/**
    * This file Copyright (c) 2011 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.jcr.wrapper;
  
  import info.magnolia.cms.core.MgnlNodeType;
  import info.magnolia.jcr.RuntimeRepositoryException;
  import info.magnolia.jcr.iterator.ChainedNodeIterator;
  import info.magnolia.jcr.iterator.FilteringNodeIterator;
  import info.magnolia.jcr.predicate.AbstractPredicate;
  
  import java.util.ArrayList;
  import java.util.List;
  
  import javax.jcr.Node;
  import javax.jcr.NodeIterator;
  import javax.jcr.PathNotFoundException;
  import javax.jcr.Property;
  import javax.jcr.RepositoryException;
  
  import org.apache.commons.lang.StringUtils;
  
  
  /**
   * This wrapper inherits nodes from the parent hierarchy. The method {@link #isAnchor()} defines
   * the anchor to which the inheritance is performed relative to. By default the anchor is of type
   * (mgnl:content).
   * <p>
   * The inheritance is then performed as follows:
   * <ul>
   * <li>try to get the node directly</li>
   * <li>find next anchor</li>
   * <li>try to get the node from the anchor</li>
   * <li>repeat until no anchor can be found anymore (root)</li>
   * </ul>
   * <p>
   * The {@link #getNodes()} and {@link #getNodes(String)} methods merge the direct and inherited children by first adding the
   * inherited children to the iterator and then the direct children.
   *
   * @version $Id$
   */
  public class InheritanceNodeWrapper extends ChildWrappingNodeWrapper {
  
      private final Node start;
      private final AbstractPredicate<Node> filter;
  
      public InheritanceNodeWrapper(Node node) {
          this(node, node);
      }
  
      public InheritanceNodeWrapper(Node node, AbstractPredicate<Node> filter) {
          this(node, node, filter);
      }
  
      public InheritanceNodeWrapper(Node node, Node start, AbstractPredicate<Node> filter) {
          super(node);
          this.start = start;
          this.filter = filter;
      }
  
      public InheritanceNodeWrapper(Node node, Node start) {
          super(node);
          this.start = start;
          this.filter = new AbstractPredicate<Node>() {
  
              @Override
              public boolean evaluateTyped(Node t) {
                  return true;
              }
         };
     }
 
     /**
      * Find the anchor for this node.
      */
     protected InheritanceNodeWrapper findAnchor() throws RepositoryException{
         if(this.getDepth() == 0){
             return null;
         }
         if(isAnchor()){
             return this;
         }
         // until the current node is the anchor
         return ((InheritanceNodeWrapper)wrapNode(this.getParent())).findAnchor();
     }
 
     /**
      * Find next anchor.
      */
     protected InheritanceNodeWrapper findNextAnchor() throws RepositoryException{
         final InheritanceNodeWrapper currentAnchor = findAnchor();
         if(currentAnchor != null && this.getDepth() >0){
             return ((InheritanceNodeWrapper)wrapNode(currentAnchor.getParent())).findAnchor();
         }
         return null;
     }
 
     /**
      * True if this node is an anchor. By default true if this node is of type {@link MgnlNodeType#NT_CONTENT}.
      */
     protected boolean isAnchor() {
         try {
             return this.isNodeType(MgnlNodeType.NT_CONTENT);
         } catch (RepositoryException e) {
             throw new RuntimeRepositoryException(e);
         }
     }
 
     /**
      * This method returns null if no node has been found.
      */
     protected Node getNodeSafely(String relPath) throws RepositoryException {
         if(getWrappedNode().hasNode(relPath)) {
             return wrapNode(getWrappedNode().getNode(relPath));
         }
 
         String innerPath = resolveInnerPath() + "/" + relPath;
         innerPath = StringUtils.removeStart(innerPath,"/");
 
         Node inherited = getNodeSafely(findNextAnchor(), innerPath);
         return inherited;
     }
 
     /**
      * Returns the inner path of the this node up to the anchor.
      */
     protected String resolveInnerPath() throws RepositoryException {
         final String path;
         InheritanceNodeWrapper anchor = findAnchor();
         // if no anchor left we are relative to the root
         if(anchor == null){
             path = this.getPath();
         }
         else{
             path = StringUtils.substringAfter(this.getPath(), anchor.getPath());
         }
         return StringUtils.removeStart(path,"/");
     }
 
