement.disbursementDate())
-                            && data.disbursementDate().equals(fromDate))
-                            || (fromDate.equals(dueDate) && data.disbursementDate().equals(fromDate))
-                            || canAddDisbursementData(data, isDueForDisbursement, excludePastUnDisbursed))
-                            && !disbursementPeriodIds.contains(data.getId());
-
-                    if (isEligible) {
-                        disbursementsByDate.computeIfAbsent(data.disbursementDate(), k -> new ArrayList<>()).add(data);
-                        disbursementPeriodIds.add(data.getId());
-                    }
-                }
-
-                for (Map.Entry<LocalDate, List<DisbursementData>> entry : disbursementsByDate.entrySet()) {
-                    List<DisbursementData> sameDateDisbursements = entry.getValue();
-
-                    if (sameDateDisbursements.size() > 1) {
-                        List<DisbursementData> disbursedTranches = sameDateDisbursements.stream().filter(DisbursementData::isDisbursed)
-                                .collect(Collectors.toList());
-
-                        if (!disbursedTranches.isEmpty()) {
-                            for (DisbursementData data : disbursedTranches) {
-                                disbursementDataList.add(new LoanSchedulePeriodDataWrapper(data, data.disbursementDate(), true));
-                            }
-                        } else {
-                            for (DisbursementData data : sameDateDisbursements) {
-                                disbursementDataList.add(new LoanSchedulePeriodDataWrapper(data, data.disbursementDate(), true));
-                            }
-                        }
-                    } else {
-                        DisbursementData data = sameDateDisbursements.get(0);
-                        disbursementDataList.add(new LoanSchedulePeriodDataWrapper(data, data.disbursementDate(), true));
-                    }
-                }
-            } else {
-                for (final DisbursementData data : disbursementData) {
-                    boolean isDueForDisbursement = data.isDueForDisbursement(loanScheduleType, fromDate, dueDate);
-                    boolean isEligible = ((fromDate.equals(this.disbursement.disbursementDate())
-                            && data.disbursementDate().equals(fromDate))
-                            || (fromDate.equals(dueDate) && data.disbursementDate().equals(fromDate))
-                            || canAddDisbursementData(data, isDueForDisbursement, excludePastUnDisbursed))
-                            && !disbursementPeriodIds.contains(data.getId());
-
-                    if (isEligible) {
-                        disbursementDataList.add(new LoanSchedulePeriodDataWrapper(data, data.disbursementDate(), true));
-                        disbursementPeriodIds.add(data.getId());
-                    }
-                }
-            }
-
-            return disbursementDataList;
-        }
-
-        private boolean hasMultipleTranchesOnSameDate(Collection<DisbursementData> disbursementData) {
-            if (disbursementData == null || disbursementData.size() <= 1) {
-                return false;
-            }
-            return disbursementData.stream().collect(Collectors.groupingBy(DisbursementData::disbursementDate, Collectors.counting()))
-                    .values().stream().anyMatch(count -> count > 1);
-        }
-
-        private List<LoanSchedulePeriodDataWrapper> collectEligibleCapitalizedIncomeData(LocalDate fromDate, LocalDate dueDate,
-                Set<Long> disbursementPeriodIds) {
-            List<LoanSchedulePeriodDataWrapper> capitalizedIncomeDataList = new ArrayList<>();
-            // Collect eligible capitalized income data
-            for (LoanTransactionRepaymentPeriodData data : capitalizedIncomeData) {
-                boolean isEligible = canAddCapitalizedIncomeData(data, fromDate, dueDate)
-                        && !disbursementPeriodIds.contains(data.getTransactionId());
-
-                if (isEligible) {
-                    capitalizedIncomeDataList.add(new LoanSchedulePeriodDataWrapper(data, data.getDate(), false));
-                    disbursementPeriodIds.add(data.getTransactionId());
-                }
-            }
-            return capitalizedIncomeDataList;
-        }
-
-        private void fillLoanSchedulePeriodData(List<LoanSchedulePeriodData> periods, List<LoanSchedulePeriodDataWrapper> combinedDataList,
-                BigDecimal disbursementChargeAmount, BigDecimal waivedChargeAmount) {
-            // Process all collected data in chronological order
-            for (LoanSchedulePeriodDataWrapper dataItem : combinedDataList) {
-                LoanSchedulePeriodData periodData;
-                if (dataItem.isDisbursement()) {
-                    // Process disbursement data
-                    DisbursementData data = (DisbursementData) dataItem.getData();
-                    periodData = createLoanSchedulePeriodData(data, disbursementChargeAmount, waivedChargeAmount);
-                } else {
-                    // Process capitalized income data
-                    LoanTransactionRepaymentPeriodData data = (LoanTransactionRepaymentPeriodData) dataItem.getData();
-                    periodData = createLoanSchedulePeriodData(data);
-                }
-
-                // Common processing for both data types
-                periods.add(periodData);
-                this.outstandingLoanPrincipalBalance = this.outstandingLoanPrincipalBalance.add(periodData.getPrincipalDisbursed());
-            }
-        }
-
-        private BigDecimal calculateDisbursedAmount(List<LoanSchedulePeriodDataWrapper> combinedDataList) {
-            BigDecimal disbursedAmount = BigDecimal.ZERO;
-            for (LoanSchedulePeriodDataWrapper dataItem : combinedDataList) {
-                if (dataItem.isDisbursement()) {
-                    DisbursementData data = (DisbursementData) dataItem.getData();
-                    disbursedAmount = disbursedAmount.add(data.getPrincipal());
-                }
-            }
-            return disbursedAmount;
-        }
-
-        private int sortPeriodDataHolders(LoanSchedulePeriodDataWrapper item1, LoanSchedulePeriodDataWrapper item2) {
-            int dateComparison = item1.getDate().compareTo(item2.getDate());
-            if (dateComparison == 0 && item1.isDisbursement() != item2.isDisbursement()) {
-                // If dates are equal, prioritize disbursement data
-                return item1.isDisbursement() ? -1 : 1;
-            }
-            return dateComparison;
-        }
-
-        private LoanSchedulePeriodData createLoanSchedulePeriodData(final DisbursementData data, BigDecimal disbursementChargeAmount,
-                BigDecimal waivedChargeAmount) {
-            BigDecimal chargeAmount = data.getChargeAmount() == null ? disbursementChargeAmount
-                    : disbursementChargeAmount.add(data.getChargeAmount()).subtract(waivedChargeAmount);
-            return LoanSchedulePeriodData.disbursementOnlyPeriod(data.disbursementDate(), data.getPrincipal(), chargeAmount,
-                    data.isDisbursed());
-        }
-
-        private LoanSchedulePeriodData createLoanSchedulePeriodData(final LoanTransactionRepaymentPeriodData data) {
-            BigDecimal feeCharges = Objects.isNull(data.getFeeChargesPortion()) ? BigDecimal.ZERO : data.getFeeChargesPortion();
-            return LoanSchedulePeriodData.disbursementOnlyPeriod(data.getDate(), data.getAmount(), feeCharges, !data.isReversed());
-        }
-
-        private boolean canAddDisbursementData(DisbursementData data, boolean isDueForDisbursement, boolean excludePastUnDisbursed) {
-            return (!excludePastUnDisbursed || data.isDisbursed() || !DateUtils.isBeforeBusinessDate(data.disbursementDate()))
-                    && isDueForDisbursement;
-        }
-
-        private boolean canAddCapitalizedIncomeData(LoanTransactionRepaymentPeriodData data, LocalDate fromDate, LocalDate dueDate) {
-            return !data.isReversed() && DateUtils.isDateInRangeFromInclusiveToExclusive(fromDate, dueDate, data.getDate());
-        }
-
-    }
-
     protected static class LoanTransactionsMapper implements RowMapper<LoanTransactionData> {
 
         private final DatabaseSpecificSQLGenerator sqlGenerator;

