import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.util.*;
import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.sql.*;

public class ServPost extends HttpServlet {

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

        String mode = request.getParameter( "mode" );

        if(mode == null)
            mode = "read";

            switch(mode){
                case "create":
                                create(request, response);
                                break;

                case "read":
                                read(request, response);
                                break;

                case "update":
                                update(request, response);
                                break;

                case "delete":
                                delete(request, response);
                                break;

                default:    System.out.println("Invalid Param");
            }
    }

    protected void delete(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException{
        response.setContentType("text/xml");

        String driver = "com.mysql.jdbc.Driver";
        Connection con = null;
        Statement stmt = null;

        try {
            Class.forName(driver).newInstance();
            String url = "jdbc:mysql://localhost/coke_db?user=root&password=root";
            con = DriverManager.getConnection(url);
            stmt = con.createStatement();

            stmt.executeUpdate("Delete From produkt where produkt_id > 0;");
            System.out.println("Database cleared");

        }
        catch (SQLException | InstantiationException | IllegalAccessException | ClassNotFoundException e) {
            e.printStackTrace();
            System.out.println("Exception");
        }
    }

    protected void create(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException{

        response.setContentType("text/xml");
        String name = request.getParameter( "name" );
        String sugar = request.getParameter( "sugar" );
        String shelflife = request.getParameter( "shelflife" );

        String driver = "com.mysql.jdbc.Driver";
        Connection con = null;
        Statement stmt = null;

        try {
            Class.forName(driver).newInstance();
            String url = "jdbc:mysql://localhost/coke_db?user=root&password=root";
            con = DriverManager.getConnection(url);
            stmt = con.createStatement();

            if (name == null | sugar == null | shelflife == null){
                System.out.println("Dont worked:" + name + " " + shelflife + " " + sugar);
            }
            else if (!sugar.equals("") && !shelflife.equals("")) {
                stmt.executeUpdate("INSERT INTO produkt (name, mhd, zucker) VALUES ('"+ name + "','" + shelflife + "','" + sugar + "')");
                System.out.println("Worked: all");
            }
            else if (sugar.equals("") && shelflife.equals("")) {
                stmt.executeUpdate("INSERT INTO produkt (name) VALUES ('"+ name + "')");
                System.out.println("Worked: name");
            }
            else if (!sugar.equals("") && shelflife.equals("")) {
                stmt.executeUpdate("INSERT INTO produkt (name, zucker) VALUES ('"+ name + "','" + sugar + "')");
                System.out.println("Worked: name+sugar");
            }
            else if (sugar.equals("") && !shelflife.equals("")) {
                stmt.executeUpdate("INSERT INTO produkt (name, mhd) VALUES ('"+ name + "','" + shelflife + "')");
                System.out.println("Worked: name+shelf life");
            }

            stmt.close();
            con.close();

        }
        catch (SQLException | InstantiationException | IllegalAccessException | ClassNotFoundException e) {
            e.printStackTrace();
        System.out.println("Exception");
        }

    }

    protected void read(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException{

        PrintWriter out = response.getWriter();
        response.setContentType("text/xml");

        String driver = "com.mysql.jdbc.Driver";
        Connection con = null;
        ResultSet rst = null;
        Statement stmt = null;

        try {
        Class.forName(driver).newInstance();
        String url = "jdbc:mysql://localhost/coke_db?user=root&password=root";
        con = DriverManager.getConnection(url);
        stmt = con.createStatement();
        rst = stmt.executeQuery("SELECT * FROM produkt;");

        String name;
        String sugar;
        String shelflife;
        String id;

        out.println("<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?>");
        out.println("<storage>");

        while(rst.next()){
            name = rst.getString("name");
            shelflife = rst.getString("mhd");
            sugar = rst.getString("zucker");
            id = rst.getString("produkt_id");

            out.println("<product>");
                out.println("<id>" + id +"</id>");
                out.println("<name>" + name +"</name>");
                out.println("<sugarcontent>" + sugar + "</sugarcontent>");
                out.println("<shelflife>" + shelflife + "</shelflife>");
            out.println("</product>");
        }
        }
        catch (SQLException | InstantiationException | IllegalAccessException | ClassNotFoundException e) {
            e.printStackTrace();
        System.out.println("Exception");
        }
        out.println("</storage>");
    }

    protected void update(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException{
        response.setContentType("text/xml");
        String id = request.getParameter( "id" );
        String name = request.getParameter( "name" );
        String sugar = request.getParameter( "sugar" );
        String shelflife = request.getParameter( "shelflife" );

        String driver = "com.mysql.jdbc.Driver";
        Connection con = null;
        Statement stmt = null;

        try {
            Class.forName(driver).newInstance();
            String url = "jdbc:mysql://localhost/coke_db?user=root&password=root";
            con = DriverManager.getConnection(url);
            stmt = con.createStatement();

            if (name == null | sugar == null | shelflife == null){
                System.out.println("Dont worked:" + name + " " + shelflife + " " + sugar);
                name = ""; sugar = ""; shelflife = "";
            }
            else
            if ( name != "" & sugar != "" & shelflife != "" ){
                stmt.executeUpdate("UPDATE produkt SET name='" + name + "', mhd='" + shelflife + "',zucker='" + sugar + "' Where produkt_id='" + id + "'");
                System.out.println("Updated: all");
            }
            else{
                if ( name != "" ){
                    stmt.executeUpdate("UPDATE produkt SET name='" + name + "' Where produkt_id='" + id + "'");
                    System.out.println("Updated: name");
                }
                if ( sugar != "" ){
                    stmt.executeUpdate("UPDATE produkt SET zucker='" + sugar + "' Where produkt_id='" + id + "'");
                    System.out.println("Updated: sugar");
                }
                if ( shelflife != "" ){
                    stmt.executeUpdate("UPDATE produkt SET mhd='" + shelflife + "' Where produkt_id='" + id + "'");
                    System.out.println("Updated: shelflife");
                }
            }

            stmt.close();
            con.close();

        }
        catch (SQLException | InstantiationException | IllegalAccessException | ClassNotFoundException e) {
            e.printStackTrace();
        System.out.println("Exception");
        }

    }


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

    }
}