/**
    * This file Copyright (c) 2013-2014 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.pages.app.action;
  
  import info.magnolia.cms.core.version.VersionManager;
  import info.magnolia.ui.api.action.AbstractAction;
  import info.magnolia.ui.api.action.ActionExecutionException;
  import info.magnolia.ui.api.location.LocationController;
  import info.magnolia.ui.contentapp.detail.DetailLocation;
  import info.magnolia.ui.contentapp.detail.DetailView;
  import info.magnolia.ui.vaadin.integration.jcr.AbstractJcrNodeAdapter;
  
  import javax.inject.Inject;
  import javax.jcr.RepositoryException;
  import javax.jcr.version.Version;
  import javax.jcr.version.VersionIterator;
  
  import org.apache.commons.lang3.StringUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Opens a preview of the previous version of the selected page.
   */
  public class PreviewPreviousVersionAction extends AbstractAction<PreviewPreviousVersionActionDefinition> {
      private final Logger log = LoggerFactory.getLogger(getClass());
      private final AbstractJcrNodeAdapter nodeItemToEdit;
      private final LocationController locationController;
      private final VersionManager versionManager;
  
      @Inject
      public PreviewPreviousVersionAction(PreviewPreviousVersionActionDefinition definition, AbstractJcrNodeAdapter nodeItemToEdit, LocationController locationController, VersionManager versionManager) {
          super(definition);
          this.nodeItemToEdit = nodeItemToEdit;
          this.locationController = locationController;
          this.versionManager = versionManager;
      }
  
      @Override
      public void execute() throws ActionExecutionException {
          try {
              final String path = nodeItemToEdit.getJcrItem().getPath();
              final String previousVersion = getPreviousVersion();
              DetailLocation location = new DetailLocation("pages", "detail", DetailView.ViewType.VIEW, path, previousVersion);
              locationController.goTo(location);
  
          } catch (RepositoryException e) {
              throw new ActionExecutionException("Could not execute PreviewPreviousVersionAction: ", e);
          }
      }
  
      /**
       * @return Last version if present or an empty string if no version are available.
       */
      private String getPreviousVersion() throws RepositoryException {
          String previousVersion = StringUtils.EMPTY;
          VersionIterator versionIterator = versionManager.getAllVersions(nodeItemToEdit.getJcrItem());
          // Check.
          if (versionIterator == null) {
              return previousVersion;
          }
          // Get last Version.
          while (versionIterator.hasNext()) {
              Version version = versionIterator.nextVersion();
              previousVersion = version.getName();
          }
  
          return previousVersion;
     }
 
 }