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

@@ -0,0 +1,418 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.fineract.portfolio.loanaccount.service;
+
+import java.math.BigDecimal;
+import java.time.LocalDate;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Set;
+import java.util.stream.Collectors;
+import lombok.RequiredArgsConstructor;
+import org.apache.fineract.infrastructure.core.service.DateUtils;
+import org.apache.fineract.organisation.monetary.data.CurrencyData;
+import org.apache.fineract.organisation.monetary.domain.MonetaryCurrency;
+import org.apache.fineract.organisation.monetary.domain.Money;
+import org.apache.fineract.portfolio.loanaccount.data.DisbursementData;
+import org.apache.fineract.portfolio.loanaccount.data.LoanSchedulePeriodDataWrapper;
+import org.apache.fineract.portfolio.loanaccount.data.RepaymentScheduleRelatedLoanData;
+import org.apache.fineract.portfolio.loanaccount.domain.LoanRepaymentScheduleInstallment;
+import org.apache.fineract.portfolio.loanaccount.domain.LoanRepaymentScheduleInstallmentRepository;
+import org.apache.fineract.portfolio.loanaccount.domain.LoanTransactionRepaymentPeriodData;
+import org.apache.fineract.portfolio.loanaccount.loanschedule.data.LoanScheduleData;
+import org.apache.fineract.portfolio.loanaccount.loanschedule.data.LoanSchedulePeriodData;
+import org.apache.fineract.portfolio.loanaccount.loanschedule.domain.LoanScheduleType;
+import org.springframework.stereotype.Service;
+
+@Service
+@RequiredArgsConstructor
+public class LoanRepaymentScheduleService {
+
+    private final LoanRepaymentScheduleInstallmentRepository loanRepaymentScheduleInstallmentRepository;
+
+    public LoanScheduleData findLoanScheduleData(final Long loanId, final RepaymentScheduleRelatedLoanData repaymentScheduleRelatedLoanData,
+            Collection<DisbursementData> disbursementData, Collection<LoanTransactionRepaymentPeriodData> capitalizedIncomeData,
+            boolean isInterestRecalculationEnabled, LoanScheduleType loanScheduleType) {
+        final List<LoanRepaymentScheduleInstallment> installments = this.loanRepaymentScheduleInstallmentRepository.findByLoanId(loanId);
+
+        return extractLoanScheduleData(installments, repaymentScheduleRelatedLoanData, disbursementData, capitalizedIncomeData,
+                isInterestRecalculationEnabled, loanScheduleType);
+    }
+
+    public LoanScheduleData extractLoanScheduleData(final List<LoanRepaymentScheduleInstallment> installments,
+            final RepaymentScheduleRelatedLoanData repaymentScheduleRelatedLoanData, Collection<DisbursementData> disbursementData,
+            Collection<LoanTransactionRepaymentPeriodData> capitalizedIncomeData, boolean isInterestRecalculationEnabled,
+            LoanScheduleType loanScheduleType) {
+
+        final CurrencyData currency = repaymentScheduleRelatedLoanData.getCurrency();
+        final DisbursementData disbursement = repaymentScheduleRelatedLoanData.disbursementData();
+        final BigDecimal totalFeeChargesDueAtDisbursement = repaymentScheduleRelatedLoanData.getTotalFeeChargesAtDisbursement();
+        LocalDate lastDueDate = disbursement.disbursementDate();
+        BigDecimal outstandingLoanPrincipalBalance = disbursement.getPrincipal();
+        boolean excludePastUnDisbursed = isInterestRecalculationEnabled;
+
+        BigDecimal waivedChargeAmount = BigDecimal.ZERO;
+        for (DisbursementData disbursementDetail : disbursementData) {
+            waivedChargeAmount = waivedChargeAmount.add(disbursementDetail.getWaivedChargeAmount());
+        }
+        final LoanSchedulePeriodData disbursementPeriod = LoanSchedulePeriodData.disbursementOnlyPeriod(disbursement.disbursementDate(),
+                disbursement.getPrincipal(), totalFeeChargesDueAtDisbursement, disbursement.isDisbursed());
+
+        final List<LoanSchedulePeriodData> periods = new ArrayList<>();
+        final MonetaryCurrency monCurrency = new MonetaryCurrency(currency.getCode(), currency.getDecimalPlaces(),
+                currency.getInMultiplesOf());
+        BigDecimal totalPrincipalDisbursed = BigDecimal.ZERO;
+        BigDecimal disbursementChargeAmount = totalFeeChargesDueAtDisbursement;
+        if (disbursementData.isEmpty()) {
+            periods.add(disbursementPeriod);
+            totalPrincipalDisbursed = Money.of(monCurrency, disbursement.getPrincipal()).getAmount();
+        } else {
+            if (!disbursement.isDisbursed()) {
+                excludePastUnDisbursed = false;
+            }
+            for (DisbursementData data : disbursementData) {
+                if (data.getChargeAmount() != null) {
+                    disbursementChargeAmount = disbursementChargeAmount.subtract(data.getChargeAmount());
+                }
+            }
+            outstandingLoanPrincipalBalance = BigDecimal.ZERO;
+        }
+
+        Money totalPrincipalExpected = Money.zero(monCurrency);
+        Money totalPrincipalPaid = Money.zero(monCurrency);
+        Money totalInterestCharged = Money.zero(monCurrency);
+        Money totalFeeChargesCharged = Money.zero(monCurrency);
+        Money totalPenaltyChargesCharged = Money.zero(monCurrency);
+        Money totalWaived = Money.zero(monCurrency);
+        Money totalWrittenOff = Money.zero(monCurrency);
+        Money totalRepaymentExpected = Money.zero(monCurrency);
+        Money totalRepayment = Money.zero(monCurrency);
+        Money totalPaidInAdvance = Money.zero(monCurrency);
+        Money totalPaidLate = Money.zero(monCurrency);
+        Money totalOutstanding = Money.zero(monCurrency);
+        Money totalCredits = Money.zero(monCurrency);
+
+        // update totals with details of fees charged during disbursement
+        totalFeeChargesCharged = totalFeeChargesCharged.plus(disbursementPeriod.getFeeChargesDue().subtract(waivedChargeAmount));
+        totalRepaymentExpected = totalRepaymentExpected.plus(disbursementPeriod.getFeeChargesDue()).minus(waivedChargeAmount);
+        totalRepayment = totalRepayment.plus(disbursementPeriod.getFeeChargesPaid()).minus(waivedChargeAmount);
+        totalOutstanding = totalOutstanding.plus(disbursementPeriod.getFeeChargesDue()).minus(disbursementPeriod.getFeeChargesPaid());
+
+        Integer loanTermInDays = 0;
+        Set<Long> disbursementPeriodIds = new HashSet<>();
+
+        for (LoanRepaymentScheduleInstallment installment : installments) {
+            final Integer period = installment.getInstallmentNumber();
+            LocalDate fromDate = installment.getFromDate();
+            final LocalDate dueDate = installment.getDueDate();
+            final LocalDate obligationsMetOnDate = installment.getObligationsMetOnDate();
+            final boolean complete = installment.isObligationsMet();
+
+            List<LoanSchedulePeriodDataWrapper> combinedDataList = new ArrayList<>();
+            combinedDataList.addAll(collectEligibleDisbursementData(loanScheduleType, disbursementData, fromDate, dueDate,
+                    disbursementPeriodIds, disbursement, excludePastUnDisbursed));
+            combinedDataList.addAll(collectEligibleCapitalizedIncomeData(capitalizedIncomeData, fromDate, dueDate, disbursementPeriodIds));
+            combinedDataList.sort(this::sortPeriodDataHolders);
+            outstandingLoanPrincipalBalance = fillLoanSchedulePeriodData(periods, combinedDataList, disbursementChargeAmount,
+                    waivedChargeAmount, outstandingLoanPrincipalBalance);
+
+            BigDecimal disbursedAmount = calculateDisbursedAmount(combinedDataList);
+
+            // Add the Charge back or Credits to the initial amount to avoid negative balance
+            final BigDecimal principalCredits = installment.getCreditedPrincipal() != null ? installment.getCreditedPrincipal()
+                    : BigDecimal.ZERO;
+            final BigDecimal feeCredits = installment.getCreditedFee() != null ? installment.getCreditedFee() : BigDecimal.ZERO;
+            final BigDecimal penaltyCredits = installment.getCreditedPenalty() != null ? installment.getCreditedPenalty() : BigDecimal.ZERO;
+            final BigDecimal credits = principalCredits.add(feeCredits).add(penaltyCredits);
+            outstandingLoanPrincipalBalance = outstandingLoanPrincipalBalance.add(principalCredits);
+
+            totalPrincipalDisbursed = totalPrincipalDisbursed.add(disbursedAmount);
+
+            Integer daysInPeriod = 0;
+            if (fromDate != null) {
+                daysInPeriod = DateUtils.getExactDifferenceInDays(fromDate, dueDate);
+                loanTermInDays = loanTermInDays + daysInPeriod;
+            }
+
+            final BigDecimal principalDue = installment.getPrincipal() != null ? installment.getPrincipal() : BigDecimal.ZERO;
+            totalPrincipalExpected = totalPrincipalExpected.plus(principalDue);
+            final BigDecimal principalPaid = installment.getPrincipalCompleted() != null ? installment.getPrincipalCompleted()
+                    : BigDecimal.ZERO;
+            totalPrincipalPaid = totalPrincipalPaid.plus(principalPaid);
+            final BigDecimal principalWrittenOff = installment.getPrincipalWrittenOff() != null ? installment.getPrincipalWrittenOff()
+                    : BigDecimal.ZERO;
+
+            final BigDecimal principalOutstanding = principalDue.subtract(principalPaid).subtract(principalWrittenOff);
+
+            final BigDecimal interestExpectedDue = installment.getInterestCharged() != null ? installment.getInterestCharged()
+                    : BigDecimal.ZERO;
+            totalInterestCharged = totalInterestCharged.plus(interestExpectedDue);
+            final BigDecimal interestPaid = installment.getInterestPaid() != null ? installment.getInterestPaid() : BigDecimal.ZERO;
+            final BigDecimal interestWaived = installment.getInterestWaived() != null ? installment.getInterestWaived() : BigDecimal.ZERO;
+            final BigDecimal interestWrittenOff = installment.getInterestWrittenOff() != null ? installment.getInterestWrittenOff()
+                    : BigDecimal.ZERO;
+            final BigDecimal accrualInterest = installment.getInterestAccrued() != null ? installment.getInterestAccrued()
+                    : BigDecimal.ZERO;
+
+            final BigDecimal interestActualDue = interestExpectedDue.subtract(interestWaived).subtract(interestWrittenOff);
+            final BigDecimal interestOutstanding = interestActualDue.subtract(interestPaid);
+
+            final BigDecimal feeChargesExpectedDue = installment.getFeeChargesCharged() != null ? installment.getFeeChargesCharged()
+                    : BigDecimal.ZERO;
+            totalFeeChargesCharged = totalFeeChargesCharged.plus(feeChargesExpectedDue);
+            final BigDecimal feeChargesPaid = installment.getFeeChargesPaid() != null ? installment.getFeeChargesPaid() : BigDecimal.ZERO;
+            final BigDecimal feeChargesWaived = installment.getFeeChargesWaived() != null ? installment.getFeeChargesWaived()
+                    : BigDecimal.ZERO;
+            final BigDecimal feeChargesWrittenOff = installment.getFeeChargesWrittenOff() != null ? installment.getFeeChargesWrittenOff()
+                    : BigDecimal.ZERO;
+
+            final BigDecimal feeChargesActualDue = feeChargesExpectedDue.subtract(feeChargesWaived).subtract(feeChargesWrittenOff);
+            final BigDecimal feeChargesOutstanding = feeChargesActualDue.subtract(feeChargesPaid);
+
+            final BigDecimal penaltyChargesExpectedDue = installment.getPenaltyCharges() != null ? installment.getPenaltyCharges()
+                    : BigDecimal.ZERO;
+            totalPenaltyChargesCharged = totalPenaltyChargesCharged.plus(penaltyChargesExpectedDue);
+            final BigDecimal penaltyChargesPaid = installment.getPenaltyChargesPaid() != null ? installment.getPenaltyChargesPaid()
+                    : BigDecimal.ZERO;
+            final BigDecimal penaltyChargesWaived = installment.getPenaltyChargesWaived() != null ? installment.getPenaltyChargesWaived()
+                    : BigDecimal.ZERO;
+            final BigDecimal penaltyChargesWrittenOff = installment.getPenaltyChargesWrittenOff() != null
+                    ? installment.getPenaltyChargesWrittenOff()
+                    : BigDecimal.ZERO;
+
+            final BigDecimal totalPaidInAdvanceForPeriod = installment.getTotalPaidInAdvance() != null ? installment.getTotalPaidInAdvance()
+                    : BigDecimal.ZERO;
+            final BigDecimal totalPaidLateForPeriod = installment.getTotalPaidLate() != null ? installment.getTotalPaidLate()
