/**
 * This file Copyright (c) 2011-2012 Magnolia International
 * Ltd.  (http://www.magnolia-cms.com). All rights reserved.
 *
 *
 * This file is dual-licensed under both the Magnolia
 * Network Agreement and the GNU General Public License.
 * You may elect to use one or the other of these licenses.
 *
 * This file is distributed in the hope that it will be
 * useful, but AS-IS and WITHOUT ANY WARRANTY; without even the
 * implied warranty of MERCHANTABILITY or FITNESS FOR A
 * PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT.
 * Redistribution, except as permitted by whichever of the GPL
 * or MNA you select, is prohibited.
 *
 * 1. For the GPL license (GPL), you can redistribute and/or
 * modify this file under the terms of the GNU General
 * Public License, Version 3, as published by the Free Software
 * Foundation.  You should have received a copy of the GNU
 * General Public License, Version 3 along with this program;
 * if not, write to the Free Software Foundation, Inc., 51
 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * 2. For the Magnolia Network Agreement (MNA), this file
 * and the accompanying materials are made available under the
 * terms of the MNA which accompanies this distribution, and
 * is available at http://www.magnolia-cms.com/mna.html
 *
 * Any modifications to this file must keep this entire header
 * intact.
 *
 */
package info.magnolia.rendering.template.variation;

import info.magnolia.beanmerger.BeanMergerUtil;
import info.magnolia.cms.core.AggregationState;
import info.magnolia.context.MgnlContext;
import info.magnolia.rendering.template.RenderableDefinition;

/**
 * Variation resolver that will use a variation with the same name as the extension.
 *
 * @version $Id$
 */
public class ExtensionVariationResolver implements RenderableVariationResolver {

    @Override
    public RenderableDefinition resolveVariation(RenderableDefinition renderableDefinition) {

        AggregationState aggregationState = getAggregationStateSafely();
        if (aggregationState == null) {
            return null;
        }

        String extension = aggregationState.getExtension();
        RenderableDefinition variation = renderableDefinition.getVariations().get(extension);
        if (variation == null) {
            return null;
        }

        return BeanMergerUtil.merge(variation, renderableDefinition);
    }

    /**
     * This gets the aggregation state without throwing an exception if the current context is not a WebContext.
     */
    protected AggregationState getAggregationStateSafely() {
        if(MgnlContext.isWebContext()){
            return MgnlContext.getAggregationState();
        }
        return null;
    }
}