     /**
      * This method returns null if no node has been found.
      */
     protected Node getNodeSafely(InheritanceNodeWrapper anchor, String path) throws RepositoryException{
         if(anchor == null){
             return null;
         }
         if(StringUtils.isEmpty(path)){
             return anchor;
         }
         return anchor.getNodeSafely(path);
     }
 
 
     @Override
     public boolean hasNode(String relPath) throws RepositoryException {
         return getNodeSafely(relPath) != null;
     }
 
     @Override
     public Node getNode(String relPath) throws PathNotFoundException, RepositoryException {
         Node inherited = getNodeSafely(relPath);
         if (inherited == null || !filter.evaluateTyped(inherited)) {
             throw new PathNotFoundException("Can't inherit a node [" + relPath + "] on node [" + getWrappedNode().getPath() + "]");
         }
         return wrapNode(inherited);
     }
 
     @Override
     public NodeIterator getNodes() throws RepositoryException {
         List<NodeIterator> nodes = new ArrayList<NodeIterator>();
 
         // add inherited children
         try {
             Node inherited = getNodeSafely(findNextAnchor(), resolveInnerPath());
             if(inherited != null && !inherited.getPath().startsWith(this.getPath())){
                 nodes.add(inherited.getNodes());
             }
         }
         catch (RepositoryException e) {
             throw new RuntimeException("Can't inherit children from " + getWrappedNode(), e);
         }
         // add direct children
         nodes.add(getWrappedNode().getNodes());
 
         return wrapNodeIterator(new FilteringNodeIterator(new ChainedNodeIterator(nodes), filter));
     }
 
     @Override
     public NodeIterator getNodes(String namePattern) throws RepositoryException {
         List<NodeIterator> nodes = new ArrayList<NodeIterator>();
 
         // add inherited children
         try {
             Node inherited = getNodeSafely(findNextAnchor(), resolveInnerPath());
             if(inherited != null && !inherited.getPath().startsWith(this.getPath())){
                 nodes.add(inherited.getNodes(namePattern));
             }
         }
         catch (RepositoryException e) {
             throw new RepositoryException("Can't inherit children from " + getWrappedNode(), e);
         }
         // add direct children
         nodes.add(getWrappedNode().getNodes(namePattern));
 
         return wrapNodeIterator(new FilteringNodeIterator(new ChainedNodeIterator(nodes), filter));
     }
 
     @Override
     public Property getProperty(String relPath) throws PathNotFoundException, RepositoryException {
         try {
             if (getWrappedNode().hasProperty(relPath)) {
                 return getWrappedNode().getProperty(relPath);
             }
             Node inherited = getNodeSafely(findNextAnchor(), resolveInnerPath());
             if(inherited != null){
                 return inherited.getProperty(relPath);
             } else {
                 throw new PathNotFoundException("No property exists at " + relPath + " or current Session does not have read access to it.");
             }
         }
         catch (RepositoryException e) {
             throw new RepositoryException("Can't inherit property " + relPath + "  for " + getWrappedNode(), e);
         }
     }
 
     @Override
     public boolean hasProperty(String name) throws RepositoryException {
         try {
             if (getWrappedNode().hasProperty(name)) {
                 return true;
             }
             Node inherited = getNodeSafely(findNextAnchor(), resolveInnerPath());
             if (inherited != null) {
                 return inherited.hasProperty(name);
             }
         } catch (RepositoryException e) {
             throw new RuntimeException("Can't inherit nodedata " + name + "  for " + getWrappedNode(), e);
 
         }
         // creates a none existing node data in the standard manner
         return super.hasProperty(name);
     }
 
     /**
      * True if this is not a sub node of the starting point.
      */
     public boolean isInherited() {
         try {
             return !this.getPath().startsWith(start.getPath());
         } catch (RepositoryException e) {
             throw new RuntimeRepositoryException(e);
         }
     }
 
     @Override
     public Node wrapNode(Node node) {
         if(node instanceof InheritanceNodeWrapper) {
             return node;
         }
         return new InheritanceNodeWrapper(node, start, filter);
     }
 }