FINERACT-1981: Provide more general EMI calculator interface

fineract-progressive-loan/src/main/java/org/apache/fineract/portfolio/loanaccount/loanschedule/domain/AbstractProgressiveLoanScheduleGenerator.java

@@ -119,13 +119,16 @@ public abstract class AbstractProgressiveLoanScheduleGenerator implements LoanSc
                         : scheduleParams.getPeriodStartDate();
                 List<PreGeneratedLoanSchedulePeriod> expectedRepaymentPeriods = getScheduledDateGenerator()
                         .generateRepaymentPeriods(startDate, loanApplicationTerms, holidayDetailDTO);
-                emiCalculationResult = getEMICalculator().calculateEMIValueAndRateFactors(loanApplicationTerms, scheduleParams,
-                        expectedRepaymentPeriods, mc);
+                emiCalculationResult = getEMICalculator().calculateEMIValueAndRateFactors(scheduleParams.getOutstandingBalanceAsPerRest(),
+                        loanApplicationTerms.toLoanProductRelatedDetail(), expectedRepaymentPeriods, scheduleParams.getPeriodNumber(),
+                        loanApplicationTerms.getNumberOfRepayments(), mc);
             }
 
             // 5 determine principal,interest of repayment period
-            PrincipalInterest principalInterestForThisPeriod = calculatePrincipalInterestComponentsForPeriod(loanApplicationTerms,
-                    scheduleParams, emiCalculationResult, mc);
+            PrincipalInterest principalInterestForThisPeriod = getEMICalculator().calculatePrincipalInterestComponentsForPeriod(
+                    emiCalculationResult, scheduleParams.getOutstandingBalanceAsPerRest(),
+                    loanApplicationTerms.getInstallmentAmountInMultiplesOf(), scheduleParams.getPeriodNumber(),
+                    loanApplicationTerms.getActualNoOfRepaymnets(), mc);
 
             // update cumulative fields for principal
             currentPeriodParams.setPrincipalForThisPeriod(principalInterestForThisPeriod.principal());
@@ -237,9 +240,6 @@ public abstract class AbstractProgressiveLoanScheduleGenerator implements LoanSc
 
     public abstract PaymentPeriodsInOneYearCalculator getPaymentPeriodsInOneYearCalculator();
 
-    public abstract PrincipalInterest calculatePrincipalInterestComponentsForPeriod(LoanApplicationTerms loanApplicationTerms,
-            LoanScheduleParams loanScheduleParams, EMICalculationResult emiCalculationResult, MathContext mc);
-
     protected abstract EMICalculator getEMICalculator();
 
     // Private, internal methods

fineract-progressive-loan/src/main/java/org/apache/fineract/portfolio/loanaccount/loanschedule/domain/ProgressiveLoanScheduleGenerator.java

@@ -18,12 +18,7 @@
  */
 package org.apache.fineract.portfolio.loanaccount.loanschedule.domain;
 
-import java.math.BigDecimal;
-import java.math.MathContext;
 import lombok.RequiredArgsConstructor;
-import org.apache.fineract.organisation.monetary.domain.Money;
-import org.apache.fineract.portfolio.loanaccount.loanschedule.data.LoanScheduleParams;
-import org.apache.fineract.portfolio.loanproduct.calc.EMICalculationResult;
 import org.apache.fineract.portfolio.loanproduct.calc.EMICalculator;
 import org.springframework.stereotype.Component;
 