+                    : BigDecimal.ZERO;
+
+            final BigDecimal penaltyChargesActualDue = penaltyChargesExpectedDue.subtract(penaltyChargesWaived)
+                    .subtract(penaltyChargesWrittenOff);
+            final BigDecimal penaltyChargesOutstanding = penaltyChargesActualDue.subtract(penaltyChargesPaid);
+
+            final BigDecimal totalExpectedCostOfLoanForPeriod = interestExpectedDue.add(feeChargesExpectedDue)
+                    .add(penaltyChargesExpectedDue);
+
+            final BigDecimal totalDueForPeriod = principalDue.add(totalExpectedCostOfLoanForPeriod);
+            final BigDecimal totalPaidForPeriod = principalPaid.add(interestPaid).add(feeChargesPaid).add(penaltyChargesPaid);
+            final BigDecimal totalWaivedForPeriod = interestWaived.add(feeChargesWaived).add(penaltyChargesWaived);
+            totalWaived = totalWaived.plus(totalWaivedForPeriod);
+            final BigDecimal totalWrittenOffForPeriod = principalWrittenOff.add(interestWrittenOff).add(feeChargesWrittenOff)
+                    .add(penaltyChargesWrittenOff);
+            totalWrittenOff = totalWrittenOff.plus(totalWrittenOffForPeriod);
+
+            final BigDecimal totalOutstandingForPeriod = principalOutstanding.add(interestOutstanding).add(feeChargesOutstanding)
+                    .add(penaltyChargesOutstanding);
+
+            totalRepaymentExpected = totalRepaymentExpected.plus(totalDueForPeriod);
+            totalRepayment = totalRepayment.plus(totalPaidForPeriod);
+            totalPaidInAdvance = totalPaidInAdvance.plus(totalPaidInAdvanceForPeriod);
+            totalPaidLate = totalPaidLate.plus(totalPaidLateForPeriod);
+            totalOutstanding = totalOutstanding.plus(totalOutstandingForPeriod);
+            totalCredits = totalCredits.add(credits);
+
+            if (fromDate == null) {
+                fromDate = lastDueDate;
+            }
+
+            BigDecimal outstandingPrincipalBalanceOfLoan = outstandingLoanPrincipalBalance.subtract(principalDue);
+
+            // update based on current period values
+            lastDueDate = dueDate;
+            outstandingLoanPrincipalBalance = outstandingLoanPrincipalBalance.subtract(principalDue);
+
+            final boolean isDownPayment = installment.isDownPayment();
+
+            LoanSchedulePeriodData periodData;
+
+            periodData = LoanSchedulePeriodData.periodWithPayments(period, fromDate, dueDate, obligationsMetOnDate, complete, principalDue,
+                    principalPaid, principalWrittenOff, principalOutstanding, outstandingPrincipalBalanceOfLoan, interestExpectedDue,
+                    interestPaid, interestWaived, interestWrittenOff, interestOutstanding, feeChargesExpectedDue, feeChargesPaid,
+                    feeChargesWaived, feeChargesWrittenOff, feeChargesOutstanding, penaltyChargesExpectedDue, penaltyChargesPaid,
+                    penaltyChargesWaived, penaltyChargesWrittenOff, penaltyChargesOutstanding, totalPaidForPeriod,
+                    totalPaidInAdvanceForPeriod, totalPaidLateForPeriod, totalWaivedForPeriod, totalWrittenOffForPeriod, credits,
+                    isDownPayment, accrualInterest);
+
+            periods.add(periodData);
+        }
+
+        return new LoanScheduleData(currency, periods, loanTermInDays, totalPrincipalDisbursed, totalPrincipalExpected.getAmount(),
+                totalPrincipalPaid.getAmount(), totalInterestCharged.getAmount(), totalFeeChargesCharged.getAmount(),
+                totalPenaltyChargesCharged.getAmount(), totalWaived.getAmount(), totalWrittenOff.getAmount(),
+                totalRepaymentExpected.getAmount(), totalRepayment.getAmount(), totalPaidInAdvance.getAmount(), totalPaidLate.getAmount(),
+                totalOutstanding.getAmount(), totalCredits.getAmount());
+    }
+
+    private List<LoanSchedulePeriodDataWrapper> collectEligibleDisbursementData(LoanScheduleType loanScheduleType,
+            Collection<DisbursementData> disbursementData, LocalDate fromDate, LocalDate dueDate, Set<Long> disbursementPeriodIds,
+            DisbursementData mainDisbursement, boolean excludePastUnDisbursed) {
+        List<LoanSchedulePeriodDataWrapper> disbursementDataList = new ArrayList<>();
+
+        boolean hasMultipleTranchesOnSameDate = hasMultipleTranchesOnSameDate(disbursementData);
+
+        if (hasMultipleTranchesOnSameDate) {
+            Map<LocalDate, List<DisbursementData>> disbursementsByDate = new HashMap<>();
+
+            for (final DisbursementData data : disbursementData) {
+                boolean isDueForDisbursement = data.isDueForDisbursement(loanScheduleType, fromDate, dueDate);
+                boolean isEligible = ((fromDate.equals(mainDisbursement.disbursementDate()) && data.disbursementDate().equals(fromDate))
+                        || (fromDate.equals(dueDate) && data.disbursementDate().equals(fromDate))
+                        || canAddDisbursementData(data, isDueForDisbursement, excludePastUnDisbursed))
+                        && !disbursementPeriodIds.contains(data.getId());
+
+                if (isEligible) {
+                    disbursementsByDate.computeIfAbsent(data.disbursementDate(), k -> new ArrayList<>()).add(data);
+                    disbursementPeriodIds.add(data.getId());
+                }
+            }
+
+            for (Map.Entry<LocalDate, List<DisbursementData>> entry : disbursementsByDate.entrySet()) {
+                List<DisbursementData> sameDateDisbursements = entry.getValue();
+
+                if (sameDateDisbursements.size() > 1) {
+                    List<DisbursementData> disbursedTranches = sameDateDisbursements.stream().filter(DisbursementData::isDisbursed)
+                            .collect(Collectors.toList());
+
+                    if (!disbursedTranches.isEmpty()) {
+                        for (DisbursementData data : disbursedTranches) {
+                            disbursementDataList.add(new LoanSchedulePeriodDataWrapper(data, data.disbursementDate(), true));
+                        }
+                    } else {
+                        for (DisbursementData data : sameDateDisbursements) {
+                            disbursementDataList.add(new LoanSchedulePeriodDataWrapper(data, data.disbursementDate(), true));
+                        }
+                    }
+                } else {
+                    DisbursementData data = sameDateDisbursements.get(0);
+                    disbursementDataList.add(new LoanSchedulePeriodDataWrapper(data, data.disbursementDate(), true));
+                }
+            }
+        } else {
+            for (final DisbursementData data : disbursementData) {
+                boolean isDueForDisbursement = data.isDueForDisbursement(loanScheduleType, fromDate, dueDate);
+                boolean isEligible = ((fromDate.equals(mainDisbursement.disbursementDate()) && data.disbursementDate().equals(fromDate))
+                        || (fromDate.equals(dueDate) && data.disbursementDate().equals(fromDate))
+                        || canAddDisbursementData(data, isDueForDisbursement, excludePastUnDisbursed))
+                        && !disbursementPeriodIds.contains(data.getId());
+
+                if (isEligible) {
+                    disbursementDataList.add(new LoanSchedulePeriodDataWrapper(data, data.disbursementDate(), true));
+                    disbursementPeriodIds.add(data.getId());
+                }
+            }
+        }
+
+        return disbursementDataList;
+    }
+
+    private boolean hasMultipleTranchesOnSameDate(Collection<DisbursementData> disbursementData) {
+        if (disbursementData == null || disbursementData.size() <= 1) {
+            return false;
+        }
+        return disbursementData.stream().collect(Collectors.groupingBy(DisbursementData::disbursementDate, Collectors.counting())).values()
+                .stream().anyMatch(count -> count > 1);
+    }
+
+    private List<LoanSchedulePeriodDataWrapper> collectEligibleCapitalizedIncomeData(
+            Collection<LoanTransactionRepaymentPeriodData> capitalizedIncomeData, LocalDate fromDate, LocalDate dueDate,
+            Set<Long> disbursementPeriodIds) {
+        List<LoanSchedulePeriodDataWrapper> capitalizedIncomeDataList = new ArrayList<>();
+        // Collect eligible capitalized income data
+        for (LoanTransactionRepaymentPeriodData data : capitalizedIncomeData) {
+            boolean isEligible = canAddCapitalizedIncomeData(data, fromDate, dueDate)
+                    && !disbursementPeriodIds.contains(data.getTransactionId());
+
+            if (isEligible) {
+                capitalizedIncomeDataList.add(new LoanSchedulePeriodDataWrapper(data, data.getDate(), false));
+                disbursementPeriodIds.add(data.getTransactionId());
+            }
+        }
+        return capitalizedIncomeDataList;
+    }
+
+    private BigDecimal fillLoanSchedulePeriodData(List<LoanSchedulePeriodData> periods,
+            List<LoanSchedulePeriodDataWrapper> combinedDataList, BigDecimal disbursementChargeAmount, BigDecimal waivedChargeAmount,
+            BigDecimal outstandingLoanPrincipalBalance) {
+        // Process all collected data in chronological order
+        for (LoanSchedulePeriodDataWrapper dataItem : combinedDataList) {
+            LoanSchedulePeriodData periodData;
+            if (dataItem.isDisbursement()) {
+                // Process disbursement data
+                DisbursementData data = (DisbursementData) dataItem.getData();
+                periodData = createLoanSchedulePeriodData(data, disbursementChargeAmount, waivedChargeAmount);
+            } else {
+                // Process capitalized income data
+                LoanTransactionRepaymentPeriodData data = (LoanTransactionRepaymentPeriodData) dataItem.getData();
+                periodData = createLoanSchedulePeriodData(data);
+            }
+
+            // Common processing for both data types
+            periods.add(periodData);
+            outstandingLoanPrincipalBalance = outstandingLoanPrincipalBalance.add(periodData.getPrincipalDisbursed());
+        }
+        return outstandingLoanPrincipalBalance;
+    }
+
+    private BigDecimal calculateDisbursedAmount(List<LoanSchedulePeriodDataWrapper> combinedDataList) {
+        BigDecimal disbursedAmount = BigDecimal.ZERO;
+        for (LoanSchedulePeriodDataWrapper dataItem : combinedDataList) {
+            if (dataItem.isDisbursement()) {
+                DisbursementData data = (DisbursementData) dataItem.getData();
+                disbursedAmount = disbursedAmount.add(data.getPrincipal());
+            }
+        }
+        return disbursedAmount;
+    }
+
+    private int sortPeriodDataHolders(LoanSchedulePeriodDataWrapper item1, LoanSchedulePeriodDataWrapper item2) {
+        int dateComparison = item1.getDate().compareTo(item2.getDate());
+        if (dateComparison == 0 && item1.isDisbursement() != item2.isDisbursement()) {
+            // If dates are equal, prioritize disbursement data
+            return item1.isDisbursement() ? -1 : 1;
+        }
+        return dateComparison;
+    }
+
+    private LoanSchedulePeriodData createLoanSchedulePeriodData(final DisbursementData data, BigDecimal disbursementChargeAmount,
+            BigDecimal waivedChargeAmount) {
+        BigDecimal chargeAmount = data.getChargeAmount() == null ? disbursementChargeAmount
+                : disbursementChargeAmount.add(data.getChargeAmount()).subtract(waivedChargeAmount);
+        return LoanSchedulePeriodData.disbursementOnlyPeriod(data.disbursementDate(), data.getPrincipal(), chargeAmount,
+                data.isDisbursed());
+    }
+
+    private LoanSchedulePeriodData createLoanSchedulePeriodData(final LoanTransactionRepaymentPeriodData data) {
+        BigDecimal feeCharges = Objects.isNull(data.getFeeChargesPortion()) ? BigDecimal.ZERO : data.getFeeChargesPortion();
+        return LoanSchedulePeriodData.disbursementOnlyPeriod(data.getDate(), data.getAmount(), feeCharges, !data.isReversed());
+    }
+
+    private boolean canAddDisbursementData(DisbursementData data, boolean isDueForDisbursement, boolean excludePastUnDisbursed) {
+        return (!excludePastUnDisbursed || data.isDisbursed() || !DateUtils.isBeforeBusinessDate(data.disbursementDate()))
+                && isDueForDisbursement;
+    }
+
+    private boolean canAddCapitalizedIncomeData(LoanTransactionRepaymentPeriodData data, LocalDate fromDate, LocalDate dueDate) {
+        return !data.isReversed() && DateUtils.isDateInRangeFromInclusiveToExclusive(fromDate, dueDate, data.getDate());
+    }
+
+}

