/*
    * SPDX-License-Identifier: MIT
    * See LICENSE file for details.
    *
    * Copyright 2010-2026 The Waffle Project Contributors: https://github.com/Waffle/waffle/graphs/contributors
    */
   package waffle.servlet;
   
   import jakarta.servlet.http.HttpServlet;
  import jakarta.servlet.http.HttpServletRequest;
  import jakarta.servlet.http.HttpServletResponse;
  
  import java.io.IOException;
  import java.security.Principal;
  import java.util.Collections;
  import java.util.List;
  
  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;
     }
 
 }