/*
 * Code by George Kichukov for SAS 10/27/2002
 * Updated 11/24/2002 - added session creation
 * This class is used to check the username and login
 * and to create the session and stores the real name for
 * the user throughout the session. All other classes check
 * to see if the real name is null.
 */

package admin;

import java.io.*;
import java.sql.*;
import javax.servlet.*;
import javax.servlet.http.*;

import utilities.*;

public class Login extends HttpServlet
{
        private String target = "/servlet/admin.PresentMenu";
        private String errorTarget = "../admin/index.jsp";

        public void init(ServletConfig config) throws ServletException
        {
                super.init(config);
        }

        private String verifyUser(String username, String password)
        {
               try
               {
                        ResultSet rs = Retriever.getUsers();

                        String dbUsername=null;
                        String dbPassword="";
                        String dbName=null;

 while(rs.next())
                        {
                                dbUsername=rs.getString("UserName");
                                dbPassword=rs.getString("Password");
                                dbName=rs.getString("Name");

                                if((dbUsername.equals(username)) && (dbPassword.equals(password)))
                                {
                                      return dbName;
                                }

                        }
                        rs.close();

                }

                catch(SQLException e) {System.err.println("SQLException " + e.getMessage());};

                return null;
        }


        public void doGet(HttpServletRequest request,
                          HttpServletResponse response)
                          throws ServletException, IOException
        {

                // If it is a get request forward to doPost()
                doPost(request, response);
        }

 public void doPost(HttpServletRequest request,
                                HttpServletResponse response)
                                throws ServletException, IOException
        {
		//create the printwriter
           	PrintWriter out = response.getWriter();
                response.setContentType("text/html"); 

                // Get the username from the request
                String username = request.getParameter("username");

                // Get the password from the request
                String password = request.getParameter("password");

                String name =verifyUser(username, password);

                //if the username and password matched =>
                //there is a real name existing for that user
                if (name!=null)
                {
                	//check if cookies are enabled if not
                	//print a message and redirect back to login
                	if(request.getCookies() == null)
 			{
           			HTMLUtils.printRedirectPage(out, "You must enable cookies in your browser before using the advisement system.", "../index.jsp");
           			return;
 			}
                	
                       //create the HTTP Session
                       HttpSession session = request.getSession(true);
                       
                        //write the session variable
                        session.setAttribute("user",name);
						
                        // Forward the request to the target named        
                        ServletContext context = getServletContext();
                        RequestDispatcher dispatcher = context.getRequestDispatcher(target);
                        dispatcher.forward(request, response);
                }
		
		//the username and password combination were no recognized in the database so
		//redirect back to login but print a message first
                else
                {
                       HTMLUtils.printRedirectPage(out, "Sorry, Username/Password Combination is Incorrect. Please try again!", errorTarget);
         	       return;
                }
        }
}