/*
 *  Licensed to the Apache Software Foundation (ASF) under one
 *  or more contributor license agreements.  See the NOTICE file
 *  distributed with this work for additional information
 *  regarding copyright ownership.  The ASF licenses this file
 *  to you 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.codehaus.groovy.transform.stc;

import org.codehaus.groovy.ast.ClassNode;
import org.codehaus.groovy.ast.FieldNode;
import org.codehaus.groovy.ast.expr.Expression;
import org.codehaus.groovy.ast.expr.VariableExpression;

import static org.codehaus.groovy.transform.stc.StaticTypesMarker.SWITCH_CONDITION_EXPRESSION_TYPE;

/**
 * A type checking extension that will take care of handling errors which are
 * specific to enums. In particular, it will handle the enum constants within
 * a switch's case statements.
 *
 * @since 3.0.0
 */
public class EnumTypeCheckingExtension extends TypeCheckingExtension {

    /**
     * Creates the enum-specific type-checking extension.
     */
    public EnumTypeCheckingExtension(final StaticTypeCheckingVisitor staticTypeCheckingVisitor) {
        super(staticTypeCheckingVisitor);
    }

    /**
     * Resolves enum constants referenced inside switch case labels, including
     * first-class switch expressions (GROOVY-12255).
     */
    @Override
    public boolean handleUnresolvedVariableExpression(final VariableExpression vexp) {
        Expression selector = selectorOfEnclosingSwitch();
        if (selector != null) {
            ClassNode type = selector.getNodeMetaData(StaticTypesMarker.TYPE);
            if (type != null && type.isEnum()) {
                FieldNode fieldNode = type.redirect().getField(vexp.getName());
                if (fieldNode != null && fieldNode.isEnum()) {
                    vexp.putNodeMetaData(SWITCH_CONDITION_EXPRESSION_TYPE, type);
                    return true;
                }
            }
        }
        return false;
    }

    private Expression selectorOfEnclosingSwitch() {
        return typeCheckingVisitor.typeCheckingContext.getEnclosingSwitchSelector();
    }
}
