/*
    * Copyright 2007 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.kns.workflow.attribute;
  
  import java.io.StringWriter;
  import java.util.ArrayList;
  import java.util.Iterator;
  import java.util.List;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  import javax.xml.transform.Result;
  import javax.xml.transform.Source;
  import javax.xml.transform.TransformerFactory;
  import javax.xml.transform.dom.DOMSource;
  import javax.xml.transform.stream.StreamResult;
  import javax.xml.xpath.XPath;
  import javax.xml.xpath.XPathConstants;
  import javax.xml.xpath.XPathExpressionException;
  
  import org.apache.commons.lang.StringUtils;
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.kuali.rice.core.util.KeyLabelPair;
  import org.kuali.rice.kew.rule.xmlrouting.XPathHelper;
  import org.kuali.rice.kew.util.XmlHelper;
  import org.kuali.rice.kns.lookup.keyvalues.KeyValuesFinder;
  import org.kuali.rice.kns.service.DataDictionaryService;
  import org.kuali.rice.kns.service.KNSServiceLocator;
  import org.w3c.dom.Element;
  import org.w3c.dom.NamedNodeMap;
  import org.w3c.dom.Node;
  import org.w3c.dom.NodeList;
  
  
  public class KualiXmlAttributeHelper {
      private static Log LOG = LogFactory.getLog(KualiXmlRuleAttributeImpl.class);
      private static XPath xpath = XPathHelper.newXPath();
      private static final String testVal = "\'/[^\']*\'";// get the individual xpath tests.
      private static final String testVal2 = "/[^/]+/" + "*";// have to do this or the compiler gets confused by end comment.
      private static final String cleanVal = "[^/\']+";// get rid of / and ' in the resulting term.
      private static final String ruledataVal = "ruledata[^\']*\'([^\']*)";
      // TODO - enter JIRA
      // below removes wf:xstreamsafe( and )
      // below separates each wf:xstreamsafe() section into separate 'finds'
      private static final Pattern xPathPattern = Pattern.compile(testVal);
      private static final Pattern termPattern = Pattern.compile(testVal2);
      private static final Pattern cleanPattern = Pattern.compile(cleanVal);
      private static final Pattern targetPattern = Pattern.compile(ruledataVal);
  
      public static final String ATTRIBUTE_LABEL_BO_REFERENCE_PREFIX = "kuali_dd_label(";
      public static final String ATTRIBUTE_LABEL_BO_REFERENCE_SUFFIX = ")";
      public static final String ATTRIBUTE_SHORT_LABEL_BO_REFERENCE_PREFIX = "kuali_dd_short_label(";
      public static final String ATTRIBUTE_SHORT_LABEL_BO_REFERENCE_SUFFIX = ")";
      private static final String KUALI_VALUES_FINDER_REFERENCE_PREFIX = "kuali_values_finder_class(";
      private static final String KUALI_VALUES_FINDER_REFERENCE_SUFFIX = ")";
      public static final String notFound = "Label Not Found";
  
      private String lastXPath = "";
  
      /**
       * This method overrides the super class and modifies the XML that it operates on to put the name and the title in the place
       * where the super class expects to see them, even though they may no longer exist in the original XML.
       * 
       * @see org.kuali.rice.kew.rule.xmlrouting.StandardGenericXMLRuleAttribute#getConfigXML()
       */
  
      public Element processConfigXML(Element root) {
          return this.processConfigXML(root, null);
      }
  
      /**
       * This method overrides the super class and modifies the XML that it operates on to put the name and the title in the place
       * where the super class expects to see them, overwriting the original title in the XML.
       * 
       * @see org.kuali.rice.kew.rule.xmlrouting.StandardGenericXMLRuleAttribute#getConfigXML()
       */
  
      public Element processConfigXML(Element root, String[] xpathExpressionElements) {
  
          NodeList fields = root.getElementsByTagName("fieldDef");
          Element theTag = null;
          String docContent = "";
  
