/*
 * 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.netbeans.modules.gradle.persistence;

import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.io.File;
import java.util.concurrent.atomic.AtomicBoolean;
import org.netbeans.modules.j2ee.persistence.api.PersistenceScope;
import org.netbeans.modules.j2ee.persistence.api.PersistenceScopes;
import org.netbeans.modules.j2ee.persistence.spi.PersistenceScopeProvider;
import org.netbeans.modules.j2ee.persistence.spi.PersistenceScopesProvider;
import org.netbeans.modules.j2ee.persistence.spi.support.PersistenceScopesHelper;
import org.openide.filesystems.FileUtil;

/**
 * Gradle Implementation of <CODE>org.netbeans.modules.j2ee.persistence.spi.PersistenceScopesProvider</CODE> also
 * implements PropertyChangeListener to watch for changes on the persistence.xml file
 *
 * @author Daniel Mohni
 */
public class PersistenceScopesProviderImpl implements PersistenceScopesProvider, PropertyChangeListener {

    private PersistenceScopesHelper scopesHelper = null;
    private PersistenceScopeProvider scopeProvider = null;
    private final AtomicBoolean checked = new AtomicBoolean();

    /**
     * Creates a new instance of PersistenceScopesProviderImpl
     *
     * @param provider the PersistenceScopeProvider instance to use for lookups
     */
    public PersistenceScopesProviderImpl(PersistenceScopeProvider provider) {
        scopesHelper = new PersistenceScopesHelper();
        scopeProvider = provider;
    }

    /**
     * property access to the persistence scopes
     *
     * @return the PersistenceScopes instance of the current project
     */
    @Override
    public PersistenceScopes getPersistenceScopes() {
        if (checked.compareAndSet(false, true)) {
            checkScope();
        }
        return scopesHelper.getPersistenceScopes();
    }

    /**
     * checks and initialise, updates the PersistenceScopeHelper of the current project
     */
    private void checkScope() {
        PersistenceScope scope = scopeProvider.findPersistenceScope(null);

        if (scope != null) {
            File persistenceXml = FileUtil.toFile(scope.getPersistenceXml());
            scopesHelper.changePersistenceScope(scope, persistenceXml);
        } else {
            scopesHelper.changePersistenceScope(null, null);
        }
    }

    /**
     * watches for creation and deletion of the persistence.xml file
     *
     * @param evt the change event to process
     */
    @Override
    public void propertyChange(PropertyChangeEvent evt) {
        if (GradlePersistenceProvider.PROP_PERSISTENCE.equals(evt.getPropertyName())) {
            checkScope();
        }
    }

}