package at.gv.egovernment.moa.id.auth.servlet;

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

import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import at.gv.egovernment.moa.id.MOAIDException;
import at.gv.egovernment.moa.id.auth.AuthenticationServer;
import at.gv.egovernment.moa.id.auth.MOAIDAuthInitializer;
import at.gv.egovernment.moa.id.auth.WrongParametersException;
import at.gv.egovernment.moa.id.util.MOAIDMessageProvider;
import at.gv.egovernment.moa.logging.Logger;

/**
 * Servlet requested for starting a MOA ID authentication session.
 * Utilizes the {@link AuthenticationServer}.
 * 
 * @author Paul Ivancsics
 * @version $Id$
 * @see AuthenticationServer#startAuthentication
 */
public class StartAuthenticationServlet extends AuthServlet {

  /**
   * Responds with an HTML form which upon submit requests the identity link
   * from the security layer implementation.
   * <br>
   * Response:
   * <ul>
   * <li>Content type: <code>"text/html"</code></li>
   * <li>Content: see return value of {@link AuthenticationServer#startAuthentication}</li>
   * <li>Error status: <code>500</code>
   * </ul>
   * @see javax.servlet.http.HttpServlet#doGet(HttpServletRequest, HttpServletResponse)
   */
  protected void doGet(HttpServletRequest req, HttpServletResponse resp)
    throws ServletException, IOException {

		Logger.debug("GET StartAuthentication");
    String authURL = 
      req.getScheme() + "://" + 
      req.getServerName() + ":" +
      req.getServerPort() +
      req.getContextPath() + "/";
		String target = req.getParameter(PARAM_TARGET);
		String oaURL = req.getParameter(PARAM_OA);
    String bkuURL = req.getParameter(PARAM_BKU);
    String templateURL = req.getParameter(PARAM_TEMPLATE);
    String sessionID = req.getParameter(PARAM_SESSIONID);
    resp.setHeader(HEADER_EXPIRES,HEADER_VALUE_EXPIRES);
    resp.setHeader(HEADER_PRAGMA,HEADER_VALUE_PRAGMA);
    resp.setHeader(HEADER_CACHE_CONTROL,HEADER_VALUE_CACHE_CONTROL);
    resp.addHeader(HEADER_CACHE_CONTROL,HEADER_VALUE_CACHE_CONTROL_IE);
		try {
			String getIdentityLinkForm =
				AuthenticationServer.getInstance().startAuthentication(authURL, target, oaURL, templateURL, bkuURL, sessionID);
			resp.setContentType("text/html");
			PrintWriter out = new PrintWriter(resp.getOutputStream());
			out.print(getIdentityLinkForm);
			out.flush();
			Logger.debug("Finished GET StartAuthentication");
		}
    catch (WrongParametersException ex) {
      handleWrongParameters(ex, req, resp);
    }
		catch (MOAIDException ex) {
			handleError(null, ex, req, resp);
		}
  }


  /**
   * @see javax.servlet.http.HttpServlet#doPost(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)
   */
  protected void doPost(HttpServletRequest req, HttpServletResponse resp)
    throws ServletException, IOException {
    
    doGet(req, resp);
  }
  

  /**
   * Calls the web application initializer.
   * 
   * @see javax.servlet.Servlet#init(ServletConfig)
   */
  public void init(ServletConfig servletConfig) throws ServletException {
  	try {
      super.init(servletConfig);
      MOAIDAuthInitializer.initialize();
  		Logger.info(MOAIDMessageProvider.getInstance().getMessage("init.00", null));
  	}
  	catch (Exception ex) {
  		Logger.fatal(MOAIDMessageProvider.getInstance().getMessage("init.02", null), ex);
  		throw new ServletException(ex);
  	}
  }  

}