/*
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 * and open the template in the editor.
 */

import java.io.IOException;
import java.io.PrintWriter;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

/**
 *
 * @author DELL
 */
public class RemoveStudent extends HttpServlet {

    private final String SALT = "897sdn9j98u98jk";

    /**
     * Processes requests for both HTTP <code>GET</code> and <code>POST</code>
     * methods.
     *
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException, SQLException {
        response.setContentType("text/html;charset=UTF-8");
        try (PrintWriter out = response.getWriter()) {
            /* TODO output your page here. You may use following sample code. */
            HttpSession session = request.getSession();
            java.sql.Connection con
                    = DriverManager.getConnection("jdbc:mysql://localhost:3306/gp?zeroDateTimeBehavior=convertToNull", "nesma", "0184463565");
            String email = request.getParameter("email");
            String query0 = "select user_id from gp.user_login where email = AES_ENCRYPT('" + email + "',sha2('" + SALT + "',512))";
            ResultSet rs;
            java.sql.Statement st = con.createStatement();
            rs = st.executeQuery(query0);

            if (rs == null) {
                session.setAttribute("msg", "This Email does not exist!");

            } else {
                while (rs.next()) {

                    String id = rs.getString(1);
                    String query1 = "delete from gp.student_user where student_id=" + id;
                    String query2 = "delete from gp.user_login where user_id=" + id;

                    System.out.println("hereee " + id);

                    try {
                        st.executeUpdate(query1);
                        st.executeUpdate(query2);
                        request.getRequestDispatcher("admin_view_students.jsp").forward(request, response);
                    } catch (SQLException | ServletException | IOException e) {

                    }
                }
            }

        }
    }

    // <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
    /**
     * Handles the HTTP <code>GET</code> method.
     *
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        try {
            processRequest(request, response);
        } catch (SQLException ex) {
            Logger.getLogger(RemoveStudent.class.getName()).log(Level.SEVERE, null, ex);
        }
    }

    /**
     * Handles the HTTP <code>POST</code> method.
     *
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        try {
            processRequest(request, response);
        } catch (SQLException ex) {
            Logger.getLogger(RemoveStudent.class.getName()).log(Level.SEVERE, null, ex);
        }
    }

    /**
     * Returns a short description of the servlet.
     *
     * @return a String containing servlet description
     */
    @Override
    public String getServletInfo() {
        return "Short description";
    }// </editor-fold>

}