package org.apidesign.apifest08.currency;

 import java.util.Currency;

 import java.util.Hashtable;

 import java.util.Map;

 /** This is the skeleton class for your API. You need to make it public, so

  * it is accessible to your client code (currently in Task1Test.java) file.

  * <p>

  * Feel free to create additional classes or rename this one, just keep all

  * the API and its implementation in this package. Do not spread it outside

  * to other packages.

  */

 public class Convertor {

     private static final Map<String, Float> EXCHANGE_RATES = new Hashtable<String, Float>() { {

             put("CZKUSD", 1/17F);

             put("USDCZK", 17F);

             put("SKKCZK", 100/80F);

             put("CZKSKK", 80/100F);

         }

     };

     private Currency currencyFirst;

     private Currency currencySecond;

     private Convertor(Currency currencyFirst, Currency currencySecond) {

         this.currencyFirst = currencyFirst;

         this.currencySecond = currencySecond;

     }

     public static Convertor getInstanceFor(Currency currencyFirst, Currency currencySecond) {

         return new Convertor(currencyFirst, currencySecond);

     }

     public float convert(float value, Currency toCurrency) {

         if (!toCurrency.equals(currencyFirst) && !toCurrency.equals(currencySecond)) {

             throw new IllegalArgumentException("Unsupported currency for this convertor!: " + toCurrency.getCurrencyCode());

         }

         Float rate = null;

         if (toCurrency.equals(currencyFirst)) {

             rate = EXCHANGE_RATES.get(currencyFirst.getCurrencyCode() + currencySecond.getCurrencyCode());

         }

         if (toCurrency.equals(currencySecond)) {

             rate = EXCHANGE_RATES.get(currencySecond.getCurrencyCode() + currencyFirst.getCurrencyCode());

         }

         if (rate == null) {

             throw new IllegalStateException("Undefinied conversion!");

         }

         return rate*value;

     }

 }