package org.apidesign.apifest08.currency;

 import java.math.BigDecimal;

 import java.util.Currency;

 import java.util.HashMap;

 import java.util.Map;

 /**

  * Default factory for convertors. Basically it just keeps exchange rates for given currency combinations.

  * @author lukas

  *

  */

 class DefaultConvertorFactory {

 	private static final Currency SKK = Currency.getInstance("SKK");

 	private static final Currency USD = Currency.getInstance("USD");

 	private static final Currency CZK = Currency.getInstance("CZK");

 	private Map<String, Convertor> convertorMap = new HashMap<String, Convertor>();

 	public 	DefaultConvertorFactory()

 	{

 		addConvertor(CZK,USD,BigDecimal.valueOf(17),BigDecimal.valueOf(1));

 		addConvertor(CZK,SKK,BigDecimal.valueOf(80),BigDecimal.valueOf(100));

 	}

 	private void addConvertor(Currency sourceCurrency, Currency destinationCurrency, BigDecimal sourceEquivalent, BigDecimal destinationEquivalent) {

 		DefaultConvertor convertor = new DefaultConvertor(sourceEquivalent, destinationEquivalent, sourceCurrency, destinationCurrency);

 		convertorMap.put(getConvertorKey(sourceCurrency, destinationCurrency), convertor);

 		convertorMap.put(getConvertorKey(destinationCurrency, sourceCurrency), convertor.revert());

 	}

 	public Convertor getConvertor(Currency sourceCurrency, Currency destinationCurrency) throws UnsupportedConversionException

 	{

 		String convertorKey = getConvertorKey(sourceCurrency, destinationCurrency);

 		Convertor result = convertorMap.get(convertorKey);

 		if (result!=null)

 		{

 			return result;

 		}

 		else

 		{

 			throw new UnsupportedConversionException("Conversion from "+sourceCurrency+" to "+destinationCurrency+" is not supported");

 		}

 	}

 	private String getConvertorKey(Currency sourceCurrency,	Currency destinationCurrency) {

 		return sourceCurrency.getCurrencyCode()+destinationCurrency.getCurrencyCode();

 	}

 }