/*
 * Copyright (c) 2012, 2018, Werner Keil, Anatole Tresch and others.
 *
 * 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.
 *
 * Contributors: @manuela-grindei
 */
package org.javamoney.calc.securities;


import org.javamoney.calc.common.Rate;

import java.math.BigDecimal;
import java.util.List;

/**
 * The formula for the holding period return is used for calculating the return on an investment over multiple periods.
 *
 * @author Manuela Grindei
 * @see <a href="http://www.financeformulas.net/Holding_Period_Return.html">http://www.financeformulas.net/Holding_Period_Return.html</a>
 */
public class HoldingPeriodReturn {

    /**
     * Private constructor.
     */
    private HoldingPeriodReturn() {
    }

    /**
     * Calculates the holding period return.
     *
     * @param returns the list of returns per periods
     * @return the holding period return
     */
    public static BigDecimal calculate(List<Rate> returns) {
        BigDecimal product = BigDecimal.ONE;
        for (Rate rateOfReturn : returns) {
            if (rateOfReturn == null) {
                throw new IllegalArgumentException("The list of returns cannot contain null elements");
            }
            product = product.multiply(rateOfReturn.get().add(BigDecimal.ONE));
        }
        return product.subtract(BigDecimal.ONE);
    }

    /**
     * Calculates the holding period return.
     *
     * @param periodicRate    the return per period
     * @param numberOfPeriods the number of periods
     * @return the holding period return
     */
    public static BigDecimal calculateForSameReturn(Rate periodicRate, int numberOfPeriods) {
        if (periodicRate == null) {
            throw new IllegalArgumentException("The list of returns cannot contain null elements");
        }
        if (numberOfPeriods <= 0) {
            throw new IllegalArgumentException("The number of periods should be positive");
        }
        BigDecimal product = BigDecimal.ONE;
        final BigDecimal multiplicand = periodicRate.get().add(BigDecimal.ONE);
        for (int i = 0; i < numberOfPeriods; i++) {
            product = product.multiply(multiplicand);
        }

        return product.subtract(BigDecimal.ONE);
    }
}