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

@@ -90,6 +90,14 @@ public class ReprocessLoanTransactionsServiceImpl implements ReprocessLoanTransa
         handleChangedDetail(changedTransactionDetail);
     }
 
+    @Override
+    public void reprocessTransactionsWithoutChecks(final Loan loan, final LocalDate transactionDate,
+            final List<LoanTransaction> newTransactions) {
+        final List<LoanTransaction> transactions = loanTransactionRepository.findNonReversedTransactionsForReprocessingByLoan(loan);
+        transactions.addAll(newTransactions);
+        reprocessTransactionsAndFetchChangedTransactions(loan, transactions);
+    }
+
     @Override
     public void processPostDisbursementTransactions(final Loan loan) {
         loanTransactionProcessingService.processPostDisbursementTransactions(loan).ifPresent(this::handleChangedDetail);

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

@@ -22,10 +22,13 @@ import static java.math.BigDecimal.ZERO;
 
 import java.math.BigDecimal;
 import java.time.LocalDate;
+import java.util.Collection;
 import java.util.Comparator;
 import java.util.LinkedHashMap;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
+import java.util.stream.Collectors;
 import lombok.RequiredArgsConstructor;
 import org.apache.fineract.infrastructure.codes.domain.CodeValue;
 import org.apache.fineract.infrastructure.codes.domain.CodeValueRepository;
@@ -33,6 +36,7 @@ import org.apache.fineract.infrastructure.core.api.JsonCommand;
 import org.apache.fineract.infrastructure.core.data.CommandProcessingResult;
 import org.apache.fineract.infrastructure.core.data.CommandProcessingResultBuilder;
 import org.apache.fineract.infrastructure.core.domain.ExternalId;
+import org.apache.fineract.infrastructure.core.serialization.JsonParserHelper;
 import org.apache.fineract.infrastructure.core.service.DateUtils;
 import org.apache.fineract.infrastructure.core.service.ExternalIdFactory;
 import org.apache.fineract.infrastructure.event.business.domain.loan.reaging.LoanReAgeBusinessEvent;
@@ -40,14 +44,20 @@ import org.apache.fineract.infrastructure.event.business.domain.loan.reaging.Loa
 import org.apache.fineract.infrastructure.event.business.domain.loan.transaction.reaging.LoanReAgeTransactionBusinessEvent;
 import org.apache.fineract.infrastructure.event.business.domain.loan.transaction.reaging.LoanUndoReAgeTransactionBusinessEvent;
 import org.apache.fineract.infrastructure.event.business.service.BusinessEventNotifierService;
+import org.apache.fineract.organisation.monetary.data.CurrencyData;
 import org.apache.fineract.organisation.monetary.domain.Money;
 import org.apache.fineract.portfolio.common.domain.PeriodFrequencyType;
 import org.apache.fineract.portfolio.loanaccount.api.LoanApiConstants;
 import org.apache.fineract.portfolio.loanaccount.api.LoanReAgingApiConstants;
+import org.apache.fineract.portfolio.loanaccount.api.request.ReAgePreviewRequest;
+import org.apache.fineract.portfolio.loanaccount.data.DisbursementData;
+import org.apache.fineract.portfolio.loanaccount.data.RepaymentScheduleRelatedLoanData;
 import org.apache.fineract.portfolio.loanaccount.data.ScheduleGeneratorDTO;
 import org.apache.fineract.portfolio.loanaccount.domain.Loan;
+import org.apache.fineract.portfolio.loanaccount.domain.LoanRepaymentScheduleInstallment;
 import org.apache.fineract.portfolio.loanaccount.domain.LoanRepaymentScheduleTransactionProcessorFactory;
 import org.apache.fineract.portfolio.loanaccount.domain.LoanTransaction;
+import org.apache.fineract.portfolio.loanaccount.domain.LoanTransactionRepaymentPeriodData;
 import org.apache.fineract.portfolio.loanaccount.domain.LoanTransactionRepository;
 import org.apache.fineract.portfolio.loanaccount.domain.LoanTransactionType;
 import org.apache.fineract.portfolio.loanaccount.domain.reaging.LoanReAgeInterestHandlingType;
@@ -56,8 +66,12 @@ import org.apache.fineract.portfolio.loanaccount.domain.transactionprocessor.Loa
 import org.apache.fineract.portfolio.loanaccount.domain.transactionprocessor.MoneyHolder;
 import org.apache.fineract.portfolio.loanaccount.domain.transactionprocessor.TransactionCtx;
 import org.apache.fineract.portfolio.loanaccount.exception.LoanTransactionNotFoundException;
+import org.apache.fineract.portfolio.loanaccount.loanschedule.data.LoanScheduleData;
+import org.apache.fineract.portfolio.loanaccount.repository.LoanCapitalizedIncomeBalanceRepository;
 import org.apache.fineract.portfolio.loanaccount.serialization.LoanChargeValidator;
 import org.apache.fineract.portfolio.loanaccount.service.LoanAssembler;
+import org.apache.fineract.portfolio.loanaccount.service.LoanReadPlatformService;
+import org.apache.fineract.portfolio.loanaccount.service.LoanRepaymentScheduleService;
 import org.apache.fineract.portfolio.loanaccount.service.LoanScheduleService;
 import org.apache.fineract.portfolio.loanaccount.service.LoanUtilService;
 import org.apache.fineract.portfolio.loanaccount.service.ReprocessLoanTransactionsService;
@@ -69,7 +83,7 @@ import org.springframework.transaction.annotation.Transactional;
 @Service
 @RequiredArgsConstructor
 @Transactional
-public class LoanReAgingServiceImpl {
+public class LoanReAgingService {
 
     private final LoanAssembler loanAssembler;
     private final LoanReAgingValidator reAgingValidator;
@@ -83,40 +97,22 @@ public class LoanReAgingServiceImpl {
     private final LoanScheduleService loanScheduleService;
     private final ReprocessLoanTransactionsService reprocessLoanTransactionsService;
     private final CodeValueRepository codeValueRepository;
+    private final LoanRepaymentScheduleService loanRepaymentScheduleService;
+    private final LoanReadPlatformService loanReadPlatformService;
+    private final LoanCapitalizedIncomeBalanceRepository loanCapitalizedIncomeBalanceRepository;
 
