package cz.frantovo.sql.vyuka.ajax;

 import cz.frantovo.sql.vyuka.dto.Uzivatel;

 import java.io.IOException;

 import java.io.PrintWriter;

 import javax.servlet.ServletException;

 import javax.servlet.http.HttpServlet;

 import javax.servlet.http.HttpServletRequest;

 import javax.servlet.http.HttpServletResponse;

 /**

  * Servlet pro vyřizování AJAXových požadavků.

  * @author fiki

  */

 public class Servlet extends HttpServlet {

     private static final long serialVersionUID = 9102108273105288056L;

     private enum akce {

         /** Provede SQL dotaz. */

         vykonat,

         /** Vypíše historii SQL příkazů daného uživatele. */

         historie,

         /** Nápověda – průvodce */

         napoveda,

         /** Vypíše nějaké nepotřebné informace. */

         test,

         /** Pokud je požadovaná akce nesmysl. */

         chyba

     }

     /** 

      * 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 {

         /** Používáme pouze UTF-8 */

         response.setContentType("text/html;charset=UTF-8");

         request.setCharacterEncoding("UTF-8");

         PrintWriter out = response.getWriter();

         try {

             akce parametrAkce = akce.chyba;

             try {

                 parametrAkce = akce.valueOf(request.getParameter("akce"));

             } catch (Exception e) {

                 /** Chyba nebo podvržený AJAXový požadavek → zobrazíme chybovou hlášku */

             }

             Ajax a = new Ajax();

             Uzivatel uzivatel = new Uzivatel(request.getRequestedSessionId(), request.getRemoteAddr());

             switch (parametrAkce) {

                 case vykonat:

                     out.println(a.geSQLVysledek(request.getParameter("sql"), uzivatel));

                     break;

                 case historie:

                     out.println(a.getHistorie(uzivatel));

                     break;

                 case napoveda:

                     out.println("<p>Nápověda bude…</p>");

                     break;

                 case test:

                     out.println("<p>AJAX jede!</p>");

                     out.println("<ol>");

                     out.println("<li>Metoda: " + request.getMethod() + "</li>");

                     out.println("<li>Host: " + request.getRemoteHost() + "</li>");

                     out.println("<li>Adresa: " + request.getRemoteAddr() + "</li>");

                     out.println("<li>Akce: " + request.getParameter("akce") + "</li>");

                     out.println("<li>SQL: " + request.getParameter("sql") + "</li>");

                     out.println("<li>Sezení: " + request.getRequestedSessionId() + "</li>");

                     out.println("<li>URL: " + request.getRequestURL().toString() + "</li>");

                     out.println("</ol>");

                     break;

                 case chyba:

                     out.println("<p>chyba</p>");

                     break;

             }

         } finally {

             out.close();

         }

     }

     // <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 {

         processRequest(request, response);

     }

     /** 

      * 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 {

         processRequest(request, response);

     }

     /** 

      * Returns a short description of the servlet.

      * @return a String containing servlet description

      */

     @Override

     public String getServletInfo() {

         return "Servlet pro zpracování AJAXových požadavků.";

     }// </editor-fold>

 }