  
          /**
          * This section will check to see if document content has been defined in the configXML for the document type, by running an
          * XPath. If this is an empty list the xpath expression in the fieldDef is used to define the xml document content that is
          * added to the configXML. The xmldocument content is of this form, when in the document configXML. <xmlDocumentContent>
          * <org.kuali.rice.kns.bo.SourceAccountingLine> <amount> <value>%totaldollarAmount%</value> </amount>
          * </org.kuali.rice.kns.bo.SourceAccountingLine> </xmlDocumentContent> This class generates this on the fly, by creating an XML
          * element for each term in the XPath expression. When this doesn't apply XML can be coded in the configXML for the
          * ruleAttribute.
          * 
          * @see org.kuali.rice.kew.plugin.attributes.WorkflowAttribute#getDocContent()
          */
 
 
         org.w3c.dom.Document xmlDoc = null;
         if (!xmlDocumentContentExists(root)) { // XML Document content is given because the xpath is non standard
             fields = root.getElementsByTagName("fieldDef");
             xmlDoc = root.getOwnerDocument();
         }
         for (int i = 0; i < fields.getLength(); i++) { // loop over each fieldDef
             String name = null;
             if (!xmlDocumentContentExists(root)) {
                 theTag = (Element) fields.item(i);
 
                 /*
                  * Even though there may be multiple xpath test, for example one for source lines and one for target lines, the
                  * xmlDocumentContent only needs one, since it is used for formatting. The first one is arbitrarily selected, since
                  * they are virtually equivalent in structure, most of the time.
                  */
 
                 List<String> xPathTerms = getXPathTerms(theTag);
                 if (xPathTerms.size() != 0) {
                     Node iterNode = xmlDoc.createElement("xmlDocumentContent");
 
 
                     xmlDoc.normalize();
 
                     iterNode.normalize();
 
                     /*
                      * Since this method is run once per attribute and there may be multiple fieldDefs, the first fieldDef is used
                      * to create the configXML.
                      */
                     for (int j = 0; j < xPathTerms.size(); j++) {// build the configXML based on the Xpath
                         // TODO - Fix the document content element generation
                         iterNode.appendChild(xmlDoc.createElement(xPathTerms.get(j)));
                         xmlDoc.normalize();
 
                         iterNode = iterNode.getFirstChild();
                         iterNode.normalize();
 
