package org.apidesign.apifest08.test;

 import java.util.Currency;

 import junit.framework.TestCase;

 import org.apidesign.apifest08.currency.Convertor;

 import org.apidesign.apifest08.currency.exceptions.UnknownConvertorException;

 /** 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 {

     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

     	// set exchange rates

     	Convertor.setConvertorRates(Currency.getInstance("USD"), Currency.getInstance("CZK"), 15, 1);

     	Convertor.setConvertorRates(Currency.getInstance("USD"), Currency.getInstance("SKK"), 20, 1);

     	Convertor.setConvertorRates(Currency.getInstance("SKK"), Currency.getInstance("CZK"), 75, 100);

         // create new instance

         Convertor convertor = null;

         try {

           convertor = Convertor.getConvertorInstance(Currency.getInstance("USD"), Currency.getInstance("SKK"), Currency.getInstance("CZK"));

         } catch (UnknownConvertorException e) {

           e.printStackTrace();

         }

     	return convertor;

     }

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

      */

     public void testConvertorForUSDandCZKandSKK() throws Exception {

         Convertor c = createTripleConvertor();

         // convert $5 to CZK using c:

         double result = c.convert(5d, Currency.getInstance("USD"), Currency.getInstance("CZK"));

         assertEquals("Result is not 75 CZK", 75.0, result);

         // convert $5 to SKK using c:

         result = c.convert(5d, Currency.getInstance("USD"), Currency.getInstance("SKK"));

         assertEquals("Result is not 100 SKK", 100.0, result);

         // convert 200SKK to CZK using c:

         result = c.convert(200d, Currency.getInstance("SKK"), Currency.getInstance("CZK"));

         assertEquals("Result is not 150 CZK", 150.0, result);

         // convert 200SKK to USK using c:

         result = c.convert(200d, Currency.getInstance("SKK"), Currency.getInstance("USD"));

         assertEquals("Result is not 10 USD", 10.0, result);

     }

     /** 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 one.merge(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:

         double result = c.convert(5d, Currency.getInstance("USD"), Currency.getInstance("CZK"));

         assertEquals("Result is not 85 CZK", 85.0, result);

         // convert $8 to CZK using c:

         result = c.convert(8d, Currency.getInstance("USD"), Currency.getInstance("CZK"));

         assertEquals("Result is not 136 CZK", 136.0, result);

         // convert 1003CZK to USD using c:

         result = c.convert(1003d, Currency.getInstance("CZK"), Currency.getInstance("USD"));

         assertEquals("Result is not 59 USD", 59.0, result);

         // convert 16CZK using c:

         result = c.convert(16d, Currency.getInstance("CZK"), Currency.getInstance("SKK"));

         assertEquals("Result is not 20 SKK", 20.0, result);

         // convert 500SKK to CZK using c:

         result = c.convert(500d, Currency.getInstance("SKK"), Currency.getInstance("CZK"));

         assertEquals("Result is not 400 CZK", 400.0, result);

     }

 }