package org.apidesign.apifest08.test;

 import java.math.BigDecimal;

 import java.util.Currency;

 import java.util.Set;

 import junit.framework.TestCase;

 import org.apidesign.apifest08.currency.Convertor;

 import org.apidesign.apifest08.currency.ConvertorFactory;

 import org.apidesign.apifest08.currency.InvalidConversionException;

 /** There are many currencies around the world and many banks manipulate

  * with more than one or two at the same time. As banks are usually the

  * best paying clients, which is true even in case of your Convertor API,

  * it is reasonable to listen to their requests.

  * <p>

  * The quest for today is to enhance your existing convertor API to hold

  * information about many currencies and allow conversions between any of them.

  * Also, as conversion rates for diferent currencies usually arise from various

  * bank departments, there is another important need. There is a need to

  * compose two convertors into one by merging all the information about

  * currencies they know about.

  */

 public class Task2Test extends TestCase

 {

     private final static Currency CZK;

     private final static Currency SKK;

     private final static Currency USD;

     static

     {

         CZK = Currency.getInstance("CZK");

         SKK = Currency.getInstance("SKK");

         USD = Currency.getInstance("USD");

     }

     public Task2Test(String testName)

     {

         super(testName);

     }

     @Override

     protected void setUp() 

         throws Exception

     {

     }

     @Override

     protected void tearDown() 

         throws Exception

     {

     }

     // As in Task1Test, keep in mind, that there are three parts

     // of the whole system:

     // 1. there is someone who knows the current exchange rate

     // 2. there is someone who wants to do the conversion

     // 3. there is the API between 1. and 2. which allows them to communicate

     // 

     // Please backward compatibly enhance your existing API to support following

     // usecases:

     //

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

      *  SKK. Make 100 SKK == 75 CZK. This is method for the group of users that

      *  knows the exchange rate, and needs to use the API to create objects

      *  with the exchange rate. Anyone shall be ready to call this method without

      *  any other method being called previously. The API itself shall know

      *  nothing about any rates, before this method is called.

      */

     public static Convertor createTripleConvertor() {

         // Rates: 1USD = 15CZK

         // Rates: 1USD = 20SKK

         // Rates: 75CZK = 100SKK

         Convertor c = ConvertorFactory.mergeConvertors(

             ConvertorFactory.getConvertor(USD, BigDecimal.ONE, CZK, BigDecimal.valueOf(15.00)),

             ConvertorFactory.getConvertor(USD, BigDecimal.ONE, SKK, BigDecimal.valueOf(20.00))

         );

         return c;

     }

     /** Define convertor that understands three currencies. Use it.

      */

     public void testConvertorForUSDandCZKandSKK() throws Exception {

         Convertor c = createTripleConvertor();

         // convert $5 to CZK using c:

         // assertEquals("Result is 75 CZK");

         assertEquals(new BigDecimal("75.00"), c.convert(USD, CZK, BigDecimal.valueOf(5.00)));

         // convert $5 to SKK using c:

         // assertEquals("Result is 100 SKK");

         assertEquals(new BigDecimal("100.00"), c.convert(USD, SKK, BigDecimal.valueOf(5.00)));

         // convert 200SKK to CZK using c:

         // assertEquals("Result is 150 CZK");

         assertEquals(new BigDecimal("150.00"), c.convert(SKK, CZK, BigDecimal.valueOf(200.00)));

         // convert 200SKK to USK using c:

         // assertEquals("Result is 10 USD");

         assertEquals(new BigDecimal("10.00"), c.convert(SKK, USD, BigDecimal.valueOf(200.00)));

     }

     /** Merge all currency rates of convertor 1 with convertor 2.

      * Implement this using your API, preferably this method just delegates

      * into some API method which does the actual work, without requiring

      * API clients to code anything complex.

      */

     public static Convertor merge(Convertor one, Convertor two) {

         return ConvertorFactory.mergeConvertors(one, two);

     }

     /** Join the convertors from previous task, Task1Test and show that it

      * can be used to do reasonable conversions.

      */

     public void testConvertorComposition() throws Exception {

         Convertor c = merge(

             Task1Test.createCZKtoUSD(),

             Task1Test.createSKKtoCZK()

         );

         // convert $5 to CZK using c:

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

         assertEquals(new BigDecimal("85.00"), c.convert(USD, CZK, BigDecimal.valueOf(5.00)));

         // convert $8 to CZK using c:

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

         assertEquals(new BigDecimal("136.00"), c.convert(USD, CZK, BigDecimal.valueOf(8.00)));

         // convert 1003CZK to USD using c:

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

         assertEquals(new BigDecimal("59.00"), c.convert(CZK, USD, BigDecimal.valueOf(1003.00)));

         // convert 16CZK using c:

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

         assertEquals(new BigDecimal("20.00"), c.convert(CZK, SKK, BigDecimal.valueOf(16.00)));

         // convert 500SKK to CZK using c:

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

         assertEquals(new BigDecimal("400.00"), c.convert(SKK, CZK, BigDecimal.valueOf(500.00)));

     }

     public void testGetCurrencies()

     {

         Convertor c = merge(

             Task1Test.createCZKtoUSD(),

             Task1Test.createSKKtoCZK()

         );

         Set<Currency> currencies;

         currencies = c.getCurrencies();        

         assertEquals(3, currencies.size());

         assertTrue(currencies.contains(Currency.getInstance("SKK")));

         assertTrue(currencies.contains(Currency.getInstance("CZK")));

         assertTrue(currencies.contains(Currency.getInstance("USD")));

     }

     public void testGetConverstionRate()

         throws InvalidConversionException

     {

         Convertor c = merge(

             Task1Test.createCZKtoUSD(),

             Task1Test.createSKKtoCZK()

         );

         assertEquals(1.0,        c.getConversionRate(USD, USD).doubleValue(), 0.0000000000000001);

         assertEquals(17.0,       c.getConversionRate(USD, CZK).doubleValue(), 0.0000000000000001);

         assertEquals(21.25,      c.getConversionRate(USD, SKK).doubleValue(), 0.0000000000000001);

         assertEquals(1.0 / 17.0, c.getConversionRate(CZK, USD).doubleValue(), 0.0000000000000001);

         assertEquals(1.0,        c.getConversionRate(CZK, CZK).doubleValue(), 0.0000000000000001);

         assertEquals(1.25,       c.getConversionRate(CZK, SKK).doubleValue(), 0.0000000000000001);

         assertEquals(0.04705882352941176, c.getConversionRate(SKK, USD).doubleValue(), 0.0000000000000001);

         assertEquals(0.8,                 c.getConversionRate(SKK, CZK).doubleValue(), 0.0000000000000001);

         assertEquals(1.0,                 c.getConversionRate(SKK, SKK).doubleValue(), 0.0000000000000001);

     }

 }