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

/**
 * Servlet requested for selecting a BKU.
 * <br>In case of {@link AuthConfigurationProvider#getBKUSelectionType}==HTMLComplete,
 * the browser is redirected to the configured "BKU-Auswahl-URL".
 * <br>In case of {@link AuthConfigurationProvider#getBKUSelectionType}==HTMLSelect,
 * the list of available BKU's is fetched from a BKU-Auswahl server, and presented
 * to the user in an HTML form.
 * 
 * @author Paul Ivancsics
 * @version $Id$
 */
public class SelectBKUServlet extends AuthServlet {

  /**
   * 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);
    }
  }
  
  /**
   * Responds with an HTML form which requests the user to choose a BKU.
   */
  protected void doGet(HttpServletRequest req, HttpServletResponse resp)
    throws ServletException, IOException {

    Logger.debug("GET SelectBKU");
    String authURL = 
      req.getScheme() + "://" + 
      req.getServerName() + ":" +
      req.getServerPort() +
      req.getContextPath() + "/";
    String target = req.getParameter(PARAM_TARGET);
    String oaURL = req.getParameter(PARAM_OA);
    String bkuSelectionTemplateURL = req.getParameter(PARAM_BKUTEMPLATE);
    String templateURL = req.getParameter(PARAM_TEMPLATE);
    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 returnValue = AuthenticationServer.getInstance().selectBKU(
        authURL, target, oaURL, bkuSelectionTemplateURL, templateURL);
      String bkuSelectionType = AuthConfigurationProvider.getInstance().getBKUSelectionType();
      if (bkuSelectionType.equals(AuthConfigurationProvider.BKU_SELECTION_TYPE_HTMLCOMPLETE)) {
        // bkuSelectionType==HTMLComplete
        String redirectURL = returnValue;               
        resp.sendRedirect(redirectURL);
        Logger.info("REDIRECT TO: " + redirectURL);
      }
      else {
        // bkuSelectionType==HTMLSelect
        String htmlForm = returnValue;
        resp.setContentType("text/html");
        Logger.debug("HTML-Form: " + htmlForm);
        PrintWriter out = new PrintWriter(resp.getOutputStream());
        out.print(htmlForm);
        out.flush();
        Logger.debug("Finished GET SelectBKU");
      }
    }
    catch (WrongParametersException ex) {
      handleWrongParameters(ex, req, resp);
    }
    catch (Throwable ex) {
      handleError(null, ex, req, resp);
    }
  }
}