/*
 * Copyright 2012 PRODYNA AG
 *
 * Licensed under the Eclipse Public License (EPL), Version 1.0 (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.opensource.org/licenses/eclipse-1.0.php or
 * http://www.nabucco.org/License.html
 *
 * 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.nabucco.framework.generator.compiler.transformation.util.dependency;

import java.util.ArrayList;
import java.util.List;

import org.nabucco.framework.generator.compiler.transformation.NabuccoTransformationException;
import org.nabucco.framework.generator.compiler.visitor.NabuccoVisitorContext;
import org.nabucco.framework.generator.parser.model.NabuccoModel;
import org.nabucco.framework.mda.model.MdaModel;

/**
 * NabuccoDependencyResolver
 * <p/>
 * Resolves dependencies of a NABUCCO model.
 * 
 * @author Nicolas Moser, PRODYNA AG
 */
public class NabuccoDependencyResolver {

    /**
     * Singleton instance.
     */
    private static NabuccoDependencyResolver instance = new NabuccoDependencyResolver();

    /**
     * Private constructor.
     */
    private NabuccoDependencyResolver() {
    }

    /**
     * Singleton access.
     * 
     * @return the NabuccoDependencyResolver instance.
     */
    public static NabuccoDependencyResolver getInstance() {
        return instance;
    }

    /**
     * Loads necessary NABUCCO dependencies.
     * 
     * @param model
     *            the current model
     * @param rootDirectory
     *            the root directory
     * @param outDirectory
     *            the out directory
     * 
     * @return the dependend models
     */
    public List<MdaModel<NabuccoModel>> resolveDependencies(MdaModel<NabuccoModel> model, String rootDirectory,
            String outDirectory) {

        List<MdaModel<NabuccoModel>> referenceList = new ArrayList<MdaModel<NabuccoModel>>();

        NabuccoDependencyVisitor visitor = new NabuccoDependencyVisitor(rootDirectory, outDirectory);

        model.getModel().getUnit().accept(visitor, referenceList);

        return referenceList;
    }

    /**
     * Loads the NABUCCO model for a single import reference.
     * 
     * @param rootDirectory
     *            the NABUCCO root directory
     * @param pkg
     *            the package of the owning type
     * @param importString
     *            the import to resolve
     * @param outDirectory
     *            the NABUCCO out directory
     * 
     * @return the loaded NABUCCO model
     * 
     * @throws NabuccoTransformationException
     *             if the dependency cannot be resolved
     */
    public MdaModel<NabuccoModel> resolveDependency(String rootDirectory, String pkg, String importString,
            String outDirectory) throws NabuccoTransformationException {
        return NabuccoDependencySupport.loadModel(rootDirectory, pkg, importString, outDirectory);
    }

    /**
     * Loads the NABUCCO model for a single import reference.
     * 
     * @param context
     *            the visitor context holding the directory informations
     * @param importString
     *            the import to resolve
     * 
     * @return the loaded NABUCCO model
     * 
     * @throws NabuccoTransformationException
     *             if the dependency cannot be resolved
     */
    public MdaModel<NabuccoModel> resolveDependency(NabuccoVisitorContext context, String pkg, String importString)
            throws NabuccoTransformationException {
        return NabuccoDependencySupport.loadModel(context.getRootDir(), context.getPackage(), importString,
                context.getOutDir());
    }

    /**
     * Loads all possible NABUCCO dependencies.
     * <p/>
     * <b>Warning:</b> This method may cause a huge performance lag. Use carefully.
     * 
     * @param model
     *            the current model
     * @param rootDirectory
     *            the root directory
     * @param outDirectory
     *            the out directory
     * 
     * @return the dependend models
     */
    public List<MdaModel<NabuccoModel>> resolveAllDependencies(MdaModel<NabuccoModel> model, String rootDirectory,
            String outDirectory) {

        List<MdaModel<NabuccoModel>> referenceList = new ArrayList<MdaModel<NabuccoModel>>();

        NabuccoDependencyVisitor visitor = new NabuccoDependencyVisitor(rootDirectory, outDirectory);

        model.getModel().getUnit().accept(visitor, referenceList);

        return referenceList;
    }

    /**
     * Clears the dependency cache.
     */
    public void clearCache() {
        NabuccoDependencySupport.clearCache();
    }

}