package org.apidesign.apifest08.test;

 import java.math.BigDecimal;

 import java.util.Currency;

 import junit.framework.TestCase;

 import org.apidesign.apifest08.currency.Convertor;

 import org.apidesign.apifest08.currency.MonetaryAmount;

 import org.apidesign.apifest08.currency.anothervendor.ZigZaggingBidirectionalConvertor;

 /** 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 {

     public Task3Test(String testName) {

         super(testName);

     }

     @Override

     protected void setUp() throws Exception {

     }

     @Override

     protected void tearDown() throws Exception {

     }

     protected static final Currency CZK = Currency.getInstance( "CZK" );

     protected static final Currency SKK = Currency.getInstance( "SKK" );

     protected static final Currency USD = Currency.getInstance( "USD" );

     // 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.

         final MonetaryAmount oneUSD = new MonetaryAmount( 1, USD );

         final BigDecimal startAmount = new BigDecimal( 16 );

         final BigDecimal endAmount = new BigDecimal( 15 );

         final BigDecimal stepAmount = BigDecimal.ONE.movePointLeft( 2 ).negate();

         return new ContractImposingDelegatingConvertor( new ZigZaggingBidirectionalConvertor( oneUSD, CZK, startAmount, endAmount, stepAmount ) );

     }

     public void testFewQueriesForOnlineConvertor() {

         Convertor c = createOnlineCZKUSDConvertor();

         doFewQueriesForOnlineConvertor(c);

     }

     static void doFewQueriesForOnlineConvertor( final Convertor c ) {

         // convert $5 to CZK using c:

         final Convertor.ConversionResult r1 = c.convert( new Convertor.ConversionRequest( new MonetaryAmount( 5, USD ), CZK ) );

         final MonetaryAmount a1 = r1.getNetAmount();

         //assertEquals("Result is 80 CZK");

         assertNotNull( a1 );

         assertEquals( 80.0, a1.getAmount().doubleValue() );

         assertEquals( CZK, a1.getCurrency() );

         // convert $8 to CZK using c:

         final Convertor.ConversionResult r2 = c.convert( new Convertor.ConversionRequest( new MonetaryAmount( 8, USD ), CZK ) );

         final MonetaryAmount a2 = r2.getNetAmount();

         //assertEquals("Result is 127.92 CZK");

         assertNotNull( a2 );

         assertEquals( 12792.0, a2.getAmount().movePointRight( 2 ).doubleValue() );

         assertEquals( CZK, a2.getCurrency() );

         // convert $1 to CZK using c:

         final Convertor.ConversionResult r3 = c.convert( new Convertor.ConversionRequest( new MonetaryAmount( 1, USD ), CZK ) );

         final MonetaryAmount a3 = r3.getNetAmount();

         //assertEquals("Result is 15.98 CZK");

         assertNotNull( a3 );

         assertEquals( 1598.0, a3.getAmount().movePointRight( 2 ).doubleValue() );

         assertEquals( CZK, a3.getCurrency() );

         // convert 15.97CZK to USD using c:

         final BigDecimal s4 = new BigDecimal( 1597 ).movePointLeft( 2 );

         final Convertor.ConversionResult r4 = c.convert( new Convertor.ConversionRequest( new MonetaryAmount( s4, CZK ), USD ) );

         final MonetaryAmount a4 = r4.getNetAmount();

         //assertEquals("Result is 1$");

         assertNotNull( a4 );

         assertEquals( 1.0, a4.getAmount().doubleValue() );

         assertEquals( USD, a4.getCurrency() );

     }

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

      */

     public void testOnlineConvertorComposition() throws Exception {

         final Convertor c = Task2Test.merge(

             createOnlineCZKUSDConvertor(),

             Task1Test.createSKKtoCZK()

         );

         // convert 16CZK using c:

         final Convertor.ConversionResult r4 = c.convert( new Convertor.ConversionRequest( new MonetaryAmount( 16, CZK ), SKK ) );

         final MonetaryAmount a4 = r4.getNetAmount();

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

         assertNotNull( a4 );

         assertEquals( 20.0, a4.getAmount().doubleValue() );

         assertEquals( SKK, a4.getCurrency() );

         // convert 500SKK to CZK using c:

         final Convertor.ConversionResult r5 = c.convert( new Convertor.ConversionRequest( new MonetaryAmount( 500, SKK ), CZK ) );

         final MonetaryAmount a5 = r5.getNetAmount();

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

         assertNotNull( a5 );

         assertEquals( 400.0, a5.getAmount().doubleValue() );

         assertEquals( CZK, a5.getCurrency() );

         doFewQueriesForOnlineConvertor(c);

     }

 }