/**

 * Back 2 Browser Bytecode Translator

 * Copyright (C) 2012 Jaroslav Tulach <jaroslav.tulach@apidesign.org>

 *

 * This program is free software: you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation, version 2 of the License.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program. Look for COPYING file in the top folder.

 * If not, see http://opensource.org/licenses/GPL-2.0.

 */

package org.apidesign.bck2brwsr.vmtest.impl;

import org.apidesign.bck2brwsr.vmtest.*;

import java.io.File;

import java.io.FileWriter;

import java.io.IOException;

import java.lang.reflect.Method;

import java.util.ArrayList;

import java.util.List;

import org.testng.Assert;

import org.testng.ITest;

import org.testng.annotations.Factory;

import org.testng.annotations.Test;

/** A TestNG {@link Factory} that seeks for {@link Compare} annotations

 * in provided class and builds set of tests that compare the computations

 * in real as well as JavaScript virtual machines. Use as:<pre>

 * {@code @}{@link Factory} public static create() {

 *   return @{link VMTest}.{@link #create(YourClass.class);

 * }</pre>

 *

 * @author Jaroslav Tulach <jtulach@netbeans.org>

 */

public final class CompareCase implements ITest {

    private final Bck2BrwsrCase first, second;

    private final Method m;

    private CompareCase(Method m, Bck2BrwsrCase first, Bck2BrwsrCase second) {

        this.first = first;

        this.second = second;

        this.m = m;

    }

    /** Inspects <code>clazz</code> and for each {@lik Compare} method creates

     * instances of tests. Each instance runs the test in different virtual

     * machine and at the end they compare the results.

     * 

     * @param clazz the class to inspect

     * @return the set of created tests

     */

    public static Object[] create(Class<?> clazz) {

        Method[] arr = clazz.getMethods();

        List<Object> ret = new ArrayList<>();

        final Launchers l = Launchers.INSTANCE;

        ret.add(l);

        for (Method m : arr) {

            Compare c = m.getAnnotation(Compare.class);

            if (c == null) {

                continue;

            }

            final Bck2BrwsrCase real = new Bck2BrwsrCase(m, 0, null);

            final Bck2BrwsrCase js = new Bck2BrwsrCase(m, 1, l);

            final Bck2BrwsrCase brwsr = new Bck2BrwsrCase(m, 2, l);

            ret.add(real);

            ret.add(js);

            ret.add(brwsr);

            ret.add(new CompareCase(m, real, js));

            ret.add(new CompareCase(m, real, brwsr));

        }

        return ret.toArray();

    }

    /** Test that compares the previous results.

     * @throws Throwable 

     */

    @Test(dependsOnGroups = "run") public void compareResults() throws Throwable {

        Object v1 = first.value;

        Object v2 = second.value;

        if (v1 != null) {

            v1 = v1.toString();

        } else {

            v1 = "null";

        }

        Assert.assertEquals(v2, v1, "Comparing results");

    }

    /** Test name.

     * @return name of the tested method followed by a suffix

     */

    @Override

    public String getTestName() {

        return m.getName() + "[Compare " + second.typeName() + "]";

    }

    static StringBuilder dumpJS(CharSequence sb) throws IOException {

        File f = File.createTempFile("execution", ".js");

        try (FileWriter w = new FileWriter(f)) {

            w.append(sb);

        }

        return new StringBuilder(f.getPath());

    }

}