package org.apidesign.apifest08.test;

 import java.math.BigDecimal;

 import java.text.SimpleDateFormat;

 import java.util.Date;

 import junit.framework.TestCase;

 import org.apidesign.apifest08.currency.ConversionNotSupportedException;

 import org.apidesign.apifest08.currency.Convertor;

 import org.apidesign.apifest08.currency.ConvertorCurrency;

 import org.apidesign.apifest08.currency.ExchangeRateProvider;

 /** The exchange rates are not always the same. They are changing. However

  * as in order to predict the future, one needs to understand own past. That is

  * why it is important to know the exchange rate as it was at any time during

  * the past.

  * <p>

  * Today's quest is to enhance the convertor API to deal with dates.

  * One shall be able to convert a currency at any date. Each currencies rate shall

  * be associated with a range between two Date objects. In order

  * to keep compatibility with old API that knew nothing about dates, the

  * rates associated then are applicable "for eternity". Any use of existing

  * convert methods that do not accept a Date argument, uses the current

  * System.currentTimeMillis() as default date.

  */

 public class Task4Test extends TestCase {

     private static ConvertorCurrency CZK = ConvertorCurrency.getInstance("CZK");

     private static ConvertorCurrency SKK = ConvertorCurrency.getInstance("SKK");

     private static ConvertorCurrency USD = ConvertorCurrency.getInstance("USD");

     private SimpleDateFormat df;

     public Task4Test(String testName) {

         super(testName);

     }

     @Override

     protected void setUp() throws Exception {

         super.setUp();

         df = new SimpleDateFormat("yyyy-MM-dd HH:mm zzzz");

     }

     @Override

     protected void tearDown() throws Exception {

         super.tearDown();

         df = null;

     }

     // Backward compatibly enhance your existing API to support following

     // usecases:

     //

     /** Takes a convertor with any rates associated and creates new convertor

      * that returns the same values as the old one for time between from to till.

      * Otherwise it returns no results. This is just a helper method that

      * shall call some real one in the API.

      * 

      * @param old existing convertor

      * @param from initial date (inclusive)

      * @param till final date (exclusive)

      * @return new convertor

      */

     public static Convertor limitTo(Convertor old, Date from, Date till) {

         Convertor c = Convertor.createConvertorAsMerge(new Convertor[]{old});

         c.limitAllowedDates(from, till);

         return c;

     }

     public void testCompositionOfLimitedConvertors() throws Exception {

         Date d1 = df.parse("2008-10-01 0:00 GMT");

         Date d2 = df.parse("2008-10-02 0:00 GMT");

         Date d3 = df.parse("2008-10-03 0:00 GMT");

         Convertor c = Task2Test.merge(

             limitTo(Task1Test.createCZKtoUSD(), d1, d2),

             limitTo(Task1Test.createSKKtoCZK(), d2, d3)

         );

         // convert $5 to CZK using c:

         // cannot convert as no rate is applicable to current date

         try {

           c.convert(USD, CZK, new BigDecimal(5));

           fail();        

         } catch (ConversionNotSupportedException e) {

             //exception expected

         }

         // convert $8 to CZK using c:

         // cannot convert as no rate is applicable to current date

         try {

           c.convert(USD, CZK, new BigDecimal(8));

           fail();        

         } catch (ConversionNotSupportedException e) {

             //exception expected

         }

         // convert 1003CZK to USD using c:

         // cannot convert as no rate is applicable to current date

         try {

           c.convert(CZK, USD, new BigDecimal(1003));

           fail();        

         } catch (ConversionNotSupportedException e) {

             //exception expected

         }

         // convert 16CZK using c:

         // cannot convert as no rate is applicable to current date

         // ???

         try {

           c.convert(CZK, USD, new BigDecimal(16));

           fail();        

         } catch (ConversionNotSupportedException e) {

             //exception expected

         }

         // convert 500SKK to CZK using c:

         // cannot convert as no rate is applicable to current date

         try {

           c.convert(SKK, CZK, new BigDecimal(500));

           fail();        

