/**
    * This file Copyright (c) 2012-2016 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.dam.app.setup.migration;
  
  import info.magnolia.dam.jcr.DamConstants;
  import info.magnolia.jcr.util.NodeUtil;
  import info.magnolia.jcr.util.NodeVisitor;
  import info.magnolia.module.InstallContext;
  import info.magnolia.module.delta.AbstractRepositoryTask;
  import info.magnolia.module.delta.TaskExecutionException;
  
  import java.util.ArrayList;
  import java.util.List;
  
  import javax.jcr.Node;
  import javax.jcr.Session;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * This task is responsible for cleaning the content repository.<br>
   * Iterate the list of contentPathsList, get the related Node, and apply the
   * visitor to the Node tree.<br>
   * It use the {@link NodeVisitor} pattern. In order to define your own
   * NodeVisior, extend this migration task and override the addCustomVisitors()
   * protected method.<br>
   **/
  public abstract class AbstractCleanContentForDamMigrationTask extends AbstractRepositoryTask {
  
      private static final Logger log = LoggerFactory.getLogger(AbstractCleanContentForDamMigrationTask.class);
  
      private List<String> contentPathsList;
      private String contentRepository;
      protected Session contentSession;
      protected Session damSession;
  
      /**
       * Default constructor.
       */
      public AbstractCleanContentForDamMigrationTask(String taskName, String taskDescription, String contentRepository, List<String> contentPathsList) {
          super(taskName, taskDescription);
          this.contentPathsList = contentPathsList;
          this.contentRepository = contentRepository;
      }
  
      @Override
      public void doExecute(InstallContext ctx) throws TaskExecutionException {
          log.info("Start to clean Content repository ");
          try {
              // Init
              contentSession = ctx.getJCRSession(contentRepository);
              damSession = ctx.getJCRSession(DamConstants.WORKSPACE);
              for (String path : this.contentPathsList) {
                  if (!contentSession.nodeExists(path)) {
                      log.warn("'{}' path do not exist for the following repository: '{}' No Data migration will be performed", path, contentRepository);
                      continue;
                  }
                  Node contentNode = contentSession.getNode(path);
                  List<NodeVisitor> visitors = createVisitorList();
                  for (NodeVisitor visitor : visitors) {
                      NodeUtil.visit(contentNode, visitor);
                  }
              }
          } catch (Exception e) {
              log.error("Unable to clean content repository", e);
              ctx.error("Unable to perform Migration task " + getName(), e);
              throw new TaskExecutionException(e.getMessage());
         }
         log.info("Successfully execute cleanup of the content repository ");
     }
 
     /**
      * Create the NodeVisitor list used to navigate into the content tree and modify Data references.
      */
     private List<NodeVisitor> createVisitorList() {
         List<NodeVisitor> visitorList = new ArrayList<NodeVisitor>();
         List<NodeVisitor> customVisitor = addCustomVisitors();
         if (customVisitor != null) {
             visitorList.addAll(customVisitor);
         }
         return visitorList;
     }
 
     /**
      * Override in order to add your custom visitors.
      */
     abstract List<NodeVisitor> addCustomVisitors();
 
 }