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.InvalidCurrencyException;

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

 /**

  * Finish the Convertor API, and then write bodies of methods inside of this class to match the given tasks. To fullfil

  * your task, use the API define in the <code>org.apidesign.apifest08.currency</code> package. Do not you reflection, or

  * other hacks as your code shall run without any runtime permissions.

  */

 public class Task1Test extends TestCase {

   public Task1Test(String testName) {

     super(testName);

   }

   @Override

   protected void setUp() throws Exception {

   }

   @Override

   protected void tearDown() throws Exception {

   }

   //

   // Imagine 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 design such API

   //

   /**

    * Create convertor that understands two currencies, CZK and USD. Make 1 USD == 17 CZK. This is a method provided for

    * #1 group - e.g. those that know the exchange rate. They somehow need to create the objects from the API and tell

    * them the exchange rate. The API itself knows nothing about any rates, before the createCZKtoUSD method is called.

    * Creation of the convertor shall not require subclassing of any class or interface on the client side.

    * @return prepared convertor ready for converting USD to CZK and CZK to USD

    */

   public static Convertor createCZKtoUSD() {

     // set exchange rates

     Convertor.setConvertorRates(Currency.getInstance("USD"), Currency.getInstance("CZK"), 17d, 1d);

     // create new instance

     Convertor convertor = null;

     try {

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

     } catch (UnknownConvertorException e) {

       e.printStackTrace();

     }

     return convertor;

   }

   /**

    * Create convertor that understands two currencies, CZK and SKK. Make 100 SKK == 80 CZK. Again this is method for the

    * #1 group - it 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. Creation of the convertor shall not require subclassing of

    * any class or interface on the client side.

    * @return prepared convertor ready for converting SKK to CZK and CZK to SKK

    */

   public static Convertor createSKKtoCZK() {

     // set exchange rates

     Convertor.setConvertorRates(Currency.getInstance("SKK"), Currency.getInstance("CZK"), 80d, 100d);

     // create new instance

     Convertor convertor = null;

     try {

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

     } catch (UnknownConvertorException e) {

       e.printStackTrace();

     }

     return convertor;

   }

   //

   // now the methods for group #2 follow:

   // this group knows nothing about exchange rates, but knows how to use

   // the API to do conversions. It somehow (by calling one of the factory

   // methods) gets objects from the API and uses them to do the conversions.

   //

   /**

    * Use the convertor from <code>createCZKtoUSD</code> method and do few conversions with it.

    */

   public void testCurrencyCZKUSD() throws Exception {

     Convertor c = createCZKtoUSD();

     // convert $5 to CZK using c:

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

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

     // convert $8 to CZK

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

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

     // convert 1003CZK to USD

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

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

   }

   /**

    * Use the convertor from <code>createSKKtoCZK</code> method and do few conversions with it.

    */

   public void testCurrencySKKCZK() throws Exception {

     Convertor c = createSKKtoCZK();

     // convert 16CZK using c:

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

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

     // convert 500SKK to CZK

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

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

   }

   /**

    * Verify that the CZK to USD convertor knows nothing about SKK.

    */

   public void testCannotConvertToSKKwithCZKUSDConvertor() throws Exception {

     Convertor c = createCZKtoUSD();

     boolean exceptionThrown = false;

     // convert $5 to SKK, the API shall say this is not possible

     try {

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

       exceptionThrown = false;

     } catch (InvalidCurrencyException e) {

       exceptionThrown = true;

     }

     assertEquals("It should be impossible to convert to SKK with USD->CZK convertor", true, exceptionThrown);

     // convert 500 SKK to CZK, the API shall say this is not possible

     try {

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

       exceptionThrown = false;

     } catch (InvalidCurrencyException e) {

       exceptionThrown = true;

     }

     assertEquals("It should be impossible to convert from SKK with USD->CZK convertor", true, exceptionThrown);

   }

   /**

    * Verify that the CZK to SKK convertor knows nothing about USD.

    */

   public void testCannotConvertToSKKwithSKKCZKConvertor() throws Exception {

     Convertor c = createSKKtoCZK();

     boolean exceptionThrown = false;

     // convert $5 to SKK, the API shall say this is not possible

     try {

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

       exceptionThrown = false;

     } catch (InvalidCurrencyException e) {

       exceptionThrown = true;

     }

     assertEquals("It should be impossible to convert form USD with SKK->CZK convertor", true, exceptionThrown);

     // convert 500 CZK to USD, the API shall say this is not possible

     try {

       c.convert(500, Currency.getInstance("CZK"), Currency.getInstance("USD"));

       exceptionThrown = false;

     } catch (InvalidCurrencyException e) {

       exceptionThrown = true;

     }

     assertEquals("It should be impossible to convert to USD with SKK->CZK convertor", true, exceptionThrown);

   }

 }