/**
    * Copyright 2005-2013 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.mail.service.impl;
  
  import java.io.StringWriter;
  import java.util.Collection;
  import java.util.Date;
  import java.util.Map;
  
  import javax.xml.parsers.DocumentBuilder;
  import javax.xml.parsers.DocumentBuilderFactory;
  import javax.xml.parsers.ParserConfigurationException;
  import javax.xml.transform.Templates;
  import javax.xml.transform.TransformerConfigurationException;
  import javax.xml.transform.TransformerException;
  import javax.xml.transform.TransformerFactory;
  import javax.xml.transform.dom.DOMSource;
  import javax.xml.transform.stream.StreamResult;
  import javax.xml.transform.stream.StreamSource;
  
  import org.apache.commons.lang.StringUtils;
  import org.apache.log4j.Logger;
  import org.kuali.rice.core.api.mail.EmailContent;
  import org.kuali.rice.coreservice.api.style.StyleService;
  import org.kuali.rice.core.api.util.RiceConstants;
  import org.kuali.rice.core.api.util.xml.XmlHelper;
  import org.kuali.rice.core.api.util.xml.XmlJotter;
  import org.kuali.rice.kew.api.WorkflowRuntimeException;
  import org.kuali.rice.kew.api.action.ActionItem;
  import org.kuali.rice.kew.api.util.CodeTranslator;
  import org.kuali.rice.kew.doctype.bo.DocumentType;
  import org.kuali.rice.kew.feedback.web.FeedbackForm;
  import org.kuali.rice.kew.mail.CustomEmailAttribute;
  import org.kuali.rice.kew.mail.EmailStyleHelper;
  import org.kuali.rice.kew.routeheader.DocumentRouteHeaderValue;
  import org.kuali.rice.kew.routeheader.service.RouteHeaderService;
  import org.kuali.rice.kew.service.KEWServiceLocator;
  import org.kuali.rice.kew.user.UserUtils;
  import org.kuali.rice.kew.api.KewApiConstants;
  import org.kuali.rice.kim.api.identity.Person;
  import org.kuali.rice.kim.api.identity.principal.Principal;
  import org.kuali.rice.kim.api.services.KimApiServiceLocator;
  import org.kuali.rice.krad.util.GlobalVariables;
  import org.springframework.core.io.DefaultResourceLoader;
  import org.w3c.dom.Document;
  import org.w3c.dom.Element;
  import org.w3c.dom.Node;
  
  
  
  /**
   * EmailContentService that serves EmailContent customizable via XSLT style sheets
   * The global email style name is: kew.email.style
   * If this style is not found, the resource 'defaultEmailStyle.xsl' will be retrieved
   * relative to this class.
   * @author Kuali Rice Team (rice.collab@kuali.org)
   */
  public class StyleableEmailContentServiceImpl extends BaseEmailContentServiceImpl {
      private static final Logger LOG = Logger.getLogger(StyleableEmailContentServiceImpl.class);
  
      protected final String DEFAULT_EMAIL_STYLESHEET_RESOURCE_LOC = "defaultEmailStyle.xsl";
  
      protected StyleService styleService;
      protected EmailStyleHelper styleHelper = new EmailStyleHelper();
      protected String globalEmailStyleSheet = KewApiConstants.EMAIL_STYLESHEET_NAME;
  
      protected RouteHeaderService routeHeaderService;
  
      public void setStyleService(StyleService styleService) {
          this.styleService = styleService;
      }
  
      public void setGlobalEmailStyleSheet(String globalEmailStyleSheet) {
          this.globalEmailStyleSheet = globalEmailStyleSheet;
      }
  
      protected static DocumentBuilder getDocumentBuilder(boolean coalesce) {
          try {
              DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
              dbf.setCoalescing(coalesce);
              return dbf.newDocumentBuilder();
          } catch (ParserConfigurationException e) {
              String message = "Error constructing document builder";
              LOG.error(message, e);
              throw new WorkflowRuntimeException(message, e);
          }
     }
 
     protected static void addObjectXML(Document doc, Object o, Node node, String name) throws Exception {
         Element element = XmlHelper.propertiesToXml(doc, o, name);
 
         if (LOG.isDebugEnabled()) {
             LOG.debug(XmlJotter.jotNode(element));
         }
 