@@ -49,31 +44,4 @@ public class ProgressiveLoanScheduleGenerator extends AbstractProgressiveLoanSch
     protected EMICalculator getEMICalculator() {
         return emiCalculator;
     }
-
-    @Override
-    public PrincipalInterest calculatePrincipalInterestComponentsForPeriod(final LoanApplicationTerms loanApplicationTerms,
-            final LoanScheduleParams loanScheduleParams, final EMICalculationResult emiCalculationResult, final MathContext mc) {
-
-        final Money equalMonthlyInstallmentValue = loanApplicationTerms.getInstallmentAmountInMultiplesOf() != null
-                ? Money.roundToMultiplesOf(emiCalculationResult.getEqualMonthlyInstallmentValue(),
-                        loanApplicationTerms.getInstallmentAmountInMultiplesOf())
-                : emiCalculationResult.getEqualMonthlyInstallmentValue();
-        final BigDecimal rateFactorMinus1 = emiCalculationResult.getNextRepaymentPeriodRateFactorMinus1();
-        final Money calculatedInterest = loanScheduleParams.getOutstandingBalanceAsPerRest().multipliedBy(rateFactorMinus1);
-        final Money calculatedPrincipal = equalMonthlyInstallmentValue.minus(calculatedInterest);
-
-        return new PrincipalInterest(
-                adjustCalculatedPrincipalWithRemainingBalanceInLastPeriod(calculatedPrincipal, loanApplicationTerms, loanScheduleParams),
-                calculatedInterest, Money.zero(loanApplicationTerms.getCurrency()));
-    }
-
-    private Money adjustCalculatedPrincipalWithRemainingBalanceInLastPeriod(final Money calculatedPrincipal,
-            final LoanApplicationTerms loanApplicationTerms, final LoanScheduleParams loanScheduleParams) {
-        final boolean isLastRepaymentPeriod = loanScheduleParams.getPeriodNumber() == loanApplicationTerms.getActualNoOfRepaymnets();
-        if (isLastRepaymentPeriod) {
-            final Money remainingAmount = loanScheduleParams.getOutstandingBalanceAsPerRest().minus(calculatedPrincipal);
-            return calculatedPrincipal.plus(remainingAmount);
-        }
-        return calculatedPrincipal;
-    }
 }

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

@@ -20,12 +20,18 @@ package org.apache.fineract.portfolio.loanproduct.calc;
 
 import java.math.MathContext;
 import java.util.List;
-import org.apache.fineract.portfolio.loanaccount.loanschedule.data.LoanScheduleParams;
-import org.apache.fineract.portfolio.loanaccount.loanschedule.domain.LoanApplicationTerms;
+import org.apache.fineract.organisation.monetary.domain.Money;
 import org.apache.fineract.portfolio.loanaccount.loanschedule.domain.LoanScheduleModelPeriod;
+import org.apache.fineract.portfolio.loanaccount.loanschedule.domain.PrincipalInterest;
+import org.apache.fineract.portfolio.loanproduct.domain.LoanProductRelatedDetail;
 
 public interface EMICalculator {
 
-    EMICalculationResult calculateEMIValueAndRateFactors(LoanApplicationTerms loanApplicationTerms, LoanScheduleParams scheduleParams,
-            List<? extends LoanScheduleModelPeriod> expectedRepaymentPeriods, MathContext mc);
+    EMICalculationResult calculateEMIValueAndRateFactors(Money outstandingBalanceAsPerRest,
+            LoanProductRelatedDetail loanProductRelatedDetail, List<? extends LoanScheduleModelPeriod> expectedRepaymentPeriods,
+            Integer actualPeriodNumber, Integer numberOfRepayments, MathContext mc);
+
+    PrincipalInterest calculatePrincipalInterestComponentsForPeriod(EMICalculationResult emiCalculationResult,
+            Money outstandingBalanceAsPerRest, Integer installmentAmountInMultiplesOf, Integer actualPeriodNumber,
+            Integer actualNoOfRepayments, MathContext mc);
 }

