/*
 * Code by George Kichukov for SAS 12/05/2002
 * This class is used to execute user modifications on the database
 * depending on the parameters passed to it for ModifyMajorList and ModifyReq only the Courses part
 */

package admin;

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

import utilities.*;

public class QueryList extends HttpServlet
{
	private String errorTarget = "../admin/index.jsp";

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

        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
        {

               //name of the user
		String name="";
	
                PrintWriter out = response.getWriter();
                response.setContentType("text/html");

                //first thing that every servlet or jsp should do is check if user is logged in
                HttpSession session = request.getSession(false);
		
		//if not logged in redirect to login
 		if(session == null)
 		{
         		HTMLUtils.printRedirectPage(out, "You must login to the system prior to viewing this page.", errorTarget);
         		return;
 		}
 		
 		//else if logged in take the name from the session
 		else
 		{
 			name=(String)session.getAttribute("user");
 			
 			//if the name is null
 			if(name == null)
 			{
         			HTMLUtils.printRedirectPage(out, "You must login to the system prior to viewing this page.", errorTarget);
         			return;
 			}
 		
 		}

              HTMLUtils.printAdminHeader(out);
		
                //display welcome message to the user
                out.println("<p align=left>Welcome " + name + "</p>");

           
		//get the parameters
                String table=request.getParameter("table");
                String oper=request.getParameter("oper");
                String id=request.getParameter("id");
                String mID=request.getParameter("mID");
		
		//display operation summary
		out.println ("Operation: " + oper + " " + table + "<br>");
		
		String primaryKey="";
		
                //case 1: Minors
                if(table.equals("MINORS")) 
                {
                	primaryKey="MinorID";
                	
                        String sql="select * from " + table + " where " + primaryKey + "=" + id;
                        //out.println(sql);
                                
			try
		        {

		        	ResultSet rs = Retriever.executeSQL(sql);
				
				try
				{
					String dataIn=request.getParameter("NotAvailableList");

                                        if(!dataIn.equals("none"))
                                        {
                                                //parse the requirment string
                                                dataIn=RequirementParser.toMajorDatabaseString(dataIn);
                                        }
					
					rs.updateString("NotAvailableList",dataIn);
					
					rs.updateRow();
					
					out.println("Major List Modified Successfully!");
				}
				
				catch (RequirementParserException e)
				{
					out.println(e.getMessage());
				}

					
				

		         } //end try
		
		         catch(SQLException e) {out.println("SQLException " + e.getMessage());}
			
                }
                
                
                //CASE 2: COURSES
                else 
                {
                	primaryKey="CourseID";
                	
                	String fieldID="";
                        String sql="select * from " + table + " where " + primaryKey + "=" + id;
                        //out.println(sql);
                        
                        Enumeration keys; 
	      		String key1; 
	      		String value; 
				
                        //get enumeration of all paramters passed
			keys = request.getParameterNames(); 
					
			//loop through all parameters
			while (keys.hasMoreElements()) 
			{ 
			        key1 = (String) keys.nextElement(); 
			        value = request.getParameter(key1); 
					       
			        //make sure it picks up only the List field
			        if( (key1.equals("oper")) || (key1.equals("id")) || (key1.equals("mID")))
			        {
			        	//don nothing	
			        }
			         
			        else if ((key1.substring(key1.length()-4,key1.length()).equals("List")) ) 
				{
				       
					fieldID=key1; 		
				}  
				
				else
				{
					//do nothing
				}   
			}	             
			
                               
			try
		        {

		        	ResultSet rs = Retriever.executeSQL(sql);
				//out.println(fieldID + " " + request.getParameter(fieldID));
				
				try
				{
					
                	                String dataIn=request.getParameter(fieldID);

                                        if(!dataIn.equals("none"))
                                        {
                                                //parse the requirment string
                                                dataIn=RequirementParser.toCourseDatabaseString(dataIn);
                                        }


				
					rs.updateString(fieldID, dataIn );
						
					rs.updateRow();
						
					out.println("Course List Modified Successfully!");
				}
				
				catch (RequirementParserException e)
				{
					out.println(e.getMessage());
				}

		         } //end try
		
		         catch(SQLException e) {out.println("SQLException " + e.getMessage());}
		} //end else any other table
		
		HTMLUtils.printAdminFooter(out);
		
        } //end method doPost
 
} //end Query servlet