/**
    * This file Copyright (c) 2003-2010 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.cms.util;
  
  import info.magnolia.cms.core.Content;
  import info.magnolia.cms.core.ItemType;
  import info.magnolia.cms.core.Content.ContentFilter;
  
  import javax.jcr.RepositoryException;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.List;
  
  /**
   * A utility class to navigate amongst the siblings of a given node.
   * This is not synchronized.
   *
   * @author gjoseph
   * @version $Revision: $ ($Author: $)
   */
  public class SiblingsHelper {
      /**
       * Instantiates a SiblingsHelper representing the siblings of the given node and of the same type.
       */
      public static SiblingsHelper of(Content node) throws RepositoryException {
          return new SiblingsHelper(node, filterForTypeOf(node));
      }
  
      /**
       * Instantiates a SiblingsHelper representing the children of the given node,
       * where the current node is the first child of the same type as its parent.
       */
      public static SiblingsHelper childrenOf(Content parent) throws RepositoryException {
          return childrenOf(parent, parent.getItemType());
      }
  
      /**
       * Instantiates a SiblingsHelper representing the children of the given node,
       * where the current node is the first child of given type.
       */
      public static SiblingsHelper childrenOf(Content parent, ItemType childType) throws RepositoryException {
          final NodeTypeFilter filter = new NodeTypeFilter(childType);
          return childrenOf(parent, filter);
      }
  
      /**
       * Instantiates a SiblingsHelper representing the children of the given node,
       * where the current node is the first child from all that pass the filter.
       */
      public static SiblingsHelper childrenOf(Content parent, ContentFilter filter) throws RepositoryException {
          final Collection<Content> children = parent.getChildren(filter);
          if (children.size() < 1) {
              throw new IllegalStateException(parent + " has no children for " + filter);
          }
          final Content firstChild = children.iterator().next();
          return new SiblingsHelper(firstChild, filter);
      }
  
      private static NodeTypeFilter filterForTypeOf(Content node) throws RepositoryException {
          final ItemType type = node.getItemType();
          return new NodeTypeFilter(type);
      }
  
      private final List<Content> siblings;
      private final int lastIndex;
      private Content current = null;
      private int currentIndex = -1;
  
     private SiblingsHelper(Content node, Content.ContentFilter filter) throws RepositoryException {
         this.siblings = new ArrayList<Content>(node.getParent().getChildren(filter));
         this.lastIndex = siblings.size() - 1;
         this.current = node;
         // can't use indexOf to determine current index, as getParent().getChildren() returns a different instance of the node
         for (int i = 0; i <= lastIndex; i++) {
             final Content c = siblings.get(i);
             if (c.getUUID().equals(current.getUUID())) {
                 this.currentIndex = i;
                 break;
             }
         }
         if (currentIndex < 0) {
             throw new IllegalStateException("Given node not found in its own siblings.");
         }
     }
 
     // next() and prev() are not called getNext() and getPrevious() because they change the state.
     public Content next() {
         // TODO : check if iterator hasNext();
         this.currentIndex = currentIndex + 1;
         this.current = siblings.get(currentIndex);
         return current;
     }
 
     public Content prev() {
         // TODO : check if hasPrevious();
         this.currentIndex = currentIndex - 1;
         this.current = siblings.get(currentIndex);
         return current;
     }
 
     public Content goTofirst() {
         this.currentIndex = 0;
         this.current = siblings.get(currentIndex);
         return current;
     }
 
     public Content goTolast() {
         this.currentIndex = siblings.size() - 1;
         this.current = siblings.get(currentIndex);
         return current;
     }
 
     public Content getCurrent() {
         return current;
     }
 
     /**
      * Returns the zero-based index of the current node.
      */
     public int getIndex() {
         return currentIndex;
     }
 
     public boolean isFirst() {
         return currentIndex == 0;
     }
 
     public boolean isLast() {
         return currentIndex == lastIndex;
     }
 
 }