package org.apidesign.apifest08.test;

 import java.util.Calendar;

 import java.util.Date;

 import java.util.GregorianCalendar;

 import java.util.TimeZone;

 import junit.framework.TestCase;

 import org.apidesign.apifest08.currency.Convertor;

 import org.apidesign.apifest08.currency.CurrencyValue;

 import org.apidesign.apifest08.currency.ExchangeRateValue;

 /** 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 {

     public Task4Test(String testName) {

         super(testName);

     }

     @Override

     protected void setUp() throws Exception {

     }

     @Override

     protected void tearDown() throws Exception {

     }

     // 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 <AmountType, IdentifierType> Convertor<AmountType, IdentifierType> limitTo(Convertor<AmountType, IdentifierType> old, Date from, Date till) {

         return old.limitConvertor(from, till);

     }

     public void testCompositionOfLimitedConvertors() throws Exception {

         Calendar cal = new GregorianCalendar(TimeZone.getTimeZone("GMT"));

         cal.clear();

         cal.set(2008, 9, 1, 0, 0);

         Date d1 = cal.getTime(); // 2008-10-01 0:00 GMT

         cal.set(2008, 9, 2, 0, 0);

         Date d2 = cal.getTime(); // 2008-10-02 0:00 GMT

         cal.set(2008, 9, 3, 0, 0);

         Date d3 = cal.getTime(); // 2008-10-03 0:00 GMT

         Convertor<Double, String> c = Task2Test.merge(

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

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

         );

         CurrencyValue<Double, String> result;

         // convert $5 to CZK using c:

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

         try {

             c.convert("CZK", CurrencyValue.getCurrencyValue(5d, "USD"));

             fail("Should not convert");

         } catch (Exception e) {

         }

         // convert $8 to CZK using c:

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

         try {

             c.convert("CZK", CurrencyValue.getCurrencyValue(8d, "USD"));

             fail("Should not convert");

         } catch (Exception e) {

         }

         // convert 1003CZK to USD using c:

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

         try {

             c.convert("USD", CurrencyValue.getCurrencyValue(1003d, "CZK"));

             fail("Should not convert");

         } catch (Exception e) {

         }

         // convert 16CZK using c:

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

         try {

             c.convert("SKK", CurrencyValue.getCurrencyValue(16d, "CZK"));

             fail("Should not convert");

         } catch (Exception e) {

         }

         // convert 500SKK to CZK using c:

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

         try {

             c.convert("CZK", CurrencyValue.getCurrencyValue(500d, "SKK"));

             fail("Should not convert");

         } catch (Exception e) {

         }

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

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

         cal.set(2008, 9, 1, 6, 0);

         result = c.convert("CZK", CurrencyValue.getCurrencyValue(5d, "USD"), cal.getTime());

         assertEquals(CurrencyValue.getCurrencyValue(85d, "CZK"), result);

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

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

         cal.set(2008, 9, 1, 6, 0);

         result = c.convert("CZK", CurrencyValue.getCurrencyValue(8d, "USD"), cal.getTime());

         assertEquals(CurrencyValue.getCurrencyValue(136d, "CZK"), result);

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

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

         cal.set(2008, 9, 1, 6, 0);

         result = c.convert("USD", CurrencyValue.getCurrencyValue(1003d, "CZK"), cal.getTime());

         assertEquals(CurrencyValue.getCurrencyValue(59d, "USD"), result);

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

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

         cal.set(2008, 9, 2, 9, 0);

         result = c.convert("SKK", CurrencyValue.getCurrencyValue(16d, "CZK"), cal.getTime());

         assertEquals(CurrencyValue.getCurrencyValue(20d, "SKK"), result);

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

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

         cal.set(2008, 9, 2, 9, 0);

         result = c.convert("CZK", CurrencyValue.getCurrencyValue(500d, "SKK"), cal.getTime());

         assertEquals(CurrencyValue.getCurrencyValue(400d, "CZK"), result);

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

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

         cal.set(2008, 9, 1, 6, 0);

         try {

             result = c.convert("CZK", CurrencyValue.getCurrencyValue(500d, "SKK"), cal.getTime());

             fail("Should not convert");

         } catch (Exception e) {

         }

     }

     /** 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<Double, String> createSKKtoCZK2() {

         return Convertor.getConvertorDoubleString(

                 ExchangeRateValue.getExchangeRate(

                     CurrencyValue.getCurrencyValue(100d, "SKK"),

                     CurrencyValue.getCurrencyValue(90d, "CZK")));

     }

     public void testDateConvetorWithTwoDifferentRates() throws Exception {

         Calendar cal = new GregorianCalendar(TimeZone.getTimeZone("GMT"));

         cal.clear();

         cal.set(2008, 9, 1, 0, 0);

         Date d1 = cal.getTime(); // 2008-10-01 0:00 GMT

         cal.set(2008, 9, 2, 0, 0);

         Date d2 = cal.getTime(); // 2008-10-02 0:00 GMT

         cal.set(2008, 9, 3, 0, 0);

         Date d3 = cal.getTime(); // 2008-10-03 0:00 GMT

         Convertor<Double, String> c = Task2Test.merge(

             limitTo(createSKKtoCZK2(), d1, d2),

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

         );

         CurrencyValue<Double, String> result;

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

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

         cal.set(2008, 9, 2, 9, 0);

         result = c.convert("CZK", CurrencyValue.getCurrencyValue(500d, "SKK"), cal.getTime());

         assertEquals(CurrencyValue.getCurrencyValue(400d, "CZK"), result);

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

         // assertEquals("Result is 450 CZK");

         cal.set(2008, 9, 1, 6, 0);

         result = c.convert("CZK", CurrencyValue.getCurrencyValue(500d, "SKK"), cal.getTime());

         assertEquals(CurrencyValue.getCurrencyValue(450d, "CZK"), result);

     }

 }