// package org.javatrainer; // Jeff: Not needed
package esse;
/**
 * @author Anika Sindhwani, with the design and help from Jeff Offutt
 *         Date: August, 2013
 *         Version 2
 */

import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;

import java.io.*;
//import java.sql.*;

//import javax.servlet.*;
//import javax.servlet.http.*;

import javax.servlet.ServletException;
// import javax.servlet.annotation.WebServlet; // Jeff: Doesn't compile
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
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.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

/**
 * Servlet implementation class StarRating
 */
// @WebServlet("/ProjectList") // Jeff: Our compiler doesn't support this.
public class StarRating extends HttpServlet
{
   // private static final long serialVersionUID = 1L; // Jeff: Not needed

   /**
    * @see HttpServlet#doGet (HttpServletRequest request, HttpServletResponse response)
    */
   protected void doGet (HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
   {
      try
      {
         String servletPath = "/expProj/"; // Anika (Jeff: This is not used)
         // String webServerPath = "/"; // Anika
         String webServerPath = "http://cs.gmu.edu/~offutt/esse/"; // Jeff
         // String xmlPath = "c:/eclipse/"; // Anika
         String xmlPath = "/var/www/CS/webapps/offutt/WEB-INF/data/esse/"; // Jeff
         // String codeFilePath = "c:/eclipse/Projects/" + fileName + "/"; // Anika
         String codeFilePath = webServerPath + "Projects/"; // Jeff

         String fileName = request.getParameter ("name");
         String fileLanguage = request.getParameter ("language").toLowerCase();

         // Open the XML file and create list of elements
         File fXmlFile = new File (xmlPath + "projectList.xml");
         DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
         DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
         Document doc = dBuilder.parse (fXmlFile);

         //get elements from XML
         doc.getDocumentElement().normalize();
         String responseXML = new String();
         NodeList nodes = doc.getElementsByTagName ("project");
         for (int i = 0; i < nodes.getLength(); i++)
         {
            Node node = nodes.item (i);

            if (node.getNodeType() == Node.ELEMENT_NODE)
            {
               Element element = (Element) node;
               //checks data to update the right xml tags
               String fileNameFromXML = element.getElementsByTagName ("name").item(0).getTextContent();
               String fileLanguageFromXML = element.getElementsByTagName ("language").item(0).getTextContent().toLowerCase();
               if ((!fileNameFromXML.equals (fileName)) ||
                  (!fileLanguageFromXML.equals (fileLanguage)))
               {
                  continue;
               }
               //increase numberOfRatings by 1
               int numberOfRatings = Integer.parseInt (element.getElementsByTagName ("numberOfRatings").item(0).getTextContent());
               numberOfRatings ++;

               // Update the number of rankings
               element.getElementsByTagName ("numberOfRatings").item(0).setTextContent (Integer.toString (numberOfRatings));

               //Update the total of all rankings
               int totalStars = Integer.parseInt (element.getElementsByTagName ("totalStars").item(0).getTextContent());

               int newRatingFromUser = Integer.parseInt (request.getParameter ("rating"));
               totalStars += newRatingFromUser;
               String newTotalStars = Integer.toString (totalStars);

               element.getElementsByTagName ("totalStars").item(0).setTextContent (newTotalStars);

               float Average = (float) totalStars / (float) numberOfRatings;
               String newAverage = String.format ("%1.1f",Average);

               // write the content into xml file
               TransformerFactory transformerFactory = TransformerFactory.newInstance();
               Transformer transformer = transformerFactory.newTransformer();
               DOMSource source = new DOMSource (doc);
               StreamResult result = new StreamResult (new File (xmlPath + "projectList.xml"));
               transformer.transform (source, result);

               response.setContentType ("text/xml");
               PrintWriter out = response.getWriter();

               // prepare the response in XML format
               responseXML = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>";
               responseXML += "<root>";
               responseXML += "<newAverage>" + newAverage + "</newAverage>";
               responseXML += " <numberOfRatings>" + numberOfRatings + "</numberOfRatings>";
               responseXML += "</root>";

               out.write (responseXML);
               out.close();
            }  // end if (node.getNodeType() == Node.ELEMENT_NODE)
         }  // end for
      }
      catch (Exception e)
      {
         e.printStackTrace();
      }
   }
}