/*
 * Copyright 2003-2010 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.codehaus.groovy.transform.stc;

import static org.codehaus.groovy.ast.ClassHelper.GROOVY_OBJECT_TYPE;

import org.codehaus.groovy.ast.ClassHelper;
import org.codehaus.groovy.ast.ClassNode;
import org.codehaus.groovy.ast.tools.WideningCategories;

/**
 * Static support methods for {@link StaticTypeCheckingVisitor}.
 */
public abstract class StaticTypeCheckingSupport {
    /**
     * This is for internal use only. When an argument method is null, we cannot determine its type, so
     * we use this one as a wildcard.
     */
    final static ClassNode UNKNOWN_PARAMETER_TYPE = ClassHelper.make("<unknown parameter type>");

    public static boolean isBeingCompiled(ClassNode node) {
        return node.getCompileUnit() != null;
    }

    public static boolean implementsInterfaceOrIsSubclassOf(ClassNode type, ClassNode superOrInterface) {
        boolean result = type.equals(superOrInterface)
                || type.isDerivedFrom(superOrInterface)
                || type.implementsInterface(superOrInterface)
                || type == UNKNOWN_PARAMETER_TYPE;
        if (result) {
            return true;
        }
        if (superOrInterface instanceof WideningCategories.LowestUpperBoundClassNode) {
            WideningCategories.LowestUpperBoundClassNode cn = (WideningCategories.LowestUpperBoundClassNode) superOrInterface;
            result = implementsInterfaceOrIsSubclassOf(type, cn.getSuperClass());
            if (result) {
                for (ClassNode interfaceNode : cn.getInterfaces()) {
                    result = type.implementsInterface(interfaceNode);
                    if (!result) break;
                }
            }
            if (result) return true;
        } else if (superOrInterface instanceof UnionTypeClassNode) {
            UnionTypeClassNode union = (UnionTypeClassNode) superOrInterface;
            for (ClassNode delegate : union.getDelegates()) {
                if (implementsInterfaceOrIsSubclassOf(type, delegate)) return true;
            }
        }
        if (type.isArray() && superOrInterface.isArray()) {
            return implementsInterfaceOrIsSubclassOf(type.getComponentType(), superOrInterface.getComponentType());
        }
        if (GROOVY_OBJECT_TYPE.equals(superOrInterface) && !type.isInterface() && isBeingCompiled(type)) {
            return true;
            }
        return false;
    }
}