-    public CommandProcessingResult reAge(Long loanId, JsonCommand command) {
-        Loan loan = loanAssembler.assembleFrom(loanId);
+    public CommandProcessingResult reAge(final Long loanId, final JsonCommand command) {
+        final Loan loan = loanAssembler.assembleFrom(loanId);
         reAgingValidator.validateReAge(loan, command);
 
-        Map<String, Object> changes = new LinkedHashMap<>();
+        final LoanTransaction reAgeTransaction = createReAgeTransaction(loan, command);
+        loanTransactionRepository.saveAndFlush(reAgeTransaction);
+        processReAgeTransaction(loan, reAgeTransaction, true);
+        loan.updateLoanScheduleDependentDerivedFields();
+
+        final Map<String, Object> changes = new LinkedHashMap<>();
         changes.put(LoanReAgingApiConstants.localeParameterName, command.locale());
         changes.put(LoanReAgingApiConstants.dateFormatParameterName, command.dateFormat());
-
-        LoanTransaction reAgeTransaction = createReAgeTransaction(loan, command);
-        LoanReAgeParameter reAgeParameter = createReAgeParameter(reAgeTransaction, command);
-        reAgeTransaction.setLoanReAgeParameter(reAgeParameter);
-        loanTransactionRepository.saveAndFlush(reAgeTransaction);
-        final LoanRepaymentScheduleTransactionProcessor loanRepaymentScheduleTransactionProcessor = loanRepaymentScheduleTransactionProcessorFactory
-                .determineProcessor(loan.transactionProcessingStrategy());
-        if (reAgeTransaction.getTransactionDate().isBefore(reAgeTransaction.getSubmittedOnDate())
-                && !loan.isInterestBearingAndInterestRecalculationEnabled()) {
-            reprocessLoanTransactionsService.reprocessTransactionsWithPostTransactionChecks(loan, reAgeTransaction.getTransactionDate());
-        } else if (loan.isInterestBearingAndInterestRecalculationEnabled()) {
-            if (loan.isProgressiveSchedule() && ((loan.hasChargeOffTransaction() && loan.hasAccelerateChargeOffStrategy())
-                    || loan.hasContractTerminationTransaction()
-                    || (loan.isInterestRecalculationEnabled() && loan.hasReAgingTransaction()))) {
-                final ScheduleGeneratorDTO scheduleGeneratorDTO = loanUtilService.buildScheduleGeneratorDTO(loan, null);
-                loanScheduleService.regenerateRepaymentSchedule(loan, scheduleGeneratorDTO);
-            }
-            final List<LoanTransaction> loanTransactions = loanTransactionRepository.findNonReversedTransactionsForReprocessingByLoan(loan);
-            loanTransactions.add(reAgeTransaction);
-            reprocessLoanTransactionsService.reprocessParticularTransactions(loan, loanTransactions);
-        } else {
-            loanRepaymentScheduleTransactionProcessor.processLatestTransaction(reAgeTransaction,
-                    new TransactionCtx(loan.getCurrency(), loan.getRepaymentScheduleInstallments(), loan.getActiveCharges(),
-                            new MoneyHolder(loan.getTotalOverpaidAsMoney()), null));
-        }
-        loan.updateLoanScheduleDependentDerivedFields();
         persistNote(loan, command, changes);
 
         // delinquency recalculation will be triggered by the event in a decoupled way via a listener
@@ -133,9 +129,38 @@ public class LoanReAgingServiceImpl {
                 .with(changes).build();
     }
 
+    @Transactional(readOnly = true)
+    public LoanScheduleData previewReAge(final Long loanId, final String loanExternalId, final ReAgePreviewRequest reAgePreviewRequest) {
+        final Loan loan = loanId != null ? loanAssembler.assembleFrom(loanId)
+                : loanAssembler.assembleFrom(ExternalIdFactory.produce(loanExternalId), false);
+        return previewReAge(loan, reAgePreviewRequest);
+    }
+
+    private LoanScheduleData previewReAge(final Loan loan, final ReAgePreviewRequest reAgePreviewRequest) {
+        reAgingValidator.validateReAge(loan, reAgePreviewRequest);
+
+        final LoanTransaction reAgeTransaction = createReAgeTransactionFromPreviewRequest(loan, reAgePreviewRequest);
+        processReAgeTransaction(loan, reAgeTransaction, false);
+        loan.updateLoanScheduleDependentDerivedFields();
+
+        final CurrencyData currencyData = new CurrencyData(loan.getCurrencyCode(), null, loan.getCurrency().getDigitsAfterDecimal(),
+                loan.getCurrency().getInMultiplesOf(), null, null);
+        final RepaymentScheduleRelatedLoanData repaymentScheduleRelatedLoanData = new RepaymentScheduleRelatedLoanData(
+                loan.getDisbursementDate(), loan.getDisbursementDate(), currencyData, loan.getPrincipal().getAmount(),
+                loan.getInArrearsTolerance().getAmount(), ZERO);
+        final Collection<DisbursementData> disbursementData = loanReadPlatformService.retrieveLoanDisbursementDetails(loan.getId());
+        final Collection<LoanTransactionRepaymentPeriodData> capitalizedIncomeData = loanCapitalizedIncomeBalanceRepository
+                .findRepaymentPeriodDataByLoanId(loan.getId());
+        final List<LoanRepaymentScheduleInstallment> sortedInstallments = loan.getRepaymentScheduleInstallments().stream()
+                .sorted(Comparator.comparingInt(LoanRepaymentScheduleInstallment::getInstallmentNumber)).collect(Collectors.toList());
+
+        return loanRepaymentScheduleService.extractLoanScheduleData(sortedInstallments, repaymentScheduleRelatedLoanData, disbursementData,
+                capitalizedIncomeData, loan.isInterestRecalculationEnabled(), loan.getLoanProductRelatedDetail().getLoanScheduleType());
+    }
+
     public CommandProcessingResult undoReAge(Long loanId, JsonCommand command) {
         Loan loan = loanAssembler.assembleFrom(loanId);
-        reAgingValidator.validateUndoReAge(loan, command);
+        reAgingValidator.validateUndoReAge(loan);
 
         Map<String, Object> changes = new LinkedHashMap<>();
         changes.put(LoanReAgingApiConstants.localeParameterName, command.locale());
@@ -170,6 +195,35 @@ public class LoanReAgingServiceImpl {
                 .with(changes).build();
     }
 
+    private void processReAgeTransaction(final Loan loan, final LoanTransaction reAgeTransaction, final boolean withPostTransactionChecks) {
+        final LoanRepaymentScheduleTransactionProcessor loanRepaymentScheduleTransactionProcessor = loanRepaymentScheduleTransactionProcessorFactory
+                .determineProcessor(loan.transactionProcessingStrategy());
+        if (reAgeTransaction.getTransactionDate().isBefore(reAgeTransaction.getSubmittedOnDate())
+                && !loan.isInterestBearingAndInterestRecalculationEnabled()) {
+            if (withPostTransactionChecks) {
+                reprocessLoanTransactionsService.reprocessTransactionsWithPostTransactionChecks(loan,
+                        reAgeTransaction.getTransactionDate());
+            } else {
+                reprocessLoanTransactionsService.reprocessTransactionsWithoutChecks(loan, reAgeTransaction.getTransactionDate(),
+                        List.of(reAgeTransaction));
+            }
+        } else if (loan.isInterestBearingAndInterestRecalculationEnabled()) {
+            if (loan.isProgressiveSchedule() && ((loan.hasChargeOffTransaction() && loan.hasAccelerateChargeOffStrategy())
+                    || loan.hasContractTerminationTransaction()
+                    || (loan.isInterestRecalculationEnabled() && loan.hasReAgingTransaction()))) {
+                final ScheduleGeneratorDTO scheduleGeneratorDTO = loanUtilService.buildScheduleGeneratorDTO(loan, null);
+                loanScheduleService.regenerateRepaymentSchedule(loan, scheduleGeneratorDTO);
+            }
+            final List<LoanTransaction> loanTransactions = loanTransactionRepository.findNonReversedTransactionsForReprocessingByLoan(loan);
+            loanTransactions.add(reAgeTransaction);
+            reprocessLoanTransactionsService.reprocessParticularTransactions(loan, loanTransactions);
+        } else {
+            loanRepaymentScheduleTransactionProcessor.processLatestTransaction(reAgeTransaction,
+                    new TransactionCtx(loan.getCurrency(), loan.getRepaymentScheduleInstallments(), loan.getActiveCharges(),
+                            new MoneyHolder(loan.getTotalOverpaidAsMoney()), null));
+        }
+    }
+
     private void reverseReAgeTransaction(LoanTransaction reAgeTransaction, JsonCommand command) {
         ExternalId reversalExternalId = externalIdFactory.createFromCommand(command, LoanReAgingApiConstants.externalIdParameterName);
         loanChargeValidator.validateRepaymentTypeTransactionNotBeforeAChargeRefund(reAgeTransaction.getLoan(), reAgeTransaction,
@@ -199,8 +253,13 @@ public class LoanReAgingServiceImpl {
         Money txPrincipal = loan.getTotalPrincipalOutstandingUntil(transactionDate);
         BigDecimal txPrincipalAmount = txPrincipal.getAmount();
 
