package org.apidesign.apifest08.test;

 import java.math.BigDecimal;

 import junit.framework.TestCase;

 import org.apidesign.apifest08.currency.Convertor;

 import org.apidesign.apifest08.currency.ConvertorCurrency;

 import org.apidesign.apifest08.currency.ExchangeRateProvider;

 /** 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 static ConvertorCurrency currencyCZK = ConvertorCurrency.getInstance("CZK");

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

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

     public Task2Test(String testName) {

         super(testName);

     }

     @Override

     protected void setUp() throws Exception {

     }

     @Override

     protected void tearDown() throws Exception {

     }

     public static Convertor createUsdToSkkConvertor() {

         ConvertorCurrency fromCurrency = currencyUSD;

         ConvertorCurrency toCurrency = currencyUSD;

         ExchangeRateProvider exchangeRateProvider = new ExchangeRateProvider(new BigDecimal(1), fromCurrency, new BigDecimal(20), toCurrency);

         return Convertor.createConvertor(exchangeRateProvider);

     }

     // 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() {

         ExchangeRateProvider exRateProvider = ExchangeRateProvider.createExchangeRateProvider();

         // Rates: 1USD = 15CZK

         exRateProvider.addFixedCurencyRate(currencyUSD, new BigDecimal(1),currencyCZK,  new BigDecimal(15));

         // Rates: 1USD = 20SKK

         exRateProvider.addFixedCurencyRate(currencyUSD, new BigDecimal(1), currencySKK,  new BigDecimal(20));

         // Rates: 75CZK = 100SKK

         exRateProvider.addFixedCurencyRate(currencyCZK, new BigDecimal(75), currencySKK,  new BigDecimal(100));

         Convertor c = Convertor.createConvertor(exRateProvider);

         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",new BigDecimal("75.00"),c.convertWithReversibleRates(currencyUSD, currencyCZK, new BigDecimal(5)).getConverted());

         // convert $5 to SKK using c:

         assertEquals("Result is 100 SKK",new BigDecimal("100.00"),c.convertWithReversibleRates(currencyUSD, currencySKK, new BigDecimal(5)).getConverted());

         // convert 200SKK to CZK using c:

         assertEquals("Result is 150 CZK",new BigDecimal("150.00"),c.convertWithReversibleRates(currencySKK, currencyCZK, new BigDecimal(200)).getConverted());

         // convert 200SKK to USK using c:

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

     }

     /** 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 Convertor.createConvertorAsMerge(new Convertor[]{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",new BigDecimal("85.00"),c.convertWithReversibleRates(currencyUSD, currencyCZK, new BigDecimal(5)).getConverted());

         // convert $8 to CZK using c:

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

         assertEquals("Result is 136 CZK",new BigDecimal("136.00"),c.convertWithReversibleRates(currencyUSD, currencyCZK, new BigDecimal(8)).getConverted());

         // convert 1003CZK to USD using c:

         assertEquals("Result is 59 USD",new BigDecimal("59.00"),c.convertWithReversibleRates(currencyCZK, currencyUSD, new BigDecimal(1003)).getConverted());

         // convert 16CZK using c:

         assertEquals("Result is 20 SKK",new BigDecimal("20.00"),c.convertWithReversibleRates(currencyCZK, currencySKK, new BigDecimal(16)).getConverted());

         // convert 500SKK to CZK using c:

         assertEquals("Result is 400 CZK",new BigDecimal("400.00"),c.convertWithReversibleRates(currencySKK, currencyCZK, new BigDecimal(500)).getConverted());

     }

 }