                     }
                     iterNode.setTextContent("%" + xPathTerms.get(xPathTerms.size() - 1) + "%");
                     root.appendChild(iterNode);
                 }
             }
             theTag = (Element) fields.item(i);
             // check to see if a values finder is being used to set valid values for a field
             NodeList displayTagElements = theTag.getElementsByTagName("display");
             if (displayTagElements.getLength() == 1) {
                 Element displayTag = (Element) displayTagElements.item(0);
                 List valuesElementsToAdd = new ArrayList();
                 for (int w = 0; w < displayTag.getChildNodes().getLength(); w++) {
                     Node displayTagChildNode = (Node) displayTag.getChildNodes().item(w);
                     if ((displayTagChildNode != null) && ("values".equals(displayTagChildNode.getNodeName()))) {
                         if (displayTagChildNode.getChildNodes().getLength() > 0) {
                             String valuesNodeText = displayTagChildNode.getFirstChild().getNodeValue();
                             String potentialClassName = getPotentialKualiClassName(valuesNodeText, KUALI_VALUES_FINDER_REFERENCE_PREFIX, KUALI_VALUES_FINDER_REFERENCE_SUFFIX);
                             if (StringUtils.isNotBlank(potentialClassName)) {
                                 try {
                                     Class finderClass = Class.forName((String) potentialClassName);
                                     KeyValuesFinder finder = (KeyValuesFinder) finderClass.newInstance();
                                     NamedNodeMap valuesNodeAttributes = displayTagChildNode.getAttributes();
                                     Node potentialSelectedAttribute = (valuesNodeAttributes != null) ? valuesNodeAttributes.getNamedItem("selected") : null;
                                     for (Iterator iter = finder.getKeyValues().iterator(); iter.hasNext();) {
                                         KeyLabelPair keyLabelPair = (KeyLabelPair) iter.next();
                                         Element newValuesElement = root.getOwnerDocument().createElement("values");
                                         newValuesElement.appendChild(root.getOwnerDocument().createTextNode(keyLabelPair.getKey().toString()));
                                         // newValuesElement.setNodeValue(keyLabelPair.getKey().toString());
                                         newValuesElement.setAttribute("title", keyLabelPair.getLabel());
                                         if (potentialSelectedAttribute != null) {
                                             newValuesElement.setAttribute("selected", potentialSelectedAttribute.getNodeValue());
                                         }
                                         valuesElementsToAdd.add(newValuesElement);
                                     }
                                 }
                                 catch (ClassNotFoundException cnfe) {
                                     String errorMessage = "Caught an exception trying to find class '" + potentialClassName + "'";
                                     LOG.error(errorMessage, cnfe);
                                     throw new RuntimeException(errorMessage, cnfe);
                                 }
                                 catch (InstantiationException ie) {
                                     String errorMessage = "Caught an exception trying to instantiate class '" + potentialClassName + "'";
                                     LOG.error(errorMessage, ie);
                                     throw new RuntimeException(errorMessage, ie);
                                 }
                                 catch (IllegalAccessException iae) {
                                     String errorMessage = "Caught an access exception trying to instantiate class '" + potentialClassName + "'";
                                     LOG.error(errorMessage, iae);
                                     throw new RuntimeException(errorMessage, iae);
                                 }
                             }
                             else {
                                 valuesElementsToAdd.add(displayTagChildNode.cloneNode(true));
                             }
                             displayTag.removeChild(displayTagChildNode);
                         }
                     }
                 }
                 for (Iterator iter = valuesElementsToAdd.iterator(); iter.hasNext();) {
                     Element valuesElementToAdd = (Element) iter.next();
                     displayTag.appendChild(valuesElementToAdd);
                 }
             }
             if ((xpathExpressionElements != null) && (xpathExpressionElements.length > 0)) {
                 NodeList fieldEvaluationElements = theTag.getElementsByTagName("fieldEvaluation");
                 if (fieldEvaluationElements.getLength() == 1) {
                     Element fieldEvaluationTag = (Element) fieldEvaluationElements.item(0);
                     List tagsToAdd = new ArrayList();
                     for (int w = 0; w < fieldEvaluationTag.getChildNodes().getLength(); w++) {
                         Node fieldEvaluationChildNode = (Node) fieldEvaluationTag.getChildNodes().item(w);
                         Element newTagToAdd = null;
                         if ((fieldEvaluationChildNode != null) && ("xpathexpression".equals(fieldEvaluationChildNode.getNodeName()))) {
                             newTagToAdd = root.getOwnerDocument().createElement("xpathexpression");
                             newTagToAdd.appendChild(root.getOwnerDocument().createTextNode(generateNewXpathExpression(fieldEvaluationChildNode.getFirstChild().getNodeValue(), xpathExpressionElements)));
                             tagsToAdd.add(newTagToAdd);
                             fieldEvaluationTag.removeChild(fieldEvaluationChildNode);
                         }
                     }
                     for (Iterator iter = tagsToAdd.iterator(); iter.hasNext();) {
                         Element elementToAdd = (Element) iter.next();
                         fieldEvaluationTag.appendChild(elementToAdd);
                     }
                 }
             }
             theTag.setAttribute("title", getBusinessObjectTitle(theTag));
 
         }
         if (LOG.isDebugEnabled()) {
             LOG.debug(XmlHelper.jotNode(root));
             StringWriter xmlBuffer = new StringWriter();
             try {
 
                 root.normalize();
                 Source source = new DOMSource(root);
                 Result result = new StreamResult(xmlBuffer);
                 TransformerFactory.newInstance().newTransformer().transform(source, result);
             }
             catch (Exception e) {
                 LOG.debug(" Exception when printing debug XML output " + e);
             }
             LOG.debug(xmlBuffer.getBuffer());
         }
 
         return root;
     }
 
     private String generateNewXpathExpression(String currentXpathExpression, String[] newXpathExpressionElements) {
         StringBuffer returnableString = new StringBuffer();
         for (int i = 0; i < newXpathExpressionElements.length; i++) {
             String newXpathElement = newXpathExpressionElements[i];
             returnableString.append(newXpathElement);
 
