/**
 * 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 java.util.HashMap;

import org.evosuite.assertion.CheapPurityAnalyzer;
import org.objectweb.asm.ClassVisitor;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;

/**
 * It launches a <code>PurityAnalysisMethodVisitor</code> on each method.
 * This class only reads the existing bytecode.
 * 
 * @author Juan Galeotti
 */
public class PurityAnalysisClassVisitor extends ClassVisitor {

	private final CheapPurityAnalyzer purityAnalyzer;

	public static class MethodEntry {
		private final String className;
		private final String methodName;
		private final String descriptor;

		public MethodEntry(String className, String methodName,
				String descriptor) {
			this.className = className;
			this.methodName = methodName;
			this.descriptor = descriptor;
		}

		@Override
		public boolean equals(Object o) {
			if (o == null)
				return false;

			if (!o.getClass().equals(MethodEntry.class))
				return false;

			MethodEntry that = (MethodEntry) o;

			return this.className.equals(that.className)
					&& this.methodName.equals(that.methodName)
					&& this.descriptor.equals(that.descriptor);
		}

		@Override
		public int hashCode() {
			return this.className.hashCode() + this.methodName.hashCode()
					+ this.descriptor.hashCode();
		}
	}

	private final String className;
	private final HashMap<MethodEntry, PurityAnalysisMethodVisitor> method_adapters = new HashMap<MethodEntry, PurityAnalysisMethodVisitor>();

	/**
	 * <p>
	 * Constructor for StaticInitializationClassAdapter.
	 * </p>
	 * 
	 * @param visitor
	 *            a {@link org.objectweb.asm.ClassVisitor} object.
	 * @param className
	 *            a {@link java.lang.String} object.
	 */
	public PurityAnalysisClassVisitor(ClassVisitor visitor, String className,
			CheapPurityAnalyzer purityAnalyzer) {
		super(Opcodes.ASM5, visitor);
		this.className = className;
		this.purityAnalyzer = purityAnalyzer;
	}

	/** {@inheritDoc} */
	@Override
	public MethodVisitor visitMethod(int methodAccess, String name,
			String descriptor, String signature, String[] exceptions) {


		if (visitingInterface == true) {
			purityAnalyzer.addInterfaceMethod(className.replace('/', '.'),
					name, descriptor);
		} else {
			purityAnalyzer.addMethod(className.replace('/', '.'), name,
					descriptor);
			if ((methodAccess & Opcodes.ACC_ABSTRACT) != Opcodes.ACC_ABSTRACT) {
				purityAnalyzer.addMethodWithBody(className.replace('/', '.'), name,
					descriptor);
			} else {
				// The declaration of this method is abstract. So 
				// there is no method body for this method in this class
			}
		}

		MethodVisitor mv = super.visitMethod(methodAccess, name, descriptor,
				signature, exceptions);
		PurityAnalysisMethodVisitor purityAnalysisMethodVisitor = new PurityAnalysisMethodVisitor(
				className, name, descriptor, mv, purityAnalyzer);
		MethodEntry methodEntry = new MethodEntry(className, name, descriptor);
		this.method_adapters.put(methodEntry, purityAnalysisMethodVisitor);
		return purityAnalysisMethodVisitor;
	}

	@Override
	public void visitEnd() {
		for (MethodEntry method_entry : this.method_adapters.keySet()) {

			if (this.method_adapters.get(method_entry).updatesField()) {
				purityAnalyzer.addUpdatesFieldMethod(method_entry.className,
						method_entry.methodName, method_entry.descriptor);
			}
		}
	}

	private boolean visitingInterface = false;

	@Override
	public void visit(int version, int access, String name, String signature,
			String superName, String[] interfaces) {
		if ((access & Opcodes.ACC_INTERFACE) == Opcodes.ACC_INTERFACE) {
			visitingInterface = true;
		}
		super.visit(version, access, name, signature, superName, interfaces);
	}
}