package org.apidesign.apifest08.test;

import java.text.SimpleDateFormat;

import java.util.Currency;

import java.util.Date;

import junit.framework.TestCase;

import org.apidesign.apifest08.currency.Convertor;

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

/** The exchange rates are not always the same. They are changing. However

 * as in order to predict the future, one needs to understand own past. That is

 * why it is important to know the exchange rate as it was at any time during

 * the past.

 * <p>

 * Today's quest is to enhance the convertor API to deal with dates.

 * One shall be able to convert a currency at any date. Each currencies rate shall

 * be associated with a range between two Date objects. In order

 * to keep compatibility with old API that knew nothing about dates, the

 * rates associated then are applicable "for eternity". Any use of existing

 * convert methods that do not accept a Date argument, uses the current

 * System.currentTimeMillis() as default date.

 */

public class Task4Test extends TestCase {

    public Task4Test(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:

    //

    /** Takes a convertor with any rates associated and creates new convertor

     * that returns the same values as the old one for time between from to till.

     * Otherwise it returns no results. This is just a helper method that

     * shall call some real one in the API.

     * 

     * @param old existing convertor

     * @param from initial date (inclusive)

     * @param till final date (exclusive)

     * @return new convertor

     */

    public static Convertor limitTo(Convertor old, Date from, Date till) {

        return Convertor.limitExchangeRatesValidity(old, from, till);

    }

    public void testCompositionOfLimitedConvertors() throws Exception {

        SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm zzz");

        Date d1 = format.parse("2008-10-01 00:00 GMT"); // 2008-10-01 0:00 GMT

        Date d2 = format.parse("2008-10-02 00:00 GMT"); // 2008-10-02 0:00 GMT

        Date d3 = format.parse("2008-10-03 00:00 GMT"); // 2008-10-03 0:00 GMT

        Convertor c = Task2Test.merge(

            limitTo(Task1Test.createCZKtoUSD(), d1, d2),

            limitTo(Task1Test.createSKKtoCZK(), d2, d3)

        );

        Date now = new Date();

        // convert $5 to CZK using c:

        double result = 0;

        boolean exceptionThrown = false;

        try {

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

        } catch (Exception e) {

          exceptionThrown = true;

        }

        if(d1.compareTo(now) <= 0 && d2.compareTo(now) > 0) {

          System.out.println("Result.");

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

        } else {

          System.out.println("Exception.");

          assertEquals("There is no Exception while using convertor at wrong day!", true, exceptionThrown);

        }

        // convert $8 to CZK using c:

        exceptionThrown = false;

        try {

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

        } catch (Exception e) {

          exceptionThrown = true;

        }

        if(d1.compareTo(now) <= 0 && d2.compareTo(now) > 0) {

          System.out.println("Result.");

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

        } else {

          System.out.println("Exception.");

          assertEquals("There is no Exception while using convertor at wrong day!", true, exceptionThrown);

        }

        // convert 1003CZK to USD using c:

        exceptionThrown = false;

        try {

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

        } catch (Exception e) {

          exceptionThrown = true;

        }

        if(d1.compareTo(now) <= 0 && d2.compareTo(now) > 0) {

          System.out.println("Result.");

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

        } else {

          System.out.println("Exception.");

          assertEquals("There is no Exception while using convertor at wrong day!", true, exceptionThrown);

        }

        // convert 16CZK using c:

        exceptionThrown = false;

        try {

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

        } catch (Exception e) {

          exceptionThrown = true;

        }

        if(d2.compareTo(now) <= 0 && d3.compareTo(now) > 0) {

          System.out.println("Result.");

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

        } else {

          System.out.println("Exception.");

          assertEquals("There is no Exception while using convertor at wrong day!", true, exceptionThrown);

        }

        // convert 500SKK to CZK using c:

        exceptionThrown = false;

        try {

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

        } catch (Exception e) {

          exceptionThrown = true;

        }

        if(d2.compareTo(now) <= 0 && d3.compareTo(now) > 0) {

          System.out.println("Result.");

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

        } else {

          System.out.println("Exception.");

          assertEquals("There is no Exception while using convertor at wrong day!", true, exceptionThrown);

        }

    }

    /** Create convertor that understands two currencies, CZK and

     *  SKK. Make 100 SKK == 90 CZK.

     *

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

     */

    public static Convertor createSKKtoCZK2() {

      // set exchange rates

      Convertor.setConvertorRates(Currency.getInstance("SKK"), Currency.getInstance("CZK"), 90d, 100d);

      // create new instance

      Convertor convertor = null;

      try {

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

      } catch (UnknownConvertorException e) {

        e.printStackTrace();

      }

      return convertor;

    }

    public void testDateConvetorWithTwoDifferentRates() throws Exception {

        SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm zzz");

        Date d1 = format.parse("2008-10-01 00:00 GMT"); // 2008-10-01 0:00 GMT

        Date d2 = format.parse("2008-10-02 00:00 GMT"); // 2008-10-02 0:00 GMT

        Date d3 = format.parse("2008-10-03 00:00 GMT"); // 2008-10-03 0:00 GMT

        Convertor c = Task2Test.merge(

            limitTo(createSKKtoCZK2(), d1, d2),

            limitTo(Task1Test.createSKKtoCZK(), d2, d3)

        );

        // convert 500SKK to CZK using c at 2008-10-02 9:00 GMT:

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

        // convert 500SKK to CZK using c at 2008-10-01 6:00 GMT:

        // assertEquals("Result is 450 CZK");

        Date now = new Date();

        // convert 500SKK to CZK using c:

        double result = 0;

        boolean exceptionThrown = false;

        try {

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

        } catch (Exception e) {

          exceptionThrown = true;

        }

        if(d1.compareTo(now) <= 0 && d2.compareTo(now) > 0) {

          System.out.println("\nResult");

          assertEquals("Result is not 450 CZK.", 450d, result);

        } else if(d2.compareTo(now) <= 0 && d3.compareTo(now) > 0) {

          System.out.println("\nResult");

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

        } else {

          System.out.println("\nException");

          assertEquals("There is no Exception while using convertor at wrong day!", true, exceptionThrown);

        }

    }

}