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

@@ -23,15 +23,15 @@ import java.math.MathContext;
 import java.time.LocalDate;
 import java.time.Year;
 import java.util.List;
+import java.util.Objects;
 import org.apache.fineract.infrastructure.core.service.DateUtils;
 import org.apache.fineract.infrastructure.core.service.MathUtil;
 import org.apache.fineract.organisation.monetary.domain.Money;
 import org.apache.fineract.portfolio.common.domain.DaysInMonthType;
 import org.apache.fineract.portfolio.common.domain.DaysInYearType;
 import org.apache.fineract.portfolio.common.domain.PeriodFrequencyType;
-import org.apache.fineract.portfolio.loanaccount.loanschedule.data.LoanScheduleParams;
-import org.apache.fineract.portfolio.loanaccount.loanschedule.domain.LoanApplicationTerms;
 import org.apache.fineract.portfolio.loanaccount.loanschedule.domain.LoanScheduleModelPeriod;
+import org.apache.fineract.portfolio.loanaccount.loanschedule.domain.PrincipalInterest;
 import org.apache.fineract.portfolio.loanproduct.domain.LoanProductRelatedDetail;
 import org.springframework.stereotype.Component;
 
@@ -43,29 +43,13 @@ public final class ProgressiveEMICalculator implements EMICalculator {
 
     /**
      * Calculate Equal Monthly Installment value and Rate Factor -1 values for calculate Interest
-     *
-     * @param loanApplicationTerms
-     *            LoanTermApplication
-     *
-     * @param scheduleParams
-     *            Loan Schedule Params
-     *
-     * @param expectedRepaymentPeriods
-     *            Expected Repayment Periods
-     *
-     * @param mc
-     *            MathContext for rounding
-     *
-     * @return EMICalculationResult Contains rate factor for each period and calculated EMI
      */
     @Override
-    public EMICalculationResult calculateEMIValueAndRateFactors(final LoanApplicationTerms loanApplicationTerms,
-            final LoanScheduleParams scheduleParams, final List<? extends LoanScheduleModelPeriod> expectedRepaymentPeriods,
-            final MathContext mc) {
-        final LoanProductRelatedDetail loanProductRelatedDetail = loanApplicationTerms.toLoanProductRelatedDetail();
+    public EMICalculationResult calculateEMIValueAndRateFactors(final Money outstandingBalanceAsPerRest,
+            final LoanProductRelatedDetail loanProductRelatedDetail, final List<? extends LoanScheduleModelPeriod> expectedRepaymentPeriods,
+            final Integer actualPeriodNumber, final Integer numberOfRepayments, final MathContext mc) {
         final BigDecimal nominalInterestRatePerPeriod = calcNominalInterestRatePerPeriod(
                 loanProductRelatedDetail.getNominalInterestRatePerPeriod(), mc);
-        final Money outstandingBalance = scheduleParams.getOutstandingBalanceAsPerRest();
         final DaysInYearType daysInYearType = DaysInYearType.fromInt(loanProductRelatedDetail.getDaysInYearType());
         final DaysInMonthType daysInMonthType = DaysInMonthType.fromInt(loanProductRelatedDetail.getDaysInMonthType());
         final PeriodFrequencyType repaymentFrequency = loanProductRelatedDetail.getRepaymentPeriodFrequencyType();
@@ -74,7 +58,7 @@ public final class ProgressiveEMICalculator implements EMICalculator {
         final List<BigDecimal> rateFactorList = getRateFactorList(expectedRepaymentPeriods, nominalInterestRatePerPeriod, daysInYearType,
                 daysInMonthType, repaymentFrequency, repaymentEvery, mc);
 
-        return calculateEMI(loanApplicationTerms, scheduleParams, rateFactorList, outstandingBalance, mc);
+        return calculateEMI(rateFactorList, actualPeriodNumber, numberOfRepayments, outstandingBalanceAsPerRest, mc);
     }
 
     /**
@@ -203,23 +187,18 @@ public final class ProgressiveEMICalculator implements EMICalculator {
 
