/*
 * Copyright 2009-2016 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.eclipse.jdt.groovy.search;

import org.codehaus.groovy.ast.ASTNode;
import org.codehaus.groovy.ast.ClassCodeVisitorSupport;
import org.codehaus.groovy.ast.expr.BinaryExpression;
import org.codehaus.groovy.ast.expr.ConstantExpression;
import org.codehaus.groovy.ast.expr.FieldExpression;
import org.codehaus.groovy.ast.expr.VariableExpression;

/**
 * Tests to see if {@link #nodeToLookFor} exists as a sub node in the {@link ASTNode} that is passed in to {@link #doVisit(ASTNode)}
 *
 * @author Andrew Eisenberg
 * @created Apr 26, 2011
 */
public class EqualityVisitor extends ClassCodeVisitorSupport {
    private final ASTNode nodeToLookFor;

    private boolean nodeFound = false;

    public EqualityVisitor(ASTNode nodeToLookFor) {
        this.nodeToLookFor = nodeToLookFor;
    }

    public boolean doVisit(ASTNode toVisit) {
        toVisit.visit(this);
        return nodeFound;
    }

    @Override
    public void visitFieldExpression(FieldExpression expression) {
        if (nodeToLookFor == expression) {
            nodeFound = true;
        } else {
            super.visitFieldExpression(expression);
        }
    }

    @Override
    public void visitVariableExpression(VariableExpression expression) {
        if (nodeToLookFor == expression) {
            nodeFound = true;
        } else {
            super.visitVariableExpression(expression);
        }
    }

    @Override
    public void visitConstantExpression(ConstantExpression expression) {
        if (nodeToLookFor == expression) {
            nodeFound = true;
        } else {
            super.visitConstantExpression(expression);
        }
    }

    public static boolean checkForAssignment(ASTNode node, BinaryExpression binaryExpr) {
        return binaryExpr != null && new EqualityVisitor(node).doVisit(binaryExpr.getLeftExpression());
    }
}