/**
    * This file Copyright (c) 2008-2015 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.AbstractContent;
  import info.magnolia.cms.core.Content;
  import info.magnolia.cms.core.ItemType;
  import info.magnolia.cms.core.NodeData;
  
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.Comparator;
  import java.util.List;
  
  import javax.jcr.PathNotFoundException;
  import javax.jcr.RepositoryException;
  
  import org.apache.commons.lang.StringUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  
  /**
   * This wrapper inherits content from the parent hierarchy. The method {@link #isAnchor()} defines
   * the anchor to which the inheritance is performed relative to. By default the anchor is a page
   * (mgnl:content).
   * <p>
   * The inheritance is then performed as follows:
   * <ul>
   * <li>try to get the content directly</li>
   * <li>find next anchor</li>
   * <li>try to get the content from the anchor</li>
   * <li>repeat until no anchor can be found anymore (root)</li>
   * </ul>
   * <p>
   * The {@link #getChildren()} methods merge the direct and inherited children by first adding the
   * inherited children to the collection and then the direct children.
   */
  public class InheritanceContentWrapper extends ContentWrapper {
  
      private static Logger log = LoggerFactory.getLogger(InheritanceContentWrapper.class);
  
      /**
       * From where the inheritance started.
       */
      private final Content start;
  
      /**
       * Used if in the {@link #wrap(Content)} method.
       */
      public InheritanceContentWrapper(Content wrappedContent, Content start) {
          super(wrappedContent);
          this.start = start;
      }
  
      /**
       * Starts the inheritance.
       */
      public InheritanceContentWrapper(Content node) {
          this(node, node);
      }
  
      @Override
      public boolean hasContent(String name) throws RepositoryException {
          return getContentSafely(name) != null;
      }
  
     @Override
     public Content getContent(String name) throws RepositoryException {
         Content inherited = getContentSafely(name);
         if(inherited == null){
             throw new PathNotFoundException("Can't inherit a node [" + name + "] on node [" + getWrappedContent().getHandle() + "]");
         }
         return inherited;
     }
 
     @Override
     public Collection<Content> getChildren(ContentFilter filter, String namePattern, Comparator<Content> orderCriteria){
         List<Content> children = new ArrayList<Content>();
 
         // add inherited children
         try {
             Content inherited = getContentSafely(findNextAnchor(), resolveInnerPath());
             if(inherited != null){
                 children.addAll(((AbstractContent)inherited).getChildren(filter, namePattern, orderCriteria));
             }
         }
         catch (RepositoryException e) {
             throw new RuntimeException("Can't inherit children from " + getWrappedContent(), e);
         }
 
         // add direct children
         children.addAll(((AbstractContent)getWrappedContent()).getChildren(filter, namePattern, orderCriteria));
         if(orderCriteria != null){
             Collections.sort(children, orderCriteria);
         }
 
         return wrapContentNodes(children);
     }
 
     /**
      * Returns the inner path of the this node up to the anchor.
      */
     protected String resolveInnerPath() throws RepositoryException {
         final String path;
         InheritanceContentWrapper anchor = findAnchor();
         // if no anchor left we are relative to the root
         if(anchor == null){
             path = this.getHandle();
         }
         else{
             path = StringUtils.substringAfter(this.getHandle(), anchor.getHandle());
         }
         return StringUtils.removeStart(path,"/");
     }
 
     /**
      * This method returns null if no content has been found.
      */
     protected Content getContentSafely(String name) throws RepositoryException {
         if(getWrappedContent().hasContent(name)){
             return super.getContent(name);
         }
 
         String innerPath = resolveInnerPath() + "/" + name;
         innerPath = StringUtils.removeStart(innerPath,"/");
 
         Content inherited = getContentSafely(findNextAnchor(), innerPath);
         return inherited;
     }
 
     /**
      * This method returns null if no content has been found.
      */
     protected Content getContentSafely(InheritanceContentWrapper anchor, String path) throws RepositoryException{
         if(anchor == null){
             return null;
         }
         if(StringUtils.isEmpty(path)){
             return anchor;
         }
         return anchor.getContentSafely(path);
     }
 
     /**
      * Find the anchor for this node.
      */
     protected InheritanceContentWrapper findAnchor() throws RepositoryException{
         if(getLevel() ==0){
             return null;
         }
         if(isAnchor()){
             return this;
         }
         // until the current node is the anchor
         return ((InheritanceContentWrapper)getParent()).findAnchor();
     }
 
     /**
      * Find next anchor.
      */
     protected InheritanceContentWrapper findNextAnchor() throws RepositoryException{
         final InheritanceContentWrapper currentAnchor = findAnchor();
         if(currentAnchor != null && getLevel() >0){
             return ((InheritanceContentWrapper)currentAnchor.getParent()).findAnchor();
         }
         return null;
     }
 
     /**
      * True if this node is an anchor. By default true if this node is of type mgnl:content (page)
      */
     protected boolean isAnchor() {
         return isNodeType(ItemType.CONTENT.getSystemName());
     }
 
     @Override
     public NodeData getNodeData(String name) {
         try {
             if (getWrappedContent().hasNodeData(name)) {
                 return getWrappedContent().getNodeData(name);
             }
             Content inherited = getContentSafely(findNextAnchor(), resolveInnerPath());
             if(inherited != null){
                 return inherited.getNodeData(name);
             }
         }
         catch (RepositoryException e) {
             throw new RuntimeException("Can't inherit nodedata " + name + "  for " + getWrappedContent(), e);
 
         }
         // creates a none existing node data in the standard manner
         return super.getNodeData(name);
     }
 
     @Override
     public boolean hasNodeData(String name) throws RepositoryException {
         try {
             if (getWrappedContent().hasNodeData(name)) {
                 return getWrappedContent().hasNodeData(name);
             }
             Content inherited = getContentSafely(findNextAnchor(), resolveInnerPath());
             if (inherited != null) {
                 return inherited.hasNodeData(name);
             }
         } catch (RepositoryException e) {
             throw new RuntimeException("Can't inherit nodedata " + name + "  for " + getWrappedContent(), e);
 
         }
         // creates a none existing node data in the standard manner
         return super.hasNodeData(name);
     }
 
     /**
      * Wrap returned nodes. Sets the inherited flag
      */
     @Override
     protected Content wrap(Content node) {
         // only wrap once
         if(node instanceof InheritanceContentWrapper){
             return node;
         }
         return new InheritanceContentWrapper(node, start);
     }
 
     /**
      * True if this is not a sub node of the starting point.
      */
     public boolean isInherited() {
         return !getWrappedContent().getHandle().startsWith(start.getHandle());
     }
 
 }