/*
    * MIT License
    *
    * Copyright (c) 2010-2022 The Waffle Project Contributors: https://github.com/Waffle/waffle/graphs/contributors
    *
    * Permission is hereby granted, free of charge, to any person obtaining a copy
    * of this software and associated documentation files (the "Software"), to deal
    * in the Software without restriction, including without limitation the rights
    * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   * copies of the Software, and to permit persons to whom the Software is
   * furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in all
   * copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
   * SOFTWARE.
   */
  package waffle.servlet;
  
  import java.io.IOException;
  import java.security.Principal;
  import java.util.Collections;
  import java.util.List;
  
  import javax.servlet.http.HttpServlet;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  import javax.xml.XMLConstants;
  import javax.xml.parsers.ParserConfigurationException;
  import javax.xml.transform.OutputKeys;
  import javax.xml.transform.Transformer;
  import javax.xml.transform.TransformerException;
  import javax.xml.transform.TransformerFactory;
  import javax.xml.transform.dom.DOMSource;
  import javax.xml.transform.stream.StreamResult;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import org.w3c.dom.Document;
  import org.w3c.dom.Element;
  
  import waffle.util.WaffleInfo;
  
  /**
   * A servlet that returns WaffleInfo as XML.
   */
  public class WaffleInfoServlet extends HttpServlet {
  
      /** The Constant serialVersionUID. */
      private static final long serialVersionUID = 1L;
  
      /** The Constant Logger. */
      private static final Logger logger = LoggerFactory.getLogger(WaffleInfoServlet.class);
  
      @Override
      public void doGet(final HttpServletRequest request, final HttpServletResponse response) {
          this.getWaffleInfoResponse(request, response);
      }
  
      @Override
      public void doPost(final HttpServletRequest request, final HttpServletResponse response) {
          this.getWaffleInfoResponse(request, response);
      }
  
      /**
       * Gets the waffle info response.
       *
       * @param request
       *            the request
       * @param response
       *            the response
       */
      public void getWaffleInfoResponse(final HttpServletRequest request, final HttpServletResponse response) {
          final WaffleInfo info = new WaffleInfo();
          try {
              final Document doc = info.getWaffleInfo();
              final Element root = doc.getDocumentElement();
  
              // Add the Request Information Here
              final Element http = this.getRequestInfo(doc, request);
              root.insertBefore(http, root.getFirstChild());
  
              // Lookup Accounts By Name
              final String[] lookup = request.getParameterValues("lookup");
              if (lookup != null) {
                  for (final String name : lookup) {
                      root.appendChild(info.getLookupInfo(doc, name));
                  }
              }
  
              // Write the XML Response
              final TransformerFactory transfac = TransformerFactory.newInstance();
              transfac.setAttribute(XMLConstants.ACCESS_EXTERNAL_DTD, "");
             transfac.setAttribute(XMLConstants.ACCESS_EXTERNAL_STYLESHEET, "");
 
             final Transformer trans = transfac.newTransformer();
             trans.setOutputProperty(OutputKeys.INDENT, "yes");
 
             final StreamResult result = new StreamResult(response.getWriter());
             final DOMSource source = new DOMSource(doc);
             trans.transform(source, result);
             response.setContentType("application/xml");
         } catch (final ParserConfigurationException | TransformerException | IOException e) {
             WaffleInfoServlet.logger.error("", e);
             throw new RuntimeException("See logs for underlying error condition");
         }
     }
 
     /**
      * Gets the request info.
      *
      * @param doc
      *            the doc
      * @param request
      *            the request
      *
      * @return the request info
      */
     private Element getRequestInfo(final Document doc, final HttpServletRequest request) {
         final Element node = doc.createElement("request");
 
         Element value = doc.createElement("AuthType");
         value.setTextContent(request.getAuthType());
         node.appendChild(value);
 
         final Principal p = request.getUserPrincipal();
         if (p != null) {
             final Element child = doc.createElement("principal");
             child.setAttribute("class", p.getClass().getName());
 
             value = doc.createElement("name");
             value.setTextContent(p.getName());
             child.appendChild(value);
 
             value = doc.createElement("string");
             value.setTextContent(p.toString());
             child.appendChild(value);
 
             node.appendChild(child);
         }
 
         final List<String> headers = Collections.list(request.getHeaderNames());
         if (!headers.isEmpty()) {
             final Element child = doc.createElement("headers");
             for (String header : headers) {
                 value = doc.createElement(header);
                 value.setTextContent(request.getHeader(header));
                 child.appendChild(value);
             }
             node.appendChild(child);
         }
         return node;
     }
 
 }