using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using Npgsql;
using System.Security.Cryptography;

namespace WindowsFormsApp5

{
    public partial class Form1 : Form
    {
        NpgsqlConnectionStringBuilder sb;
        private string salt = "fsdfgergerg455";

        public Form1()
        {
            InitializeComponent();
            sb = new NpgsqlConnectionStringBuilder();
            sb.Database = "test5";
            sb.Host = "localhost";
            sb.Username = "postgres";
            sb.Password = "2411";
        }



        private void txtPassword_TextChanged(object sender, EventArgs e)
        {

        }

        private void txtLogin_TextChanged(object sender, EventArgs e)
        {

        }

        private void button1_Click(object sender, EventArgs e)
        {
            using (NpgsqlConnection con = new NpgsqlConnection(sb.ToString()))
            {
                if (txtLogin.Text.Trim() != "" && txtPassword.Text.Trim() != "")
                {



                    con.Open();
                    var tCommand = new NpgsqlCommand
                    {
                        Connection = con,
                        CommandText =
                            @"SELECT COUNT(*) from users where users.login = @login"
                    };
                    tCommand.Parameters.AddWithValue("@login", txtLogin.Text);

                    if (int.Parse(tCommand.ExecuteScalar().ToString()) == 0)
                    {
                        var sCommand = new NpgsqlCommand
                        {
                            Connection = con,
                            CommandText =
                                @"INSERT INTO users(Login, Password, RegDate) VALUES (@login,@password,@Regdate)"
                        };
                        MD5CryptoServiceProvider hashp = new MD5CryptoServiceProvider();
                        sCommand.Parameters.AddWithValue("@login", txtLogin.Text);
                        sCommand.Parameters.AddWithValue("@password", GetHash(txtPassword.Text + salt));
                        sCommand.Parameters.AddWithValue("@RegDate", DateTime.Now.Date);
                        MessageBox.Show(
                            "Регистрация прошла успешно!",
                            "Сообщение");
                        sCommand.ExecuteNonQuery();
                    }
                    else
                    {
                        MessageBox.Show(
                            "Уже существует пользователь с данным логином!",
                            "Сообщение");
                    }
                }
                else
                {
                    MessageBox.Show(
                        "Недопускаются пустые поля!",
                        "Сообщение");
                }
            }
        }


        public string GetHash(string input)
        {
            var md5 = MD5.Create();
            var hash = md5.ComputeHash(Encoding.UTF8.GetBytes(input));

            return Convert.ToBase64String(hash);
        }

        private void button2_Click(object sender, EventArgs e)
        {
            using (NpgsqlConnection con = new NpgsqlConnection(sb.ToString()))
            {
                con.Open();
                var kCommand = new NpgsqlCommand
                {
                    Connection = con,
                    CommandText =
                        @"SELECT COUNT(*) from users where users.password = @password and users.login = @login1"
                };
                kCommand.Parameters.AddWithValue("@password", GetHash(txtPassword.Text+salt));
                kCommand.Parameters.AddWithValue("@login1", txtLogin.Text);
                if (int.Parse(kCommand.ExecuteScalar().ToString()) == 1)
                {
                    MessageBox.Show(
                        "Вы вошли!",
                        "Сообщение");
                }
                else
                {
                    MessageBox.Show(
                        "Неверный логин или пароль!",
                        "Сообщение");
                }
            }
        }
    }
}