package questionnaire;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.IOException;
import	java.util.Vector;

import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.RequestDispatcher;
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  org.xml.sax.InputSource;
import  org.w3c.dom.Document;
import  org.w3c.dom.NodeList;
import  org.w3c.dom.Node;

/**
 * @author tsuhtan
 */
public class SaverServlet extends HttpServlet
{

	private	SaverServletConfig	config = new SaverServletConfig();
	private	class	SaverServletConfig
	{
		String	response_url = null;
	}

	/**
	 * @see javax.servlet.Servlet#init(javax.servlet.ServletConfig)
	 */
	public void init (ServletConfig sc) throws ServletException
	{
		super.init (sc);
		config.response_url = sc.getInitParameter ("response_url");			
	}

	/**
	 * @see javax.servlet.http.HttpServlet#doPost(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)
	 */
	protected void doPost (HttpServletRequest req, HttpServletResponse res)
		throws ServletException, IOException
	{
		Document doc = getRequestAsDocument (req);
		Vector	result_list = analyzeDocument (doc);
		for (int i = 0; i < result_list.size(); i++)
		{
			System.out.println (result_list.elementAt (i));
		}
		sendResponse (req, res, result_list);
	}

	private	Document	getRequestAsDocument (HttpServletRequest req)
	{
		String content_type = req.getContentType();
		int x = content_type.indexOf ('=');
		String charset = (x >= 0 ? content_type.substring (x + 1) : null);
		try {
			DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
			DocumentBuilder db = dbf.newDocumentBuilder();
			InputSource is = new InputSource (
					(charset != null ? new BufferedReader (new InputStreamReader (req.getInputStream(), charset))
										: req.getReader()));
			return db.parse (is);
		} catch (Exception e) {
			throw new RuntimeException (e);
		}
	}

	private	class	QuestionnaireResultSet
	{
		String	questionnaire_id = null;
		String	value = null;
		public	String	toString()
		{
			return "{" + questionnaire_id + "," + value + "}";
		}
	}

	private	Vector	analyzeDocument (Document doc)
	{
		Node root = doc.getFirstChild();
		NodeList result_list = root.getChildNodes();
		Vector	v = new Vector();
		int count = result_list.getLength();
		for (int i = 0; i < count; i++)
		{
			Node result = result_list.item (i);
			NodeList	result_item_list = result.getChildNodes();
			QuestionnaireResultSet rs = new QuestionnaireResultSet();
			rs.questionnaire_id = getTextNodeValueAt (result_item_list, 0);
			rs.value = getTextNodeValueAt (result_item_list, 1);
			v.add (rs);
		}
		return v;
	}

	private	String	getTextNodeValueAt (NodeList list, int index)
	{
		Node node = list.item (index).getFirstChild();
		return (node == null ? null : node.getNodeValue());
	}

	private	void sendResponse (HttpServletRequest req, HttpServletResponse res, Vector result_list)
	{
		RequestDispatcher dispatcher = req.getRequestDispatcher (this.config.response_url);
		try {
			dispatcher.forward (req, res);
		} catch (Exception e) {
			throw new RuntimeException (e);
		}
	}
}