package org.apidesign.apifest08.test;

import java.util.ArrayList;

import java.util.Collection;

import junit.framework.TestCase;

import org.apidesign.apifest08.currency.Convertor;

import org.apidesign.apifest08.currency.CurrencyValue;

import org.apidesign.apifest08.currency.ExchangeRateValue;

/** There are many currencies around the world and many banks manipulate

 * with more than one or two at the same time. As banks are usually the

 * best paying clients, which is true even in case of your Convertor API,

 * it is reasonable to listen to their requests.

 * <p>

 * The quest for today is to enhance your existing convertor API to hold

 * information about many currencies and allow conversions between any of them.

 * Also, as conversion rates for diferent currencies usually arise from various

 * bank departments, there is another important need. There is a need to

 * compose two convertors into one by merging all the information about

 * currencies they know about.

 */

public class Task2Test extends TestCase {

    public Task2Test(String testName) {

        super(testName);

    }

    @Override

    protected void setUp() throws Exception {

    }

    @Override

    protected void tearDown() throws Exception {

    }

    // As in Task1Test, keep in mind, 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 backward compatibly enhance your existing API to support following

    // usecases:

    //

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

     *  SKK. Make 100 SKK == 75 CZK. This is method for the group of users that

     *  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.

     */

    public static Convertor<Double, String> createTripleConvertor() {

        // Rates: 1USD = 15CZK

        // Rates: 1USD = 20SKK

        // Rates: 75CZK = 100SKK

        Collection<ExchangeRateValue<Double, String>> exchangeRates =

                new ArrayList<ExchangeRateValue<Double, String>>();

        exchangeRates.add(ExchangeRateValue.getExchangeRate(

                CurrencyValue.getCurrencyValue(1d, "USD"),

                CurrencyValue.getCurrencyValue(15d, "CZK")));

        exchangeRates.add(ExchangeRateValue.getExchangeRate(

                CurrencyValue.getCurrencyValue(1d, "USD"),

                CurrencyValue.getCurrencyValue(20d, "SKK")));

        exchangeRates.add(ExchangeRateValue.getExchangeRate(

                CurrencyValue.getCurrencyValue(75d, "CZK"),

                CurrencyValue.getCurrencyValue(100d, "SKK")));

        return Convertor.getConvertorDoubleString(exchangeRates);

    }

    /** Define convertor that understands three currencies. Use it.

     */

    public void testConvertorForUSDandCZKandSKK() throws Exception {

        Convertor<Double, String> c = createTripleConvertor();

        CurrencyValue<Double, String> result;

        // convert $5 to CZK using c:

        // assertEquals("Result is 75 CZK");

        result = c.convert("CZK", CurrencyValue.getCurrencyValue(5d, "USD"));

        assertEquals(CurrencyValue.getCurrencyValue(75d, "CZK"), result);

        // convert $5 to SKK using c:

        // assertEquals("Result is 100 SKK");

        result = c.convert("SKK", CurrencyValue.getCurrencyValue(5d, "USD"));

        assertEquals(CurrencyValue.getCurrencyValue(100d, "SKK"), result);

        // convert 200SKK to CZK using c:

        // assertEquals("Result is 150 CZK");

        result = c.convert("CZK", CurrencyValue.getCurrencyValue(200d, "SKK"));

        assertEquals(CurrencyValue.getCurrencyValue(150d, "CZK"), result);

        // convert 200SKK to USK using c:

        // assertEquals("Result is 10 USD");

        result = c.convert("USD", CurrencyValue.getCurrencyValue(200d, "SKK"));

        assertEquals(CurrencyValue.getCurrencyValue(10d, "USD"), result);

    }

    /** Merge all currency rates of convertor 1 with convertor 2.

     * Implement this using your API, preferably this method just delegates

     * into some API method which does the actual work, without requiring

     * API clients to code anything complex.

     */

    public static Convertor<Double, String> merge(Convertor<Double, String> one, Convertor<Double, String> two) {

        return Convertor.mergeConvertorsDoubleString(one, two);

    }

    /** Join the convertors from previous task, Task1Test and show that it

     * can be used to do reasonable conversions.

     */

    public void testConvertorComposition() throws Exception {

        Convertor<Double, String> c = merge(

                Task1Test.createCZKtoUSD(),

                Task1Test.createSKKtoCZK());

        CurrencyValue<Double, String> result;

        // convert $5 to CZK using c:

        // assertEquals("Result is 85 CZK");

        result = c.convert("CZK", CurrencyValue.getCurrencyValue(5d, "USD"));

        assertEquals(CurrencyValue.getCurrencyValue(85d, "CZK"), result);

        // convert $8 to CZK using c:

        // assertEquals("Result is 136 CZK");

        result = c.convert("CZK", CurrencyValue.getCurrencyValue(8d, "USD"));

        assertEquals(CurrencyValue.getCurrencyValue(136d, "CZK"), result);

        // convert 1003CZK to USD using c:

        // assertEquals("Result is 59 USD");

        result = c.convert("USD", CurrencyValue.getCurrencyValue(1003d, "CZK"));

        assertEquals(CurrencyValue.getCurrencyValue(59d, "USD"), result);

        // convert 16CZK using c:

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

        result = c.convert("SKK", CurrencyValue.getCurrencyValue(16d, "CZK"));

        assertEquals(CurrencyValue.getCurrencyValue(20d, "SKK"), result);

        // convert 500SKK to CZK using c:

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

        result = c.convert("CZK", CurrencyValue.getCurrencyValue(500d, "SKK"));

        assertEquals(CurrencyValue.getCurrencyValue(400d, "CZK"), result);

    }

}