/*

  * Copyright 2005-2008 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.kew.xml;

 import java.io.InputStream;

 import java.util.ArrayList;

 import java.util.Collection;

 import java.util.Iterator;

 import javax.xml.parsers.DocumentBuilder;

 import javax.xml.transform.TransformerException;

 import javax.xml.xpath.XPath;

 import javax.xml.xpath.XPathConstants;

 import javax.xml.xpath.XPathExpressionException;

 import javax.xml.xpath.XPathFactory;

 import org.apache.log4j.Logger;

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

 import org.kuali.rice.kew.edl.bo.EDocLiteAssociation;

 import org.kuali.rice.kew.edl.bo.EDocLiteDefinition;

 import org.kuali.rice.kew.edl.bo.EDocLiteStyle;

 import org.kuali.rice.kew.edl.service.EDocLiteService;

 import org.kuali.rice.kew.exception.WorkflowServiceErrorException;

 import org.kuali.rice.kew.exception.WorkflowServiceErrorImpl;

 import org.kuali.rice.kew.rule.bo.RuleAttribute;

 import org.kuali.rice.kew.service.KEWServiceLocator;

 import org.kuali.rice.kew.util.KEWConstants;

 import org.kuali.rice.kew.util.XmlHelper;

 import org.w3c.dom.Document;

 import org.w3c.dom.Element;

 import org.w3c.dom.Node;

 import org.w3c.dom.NodeList;

 /**

  * An XML parser which parses EDocLite definitions.

  *

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

  */

 public class EDocLiteXmlParser {

         private static final Logger LOG = Logger.getLogger(EDocLiteXmlParser.class);

     public static void loadXml(InputStream inputStream, String principalId) {

         DocumentBuilder db = EDLXmlUtils.getDocumentBuilder();

         XPath xpath = XPathFactory.newInstance().newXPath();

         Document doc;

         // parse and save EDocLiteDefinition, EDocLiteStyle, or EDocLiteAssociation xml from to-be-determined XML format

         //try {

         try {

             doc = db.parse(inputStream);

         } catch (Exception e) {

             throw generateException("Error parsing EDocLite XML file", e);

         }

             /*try {

                 LOG.info(XmlHelper.writeNode(doc.getFirstChild(), true));

             } catch (TransformerException e) {

                 LOG.warn("Error displaying document");

             }*/

             NodeList edls;

             try {

                 edls = (NodeList) xpath.evaluate("//edoclite", doc.getFirstChild(), XPathConstants.NODESET);

             } catch (XPathExpressionException e) {

                 throw generateException("Error evaluating XPath expression", e);

             }

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

                 Node edl = edls.item(i);

                 NodeList children = edl.getChildNodes();

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

                     Node node = children.item(j);

                     /*try {

                         LOG.info(XmlHelper.writeNode(node, true));

                     } catch (TransformerException te) {

                         LOG.warn("Error displaying node");

                     }*/

                     if (node.getNodeType() == Node.ELEMENT_NODE) {

                         Element e = (Element) node;

                         if ("style".equals(node.getNodeName())) {

                             LOG.debug("Digesting EDocLiteStyle: " + e.getAttribute("name"));

                             EDocLiteStyle style = parseEDocLiteStyle(e);

                             getEDLService().saveEDocLiteStyle(style);

                         } else if ("edl".equals(node.getNodeName())) {

                             LOG.debug("Digesting EDocLiteDefinition: " + e.getAttribute("name"));

                             EDocLiteDefinition def = parseEDocLiteDefinition(e);

                             getEDLService().saveEDocLiteDefinition(def);

                         } else if ("association".equals(node.getNodeName())) {

                             LOG.debug("Digesting EDocLiteAssociation: " + e.getAttribute("name"));

                             EDocLiteAssociation assoc = parseEDocLiteAssociation(e);

                             getEDLService().saveEDocLiteAssociation(assoc);

                         } else {

                             // LOG.debug("Unrecognized element '" + node.getNodeName() + "' in EDocLite XML doc");

                         }

                     }

                 }

             }

         //} catch (Exception e) {

         //    throw generateException("Error parsing EDocLite XML file", e);

         //}

     }

     private static WorkflowServiceErrorException generateException(String error, Throwable cause) {

         WorkflowServiceErrorException wsee = new WorkflowServiceErrorException(error, new WorkflowServiceErrorImpl(error, KEWConstants.XML_FILE_PARSE_ERROR));

         if (cause != null) {

             wsee.initCause(cause);

         }

         return wsee;

     }

     /**

      * Parses an EDocLiteAssocation

      *

      * @param e

      *            element to parse

      * @return an EDocLiteAssocation

      */

     private static EDocLiteAssociation parseEDocLiteAssociation(Element e) {

         String docType = EDLXmlUtils.getChildElementTextValue(e, "docType");

         if (docType == null) {

             throw generateMissingChildException("association", "docType");

