package org.apidesign.apifest08.test;

 import junit.framework.TestCase;

 import org.apidesign.apifest08.currency.Convertor;

 import org.apidesign.apifest08.currency.ConvertorFactory;

 import org.apidesign.apifest08.currency.CurrencyRate;

 import org.apidesign.apifest08.currency.Rate;

 /** 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 {

     }

     // 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.

         CurrencyRate onlineCurrencyRate = new CurrencyRate() {

             private int usdAmount = 100;

             private int czkAmount = 1600;

             private boolean up = false;

             public String getCurrency1() {

                 return "USD";

             }

             public String getCurrency2() {

                 return "CZK";

             }

             public Rate getRate() { //return Rate according to online status

                 Rate rate = new Rate(usdAmount, czkAmount);

                 if (up) {

                     if (czkAmount < 1600) {

                         czkAmount++;

                     } else {

                         up = false;

                         czkAmount--;

                     }

                 } else { //down

                     if (czkAmount > 1500) {

                         czkAmount--;

                     } else {

                         up = true;

                         czkAmount++;

                     }

                 }

                 return rate;

             }

         };

         return ConvertorFactory.newInstance().createConvertor(onlineCurrencyRate);

     }

     public void testFewQueriesForOnlineConvertor() {

         Convertor c = createOnlineCZKUSDConvertor();

         doFewQueriesForOnlineConvertor(c);

     }

     static void doFewQueriesForOnlineConvertor(Convertor c) {

         // convert $5 to CZK using c:

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

         assertEquals("Result is 80 CZK", 80.0, c.convert("USD", "CZK", 5), 0.001);

         // convert $8 to CZK using c:

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

         assertEquals("Result is 127.92 CZK", 127.92, c.convert("USD", "CZK", 8), 0.001);

         // convert $1 to CZK using c:

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

         assertEquals("Result is 15.98 CZK", 15.98, c.convert("USD", "CZK", 1), 0.001);

         // convert 15.97CZK to USD using c:

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

         assertEquals("Result is 1$", 1.0, c.convert("CZK", "USD", 15.97), 0.001);

     }

     /** 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 SKK");

         assertEquals("Result is 20 SKK", 20.0, c.convert("CZK", "SKK", 16), 0.001);

         // convert 500SKK to CZK using c:

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

         assertEquals("Result is 400 CZK", 400.0, c.convert("SKK", "CZK", 500), 0.001);

         doFewQueriesForOnlineConvertor(c);

     }

 }