package org.restafarian.core.security;

 import javax.servlet.ServletContext;

 import javax.servlet.http.HttpServletRequest;

 import javax.servlet.http.HttpServletResponse;

 import org.apache.commons.configuration.Configuration;

 import org.apache.commons.lang.StringUtils;

 import org.apache.commons.logging.Log;

 import org.apache.commons.logging.LogFactory;

 import org.restafarian.core.beans.Person;

 /**

  * <p>This module finds and returns the currently authenticated user.</p>

  */

 public class AuthenticatedUserManager {

         private static Log log = LogFactory.getLog(AuthenticatedUserManager.class);

         /**

          * <p>Initializes the module using the configuration.</p>

          *

          * @param context the <code>ServletContext</code> object

          * @param config the <code>Configuration</code> object

          */

         public static void init(ServletContext context, Configuration config) {

                 log.info("Initializing the AuthenticatedUserManager.");

                 // get the implentation class name from the configuration

                 String className = config.getString("authenticatedUserManager");

                 if (StringUtils.isNotEmpty(className)) {

                         log.info("Implementation class name: " + className);

                 } else {

                         className = "org.restafarian.core.utils.DefaultUserManager";

                         log.info("No user manager class name specified; configuring default user manager.");

                 }

                 // instantiate the class

                 UserManager userManager = null;

                 try {

                         userManager = (UserManager) Class.forName(className).newInstance();

                 } catch (Exception e) {

                         log.info("Exception occured instantiating user manager: " + e, e);

                         log.info("Configuring default user manager.");

                         userManager = new DefaultUserManager();

                 }

                 // initialize the instantiated class

                 userManager.init(context, config);

                 // store the initialized module in the servlet context

                 context.setAttribute("authenticatedUserManager", userManager);

         }

         /**

          * <p>Returns the currently authenticated user, or null, if there is

          * no user currently authenticated.</p>

          *

          * @param req the <code>HttpServletRequest</code> object

          * @return user the currently authenticated user

          */

         public static Person getAuthenticatedUser(HttpServletRequest req) {

                 ServletContext context = req.getSession().getServletContext();

                 UserManager userManager = (UserManager) context.getAttribute("authenticatedUserManager");

                 if (userManager == null) {

                         userManager = new DefaultUserManager();

                         if (log.isDebugEnabled()) {

                                 log.debug("No user manager configured; employing default user manager.");

                         }

                 }

                 return userManager.getAuthenticatedUser(req);

         }

         /**

          * <p>Sets the currently authenticated user.</p>

          *

          * @param req the <code>HttpServletRequest</code> object

          * @param res the <code>HttpServletResponse</code> object

          * @param user the currently authenticated user

          */

         public void setAuthenticatedUser(HttpServletRequest req, HttpServletResponse res, Person user) {

                 ServletContext context = req.getSession().getServletContext();

                 UserManager userManager = (UserManager) context.getAttribute("authenticatedUserManager");

                 if (userManager == null) {

                         userManager = new DefaultUserManager();

                         if (log.isDebugEnabled()) {

                                 log.debug("No user manager configured; employing default user manager.");

                         }

                 }

                 userManager.setAuthenticatedUser(req, res, user);

         }

 }