         if (node == null) {
             node = doc;
         }
 
         node.appendChild(element);
     }
 
     protected static void addTextElement(Document doc, Element baseElement, String elementName, Object elementData) {
         Element element = doc.createElement(elementName);
         String dataValue = "";
         if (elementData != null) {
         	dataValue = elementData.toString();
         }
         element.appendChild(doc.createTextNode(dataValue));
         baseElement.appendChild(element);
     }
 
     protected static void addCDataElement(Document doc, Element baseElement, String elementName, Object elementData) {
         Element element = doc.createElement(elementName);
         String dataValue = "";
         if (elementData != null) {
             dataValue = elementData.toString();
         }
         element.appendChild(doc.createCDATASection(dataValue));
         baseElement.appendChild(element);
     }
 
     protected static void addTimestampElement(Document doc, Element baseElement, String elementName, Date elementData) {
         addTextElement(doc, baseElement, elementName, RiceConstants.getDefaultDateFormat().format(elementData));
     }
 
     protected static void addDelegatorElement(Document doc, Element baseElement, ActionItem actionItem) {
         Element delegatorElement = doc.createElement("delegator");
         if ( (actionItem.getDelegatorPrincipalId() != null) && (actionItem.getDelegatorPrincipalId() != null) ) {
             // add empty delegator element
             baseElement.appendChild(delegatorElement);
             return;
         }
         String delegatorType = "";
         String delegatorId = "";
         String delegatorDisplayValue = "";
         if (actionItem.getDelegatorPrincipalId() != null) {
             delegatorType = "user";
             delegatorId = actionItem.getDelegatorPrincipalId();
             Principal delegator = KimApiServiceLocator.getIdentityService().getPrincipal(delegatorId);
             
             if (delegator == null) {
             	LOG.error("Cannot find user for id " + delegatorId);
             	delegatorDisplayValue = "USER NOT FOUND";
             } else {
             	delegatorDisplayValue = UserUtils.getTransposedName(GlobalVariables.getUserSession(), delegator);
             }
         } else if (actionItem.getDelegatorPrincipalId() != null) {
             delegatorType = "workgroup";
             delegatorId = actionItem.getDelegatorGroupId().toString();
             delegatorDisplayValue = KimApiServiceLocator.getGroupService().getGroup(actionItem.getDelegatorGroupId()).getName();
         }
         delegatorElement.setAttribute("type", delegatorType);
         // add the id element
         Element idElement = doc.createElement("id");
         idElement.appendChild(doc.createTextNode(delegatorId));
         delegatorElement.appendChild(idElement);
         // add the display value element
         Element displayValElement = doc.createElement("displayValue");
         displayValElement.appendChild(doc.createTextNode(delegatorDisplayValue));
         delegatorElement.appendChild(displayValElement);
         baseElement.appendChild(delegatorElement);
     }
 
     protected static void addWorkgroupRequestElement(Document doc, Element baseElement, ActionItem actionItem) {
         Element workgroupElement = doc.createElement("workgroupRequest");
         if (actionItem.getGroupId() != null) {
             // add the id element
             Element idElement = doc.createElement("id");
             idElement.appendChild(doc.createTextNode(actionItem.getGroupId()));
             workgroupElement.appendChild(idElement);
             // add the display value element
             Element displayValElement = doc.createElement("displayValue");
             displayValElement.appendChild(doc.createTextNode(actionItem.getGroupId()));
             workgroupElement.appendChild(displayValElement);
         }
         baseElement.appendChild(workgroupElement);
     }
 
     /**
      * This method is used to add the given {@link ActionItem} to the given {@link org.w3c.dom.Document} in a summarized
      * form for use in weekly or daily type reminder e-mails.
      *
      * @param doc - Document to have the ActionItem added to
      * @param actionItem - the action item being added
      * @param user - the current user
      * @param node - the node object to add the actionItem XML to (defaults to the doc variable if null is passed in)
      * @throws Exception
      */
     protected void addSummarizedActionItem(Document doc, ActionItem actionItem, Person user, Node node, DocumentRouteHeaderValue routeHeader) throws Exception {
         if (node == null) {
             node = doc;
         }
 
         Element root = doc.createElement("summarizedActionItem");
 