-        return new LoanTransaction(loan, loan.getOffice(), LoanTransactionType.REAGE, transactionDate, txPrincipalAmount, txPrincipalAmount,
-                ZERO, ZERO, ZERO, null, false, null, txExternalId);
+        final LoanTransaction reAgeTransaction = new LoanTransaction(loan, loan.getOffice(), LoanTransactionType.REAGE, transactionDate,
+                txPrincipalAmount, txPrincipalAmount, ZERO, ZERO, ZERO, null, false, null, txExternalId);
+
+        final LoanReAgeParameter reAgeParameter = createReAgeParameter(reAgeTransaction, command);
+        reAgeTransaction.setLoanReAgeParameter(reAgeParameter);
+
+        return reAgeTransaction;
     }
 
     private LoanReAgeParameter createReAgeParameter(LoanTransaction reAgeTransaction, JsonCommand command) {
@@ -235,4 +294,43 @@ public class LoanReAgingServiceImpl {
             this.noteRepository.saveAndFlush(newNote);
         }
     }
+
+    private LoanTransaction createReAgeTransactionFromPreviewRequest(final Loan loan, final ReAgePreviewRequest reAgePreviewRequest) {
+        LocalDate transactionDate = DateUtils.getBusinessLocalDate();
+        final Locale locale = reAgePreviewRequest.getLocale() != null ? Locale.forLanguageTag(reAgePreviewRequest.getLocale())
+                : Locale.getDefault();
+        final LocalDate startDate = JsonParserHelper.convertFrom(reAgePreviewRequest.getStartDate(), LoanReAgingApiConstants.startDate,
+                reAgePreviewRequest.getDateFormat(), locale);
+        if (transactionDate.isAfter(startDate)) {
+            transactionDate = startDate;
+        }
+
+        final Money txPrincipal = loan.getTotalPrincipalOutstandingUntil(transactionDate);
+        final BigDecimal txPrincipalAmount = txPrincipal.getAmount();
+
+        final LoanTransaction reAgeTransaction = new LoanTransaction(loan, loan.getOffice(), LoanTransactionType.REAGE, transactionDate,
+                txPrincipalAmount, txPrincipalAmount, ZERO, ZERO, ZERO, null, false, null, null);
+
+        final LoanReAgeParameter reAgeParameter = createReAgeParameterFromPreviewRequest(reAgeTransaction, reAgePreviewRequest);
+        reAgeTransaction.setLoanReAgeParameter(reAgeParameter);
+
+        return reAgeTransaction;
+    }
+
+    private LoanReAgeParameter createReAgeParameterFromPreviewRequest(final LoanTransaction reAgeTransaction,
+            final ReAgePreviewRequest reAgePreviewRequest) {
+        final PeriodFrequencyType periodFrequencyType = PeriodFrequencyType.valueOf(reAgePreviewRequest.getFrequencyType());
+        final Locale locale = reAgePreviewRequest.getLocale() != null ? Locale.forLanguageTag(reAgePreviewRequest.getLocale())
+                : Locale.getDefault();
+        final LocalDate startDate = JsonParserHelper.convertFrom(reAgePreviewRequest.getStartDate(), LoanReAgingApiConstants.startDate,
+                reAgePreviewRequest.getDateFormat(), locale);
+        final Integer numberOfInstallments = reAgePreviewRequest.getNumberOfInstallments();
+        final Integer periodFrequencyNumber = reAgePreviewRequest.getFrequencyNumber();
+
+        final LoanReAgeInterestHandlingType reAgeInterestHandlingType = LoanReAgeInterestHandlingType.DEFAULT;
+
+        return new LoanReAgeParameter(reAgeTransaction, periodFrequencyType, periodFrequencyNumber, startDate, numberOfInstallments,
+                reAgeInterestHandlingType, null);
+    }
+
 }

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

@@ -24,6 +24,7 @@ import java.time.LocalDate;
 import java.util.ArrayList;
 import java.util.Comparator;
 import java.util.List;
+import java.util.Locale;
 import java.util.Optional;
 import lombok.RequiredArgsConstructor;
 import org.apache.fineract.infrastructure.codes.domain.CodeValue;
@@ -33,8 +34,10 @@ import org.apache.fineract.infrastructure.core.data.ApiParameterError;
 import org.apache.fineract.infrastructure.core.data.DataValidatorBuilder;
 import org.apache.fineract.infrastructure.core.exception.GeneralPlatformDomainRuleException;
 import org.apache.fineract.infrastructure.core.exception.PlatformApiDataValidationException;
+import org.apache.fineract.infrastructure.core.serialization.JsonParserHelper;
 import org.apache.fineract.portfolio.loanaccount.api.LoanApiConstants;
 import org.apache.fineract.portfolio.loanaccount.api.LoanReAgingApiConstants;
+import org.apache.fineract.portfolio.loanaccount.api.request.ReAgePreviewRequest;
 import org.apache.fineract.portfolio.loanaccount.domain.Loan;
 import org.apache.fineract.portfolio.loanaccount.domain.LoanTransaction;
 import org.apache.fineract.portfolio.loanaccount.domain.LoanTransactionRepository;
@@ -57,6 +60,12 @@ public class LoanReAgingValidator {
         validateReAgeOutstandingBalance(loan, command);
     }
 
+    public void validateReAge(final Loan loan, final ReAgePreviewRequest reAgePreviewRequest) {
+        validateReAgeRequest(loan, reAgePreviewRequest);
+        validateReAgeBusinessRules(loan);
+        validateReAgeOutstandingBalance(loan, reAgePreviewRequest);
+    }
+
     private void validateReAgeRequest(Loan loan, JsonCommand command) {
         List<ApiParameterError> dataValidationErrors = new ArrayList<>();
         DataValidatorBuilder baseDataValidator = new DataValidatorBuilder(dataValidationErrors).resource("loan.reAge");
@@ -145,7 +154,7 @@ public class LoanReAgingValidator {
         }
     }
 
-    public void validateUndoReAge(Loan loan, JsonCommand command) {
+    public void validateUndoReAge(Loan loan) {
         validateUndoReAgeBusinessRules(loan);
     }
 
@@ -181,4 +190,42 @@ public class LoanReAgingValidator {
         }
     }
 
+    private void validateReAgeRequest(final Loan loan, final ReAgePreviewRequest reAgePreviewRequest) {
+        final List<ApiParameterError> dataValidationErrors = new ArrayList<>();
+        final DataValidatorBuilder baseDataValidator = new DataValidatorBuilder(dataValidationErrors).resource("loan.reAge");
+
+        final Locale locale = reAgePreviewRequest.getLocale() != null ? Locale.forLanguageTag(reAgePreviewRequest.getLocale())
+                : Locale.getDefault();
+        final LocalDate startDate = JsonParserHelper.convertFrom(reAgePreviewRequest.getStartDate(), LoanReAgingApiConstants.startDate,
+                reAgePreviewRequest.getDateFormat(), locale);
+
+        if (loan.isProgressiveSchedule()) {
+            baseDataValidator.reset().parameter(LoanReAgingApiConstants.startDate).value(startDate)
+                    .validateDateAfterOrEqual(loan.getDisbursementDate());
+        } else {
+            baseDataValidator.reset().parameter(LoanReAgingApiConstants.startDate).value(startDate)
+                    .validateDateAfter(loan.getMaturityDate());
+        }
+
+        throwExceptionIfValidationErrorsExist(dataValidationErrors);
+    }
+
+    private void validateReAgeOutstandingBalance(final Loan loan, final ReAgePreviewRequest reAgePreviewRequest) {
+        final LocalDate businessDate = getBusinessLocalDate();
+        Locale locale = reAgePreviewRequest.getLocale() != null ? Locale.forLanguageTag(reAgePreviewRequest.getLocale())
+                : Locale.getDefault();
+        final LocalDate startDate = JsonParserHelper.convertFrom(reAgePreviewRequest.getStartDate(), LoanReAgingApiConstants.startDate,
+                reAgePreviewRequest.getDateFormat(), locale);
+
+        final boolean isBackdated = businessDate.isAfter(startDate);
+        if (isBackdated) {
+            return;
+        }
+
+        if (loan.getSummary().getTotalPrincipalOutstanding().compareTo(java.math.BigDecimal.ZERO) == 0) {
+            throw new GeneralPlatformDomainRuleException("error.msg.loan.reage.no.outstanding.balance.to.reage",
+                    "Loan cannot be re-aged as there are no outstanding balances to be re-aged", loan.getId());
+        }
+    }
+
 }

fineract-provider/src/main/java/org/apache/fineract/portfolio/loanaccount/starter/LoanAccountConfiguration.java

@@ -152,6 +152,7 @@ import org.apache.fineract.portfolio.loanaccount.service.LoanOfficerService;
 import org.apache.fineract.portfolio.loanaccount.service.LoanReadPlatformService;
 import org.apache.fineract.portfolio.loanaccount.service.LoanReadPlatformServiceImpl;
 import org.apache.fineract.portfolio.loanaccount.service.LoanRefundService;
+import org.apache.fineract.portfolio.loanaccount.service.LoanRepaymentScheduleService;
 import org.apache.fineract.portfolio.loanaccount.service.LoanScheduleService;
 import org.apache.fineract.portfolio.loanaccount.service.LoanStatusChangePlatformService;
 import org.apache.fineract.portfolio.loanaccount.service.LoanStatusChangePlatformServiceImpl;
@@ -350,7 +351,8 @@ public class LoanAccountConfiguration {
             LoanTransactionProcessingService loanTransactionProcessingService, LoanBalanceService loanBalanceService,
             LoanCapitalizedIncomeBalanceRepository loanCapitalizedIncomeBalanceRepository,
             LoanBuyDownFeeBalanceRepository loanBuyDownFeeBalanceRepository,
-            @Lazy InterestRefundServiceDelegate interestRefundServiceDelegate, LoanMaximumAmountCalculator loanMaximumAmountCalculator) {
+            @Lazy InterestRefundServiceDelegate interestRefundServiceDelegate, LoanMaximumAmountCalculator loanMaximumAmountCalculator,
+            LoanRepaymentScheduleService loanRepaymentScheduleService) {
         return new LoanReadPlatformServiceImpl(jdbcTemplate, context, loanRepositoryWrapper, applicationCurrencyRepository,
                 loanProductReadPlatformService, clientReadPlatformService, groupReadPlatformService, loanDropdownReadPlatformService,
                 fundReadPlatformService, chargeReadPlatformService, codeValueReadPlatformService, calendarReadPlatformService,
@@ -359,7 +361,7 @@ public class LoanAccountConfiguration {
                 delinquencyReadPlatformService, loanTransactionRepository, loanChargePaidByReadService, loanTransactionRelationReadService,
                 loanForeclosureValidator, loanTransactionMapper, loanTransactionProcessingService, loanBalanceService,
                 loanCapitalizedIncomeBalanceRepository, loanBuyDownFeeBalanceRepository, interestRefundServiceDelegate,
-                loanMaximumAmountCalculator);
+                loanMaximumAmountCalculator, loanRepaymentScheduleService);
     }
 