             /*
              * Append the given xpath expression onto the end of the stringbuffer only in the following cases - if there is only one
              * element in the string array - if there is more than one element in the string array and if the current element is not
              * the last element
              */
             if (((i + 1) != newXpathExpressionElements.length) || (newXpathExpressionElements.length == 1)) {
                 returnableString.append(currentXpathExpression);
             }
         }
         return returnableString.toString();
     }
 
     /**
      * This method gets all of the text from the xpathexpression element.
      * 
      * @param root
      * @return
      */
     private String getXPathText(Element root) {
         try {
             String textContent = null;
             Node node = (Node) xpath.evaluate(".//xpathexpression", root, XPathConstants.NODE);
             if (node != null) {
                 textContent = node.getTextContent();
             }
             return textContent;
         }
         catch (XPathExpressionException e) {
             LOG.error("No XPath expression text found in element xpathexpression of configXML for document. " + e);
             return null;
             // throw e; Just writing labels or doing routing report.
         }
     }
 
     /**
      * This method uses an XPath expression to determine if the content of the xmlDocumentContent is empty
      * 
      * @param root
      * @return
      */
     private boolean xmlDocumentContentExists(Element root) {
         try {
             if (((NodeList) xpath.evaluate("//xmlDocumentContent", root, XPathConstants.NODESET)).getLength() == 0) {
                 return false;
             }
         }
         catch (XPathExpressionException e) {
             LOG.error("Error parsing xmlDocumentConfig.  " + e);
             return false;
         }
         return true;
     }
 
     public static String getPotentialKualiClassName(String testString, String prefixIndicator, String suffixIndicator) {
         if ((StringUtils.isNotBlank(testString)) && (testString.startsWith(prefixIndicator)) && (testString.endsWith(suffixIndicator))) {
             return testString.substring(prefixIndicator.length(), testString.lastIndexOf(suffixIndicator));
         }
         return null;
     }
 
     /**
      * Method to look up the title of each fieldDef tag in the RuleAttribute xml. This method checks the following items in the
      * following order:
      * <ol>
      * <li>Check for the business object name from {@link #getBusinessObjectName(Element)}. If it is not found or blank and the
      * 'title' attribute of the fieldDef tag is specified then return the value of the 'title' attribute.
      * <li>Check for the business object name from {@link #getBusinessObjectName(Element)}. If it is found try getting the data
      * dictionary label related to the business object name and the attribute name (found in the xpath expression)
      * <li>Check for the data dictionary title value using the attribute name (found in the xpath expression) and the KFS stand in
      * business object for attributes (see {@link KFSConstants#STAND_IN_BUSINESS_OBJECT_FOR_ATTRIBUTES}
      * <li>Check for the data dictionary title value using the xpath attribute name found in the xpath expression section. Use that
      * attribute name to get the label out of the KFS stand in business object for attributes (see
      * {@link KFSConstants#STAND_IN_BUSINESS_OBJECT_FOR_ATTRIBUTES}
      * <li>Check for the data dictionary title value using the xpath attribute name found in the xpath expression in the
      * wf:ruledata() section. Use that attribute name to get the label out of the KFS stand in business object for attributes (see
      * {@link KFSConstants#STAND_IN_BUSINESS_OBJECT_FOR_ATTRIBUTES}
      * </ol>
      * 
      * @param root - the element of the fieldDef tag
      */
     private String getBusinessObjectTitle(Element root) {
         String businessObjectName = null;
         String businessObjectText = root.getAttribute("title");
         String potentialClassNameLongLabel = getPotentialKualiClassName(businessObjectText, ATTRIBUTE_LABEL_BO_REFERENCE_PREFIX, ATTRIBUTE_LABEL_BO_REFERENCE_SUFFIX);
         String potentialClassNameShortLabel = getPotentialKualiClassName(businessObjectText, ATTRIBUTE_SHORT_LABEL_BO_REFERENCE_PREFIX, ATTRIBUTE_SHORT_LABEL_BO_REFERENCE_SUFFIX);
         // we assume they want the long label... but allow for the short label
         boolean requestedShortLabel = false;
 
         if (StringUtils.isNotBlank(potentialClassNameLongLabel)) {
             businessObjectName = potentialClassNameLongLabel;
         }
         else if (StringUtils.isNotBlank(potentialClassNameShortLabel)) {
             businessObjectName = potentialClassNameShortLabel;
             requestedShortLabel = true;
         }
         if (StringUtils.isNotBlank(businessObjectName)) {
             DataDictionaryService DDService = KNSServiceLocator.getDataDictionaryService();
 