         // add in all items from action list as preliminary default dataset
         addTextElement(doc, root, "documentId", actionItem.getDocumentId());
         addTextElement(doc, root, "docName", actionItem.getDocName());
         addCDataElement(doc, root, "docLabel", actionItem.getDocLabel());
         addCDataElement(doc, root, "docTitle", actionItem.getDocTitle());
         //DocumentRouteHeaderValue routeHeader = getRouteHeader(actionItem);
         addTextElement(doc, root, "docRouteStatus", routeHeader.getDocRouteStatus());
         addCDataElement(doc, root, "routeStatusLabel", routeHeader.getRouteStatusLabel());
         addTextElement(doc, root, "actionRequestCd", actionItem.getActionRequestCd());
         addTextElement(doc, root, "actionRequestLabel", CodeTranslator.getActionRequestLabel(
                 actionItem.getActionRequestCd()));
         addDelegatorElement(doc, root, actionItem);
         addTimestampElement(doc, root, "createDate", routeHeader.getCreateDate());
         addWorkgroupRequestElement(doc, root, actionItem);
         if (actionItem.getDateTimeAssigned() != null)
             addTimestampElement(doc, root, "dateAssigned", actionItem.getDateTimeAssigned().toDate());
 
         node.appendChild(root);
     }
 
     public DocumentRouteHeaderValue getRouteHeader(ActionItem actionItem) {
     	if (routeHeaderService == null) {
     		routeHeaderService = KEWServiceLocator.getRouteHeaderService();
     	}
         return routeHeaderService.getRouteHeader(actionItem.getDocumentId());
     }
 
     protected Map<String,DocumentRouteHeaderValue> getRouteHeaders(Collection<ActionItem> actionItems) {
     	if (routeHeaderService == null) {
     		routeHeaderService = KEWServiceLocator.getRouteHeaderService();
     	}
     	return routeHeaderService.getRouteHeadersForActionItems(actionItems);
     }
     
     protected static String transform(Templates style, Document doc) {
         StringWriter writer = new StringWriter();
         StreamResult result = new StreamResult(writer);
 
         try {
             style.newTransformer().transform(new DOMSource(doc), result);
             return writer.toString();
         } catch (TransformerException te) {
             String message = "Error transforming DOM";
             LOG.error(message, te);
             throw new WorkflowRuntimeException(message, te);
         }
     }
 
     /**
      * This method retrieves the style from the system using the given name. If none is found the default style xsl file
      * defined by {@link #DEFAULT_EMAIL_STYLESHEET_RESOURCE_LOC} is used.
      *
      * @param styleName
      * @return a valid {@link javax.xml.transform.Templates} using either the given styleName or the default xsl style file
      */
     protected Templates getStyle(String styleName) {
         Templates style = null;
         try {
             style = styleService.getStyleAsTranslet(styleName);
         } catch (TransformerConfigurationException tce) {
             String message = "Error obtaining style '" + styleName + "', using default";
             LOG.error(message, tce);
             // throw new WorkflowRuntimeException("Error obtaining style '" + styleName + "'", tce);
         }
 
         if (style == null) {
             LOG.warn("Could not find specified style, " + styleName + ", using default");
             try {
 
                 style = TransformerFactory.newInstance().newTemplates(new StreamSource(new DefaultResourceLoader().getResource("classpath:org/kuali/rice/kew/mail/" + DEFAULT_EMAIL_STYLESHEET_RESOURCE_LOC).getInputStream()));
             } catch (Exception tce) {
                 String message = "Error obtaining default style from resource: " + DEFAULT_EMAIL_STYLESHEET_RESOURCE_LOC;
                 LOG.error(message, tce);
                 throw new WorkflowRuntimeException("Error obtaining style '" + styleName + "'", tce);
             }
         }
         return style;
     }
 
     protected EmailContent generateEmailContent(String styleName, Document doc) {
         Templates style = getStyle(styleName);
         return styleHelper.generateEmailContent(style, doc);
     }
 
     protected EmailContent generateReminderForActionItems(Person user, Collection<ActionItem> actionItems, String name, String style) {
         DocumentBuilder db = getDocumentBuilder(false);
         Document doc = db.newDocument();
         Element element = doc.createElement(name);
         Map<String,DocumentRouteHeaderValue> routeHeaders = getRouteHeaders(actionItems);
         
         setStandardAttributes(element);
         doc.appendChild(element);
 
         try {
             addObjectXML(doc, user, element, "user");
             for (ActionItem actionItem: actionItems) {
                 try {
                     addSummarizedActionItem(doc, actionItem, user, element, routeHeaders.get(actionItem.getDocumentId()));
                 } catch (Exception e) {
                     String message = "Error generating XML for action item: " + actionItem;
                     LOG.error(message, e);
                     throw new WorkflowRuntimeException(e);
                 }
             }
 
