package org.apidesign.apifest08.test;

 import java.math.BigDecimal;

 import org.apidesign.apifest08.currency.ConvertorCurrency;

 import org.apidesign.apifest08.currency.ExchangeRate;

 import org.apidesign.apifest08.currency.IExchangeRateEngine;

 /** Exchange rate engine which is periodicaly changing echange rate.

  *  See <a href="http://wiki.apidesign.org/wiki/APIFest08:Task3">http://wiki.apidesign.org/wiki/APIFest08:Task3</a> for further description.

  *

  * @author arnostvalicek

  */

 public class BouncingExchangeRateEngine implements IExchangeRateEngine {

     ConvertorCurrency fromCurrency;

     BigDecimal fromValue;

     ConvertorCurrency toCurrency;

     BigDecimal toValueStart;

     BigDecimal toValueStop;

     BigDecimal step;

     BigDecimal toValue;

     private BouncingExchangeRateEngine(ConvertorCurrency fromCurrency, BigDecimal fromValue, ConvertorCurrency toCurrency, BigDecimal toValueStart, BigDecimal toValueStop, BigDecimal step) {

         this.fromCurrency = fromCurrency;

         this.fromValue = fromValue;

         this.toCurrency = toCurrency;

         this.toValueStart = toValueStart;

         this.toValueStop = toValueStop;

         this.step = step;

         this.toValue = toValueStart;

     }

     public static IExchangeRateEngine create(ConvertorCurrency fromCurrency, BigDecimal fromValue, ConvertorCurrency toCurrency, BigDecimal toValueStart, BigDecimal toValueStop, BigDecimal step) {

         return new BouncingExchangeRateEngine(fromCurrency, fromValue, toCurrency, toValueStart, toValueStop, step);

     }

     public ExchangeRate getExchangeRate(ConvertorCurrency fromCurrency, ConvertorCurrency toCurrency) {

         if (!fromCurrency.equals(this.fromCurrency)) {

             return null;

         }

         if (!toCurrency.equals(this.toCurrency)) {

             return null;

         }

         ExchangeRate result = new ExchangeRate(fromValue, toValue);

         toValue = toValue.add(step);

 //        if (step.signum()==1 && toValueStop.compareTo(toValue)==0) {

 //            System.out.println("A");

 //            toValue=toValueStop;

 //            step = step.negate();

 //            BigDecimal x = toValueStart;

 //            toValueStart=toValueStop;

 //            toValueStop=x;

 //        } else if (step.signum()==-1 && toValueStop.compareTo(toValue)==0) {

 //            System.out.println("B");

 //            toValue=toValueStop;

 //            step = step.negate();

 //            BigDecimal x = toValueStart;

 //            toValueStart=toValueStop;

 //            toValueStop=x;

 //        }

         if (toValueStop.compareTo(toValue)==0) {

             toValue=toValueStop;

             step = step.negate();

             BigDecimal x = toValueStart;

             toValueStart=toValueStop;

             toValueStop=x;

         }        

         return result;

     }

 }