     @Bean

fineract-provider/src/test/java/org/apache/fineract/portfolio/loanaccount/api/ReAgePreviewRequestValidationTest.java

@@ -0,0 +1,361 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.fineract.portfolio.loanaccount.api;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import jakarta.validation.Validation;
+import jakarta.validation.Validator;
+import lombok.extern.slf4j.Slf4j;
+import org.apache.fineract.portfolio.loanaccount.api.request.ReAgePreviewRequest;
+import org.hibernate.validator.HibernateValidator;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.autoconfigure.context.MessageSourceAutoConfiguration;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Import;
+import org.springframework.test.context.ContextConfiguration;
+
+@Slf4j
+@SpringBootTest
+@ContextConfiguration(classes = { ReAgePreviewRequestValidationTest.TestConfig.class })
+class ReAgePreviewRequestValidationTest {
+
+    @Configuration
+    @Import({ MessageSourceAutoConfiguration.class })
+    static class TestConfig {
+
+        @Bean
+        public Validator validator() {
+            return Validation.byProvider(HibernateValidator.class).configure().buildValidatorFactory().getValidator();
+        }
+    }
+
+    @Autowired
+    private Validator validator;
+
+    @Test
+    void invalidAllBlank() {
+        var params = ReAgePreviewRequest.builder().build();
+
+        var errors = validator.validate(params);
+
+        assertThat(errors).hasSizeGreaterThanOrEqualTo(6);
+        assertThat(errors).anyMatch(e -> e.getPropertyPath().toString().equals("frequencyNumber"));
+        assertThat(errors).anyMatch(e -> e.getPropertyPath().toString().equals("frequencyType"));
+        assertThat(errors).anyMatch(e -> e.getPropertyPath().toString().equals("startDate"));
+        assertThat(errors).anyMatch(e -> e.getPropertyPath().toString().equals("numberOfInstallments"));
+        assertThat(errors).anyMatch(e -> e.getPropertyPath().toString().equals("dateFormat"));
+        assertThat(errors).anyMatch(e -> e.getPropertyPath().toString().equals("locale"));
+    }
+
+    @Test
+    void invalidFrequencyNumberNull() {
+        var params = validParams();
+        params.setFrequencyNumber(null);
+
+        var errors = validator.validate(params);
+
+        assertThat(errors).hasSize(1);
+        assertThat(errors).anyMatch(e -> e.getPropertyPath().toString().equals("frequencyNumber"));
+        assertThat(errors).anyMatch(e -> e.getMessage().equals("The parameter 'frequencyNumber' is mandatory."));
+    }
+
+    @Test
+    void invalidFrequencyNumberZero() {
+        var params = validParams();
+        params.setFrequencyNumber(0);
+
+        var errors = validator.validate(params);
+
+        assertThat(errors).hasSize(1);
+        assertThat(errors).anyMatch(e -> e.getPropertyPath().toString().equals("frequencyNumber"));
+        assertThat(errors).anyMatch(e -> e.getMessage().equals("The parameter 'frequencyNumber' must be at least 1."));
+    }
+
+    @Test
+    void invalidFrequencyNumberNegative() {
+        var params = validParams();
+        params.setFrequencyNumber(-1);
+
+        var errors = validator.validate(params);
+
+        assertThat(errors).hasSize(1);
+        assertThat(errors).anyMatch(e -> e.getPropertyPath().toString().equals("frequencyNumber"));
+        assertThat(errors).anyMatch(e -> e.getMessage().equals("The parameter 'frequencyNumber' must be at least 1."));
+    }
+
+    @Test
+    void invalidFrequencyTypeNull() {
+        var params = validParams();
+        params.setFrequencyType(null);
+
+        var errors = validator.validate(params);
+
+        assertThat(errors).hasSizeGreaterThanOrEqualTo(1);
+        assertThat(errors).anyMatch(e -> e.getPropertyPath().toString().equals("frequencyType"));
+        assertThat(errors).anyMatch(e -> e.getMessage().equals("The parameter 'frequencyType' is mandatory."));
+    }
+
+    @Test
+    void invalidFrequencyTypeEmpty() {
+        var params = validParams();
+        params.setFrequencyType("");
+
+        var errors = validator.validate(params);
+
+        assertThat(errors).hasSizeGreaterThanOrEqualTo(1);
+        assertThat(errors).anyMatch(e -> e.getPropertyPath().toString().equals("frequencyType"));
+        assertThat(errors).anyMatch(e -> e.getMessage().equals("The parameter 'frequencyType' is mandatory."));
+    }
+
+    @Test
+    void invalidFrequencyTypeBlank() {
+        var params = validParams();
+        params.setFrequencyType("  ");
+
+        var errors = validator.validate(params);
+
+        assertThat(errors).hasSizeGreaterThanOrEqualTo(1);
+        assertThat(errors).anyMatch(e -> e.getPropertyPath().toString().equals("frequencyType"));
+    }
+
+    @Test
+    void invalidFrequencyTypeInvalidEnum() {
+        var params = validParams();
+        params.setFrequencyType("NOT_A_VALID_ENUM");
+
+        var errors = validator.validate(params);
+
+        assertThat(errors).hasSize(1);
+        assertThat(errors).anyMatch(e -> e.getPropertyPath().toString().equals("frequencyType"));
+        assertThat(errors).anyMatch(e -> e.getMessage()
+                .equals("The parameter 'frequencyType' must be valid PeriodFrequencyType value. Provided value: 'NOT_A_VALID_ENUM'."));
+    }
+
+    @Test
+    void invalidStartDateNull() {
+        var params = validParams();
+        params.setStartDate(null);
+
+        var errors = validator.validate(params);
+
+        assertThat(errors).hasSizeGreaterThanOrEqualTo(1);
+        assertThat(errors).anyMatch(e -> e.getPropertyPath().toString().equals("startDate"));
+        assertThat(errors).anyMatch(e -> e.getMessage().equals("The parameter 'startDate' is mandatory."));
+    }
+
+    @Test
+    void invalidStartDateEmpty() {
+        var params = validParams();
+        params.setStartDate("");
+
+        var errors = validator.validate(params);
+
+        assertThat(errors).hasSizeGreaterThanOrEqualTo(1);
+        assertThat(errors).anyMatch(e -> e.getPropertyPath().toString().equals("startDate"));
+        assertThat(errors).anyMatch(e -> e.getMessage().equals("The parameter 'startDate' is mandatory."));
+    }
+
+    @Test
+    void invalidStartDateBlank() {
+        var params = validParams();
+        params.setStartDate("  ");
+
+        var errors = validator.validate(params);
+
+        assertThat(errors).hasSizeGreaterThanOrEqualTo(1);
+        assertThat(errors).anyMatch(e -> e.getPropertyPath().toString().equals("startDate"));
+    }
+
+    @Test
+    void invalidStartDateFormat() {
+        var params = validParams();
+        params.setStartDate("2025-05-12");
+
+        var errors = validator.validate(params);
+
+        assertThat(errors).hasSize(1);
+        assertThat(errors).anyMatch(e -> e.getMessage().equals("Wrong local date fields."));
+    }
+
+    @Test
+    void invalidNumberOfInstallmentsNull() {
+        var params = validParams();
+        params.setNumberOfInstallments(null);
+
+        var errors = validator.validate(params);
+
+        assertThat(errors).hasSize(1);
+        assertThat(errors).anyMatch(e -> e.getPropertyPath().toString().equals("numberOfInstallments"));
+        assertThat(errors).anyMatch(e -> e.getMessage().equals("The parameter 'numberOfInstallments' is mandatory."));
+    }
+
+    @Test
+    void invalidNumberOfInstallmentsZero() {
+        var params = validParams();
+        params.setNumberOfInstallments(0);
+
+        var errors = validator.validate(params);
+
+        assertThat(errors).hasSize(1);
+        assertThat(errors).anyMatch(e -> e.getPropertyPath().toString().equals("numberOfInstallments"));
+        assertThat(errors).anyMatch(e -> e.getMessage().equals("The parameter 'numberOfInstallments' must be at least 1."));
+    }
+
+    @Test
+    void invalidNumberOfInstallmentsNegative() {
+        var params = validParams();
+        params.setNumberOfInstallments(-1);
+
+        var errors = validator.validate(params);
+
+        assertThat(errors).hasSize(1);
+        assertThat(errors).anyMatch(e -> e.getPropertyPath().toString().equals("numberOfInstallments"));
+        assertThat(errors).anyMatch(e -> e.getMessage().equals("The parameter 'numberOfInstallments' must be at least 1."));
+    }
+
+    @Test
+    void invalidDateFormatNull() {
+        var params = validParams();
+        params.setDateFormat(null);
+
+        var errors = validator.validate(params);
+
+        assertThat(errors).hasSizeGreaterThanOrEqualTo(1);
+        assertThat(errors).anyMatch(e -> e.getPropertyPath().toString().equals("dateFormat"));
+        assertThat(errors).anyMatch(e -> e.getMessage().equals("The parameter 'dateFormat' is mandatory."));
+    }
+
+    @Test
+    void invalidDateFormatEmpty() {
+        var params = validParams();
+        params.setDateFormat("");
+
+        var errors = validator.validate(params);
+
+        assertThat(errors).hasSizeGreaterThanOrEqualTo(1);
+        assertThat(errors).anyMatch(e -> e.getPropertyPath().toString().equals("dateFormat"));
+    }
+
+    @Test
+    void invalidDateFormatMismatch() {
+        var params = validParams();
+        params.setDateFormat("yyyy-MM-dd");
+
+        var errors = validator.validate(params);
+
+        assertThat(errors).hasSize(1);
+        assertThat(errors).anyMatch(e -> e.getMessage().equals("Wrong local date fields."));
+    }
+
+    @Test
+    void invalidLocaleNull() {
+        var params = validParams();
+        params.setLocale(null);
+
+        var errors = validator.validate(params);
+
+        assertThat(errors).hasSizeGreaterThanOrEqualTo(1);
+        assertThat(errors).anyMatch(e -> e.getPropertyPath().toString().equals("locale"));
+        assertThat(errors).anyMatch(e -> e.getMessage().equals("The parameter 'locale' is mandatory."));
+    }
+
+    @Test
+    void invalidLocaleEmpty() {
+        var params = validParams();
+        params.setLocale("");
+
+        var errors = validator.validate(params);
+
+        assertThat(errors).hasSizeGreaterThanOrEqualTo(1);
+        assertThat(errors).anyMatch(e -> e.getPropertyPath().toString().equals("locale"));
+    }
+
+    @Test
+    void invalidLocaleInvalidFormat() {
+        var params = validParams();
+        params.setLocale("invalid-locale");
+
+        var errors = validator.validate(params);
+
+        assertThat(errors).hasSize(1);
+        assertThat(errors).anyMatch(e -> e.getPropertyPath().toString().equals("locale"));
+    }
+
+    @Test
+    void validAllParams() {
+        var params = validParams();
+
+        var errors = validator.validate(params);
+
+        assertThat(errors).isEmpty();
+    }
+
+    @Test
+    void validParamsWithDaysFrequency() {
+        var params = validParams();
+        params.setFrequencyType("DAYS");
+        params.setFrequencyNumber(30);
+
+        var errors = validator.validate(params);
+
+        assertThat(errors).isEmpty();
+    }
+
+    @Test
+    void validParamsWithWeeksFrequency() {
+        var params = validParams();
+        params.setFrequencyType("WEEKS");
+        params.setFrequencyNumber(4);
+
+        var errors = validator.validate(params);
+
+        assertThat(errors).isEmpty();
+    }
+
+    @Test
+    void validParamsWithYearsFrequency() {
+        var params = validParams();
+        params.setFrequencyType("YEARS");
+        params.setFrequencyNumber(1);
+
+        var errors = validator.validate(params);
+
+        assertThat(errors).isEmpty();
+    }
+
+    @Test
+    void validParamsWithAlternativeLocale() {
+        var params = validParams();
+        params.setLocale("en_US");
+
+        var errors = validator.validate(params);
+
+        assertThat(errors).isEmpty();
+    }
+
+    private ReAgePreviewRequest validParams() {
+        return ReAgePreviewRequest.builder().frequencyNumber(1).frequencyType("MONTHS").startDate("12-05-2025").numberOfInstallments(6)
+                .dateFormat("dd-MM-yyyy").locale("en").build();
+    }
+
+}