         } catch (Exception e) {
             String message = "Error generating XML for action items: " + actionItems;
             LOG.error(message, e);
             throw new WorkflowRuntimeException(e);
         }
 
         return generateEmailContent(style, doc);
     }
 
     protected void setStandardAttributes(Element e) {
         e.setAttribute("env", getDeploymentEnvironment());
         e.setAttribute("applicationEmailAddress", getApplicationEmailAddress());
         e.setAttribute("actionListUrl", getActionListUrl());
         e.setAttribute("preferencesUrl", getPreferencesUrl());
     }
 
     /**
      * This method generates an {@link EmailContent} object using the given parameters.  Part of this operation includes
      * serializing the given {@link ActionItem} to XML. The following objects and methods are included in the serialization:
      *
      * <ul>
      * <li>{@link Person}</li>
      * <li>{@link Person#getPrincipalName()}</li>
      * <li>{@link DocumentRouteHeaderValue}</li>
      * <li>{@link DocumentRouteHeaderValue#getInitiatorUser()}</li>
      * <li>{@link DocumentRouteHeaderValue#getDocumentType()}</li>
      * <li>{@link Person}</li>
      * </ul>
      *
      * @param user - the current user
      * @param actionItem - the action item being added
      * @param documentType - the document type that the custom email style sheet will come from
      * @param node - the node object to add the actionItem XML to (defaults to the doc variable if null is passed in)
      * @throws Exception
      */
     @Override
 	public EmailContent generateImmediateReminder(Person user, ActionItem actionItem, DocumentType documentType) {
         if (user != null) {
             LOG.info("Starting generation of immediate email reminder...");
        	    LOG.info("Action Id: " + actionItem.getId() +
     			 ";  ActionRequestId: " + actionItem.getActionRequestId() + 
     			 ";  Action Item Principal Id: " + actionItem.getPrincipalId());
             LOG.info("User Principal Id: " + user.getPrincipalId());
             // change style name based on documentType when configurable email style on document is implemented...
             String styleSheet = documentType.getCustomEmailStylesheet();
             LOG.debug(documentType.getName() + " style: " + styleSheet);
             if (styleSheet == null) {
                 styleSheet = globalEmailStyleSheet;
             }
 
             LOG.info("generateImmediateReminder using style sheet: "+ styleSheet + " for Document Type " + documentType.getName());
             // return generateReminderForActionItems(user, actionItems, "immediateReminder", styleSheet);
             DocumentBuilder db = getDocumentBuilder(false);
             Document doc = db.newDocument();
             Element element = doc.createElement("immediateReminder");
             setStandardAttributes(element);
             doc.appendChild(element);
 
             try {
                 addObjectXML(doc, user, element, "user");
                 // addActionItem(doc, actionItem, user, node);
                 Node node = element;
                 if (node == null) {
                     node = doc;
                 }
 
                 Element root = doc.createElement("actionItem");
                 // append the custom body and subject if they exist
                 try {
                     CustomEmailAttribute customEmailAttribute = getCustomEmailAttribute(user, actionItem);
                     if (customEmailAttribute != null) {
                         String customBody = customEmailAttribute.getCustomEmailBody();
                         if (!org.apache.commons.lang.StringUtils.isEmpty(customBody)) {
                             Element bodyElement = doc.createElement("customBody");
                             bodyElement.appendChild(doc.createTextNode(customBody));
                             root.appendChild(bodyElement);
                         }
                         String customEmailSubject = customEmailAttribute.getCustomEmailSubject();
                         if (!org.apache.commons.lang.StringUtils.isEmpty(customEmailSubject)) {
                             Element subjectElement = doc.createElement("customSubject");
                             subjectElement.appendChild(doc.createTextNode(customEmailSubject));
                             root.appendChild(subjectElement);
                         }
                     }
                 } catch (Exception e) {
                     LOG.error("Error when checking for custom email body and subject.", e);
                 }
                 Person person = KimApiServiceLocator.getPersonService().getPerson(actionItem.getPrincipalId());
                 DocumentRouteHeaderValue header = getRouteHeader(actionItem);
                 // keep adding stuff until we have all the xml we need to formulate the message :/
                 addObjectXML(doc, actionItem, root, "actionItem");
                 addObjectXML(doc, person, root, "actionItemPerson");
                 addTextElement(doc, root, "actionItemPrincipalId", person.getPrincipalId());
                 addTextElement(doc, root, "actionItemPrincipalName", person.getPrincipalName());
                 addDocumentHeaderXML(doc, header, root, "doc");
                 addObjectXML(doc, header.getInitiatorPrincipal(), root, "docInitiator");
                 addTextElement(doc, root, "docInitiatorDisplayName", header.getInitiatorDisplayName());
                 addObjectXML(doc, header.getDocumentType(), root, "documentType");
 
