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;

 import org.apidesign.apifest08.currency.IExchangeRateEngine;

 /** The exchange rates are not always the same. They are changing. Day by day,

  * hour by hour, minute by minute. For every bank it is important to always

  * have the actual exchange rate available in the system. That is why let's

  * create a pluggable convertor that will always have up to date value of its

  * exchange rate.

  * <p>

  * The quest for today is to allow 3rd party developer to write a convertor

  * that adjusts its exchange rate everytime it is queried. This convertor is

  * written by independent vendor, the vendor knows only your Convertor API,

  * he does not know how the whole system looks and how the convertor is supposed

  * to be used.

  */

 public class Task3Test extends TestCase {

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

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

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

     public Task3Test(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:

     //

     /** Without knowing anything about the surrounding system, write an

      * implementation of convertor that will return different rates everytime

      * it is queried. Convert USD to CZK and vice versa. Start with the rate of

      * 1USD = 16CZK and adjust it in favor of CZK by 0.01 CZK with every query.

      * As soon as you reach 1USD = 15CZK adjust it by 0.01 CZK in favor of USD

      * until you reach 1USD = 16CZK

      *

      * @return new instance of "online" USD and CZK convertor starting with rate 1USD = 16CZK

      */

     public static Convertor createOnlineCZKUSDConvertor() {

         // initial rate: 1USD = 16CZK

         // 2nd query 1USD = 15.99CZK

         // 3rd query 1USD = 15.98CZK

         // until 1USD = 15.00CZK

         // then 1USD = 15.01CZK

         // then 1USD = 15.02CZK

         // and so on and on up to 1USD = 16CZK

         // and then another round to 15, etc.

         IExchangeRateEngine engine = BouncingExchangeRateEngine.create(

                 currencyUSD,  new BigDecimal(1),

                 currencyCZK, 

                 new BigDecimal(16),new BigDecimal(15),

                 new BigDecimal("-0.01"));

         ExchangeRateProvider exRateProvider = ExchangeRateProvider.createExchangeRateProvider(engine);

         Convertor convertor = Convertor.createConvertor(exRateProvider);

         return convertor;

     }

     public void testFewQueriesForOnlineConvertor() {

         Convertor c = createOnlineCZKUSDConvertor();

         doFewQueriesForOnlineConvertor(c);

     }

     static void doFewQueriesForOnlineConvertor(Convertor c) {

         // convert $5 to CZK using c:

         assertEquals("Result is 80 CZK", new BigDecimal("80.00"), c.convertWithReversibleRates(currencyUSD, currencyCZK, new BigDecimal(5)).getConverted());

         // convert $8 to CZK using c:

         assertEquals("Result is 127.92 CZK", new BigDecimal("127.92"), c.convertWithReversibleRates(currencyUSD, currencyCZK, new BigDecimal(8)).getConverted());

         // convert $1 to CZK using c:

         assertEquals("Result is 15.98 CZK", new BigDecimal("15.98"), c.convertWithReversibleRates(currencyUSD, currencyCZK, new BigDecimal(1)).getConverted());

         // convert 15.97CZK to USD using c:

         assertEquals("Result is 15.98 CZK", new BigDecimal("1.00"), c.convertWithReversibleRates(currencyCZK, currencyUSD , new BigDecimal("15.97")).getConverted());

     }

     /** Join the convertors and show they behave sane.

      */

     public void testOnlineConvertorComposition() throws Exception {

         Convertor c = Task2Test.merge(

             createOnlineCZKUSDConvertor(),

             Task1Test.createSKKtoCZK()

         );

         // convert 16CZK to SKK using c:

         assertEquals("Result is 20 CZK", 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());

         doFewQueriesForOnlineConvertor(c);

     }

 //    public void testBouncing() {

 //        Convertor c=createOnlineCZKUSDConvertor();

 //        

 //        IExchangeRateEngine engine = BouncingExchangeRateEngine.create(

 //                currencyUSD,  new BigDecimal(1),

 //                currencyCZK, 

 //                new BigDecimal("16.00"),new BigDecimal("15.00"),

 //                new BigDecimal("-0.01"));        

 //        

 //        for (int i=0;i<300;i++) {

 //            System.out.println(engine.getExchangeRate(currencyUSD, currencyCZK).getToValue());

 //        }

 //    }

 }