package org.apidesign.apifest08.currency;

 import java.math.BigDecimal;

 import java.util.Date;

 import java.util.HashMap;

 import java.util.Map;

 /**

  * Exchange rate provider. Provides fixed exchange rate which does not depend

  * on date (method {@link #getExchangeRate()} ).

  * 

  * Date dependend exchange rate to be implemented.

  * 

  * @author arnostvalicek

  */

 public class ExchangeRateProvider {

     BigDecimal fromValue, toValue;

     ConvertorCurrency fromCurrency, toCurrency;

     Map exchangeRateMap = new HashMap();

     /**

      * Simple constructor for <code>ExchangeRateProviderM</code> which can provide fixed exchange rate.

      * 

      * Describes conversion <em>from ONE</em> to <em>to ONE</em> currency.

      * 

      * @param fromValue From value. BigDecimal value, precision should be set to currency precision.

      * @param fromCurrency From currency.

      * @param toValue To value. BigDecimal value, precision should be set to currency precision.

      * @param toCurrency To currency.

      * @deprecated deprecated since task2. Use {@link #createExchangeRateProvider() } instead of this constructor.

      */

     public ExchangeRateProvider(BigDecimal fromValue, ConvertorCurrency fromCurrency, BigDecimal toValue, ConvertorCurrency toCurrency) {

         this.fromValue = fromValue;

         this.toValue = toValue;

         this.fromCurrency = fromCurrency;

         this.toCurrency = toCurrency;

     }

     private ExchangeRateProvider() {

     }

     /**

      * Static method to create new exchange rate provider. This exchange rate provider does not contain

      * any exchange rates (this is difference to public constructor).

      * @return New <code>ExchangeRateProvider</code>

      */

     public static ExchangeRateProvider createExchangeRateProvider() {

         ExchangeRateProvider provider = new ExchangeRateProvider();

         return provider;

     }

     /**

      * Add new exchange rate to <code></code> to this exchange rate provider.

      * <p>

      * Example of specifiing conversion rate: 100 SKK == 80 CZK:<br>

      * <code>addFixedCurencyRate(ConvertorCurrency.getInstance("SKK"), new BigDecimal(100), ConvertorCurrency.getInstance("CZK"),  new BigDecimal(80));</code>

      * <p>

      * 

      * @param fromCurrency Source currency.

      * @param fromValue Valye for from currency.

      * @param toCurrency Target currency.

      * @param toValue Value for target currency.

      */

     public synchronized void addFixedCurencyRate(ConvertorCurrency fromCurrency, BigDecimal fromValue, ConvertorCurrency toCurrency, BigDecimal toValue) {

         if (fromValue==null) {

             throw new NullPointerException("fromValue can't be null");

         }

         if (toValue==null) {

             throw new NullPointerException("toValue can't be null");

         }

         Map map2 = (Map) exchangeRateMap.get(fromCurrency);

         if (map2==null) {

             map2 = new HashMap();

             exchangeRateMap.put(fromCurrency, map2);

         }

         ExchangeRate rate = new ExchangeRate(fromValue, toValue);

         map2.put(toCurrency, rate);

     }

     /**

      * Get fixed exange rate for currencies (from->to).

      * @return Returns exchange rate.

      * @deprecated deprecated since task2. Use {@link #getExchangeRate(ConvertorCurrency, ConvertorCurrency) }

      */

     public ExchangeRate getExchangeRate() {

         return new ExchangeRate(fromValue, toValue);

     }

     /**

      * Get fixed exange rate for currencies (from->to).

      * @return Returns exchange rate or <code>null</code> if exchange rate not found.

      */

     public ExchangeRate getExchangeRate(ConvertorCurrency fromCurrency, ConvertorCurrency toCurrency) {

         return getExchangeRateImpl(fromCurrency, toCurrency);

     }

     /**

      * Get fixed exange rate for currencies (from->to) or reversed exchange rate (to->from).

      * @return Returns exchange rate or <code>null</code> if exchange rate not found.

      */

     public ExchangeRate getReversibleExchangeRate(ConvertorCurrency fromCurrency, ConvertorCurrency toCurrency) {

        ExchangeRate rate = getExchangeRateImpl(fromCurrency, toCurrency);

        if (rate==null) {

            ExchangeRate revertedRate = getExchangeRateImpl(toCurrency, fromCurrency);

            if (revertedRate!=null) {

             rate = ExchangeRate.createRevertedRate(revertedRate);

            }

        }

        return rate;

     }

     /**

      * Get exchange rate for currencies (from->to) based on provided date.

      * @param date Date for which exchange rate should be provided.

      * @return Returns exchange rate 

      * @deprecated deprecated since task2. No real implementation in version2.

      */

     public ExchangeRate getExchangeRate(Date date) {

         return new ExchangeRate(fromValue, toValue);

     }

     ConvertorCurrency getFromCurrency() {

         return fromCurrency;

     }

     ConvertorCurrency getToCurrency() {

         return toCurrency;

     }

     private ExchangeRate getExchangeRateImpl(ConvertorCurrency fromCurrency, ConvertorCurrency toCurrency) {

         if (fromValue != null && toValue != null && fromCurrency.equals(this.fromCurrency) && toCurrency.equals(this.toCurrency)) {

             return new ExchangeRate(fromValue, toValue);

         }

         //return new ExchangeRate(fromValue, toValue);

         Map map2 = (Map) exchangeRateMap.get(fromCurrency);

         if (map2 == null) {

             return null;

         }

         ExchangeRate result = (ExchangeRate) map2.get(toCurrency);

         return result;

     }

 }