                 node.appendChild(root);
             } catch (Exception e) {
                 String message = "Error generating immediate reminder XML for action item: " + actionItem;
                 LOG.error(message, e);
                 throw new WorkflowRuntimeException(e);
             }
             LOG.info("Leaving generation of immeidate email reminder...");
             return generateEmailContent(styleSheet, doc);
         }
         LOG.info("Skipping generation of immediate email reminder due to the user being null");
         return null;
     }
     
     /**
      * This method handles converting the DocumentRouteHeaderValue into an XML representation.  The reason we can't just use
      * propertiesToXml like we have elsewhere is because the doc header has a String attached to it that has the XML document
      * content in it.  The default serialization of this will serialize this as a String so we will end up with escaped XML
      * in our output which we won't be able to process with the email stylesheet.  So we need to read the xml content from
      * the document and parse it into a DOM object so it can be appended to our output.
      */
     protected void addDocumentHeaderXML(Document document, DocumentRouteHeaderValue documentHeader, Node node, String elementName) throws Exception {
     	Element element = XmlHelper.propertiesToXml(document, documentHeader, elementName);
     	// now we need to "fix" the xml document content because it's going to be in there as escaped XML
     	Element docContentElement = (Element)element.getElementsByTagName("docContent").item(0);
     	String documentContent = docContentElement.getTextContent();
     	
     	if (!StringUtils.isBlank(documentContent) && documentContent.startsWith("<")) {
     		Document documentContentXML = XmlHelper.readXml(documentContent);
     		Element documentContentElement = documentContentXML.getDocumentElement();
     		documentContentElement = (Element)document.importNode(documentContentElement, true);
     	
     		// remove the old, bad text content
     		docContentElement.removeChild(docContentElement.getFirstChild());
     	
     		// replace with actual XML
     		docContentElement.appendChild(documentContentElement);
         } else {
             // in this case it means that the XML is encrypted, unfortunately, we have no way to decrypt it since
             // the key is stored in the client application.  We will just include the doc content since none of our
             // current IU clients will be using this feature right away
 
             // remove the old, bad text content
             docContentElement.removeChild(docContentElement.getFirstChild());
         }
     	
     	if (LOG.isDebugEnabled()) {
             LOG.debug(XmlJotter.jotNode(element));
         }
 
         node.appendChild(element);
     }
 
     @Override
 	public EmailContent generateWeeklyReminder(Person user, Collection<ActionItem> actionItems) {
         return generateReminderForActionItems(user, actionItems, "weeklyReminder", globalEmailStyleSheet);
     }
 
     @Override
 	public EmailContent generateDailyReminder(Person user, Collection<ActionItem> actionItems) {
         return generateReminderForActionItems(user, actionItems, "dailyReminder", globalEmailStyleSheet);
     }
 
     @Override
 	public EmailContent generateFeedback(FeedbackForm form) {
         DocumentBuilder db = getDocumentBuilder(true);
         Document doc = db.newDocument();
         String styleSheet = globalEmailStyleSheet;
 
         // if the doc type is specified, see if that doc has a custom email stylesheet and use it
         // NOTE: do we need to do this for feedback? presumably feedback will be going back to admins
         /*String docTypeName = form.getDocumentType();
         if (!StringUtils.isBlank(docTypeName)) {
             DocumentType docType = KEWServiceLocator.getDocumentTypeService().findByName(docTypeName);
             if (docType == null) {
                 LOG.error("User specified document type '" + docTypeName + "' in feedback form, but the document type was not found in the system");
             } else {
                 if (docType.getCustomEmailStylesheet() != null) {
                     styleSheet = docType.getCustomEmailStylesheet();
                 }
             }
         }*/
         LOG.info("form: " + form.getDocumentId());
         try {
             addObjectXML(doc, form, null, "feedback");
         } catch (Exception e) {
             String message = "Error generating XML for feedback form: " + form;
             LOG.error(message, e);
             throw new WorkflowRuntimeException(message, e);
         }
         setStandardAttributes(doc.getDocumentElement());
 
         return generateEmailContent(styleSheet, doc);
     }
 }