         } catch (ConversionNotSupportedException e) {

             //exception expected

         }

         // convert $5 to CZK using c at 2008-10-01 6:00 GMT:

         // assertEquals("Result is 85 CZK");

         assertEquals("Result is 85 CZK", new BigDecimal("85.00"), c.convertWithReversibleRates(USD, CZK , new BigDecimal("5"),df.parse("2008-10-01 6:00 GMT")).getConverted());        

         // convert $8 to CZK using c at 2008-10-01 6:00 GMT:

         // assertEquals("Result is 136 CZK");

         assertEquals("Result is 136 CZK", new BigDecimal("136.00"), c.convertWithReversibleRates(USD, CZK , new BigDecimal("8"),df.parse("2008-10-01 6:00 GMT")).getConverted());        

         // convert 1003CZK to USD using c at 2008-10-01 6:00 GMT:

         // assertEquals("Result is 59 USD");

         assertEquals("Result is 59 USD", new BigDecimal("59.00"), c.convertWithReversibleRates(CZK, USD , new BigDecimal("1003"),df.parse("2008-10-01 6:00 GMT")).getConverted());        

         // convert 16CZK using c at 2008-10-02 9:00 GMT:

         // assertEquals("Result is 20 SKK");

         assertEquals("Result is 20 SKK", new BigDecimal("20.00"), c.convertWithReversibleRates(CZK, SKK , new BigDecimal("16"),df.parse("2008-10-02 9:00 GMT")).getConverted());        

         // convert 500SKK to CZK using c at 2008-10-02 9:00 GMT:

         // assertEquals("Result is 400 CZK");

         assertEquals("Result is 400 SKK", new BigDecimal("400.00"), c.convertWithReversibleRates(SKK, CZK , new BigDecimal("500"),df.parse("2008-10-02 9:00 GMT")).getConverted());        

         // convert 500SKK to CZK using c at 2008-10-01 6:00 GMT:

         // cannot convert as no rate is applicable to current date

         try {

           c.convertWithReversibleRates(SKK, CZK , new BigDecimal("500"),df.parse("2008-10-01 6:00 GMT")).getConverted();        

           fail();        

         } catch (ConversionNotSupportedException e) {

             //exception expected

         }

     }

     /** Create convertor that understands two currencies, CZK and

      *  SKK. Make 100 SKK == 90 CZK.

      *

      * @return prepared convertor ready for converting SKK to CZK and CZK to SKK

      */

     public static Convertor createSKKtoCZK2() {

         ExchangeRateProvider exchangeRateProvider = ExchangeRateProvider.createExchangeRateProvider();

         exchangeRateProvider.addFixedCurencyRate(SKK, new BigDecimal("100.00"), CZK, new BigDecimal("90.00"));

         Convertor c  = Convertor.createConvertor(exchangeRateProvider);

         return c;

     }

     public void testDateConvetorWithTwoDifferentRates() throws Exception {

         Date d1 = df.parse("2008-10-01 0:00 GMT");

         Date d2 = df.parse("2008-10-02 0:00 GMT");

         Date d3 = df.parse("2008-10-03 0:00 GMT");

         Convertor c = Task2Test.merge(

             limitTo(createSKKtoCZK2(), d1, d2),

             limitTo(Task1Test.createSKKtoCZK(), d2, d3)

         );

         // convert 500SKK to CZK using c at 2008-10-02 9:00 GMT:

         assertEquals("Result is 400 CZK", new BigDecimal("400.00"), c.convertWithReversibleRates(SKK, CZK , new BigDecimal("500"),df.parse("2008-10-02 9:00 GMT")).getConverted());        

         // convert 500SKK to CZK using c at 2008-10-01 6:00 GMT:

         assertEquals("Result is 450 CZK", new BigDecimal("450.00"), c.convertWithReversibleRates(SKK, CZK , new BigDecimal("500"),df.parse("2008-10-01 9:00 GMT")).getConverted());        

     }

 }