/**
 * 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.instrumentation;

import static org.objectweb.asm.Opcodes.INVOKESTATIC;

import java.util.LinkedList;
import java.util.List;

import org.evosuite.testcase.execution.ExecutionTracer;
import org.objectweb.asm.Label;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;
import org.objectweb.asm.Type;

/**
 * Adds a call to ExecutionTracer.passedClassInitializationMethod() when
 * the <clinit> method begins its execution.
 *
 * @author Juan Galeotti
 */
public class ExitClassInitMethodAdapter extends MethodVisitor {

	private static final String EXIT_CLASS_INIT = "exitClassInit";
	private final String className;
	private final String methodName;
	private Label startingTryLabel;
	private Label endingTryLabel;

	/**
	 * <p>Constructor for PutStaticMethodAdapter.</p>
	 *
	 * @param mv a {@link org.objectweb.asm.MethodVisitor} object.
	 * @param className a {@link java.lang.String} object.
	 * @param finalFields a {@link java.util.List} object.
	 */
	public ExitClassInitMethodAdapter(String className, String methodName,
			MethodVisitor mv) {
		super(Opcodes.ASM5, mv);
		this.className = className;
		this.methodName = methodName;
	}

	@Override
	public void visitInsn(int opcode) {
		if (opcode == Opcodes.RETURN && (methodName.equals("<clinit>"))) {

			String executionTracerClassName = ExecutionTracer.class.getName()
					.replace('.', '/');
			String executionTracerDescriptor = Type.getMethodDescriptor(
					Type.VOID_TYPE, Type.getType(String.class));

			String classNameWithDots = className.replace('/', '.');
			super.visitLdcInsn(classNameWithDots);
			super.visitMethodInsn(INVOKESTATIC, executionTracerClassName,
					EXIT_CLASS_INIT, executionTracerDescriptor, false);

		}
		super.visitInsn(opcode);
	}

	@Override
	public void visitCode() {
		super.visitCode();
		if (methodName.equals("<clinit>")) {

			startingTryLabel = new Label();
			endingTryLabel = new Label();
			super.visitLabel(startingTryLabel);
		}
	}

	@Override
	public void visitEnd() {
		if (methodName.equals("<clinit>")) {
			super.visitLabel(endingTryLabel);
			String executionTracerClassName = ExecutionTracer.class.getName()
					.replace('.', '/');
			String executionTracerDescriptor = Type.getMethodDescriptor(
					Type.VOID_TYPE, Type.getType(String.class));

			String classNameWithDots = className.replace('/', '.');
			super.visitLdcInsn(classNameWithDots);
			super.visitMethodInsn(INVOKESTATIC, executionTracerClassName,
					EXIT_CLASS_INIT, executionTracerDescriptor, false);
			super.visitInsn(Opcodes.ATHROW);

			// regenerate try-catch table
			for (TryCatchBlock tryCatchBlock : tryCatchBlocks) {
				super.visitTryCatchBlock(tryCatchBlock.start,
						tryCatchBlock.end, tryCatchBlock.handler,
						tryCatchBlock.type);
			}
			// add new try-catch for exiting method
			super.visitTryCatchBlock(startingTryLabel, endingTryLabel,
					endingTryLabel, null);
		}
		super.visitEnd();
	}

	private static class TryCatchBlock {
		public TryCatchBlock(Label start, Label end, Label handler, String type) {
			this.start = start;
			this.end = end;
			this.handler = handler;
			this.type = type;
		}

		Label start;
		Label end;
		Label handler;
		String type;
	}

	private final List<TryCatchBlock> tryCatchBlocks = new LinkedList<TryCatchBlock>();

	@Override
	public void visitTryCatchBlock(Label start, Label end, Label handler,
			String type) {
		if (methodName.equals("<clinit>")) {
			TryCatchBlock block = new TryCatchBlock(start, end, handler, type);
			tryCatchBlocks.add(block);
		}
		super.visitTryCatchBlock(start, end, handler, type);
	}

}