             String title = null;
             String targetVal = lastXPath; // Assume the attribute is the last term in the XPath expression
 
             if (LOG.isErrorEnabled()) {
                 LOG.debug("Finding title in BO=" + businessObjectName + " ObjectName=" + targetVal);
             }
 
             if (StringUtils.isNotBlank(targetVal)) {
                 // try to get the label based on the bo name and xpath attribute
                 if (requestedShortLabel) {
                     title = DDService.getAttributeShortLabel(businessObjectName, targetVal);
                 }
                 else {
                     title = DDService.getAttributeLabel(businessObjectName, targetVal);
                 }
                 if (StringUtils.isNotBlank(title)) {
                     return title;
                 }
             }
             // try to get the label based on the business object and xpath ruledata section
             targetVal = getRuleData(root);
             if (LOG.isErrorEnabled()) {
                 LOG.debug("Finding title in BO=" + businessObjectName + " ObjectName=" + targetVal);
             }
             if (StringUtils.isNotBlank(targetVal)) {
                 title = DDService.getAttributeLabel(businessObjectName, targetVal);
                 if (StringUtils.isNotBlank(title)) {
                     return title;
                 }
             }
             // If haven't found a label yet, its probably because there is no xpath. Use the name attribute to determine the BO
             // attribute to use.
             targetVal = root.getAttribute("name");
             if (LOG.isErrorEnabled()) {
                 LOG.debug("Finding title in BO=" + businessObjectName + " ObjectName=" + targetVal);
             }
             title = DDService.getAttributeLabel(businessObjectName, targetVal);
 
             if (StringUtils.isNotBlank(title)) {
                 return title;
             }
         }
         // return any potentially hard coded title info
         else if ( (StringUtils.isNotBlank(businessObjectText)) && (StringUtils.isBlank(businessObjectName)) ) {
         	return businessObjectText;
         }
         return notFound;
 
     }
 
     /**
      * This method gets the contents of the ruledata function in the xpath statement in the XML
      * 
      * @param root
      * @return
      */
     private String getRuleData(Element root) {
         String xPathRuleTarget = getXPathText(root);
 
         // This pattern may need to change to get the last stanza of the xpath
         if (StringUtils.isNotBlank(xPathRuleTarget)) {
             Matcher ruleTarget = targetPattern.matcher(xPathRuleTarget);
             if (ruleTarget.find()) {
                 xPathRuleTarget = ruleTarget.group(1);
             }
         }
         return xPathRuleTarget;
     }
 
     private List<String> getXPathTerms(Element myTag) {
 
         Matcher xPathTarget;
         String firstMatch;
         List<String> xPathTerms = new ArrayList();
         String allText = getXPathText(myTag);// grab the whole xpath expression
         if (StringUtils.isNotBlank(allText)) {
             xPathTarget = xPathPattern.matcher(allText);
             Matcher termTarget;
             Matcher cleanTarget;
             int theEnd = 0;// Have to define this or the / gets used up with the match and every other term is returned.
 
             xPathTarget.find(theEnd);
             theEnd = xPathTarget.end() - 1;
             firstMatch = xPathTarget.group();
 
 
             termTarget = termPattern.matcher(firstMatch);
             int theEnd2 = 0;
             while (termTarget.find(theEnd2)) { // get each term, clean them up, and add to the list.
                 theEnd2 = termTarget.end() - 1;
                 cleanTarget = cleanPattern.matcher(termTarget.group());
                 cleanTarget.find();
                 lastXPath = cleanTarget.group();
                 xPathTerms.add(lastXPath);
 
             }
         }
         return xPathTerms;
     }
 
     private String getLastXPath(Element root) {
         List<String> tempList = getXPathTerms(root);
         return tempList.get(tempList.size());
     }
 }