/**
    * Copyright 2005-2016 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;
  
  import org.kuali.rice.core.api.mail.EmailContent;
  import org.kuali.rice.core.api.util.xml.XmlJotter;
  import org.kuali.rice.kew.api.WorkflowRuntimeException;
  import org.w3c.dom.Document;
  import org.w3c.dom.Node;
  
  import javax.xml.transform.Templates;
  import javax.xml.transform.TransformerException;
  import javax.xml.transform.dom.DOMResult;
  import javax.xml.transform.dom.DOMSource;
  import javax.xml.xpath.XPath;
  import javax.xml.xpath.XPathConstants;
  import javax.xml.xpath.XPathExpressionException;
  import javax.xml.xpath.XPathFactory;
  
  
  /**
   * A class which has some convenience methods for handling Emails and stylesheets. 
   * 
   * @author Kuali Rice Team (rice.collab@kuali.org)
   *
   */
  public class EmailStyleHelper {
  
      private static final org.apache.log4j.Logger LOG = org.apache.log4j.Logger.getLogger(EmailStyleHelper.class);
      
      public EmailContent generateEmailContent(Templates style, Document document) {
  	DOMResult result = new DOMResult();
          if (LOG.isDebugEnabled()) {
              LOG.debug("Input document: " + XmlJotter.jotNode(document.getDocumentElement(), true));
          }
          try {
              style.newTransformer().transform(new DOMSource(document), result);
          } catch (TransformerException te) {
              String message = "Error transforming immediate reminder DOM";
              LOG.error(message, te);
              throw new WorkflowRuntimeException(message, te);
          }
  
          Node node = result.getNode();
  
          if (LOG.isDebugEnabled()) {
              LOG.debug("Email to be sent: " + XmlJotter.jotNode(node));
          }
          XPathFactory xpf = XPathFactory.newInstance();
          XPath xpath = xpf.newXPath();
          try {
              String subject = (String) xpath.evaluate("/email/subject", node, XPathConstants.STRING);
              String body = (String) xpath.evaluate("/email/body", node, XPathConstants.STRING);
              // simple heuristic to determine whether content is HTML
              return new EmailContent(subject, body, body.matches("(?msi).*<(\\w+:)?html.*"));
          } catch (XPathExpressionException xpee) {
              throw new WorkflowRuntimeException("Error evaluating generated email content", xpee);
          }
      }
  
  }