/**
    * This file Copyright (c) 2003-2015 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.importexport.filters;
  
  import java.util.ArrayList;
  import java.util.List;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import org.xml.sax.Attributes;
  import org.xml.sax.SAXException;
  import org.xml.sax.XMLReader;
  import org.xml.sax.helpers.AttributesImpl;
  import org.xml.sax.helpers.XMLFilterImpl;
  
  
  /**
   * A base abstract filter that can be sub-classed in order to easily implement removal of properties based on their
   * name/content.
   */
  public abstract class SkipNodePropertyFilter extends XMLFilterImpl {
  
      protected Logger log = LoggerFactory.getLogger(getClass());
  
      protected String lastNodeName;
  
      protected boolean skipProperty;
  
      protected boolean invalue;
  
      private List<BufferedElement> elementBuffer = new ArrayList<BufferedElement>();
  
      /**
       * Instantiates a new filter.
       * @param parent wrapped XMLReader
       */
      public SkipNodePropertyFilter(XMLReader parent) {
          super(parent);
      }
  
      /**
       * {@inheritDoc}
       */
      @Override
      public void endElement(String uri, String localName, String qName) throws SAXException {
  
          if (skipProperty) {
              if ("sv:property".equals(qName)) {
                  skipProperty = false;
                  invalue = false;
                  elementBuffer.clear();
              }
              return;
          }
  
          super.endElement(uri, localName, qName);
      }
  
      /**
       * {@inheritDoc}
       */
      @Override
      public void characters(char[] ch, int start, int length) throws SAXException {
          if (!skipProperty) {
              super.characters(ch, start, length);
          }
          else {
              if (invalue) {
                 invalue = false;
                 // Arrays.copyOfRange(ch, start, start + length)
                 char[] range = new char[length];
                 System.arraycopy(ch, start, range, 0, length);
                 String textContent = new String(range);
 
                 // skip only if filter() say so
                 boolean skip = filter(textContent, lastNodeName);
 
                 if (!skip) {
                     while (!elementBuffer.isEmpty()) {
                         BufferedElement be = elementBuffer.remove(0);
                         super.startElement(be.getUri(), be.getLocalName(), be.getQName(), be.getAtts());
                     }
                     super.characters(ch, start, length);
                     skipProperty = false;
                 }
             }
 
         }
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public void startElement(String uri, String localName, String qName, Attributes atts) throws SAXException {
 
         String svname = atts.getValue("sv:name");
         if ("sv:node".equals(qName)) {
             lastNodeName = svname;
         }
         else if ("sv:property".equals(qName) && (getFilteredPropertyName().equals(svname))) {
             elementBuffer.add(new BufferedElement(uri, localName, qName, new AttributesImpl(atts)));
 
             skipProperty = true;
             invalue = false;
         }
         else if (skipProperty && "sv:value".equals(qName)) {
             elementBuffer.add(new BufferedElement(uri, localName, qName, new AttributesImpl(atts)));
             invalue = true;
         }
 
         if (skipProperty) {
             return;
         }
         super.startElement(uri, localName, qName, atts);
 
     }
 
     /**
      * Implement this method to specify the name of the property you want to filter.
      * @return filtered property name
      */
     protected abstract String getFilteredPropertyName();
 
     /**
      * Implement this method to specificy if a given property (given its value and the parent node name) should be
      * removed.
      * @param propertyValue property value
      * @param parentNodeName parent node name
      * @return <code>true</code> if this property should be removed
      */
     protected abstract boolean filter(String propertyValue, String parentNodeName);
 
     /**
      * Temporary element storage node.
      */
     public static class BufferedElement {
 
         private String uri;
 
         private String localName;
 
         private String qName;
 
         private Attributes atts;
 
         public BufferedElement(String uri, String localName, String qName, Attributes atts) {
             this.atts = atts;
             this.localName = localName;
             this.qName = qName;
             this.uri = uri;
         }
 
         /**
          * Returns the uri.
          * @return the uri
          */
         public String getUri() {
             return uri;
         }
 
         /**
          * Sets the uri.
          * @param uri the uri to set
          */
         public void setUri(String uri) {
             this.uri = uri;
         }
 
         /**
          * Returns the localName.
          * @return the localName
          */
         public String getLocalName() {
             return localName;
         }
 
         /**
          * Sets the localName.
          * @param localName the localName to set
          */
         public void setLocalName(String localName) {
             this.localName = localName;
         }
 
         /**
          * Returns the qName.
          * @return the qName
          */
         public String getQName() {
             return qName;
         }
 
         /**
          * Sets the qName.
          * @param name the qName to set
          */
         public void setQName(String name) {
             qName = name;
         }
 
         /**
          * Returns the atts.
          * @return the atts
          */
         public Attributes getAtts() {
             return atts;
         }
 
         /**
          * Sets the atts.
          * @param atts the atts to set
          */
         public void setAtts(Attributes atts) {
             this.atts = atts;
         }
     }
 }