         }

         EDocLiteAssociation assoc = new EDocLiteAssociation();

         assoc.setEdlName(docType);

         assoc.setDefinition(EDLXmlUtils.getChildElementTextValue(e, "definition"));

         assoc.setStyle(EDLXmlUtils.getChildElementTextValue(e, "style"));

         assoc.setActiveInd(Boolean.valueOf(EDLXmlUtils.getChildElementTextValue(e, "active")));

         return assoc;

     }

     /**

      * Parses an EDocLiteStyle

      *

      * @param e

      *            element to parse

      * @return an EDocLiteStyle

      */

     private static EDocLiteStyle parseEDocLiteStyle(Element e) {

         String name = e.getAttribute("name");

         if (name == null || name.length() == 0) {

             throw generateMissingAttribException("style", "name");

         }

         EDocLiteStyle style = new EDocLiteStyle();

         style.setName(name);

         Element stylesheet = null;

         NodeList children = e.getChildNodes();

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

             Node child = children.item(i);

             /*

              * LOG.debug("NodeName: " + child.getNodeName()); LOG.debug("LocalName: " + child.getLocalName()); LOG.debug("Prefix: " + child.getPrefix()); LOG.debug("NS URI: " + child.getNamespaceURI());

              */

             if (child.getNodeType() == Node.ELEMENT_NODE && "xsl:stylesheet".equals(child.getNodeName())) {

                 stylesheet = (Element) child;

                 break;

             }

         }

         if (stylesheet == null) {

             throw generateMissingChildException("style", "xsl:stylesheet");

         }

         try {

             style.setXmlContent(XmlHelper.writeNode(stylesheet, true));

         } catch (TransformerException te) {

             throw generateSerializationException("style", te);

         }

         return style;

     }

     /**

      * Parses an EDocLiteDefinition

      *

      * @param e

      *            element to parse

      * @return an EDocLiteDefinition

      */

     private static EDocLiteDefinition parseEDocLiteDefinition(Element e) {

         EDocLiteDefinition def = new EDocLiteDefinition();

         String name = e.getAttribute("name");

         if (name == null || name.length() == 0) {

             throw generateMissingAttribException(EDLXmlUtils.EDL_E, "name");

         }

         def.setName(name);

         // do some validation to ensure that any attributes referenced actually exist

         // blow up if there is a problem

         XPath xpath = XPathFactory.newInstance().newXPath();

         NodeList fields;

         try {

             fields = (NodeList) xpath.evaluate("fieldDef", e, XPathConstants.NODESET);

         } catch (XPathExpressionException xpee) {

             throw new RuntimeException("Invalid EDocLiteDefinition", xpee);

         }

         if (fields != null) {

             Collection invalidAttributes = new ArrayList(5);

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

                 Node node = (Node) fields.item(i);

                 // they should all be Element...

                 if (node instanceof Element) {

                     Element field = (Element) node;

                     // rely on XML validation to ensure this is present

                     String fieldName = field.getAttribute("name");

                     String attribute = field.getAttribute("attributeName");

                     if (attribute != null && attribute.length() > 0) {

                         RuleAttribute ruleAttrib = KEWServiceLocator.getRuleAttributeService().findByName(attribute);

                         if (ruleAttrib == null) {

                             LOG.error("Invalid attribute referenced in EDocLite definition: " + attribute);

                             invalidAttributes.add("Attribute '" + attribute + "' referenced in field '" + fieldName + "' not found");

                         }

                     }

                 }

             }

             if (invalidAttributes.size() > 0) {

                 LOG.error("Invalid attributes referenced in EDocLite definition");

                 StringBuffer message = new StringBuffer("EDocLite definition contains references to non-existent attributes;\n");

                 Iterator it = invalidAttributes.iterator();

                 while (it.hasNext()) {

                     message.append(it.next());

                     message.append("\n");

                 }

                 throw new RuntimeException(message.toString());

             }

         }

         try {

             def.setXmlContent(XmlHelper.writeNode(e, true));

         } catch (TransformerException te) {

             throw generateSerializationException(EDLXmlUtils.EDL_E, te);

         }

         return def;

     }

     private static WorkflowServiceErrorException generateMissingAttribException(String element, String attrib) {

         return generateException("EDocLite '" + element + "' element must contain a '" + attrib + "' attribute", null);

     }

     private static WorkflowServiceErrorException generateMissingChildException(String element, String child) {

         return generateException("EDocLite '" + element + "' element must contain a '" + child + "' child element", null);

     }

     private static WorkflowServiceErrorException generateSerializationException(String element, TransformerException cause) {

         return generateException("Error serializing EDocLite '" + element + "' element", cause);

     }

     private static EDocLiteService getEDLService() {

             return KEWServiceLocator.getEDocLiteService();

     }

 }