/**

  * Copyright 2005-2011 The Kuali Foundation

  *

  * Licensed under the Educational Community License, Version 2.0 (the "License");

  * you may not use this file except in compliance with the License.

  * You may obtain a copy of the License at

  *

  * http://www.opensource.org/licenses/ecl2.php

  *

  * Unless required by applicable law or agreed to in writing, software

  * distributed under the License is distributed on an "AS IS" BASIS,

  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

  * See the License for the specific language governing permissions and

  * limitations under the License.

  */

 package org.kuali.rice.edl.impl.components;

 import java.util.ArrayList;

 import java.util.List;

 import org.kuali.rice.edl.impl.EDLContext;

 import org.kuali.rice.edl.impl.EDLModelComponent;

 import org.kuali.rice.edl.impl.EDLXmlUtils;

 import org.kuali.rice.edl.impl.RequestParser;

 import org.w3c.dom.Document;

 import org.w3c.dom.Element;

 import org.w3c.dom.Node;

 import org.w3c.dom.NodeList;

 /**

  * Versions the data element if necessary by checking 'currentVersion' param on request.  If this request is

  * a doc handler request this will configure the dom so the next request will cause the data to be incremented.

  *

  * @author Kuali Rice Team (rice.collab@kuali.org)

  *

  */

 public class VersioningPreprocessor implements EDLModelComponent {

     private static final org.apache.log4j.Logger LOG = org.apache.log4j.Logger.getLogger(VersioningPreprocessor.class);

         public void updateDOM(Document dom, Element configElement, EDLContext edlContext) {

                 RequestParser requestParser = edlContext.getRequestParser();

                 boolean incrementVersion = edlContext.getUserAction().isIncrementVersionAction();

                 boolean replaceVersion = edlContext.getUserAction().isReplaceVersionAction();

                 Element edlContentElement = EDLXmlUtils.getEDLContent(dom, false);

                 Element dataElement = EDLXmlUtils.getDataFromEDLDocument(edlContentElement, false);

                 Element currentVersion = findCurrentVersion(dom);

                 if (currentVersion == null) {

                         Integer currentVersionCount = new Integer(0);

                         currentVersion = EDLXmlUtils.getVersionFromData(dataElement, currentVersionCount);

                 } else if (incrementVersion)  {

                         currentVersion.getAttributeNode("current").setNodeValue("false");

                         int currentVersionCount = new Integer(currentVersion.getAttribute("version")).intValue() + 1;

                         EDLXmlUtils.getVersionFromData(dataElement, new Integer(currentVersionCount));

                 } else if (replaceVersion) {

                     NodeList children = currentVersion.getChildNodes();

                     // important to store these in the last for removal later because we can't safely removeChild in the first for-loop below

                     List<Node> childrenToRemove = new ArrayList<Node>();

                     for (int index = 0; index < children.getLength(); index++) {

                         childrenToRemove.add(children.item(index));

                     }

                     for (Node childToRemove : childrenToRemove) {

                         currentVersion.removeChild(childToRemove);

                     }

                 }

                 requestParser.setAttribute("currentVersion", currentVersion.getAttribute("currentVersion"));

         }

         public static Element findCurrentVersion(Document dom) {

                 Element edlContentElement = EDLXmlUtils.getEDLContent(dom, false);

                 Element dataElement = EDLXmlUtils.getDataFromEDLDocument(edlContentElement, false);

                 NodeList versionElements = dataElement.getElementsByTagName(EDLXmlUtils.VERSION_E);

                 for (int i = 0; i < versionElements.getLength(); i++) {

                         Element version = (Element) versionElements.item(i);

                         Boolean currentVersion = new Boolean(version.getAttribute("current"));

                         if (currentVersion.booleanValue()) {

                                 return version;

                         }

                 }

                 return null;

         }

 }