     /**
      * Calculate EMI parts and return an EMI calculation result object with repayment installment rate factors
-     *
-     * @param rateFactorList
-     * @param outstandingBalanceForRest
-     * @param mc
-     * @return
      */
-    EMICalculationResult calculateEMI(final LoanApplicationTerms loanApplicationTerms, final LoanScheduleParams loanScheduleParams,
-            final List<BigDecimal> rateFactorList, final Money outstandingBalanceForRest, final MathContext mc) {
+    EMICalculationResult calculateEMI(final List<BigDecimal> rateFactorList, final Integer actualPeriodNumber,
+            final Integer numberOfRepayments, final Money outstandingBalanceForRest, final MathContext mc) {
         final BigDecimal rateFactorN = MathUtil.stripTrailingZeros(calculateRateFactorN(rateFactorList, mc));
         final BigDecimal fnResult = MathUtil.stripTrailingZeros(calculateFnResult(rateFactorList, mc));
 
-        final Money emiValue = Money.of(loanApplicationTerms.getCurrency(),
+        final Money emiValue = Money.of(outstandingBalanceForRest.getCurrency(),
                 calculateEMIValue(rateFactorN, outstandingBalanceForRest.getAmount(), fnResult, mc));
         final List<BigDecimal> rateFactorMinus1List = getRateFactorMinus1List(rateFactorList, mc);
 
-        final Money adjustedEqualMonthlyInstallmentValue = adjustEMIForMoreStreamlinedRepaymentSchedule(loanApplicationTerms,
-                loanScheduleParams, emiValue, rateFactorMinus1List, mc);
+        final Money adjustedEqualMonthlyInstallmentValue = adjustEMIForMoreStreamlinedRepaymentSchedule(actualPeriodNumber,
+                numberOfRepayments, outstandingBalanceForRest, emiValue, rateFactorMinus1List, mc);
 
         return new EMICalculationResult(adjustedEqualMonthlyInstallmentValue, rateFactorMinus1List);
     }
@@ -228,23 +207,16 @@ public final class ProgressiveEMICalculator implements EMICalculator {
      * Due to rounding or unequal installments, the first calculated EMI might not be the best one! Reiterate with
      * adjusted EMI to get a better streamlined repayment schedule (less difference between calculated EMI and last
      * installment EMI).
-     *
-     * @param loanApplicationTerms
-     * @param loanScheduleParams
-     * @param equalMonthlyInstallmentValue
-     * @param rateFactorMinus1List
-     * @param mc
-     * @return
      */
-    Money adjustEMIForMoreStreamlinedRepaymentSchedule(final LoanApplicationTerms loanApplicationTerms,
-            final LoanScheduleParams loanScheduleParams, final Money equalMonthlyInstallmentValue, List<BigDecimal> rateFactorMinus1List,
+    Money adjustEMIForMoreStreamlinedRepaymentSchedule(final Integer actualPeriodNumber, final Integer numberOfRepayments,
+            final Money outstandingBalanceAsPerRest, final Money equalMonthlyInstallmentValue, List<BigDecimal> rateFactorMinus1List,
             final MathContext mc) {
-        int numberOfUpcomingPeriods = loanApplicationTerms.getNumberOfRepayments() - loanScheduleParams.getPeriodNumber() + 1;
+        int numberOfUpcomingPeriods = numberOfRepayments - actualPeriodNumber + 1;
         if (numberOfUpcomingPeriods < 2) {
             return equalMonthlyInstallmentValue;
         }
 
-        RepaymentScheduleModel repaymentScheduleModel = generateRepaymentScheduleModel(loanApplicationTerms, loanScheduleParams,
+        RepaymentScheduleModel repaymentScheduleModel = generateRepaymentScheduleModel(numberOfRepayments, outstandingBalanceAsPerRest,
                 equalMonthlyInstallmentValue, rateFactorMinus1List);
         Money calculatedLastEMI = repaymentScheduleModel.getScheduleList().get(repaymentScheduleModel.getScheduleList().size() - 1).emi();
         Money originalDifference = calculatedLastEMI.minus(equalMonthlyInstallmentValue);
@@ -262,8 +234,8 @@ public final class ProgressiveEMICalculator implements EMICalculator {
             Money adjustment = originalDifference.dividedBy(numberOfUpcomingPeriods, mc.getRoundingMode());
 
