/**
 * Copyright (C) 2010-2017 Gordon Fraser, Andrea Arcuri and EvoSuite
 * contributors
 *
 * This file is part of EvoSuite.
 *
 * EvoSuite is free software: you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published
 * by the Free Software Foundation, either version 3.0 of the License, or
 * (at your option) any later version.
 *
 * EvoSuite 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
 * Lesser Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with EvoSuite. If not, see <http://www.gnu.org/licenses/>.
 */
package org.evosuite.testcase.execution.reset;

import java.lang.reflect.Method;
import java.util.List;

import org.evosuite.Properties;
import org.evosuite.TestGenerationContext;
import org.evosuite.TimeController;
import org.evosuite.coverage.mutation.MutationObserver;
import org.evosuite.runtime.LoopCounter;
import org.evosuite.runtime.Runtime;
import org.evosuite.runtime.classhandling.ClassResetter;
import org.evosuite.runtime.sandbox.Sandbox;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * This class implements the actual invocation to the __STATIC_RESET() method
 * when a class is decided to be re-initialized
 * 
 * @author galeotti
 */
class ClassReInitializeExecutor {

	private final static Logger logger = LoggerFactory.getLogger(ClassReInitializeExecutor.class);

	private static final ClassReInitializeExecutor instance = new ClassReInitializeExecutor();

	private ClassReInitializeExecutor() {
	}

	public synchronized static ClassReInitializeExecutor getInstance() {
		return instance;
	}

	/**
	 * Resets the classes in the list using the Class Loader from the current
	 * Test Generation context
	 * 
	 * @param classesToReset
	 */
	public void resetClasses(List<String> classesToReset) {
		ClassLoader loader = TestGenerationContext.getInstance().getClassLoaderForSUT();
		resetClasses(classesToReset, loader);
	}

	/**
	 * Resets the classes passes in the list using the given class loader
	 * 
	 * @param classesToReset
	 * @param loader
	 */
	public void resetClasses(List<String> classesToReset, ClassLoader loader) {
		// try to reset each collected class

		ClassResetter.getInstance().setClassLoader(loader);

		long start = System.currentTimeMillis();

		for (String className : classesToReset) {
			// re-initialization can be expensive
			long elapsed = System.currentTimeMillis() - start;

			if (!className.equals(Properties.TARGET_CLASS)
					&& (!TimeController.getInstance().isThereStillTimeInThisPhase()
							|| elapsed > Properties.TIMEOUT_RESET)) {
				// Note: we no longer cancel the class re-initialization since
				// it might leave the static data in an inconsistent state
			}
			resetClass(className);
		}
	}

	private void resetClass(String className) {

		// className.__STATIC_RESET() exists
		logger.debug("Resetting class " + className);

		int mutationActive = MutationObserver.activeMutation;
		MutationObserver.deactivateMutation();

		// execute __STATIC_RESET()
		Sandbox.goingToExecuteSUTCode();
		TestGenerationContext.getInstance().goingToExecuteSUTCode();

		Runtime.getInstance().resetRuntime(); // it is important to initialize
												// the VFS
		boolean wasLoopCheckOn = LoopCounter.getInstance().isActivated();

		try {
			Method resetMethod = ClassResetter.getInstance().getResetMethod(className);
			if (resetMethod != null) {
				LoopCounter.getInstance().setActive(false);
				resetMethod.invoke(null, (Object[]) null);
			}
		} catch (Throwable e) {
			ClassResetter.getInstance().logWarn(className,
					e.getClass() + " thrown during execution of method  __STATIC_RESET() for class " + className + ", "
							+ e.getCause());
		} finally {
			Sandbox.doneWithExecutingSUTCode();
			TestGenerationContext.getInstance().doneWithExecutingSUTCode();
			MutationObserver.activateMutation(mutationActive);
			LoopCounter.getInstance().setActive(wasLoopCheckOn);
		}
	}
}