fineract-provider/src/test/java/org/apache/fineract/portfolio/loanaccount/service/reaging/LoanReAgingValidatorTest.java

@@ -113,7 +113,7 @@ class LoanReAgingValidatorTest {
         // then
         assertThat(result).isNotNull();
         assertThat(result.getGlobalisationMessageCode()).isEqualTo("validation.msg.validation.errors.exist");
-        assertThat(result.getErrors().get(0).getUserMessageGlobalisationCode())
+        assertThat(result.getErrors().getFirst().getUserMessageGlobalisationCode())
                 .isEqualTo("validation.msg.loan.reAge.externalId.exceeds.max.length");
     }
 
@@ -137,7 +137,7 @@ class LoanReAgingValidatorTest {
         // then
         assertThat(result).isNotNull();
         assertThat(result.getGlobalisationMessageCode()).isEqualTo("validation.msg.validation.errors.exist");
-        assertThat(result.getErrors().get(0).getUserMessageGlobalisationCode())
+        assertThat(result.getErrors().getFirst().getUserMessageGlobalisationCode())
                 .isEqualTo("validation.msg.loan.reAge.startDate.cannot.be.blank");
     }
 
@@ -161,7 +161,7 @@ class LoanReAgingValidatorTest {
         // then
         assertThat(result).isNotNull();
         assertThat(result.getGlobalisationMessageCode()).isEqualTo("validation.msg.validation.errors.exist");
-        assertThat(result.getErrors().get(0).getUserMessageGlobalisationCode())
+        assertThat(result.getErrors().getFirst().getUserMessageGlobalisationCode())
                 .isEqualTo("validation.msg.loan.reAge.frequencyType.cannot.be.blank");
     }
 
@@ -185,7 +185,7 @@ class LoanReAgingValidatorTest {
         // then
         assertThat(result).isNotNull();
         assertThat(result.getGlobalisationMessageCode()).isEqualTo("validation.msg.validation.errors.exist");
-        assertThat(result.getErrors().get(0).getUserMessageGlobalisationCode())
+        assertThat(result.getErrors().getFirst().getUserMessageGlobalisationCode())
                 .isEqualTo("validation.msg.loan.reAge.frequencyNumber.cannot.be.blank");
     }
 
@@ -210,7 +210,7 @@ class LoanReAgingValidatorTest {
         // then
         assertThat(result).isNotNull();
         assertThat(result.getGlobalisationMessageCode()).isEqualTo("validation.msg.validation.errors.exist");
-        assertThat(result.getErrors().get(0).getUserMessageGlobalisationCode())
+        assertThat(result.getErrors().getFirst().getUserMessageGlobalisationCode())
                 .isEqualTo("validation.msg.loan.reAge.frequencyNumber.not.greater.than.zero");
     }
 
@@ -234,7 +234,7 @@ class LoanReAgingValidatorTest {
         // then
         assertThat(result).isNotNull();
         assertThat(result.getGlobalisationMessageCode()).isEqualTo("validation.msg.validation.errors.exist");
-        assertThat(result.getErrors().get(0).getUserMessageGlobalisationCode())
+        assertThat(result.getErrors().getFirst().getUserMessageGlobalisationCode())
                 .isEqualTo("validation.msg.loan.reAge.numberOfInstallments.cannot.be.blank");
     }
 
@@ -259,7 +259,7 @@ class LoanReAgingValidatorTest {
         // then
         assertThat(result).isNotNull();
         assertThat(result.getGlobalisationMessageCode()).isEqualTo("validation.msg.validation.errors.exist");
-        assertThat(result.getErrors().get(0).getUserMessageGlobalisationCode())
+        assertThat(result.getErrors().getFirst().getUserMessageGlobalisationCode())
                 .isEqualTo("validation.msg.loan.reAge.numberOfInstallments.not.greater.than.zero");
     }
 
@@ -284,7 +284,7 @@ class LoanReAgingValidatorTest {
         // then
         assertThat(result).isNotNull();
         assertThat(result.getGlobalisationMessageCode()).isEqualTo("validation.msg.validation.errors.exist");
-        assertThat(result.getErrors().get(0).getUserMessageGlobalisationCode())
+        assertThat(result.getErrors().getFirst().getUserMessageGlobalisationCode())
                 .isEqualTo("validation.msg.loan.reAge.numberOfInstallments.not.greater.than.zero");
     }
 
@@ -301,7 +301,7 @@ class LoanReAgingValidatorTest {
         // then
         assertThat(result).isNotNull();
         assertThat(result.getGlobalisationMessageCode()).isEqualTo("validation.msg.validation.errors.exist");
-        assertThat(result.getErrors().get(0).getUserMessageGlobalisationCode())
+        assertThat(result.getErrors().getFirst().getUserMessageGlobalisationCode())
                 .isEqualTo("validation.msg.loan.reAge.startDate.is.less.than.date");
     }
 
@@ -371,10 +371,9 @@ class LoanReAgingValidatorTest {
         List<LoanTransaction> transactions = List.of(loanTransaction(LoanTransactionType.DISBURSEMENT, actualDate.minusDays(3)));
         Loan loan = loan();
         given(loan.getLoanTransactions()).willReturn(transactions);
-        JsonCommand command = jsonCommand();
         // when
         GeneralPlatformDomainRuleException result = assertThrows(GeneralPlatformDomainRuleException.class,
-                () -> underTest.validateUndoReAge(loan, command));
+                () -> underTest.validateUndoReAge(loan));
         // then
         assertThat(result).isNotNull();
         assertThat(result.getGlobalisationMessageCode()).isEqualTo("error.msg.loan.reage.reaging.transaction.missing");
@@ -390,9 +389,8 @@ class LoanReAgingValidatorTest {
                         OffsetDateTime.of(actualDate, LocalTime.of(9, 0), ZoneOffset.UTC)));
         Loan loan = loan();
         given(loan.getLoanTransactions()).willReturn(transactions);
-        JsonCommand command = jsonCommand();
         // when
-        underTest.validateUndoReAge(loan, command);
+        underTest.validateUndoReAge(loan);
         // then no exception thrown
     }