             Money adjustedEqualMonthlyInstallmentValue = equalMonthlyInstallmentValue.plus(adjustment);
-            RepaymentScheduleModel repaymentScheduleModelWithAdjustedEMI = generateRepaymentScheduleModel(loanApplicationTerms,
-                    loanScheduleParams, adjustedEqualMonthlyInstallmentValue, rateFactorMinus1List);
+            RepaymentScheduleModel repaymentScheduleModelWithAdjustedEMI = generateRepaymentScheduleModel(numberOfRepayments,
+                    outstandingBalanceAsPerRest, adjustedEqualMonthlyInstallmentValue, rateFactorMinus1List);
             Money calculatedLastEMIAfterAdjustment = repaymentScheduleModelWithAdjustedEMI.getScheduleList()
                     .get(repaymentScheduleModelWithAdjustedEMI.getScheduleList().size() - 1).emi();
             Money differenceAfterEMIAdjustment = calculatedLastEMIAfterAdjustment.minus(adjustedEqualMonthlyInstallmentValue);
@@ -275,16 +247,15 @@ public final class ProgressiveEMICalculator implements EMICalculator {
         }
     }
 
-    RepaymentScheduleModel generateRepaymentScheduleModel(LoanApplicationTerms loanApplicationTerms, LoanScheduleParams loanScheduleParams,
+    RepaymentScheduleModel generateRepaymentScheduleModel(final Integer numberOfRepayments, final Money outstandingBalanceAsPerRest,
             Money equalMonthlyInstallmentValue, List<BigDecimal> rateFactorMinus1List) {
         RepaymentScheduleModel repaymentScheduleModel = new RepaymentScheduleModel();
-        Money balanceOfLoan = loanScheduleParams.getOutstandingBalanceAsPerRest();
-        for (int i = 0; i < loanApplicationTerms.getNumberOfRepayments(); i++) {
+        Money balanceOfLoan = outstandingBalanceAsPerRest;
+        for (int i = 0; i < numberOfRepayments; i++) {
             final Money calculatedInterest = balanceOfLoan.multipliedBy(rateFactorMinus1List.get(i));
             // WE need to calculate EMI differently for last installment (decided by number of repayments or when
             // schedule got shorter then planned)
-            if (balanceOfLoan.isLessThan(equalMonthlyInstallmentValue.minus(calculatedInterest))
-                    || i == loanApplicationTerms.getNumberOfRepayments() - 1) {
+            if (balanceOfLoan.isLessThan(equalMonthlyInstallmentValue.minus(calculatedInterest)) || i == numberOfRepayments - 1) {
                 equalMonthlyInstallmentValue = balanceOfLoan.plus(calculatedInterest);
             }
             final Money calculatedPrincipal = equalMonthlyInstallmentValue.minus(calculatedInterest);
@@ -302,9 +273,6 @@ public final class ProgressiveEMICalculator implements EMICalculator {
     /**
      * Rate factor -1 values
      *
-     * @param rateFactors
-     * @param mc
-     * @return
      */
     List<BigDecimal> getRateFactorMinus1List(final List<BigDecimal> rateFactors, final MathContext mc) {
         return rateFactors.stream().map(it -> it.subtract(BigDecimal.ONE, mc)).toList();
@@ -312,10 +280,6 @@ public final class ProgressiveEMICalculator implements EMICalculator {
 
     /**
      * Calculate Rate Factor Product from rate factors
-     *
-     * @param rateFactors
-     * @param mc
-     * @return
      */
     BigDecimal calculateRateFactorN(final List<BigDecimal> rateFactors, final MathContext mc) {
         return rateFactors.stream().reduce(BigDecimal.ONE, (BigDecimal acc, BigDecimal value) -> acc.multiply(value, mc));
@@ -323,10 +287,6 @@ public final class ProgressiveEMICalculator implements EMICalculator {
 
