/*******************************************************************************
 * Copyright (c) 2006, 2015 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.jdt.text.tests.performance;

import java.io.PrintWriter;
import java.io.StringWriter;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.Vector;

import org.eclipse.test.performance.PerformanceMeter;

import junit.framework.Test;
import junit.framework.TestCase;
import junit.framework.TestSuite;


/**
* @since 3.3
*/
public class PerfTestSuite extends TestSuite {
	public PerfTestSuite() {
		super();
	}

	public PerfTestSuite(Class<?> theClass, String name) {
		super(name);
		try {
			getTestConstructor(theClass); // Avoid generating multiple error messages
		} catch (NoSuchMethodException e) {
			addTest(warning("Class "+theClass.getName()+" has no public constructor TestCase(String name) or TestCase()"));  //$NON-NLS-1$//$NON-NLS-2$
			return;
		}

		if (!Modifier.isPublic(theClass.getModifiers())) {
			addTest(warning("Class "+theClass.getName()+" is not public"));  //$NON-NLS-1$//$NON-NLS-2$
			return;
		}

		Class<?> superClass= theClass;
		Vector<String> names= new Vector<>();
		while (Test.class.isAssignableFrom(superClass)) {
			for (Method method : superClass.getDeclaredMethods()) {
				addPerformanceTestMethod(method, names, theClass);
			}
			superClass= superClass.getSuperclass();
		}
	}

	private void addPerformanceTestMethod(Method m, Vector<String> names, Class<?> theClass) {
		String name= m.getName();
		if (names.contains(name))
			return;
		if (!isPublicMeasureMethod(m)) {
			if (isMeasureMethod(m))
				addTest(warning("Test method isn't public: "+m.getName())); //$NON-NLS-1$
			return;
		}
		names.addElement(name);
		addTest(createPerformanceTest(theClass, name));
	}

	private boolean isPublicMeasureMethod(Method m) {
		return isMeasureMethod(m) && Modifier.isPublic(m.getModifiers());
	 }

	private boolean isMeasureMethod(Method m) {
		String name= m.getName();
		Class<?>[] parameters= m.getParameterTypes();
		Class<?> returnType= m.getReturnType();
		return parameters.length == 1 && name.startsWith("measure") && returnType.equals(Void.TYPE) && PerformanceMeter.class.isAssignableFrom(parameters[0]); //$NON-NLS-1$
	 }

	public PerfTestSuite(Class<?> theClass) {
		this(theClass, theClass.getName());
	}

	public PerfTestSuite(String name) {
		super(name);
	}

	/**
	 * ... buried deep in the mountains in a lonely camp of the Swiss army...
	 *
	 * @param theClass the class to be scanned for <code>measure</code> methods
	 * @param name hte name of the test
	 * @return a new performance test
	 */
	static public Test createPerformanceTest(Class<?> theClass, String name) {
		Constructor<?> constructor;
		try {
			constructor= getTestConstructor(theClass);
		} catch (NoSuchMethodException e) {
			return warning("Class "+theClass.getName()+" has no public constructor TestCase(String name) or TestCase()"); //$NON-NLS-1$ //$NON-NLS-2$
		}
		Object test;
		try {
			if (constructor.getParameterTypes().length == 0) {
				test= constructor.newInstance(new Object[0]);
				if (test instanceof TestCase)
					((TestCase) test).setName(name);
			} else {
				test= constructor.newInstance(name);
			}
		} catch (InstantiationException e) {
			return(warning("Cannot instantiate test case: "+name+" ("+exceptionToString(e)+")")); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
		} catch (InvocationTargetException e) {
			return(warning("Exception in constructor: "+name+" ("+exceptionToString(e.getTargetException())+")")); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
		} catch (IllegalAccessException e) {
			return(warning("Cannot access test case: "+name+" ("+exceptionToString(e)+")")); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
		}
		return (Test) test;
	}

	private static String exceptionToString(Throwable t) {
		StringWriter stringWriter= new StringWriter();
		PrintWriter writer= new PrintWriter(stringWriter);
		t.printStackTrace(writer);
		return stringWriter.toString();

	}

	public static Test warning(final String message) {
		return new TestCase("warning") { //$NON-NLS-1$
			@Override
			protected void runTest() {
				fail(message);
			}
		};
	}
}