/*
* Copyright (c) 2005-2011 Grameen Foundation USA
* All rights reserved.
*
* Licensed 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.
*
* See also http://www.apache.org/licenses/LICENSE-2.0.html for an
* explanation of the license and how it is applied.
*/
package org.mifos.clientportfolio.newloan.domain;
import java.math.BigDecimal;
import org.mifos.accounts.productdefinition.util.helpers.GraceType;
import org.mifos.framework.util.helpers.Money;
public class DecliningBalanceWithEqualPrincipalInstallmentsLoanInterestCalculator implements LoanInterestCalculator {
@Override
public Money calculate(LoanInterestCalculationDetails loanInterestCalculationDetails) {
Money loanAmount = loanInterestCalculationDetails.getLoanAmount();
GraceType graceType = loanInterestCalculationDetails.getGraceType();
Integer gracePeriodDuration = loanInterestCalculationDetails.getGracePeriodDuration();
Integer numberOfInstallments = loanInterestCalculationDetails.getNumberOfInstallments();
Double interestFractionalRatePerInstallment = loanInterestCalculationDetails.getInterestFractionalRatePerInstallment();
return getDecliningEPIAmount_v2(graceType, gracePeriodDuration, numberOfInstallments, loanAmount, interestFractionalRatePerInstallment);
}
private Money getDecliningEPIAmount_v2(GraceType graceType, Integer gracePeriodDuration, Integer numberOfInstallments, Money loanAmount, Double interestFractionalRatePerInstallment) {
Money interest = new Money(loanAmount.getCurrency(), "0");
if (graceType.equals(GraceType.PRINCIPALONLYGRACE)) {
Money graceInterestPayments = getDecliningInterestAmountGrace_v2(loanAmount, gracePeriodDuration, interestFractionalRatePerInstallment);
Money nonGraceInterestPayments = getDecliningEPIAmountNonGrace_v2(numberOfInstallments - gracePeriodDuration, loanAmount, interestFractionalRatePerInstallment);
interest = graceInterestPayments.add(nonGraceInterestPayments);
} else {
interest = getDecliningEPIAmountNonGrace_v2(numberOfInstallments, loanAmount, interestFractionalRatePerInstallment);
}
return interest;
}
private Money getDecliningInterestAmountGrace_v2(Money loanAmount, Integer gracePeriodDuration, Double interestFractionalRatePerInstallment) {
return loanAmount.multiply(interestFractionalRatePerInstallment).multiply(gracePeriodDuration.doubleValue());
}
// the decliningEPI amount = sum of interests for all installments
private Money getDecliningEPIAmountNonGrace_v2(final int numNonGraceInstallments, Money loanAmount, Double interestFractionalRatePerInstallment) {
Money principalBalance = loanAmount;
Money principalPerPeriod = principalBalance.divide(new BigDecimal(numNonGraceInstallments));
Money totalInterest = new Money(loanAmount.getCurrency(), "0");
for (int i = 0; i < numNonGraceInstallments; i++) {
Money interestThisPeriod = principalBalance.multiply(interestFractionalRatePerInstallment);
totalInterest = totalInterest.add(interestThisPeriod);
principalBalance = principalBalance.subtract(principalPerPeriod);
}
return totalInterest;
}
}