     /**
      * Summarize Fn values
-     *
-     * @param rateFactors
-     * @param mc
-     * @return
      */
     BigDecimal calculateFnResult(final List<BigDecimal> rateFactors, final MathContext mc) {
         return rateFactors.stream().skip(1).reduce(BigDecimal.ONE,
@@ -335,12 +295,6 @@ public final class ProgressiveEMICalculator implements EMICalculator {
 
     /**
      * Calculate the EMI (Equal Monthly Installment) value
-     *
-     * @param rateFactorN
-     * @param outstandingBalanceForRest
-     * @param fnResult
-     * @param mc
-     * @return
      */
     BigDecimal calculateEMIValue(final BigDecimal rateFactorN, final BigDecimal outstandingBalanceForRest, final BigDecimal fnResult,
             final MathContext mc) {
@@ -484,13 +438,6 @@ public final class ProgressiveEMICalculator implements EMICalculator {
     /**
      * Calculate Rate Factor based on Partial Period
      *
-     * @param interestRate
-     * @param repaymentEvery
-     * @param cumulatedPeriodRatio
-     * @param actualDaysInPeriod
-     * @param calculatedDaysInPeriod
-     * @param mc
-     * @return
      */
     BigDecimal rateFactorByRepaymentPartialPeriod(final BigDecimal interestRate, final BigDecimal repaymentEvery,
             final BigDecimal cumulatedPeriodRatio, final BigDecimal actualDaysInPeriod, final BigDecimal calculatedDaysInPeriod,
@@ -516,4 +463,31 @@ public final class ProgressiveEMICalculator implements EMICalculator {
     BigDecimal fnValue(final BigDecimal previousFnValue, final BigDecimal currentRateFactor, final MathContext mc) {
         return BigDecimal.ONE.add(previousFnValue.multiply(currentRateFactor, mc), mc);
     }
+
+    @Override
+    public PrincipalInterest calculatePrincipalInterestComponentsForPeriod(final EMICalculationResult emiCalculationResult,
+            final Money outstandingBalanceAsPerRest, final Integer installmentAmountInMultiplesOf, final Integer actualPeriodNumber,
+            final Integer actualNoOfRepayments, final MathContext mc) {
+
+        final Money equalMonthlyInstallmentValue = installmentAmountInMultiplesOf != null
+                ? Money.roundToMultiplesOf(emiCalculationResult.getEqualMonthlyInstallmentValue(), installmentAmountInMultiplesOf)
+                : emiCalculationResult.getEqualMonthlyInstallmentValue();
+        final BigDecimal rateFactorMinus1 = emiCalculationResult.getNextRepaymentPeriodRateFactorMinus1();
+        final Money calculatedInterest = outstandingBalanceAsPerRest.multipliedBy(rateFactorMinus1);
+        final Money calculatedPrincipal = equalMonthlyInstallmentValue.minus(calculatedInterest);
+        return new PrincipalInterest(
+                adjustCalculatedPrincipalWithRemainingBalanceInLastPeriod(calculatedPrincipal, outstandingBalanceAsPerRest,
+                        actualPeriodNumber, actualNoOfRepayments),
+                calculatedInterest, Money.zero(equalMonthlyInstallmentValue.getCurrency()));
+    }
+
+    Money adjustCalculatedPrincipalWithRemainingBalanceInLastPeriod(final Money calculatedPrincipal,
+            final Money outstandingBalanceAsPerRest, final Integer actualPeriodNumber, final Integer actualNoOfRepayments) {
+        final boolean isLastRepaymentPeriod = Objects.equals(actualPeriodNumber, actualNoOfRepayments);
+        if (isLastRepaymentPeriod) {
+            final Money remainingAmount = outstandingBalanceAsPerRest.minus(calculatedPrincipal);
+            return calculatedPrincipal.plus(remainingAmount);
+        }
+        return calculatedPrincipal;
+    }
 }