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

namespace WindowsFormsApp4
{
    public partial class Auth: Form
    {
        readonly string connStr = ConfigurationManager.ConnectionStrings["PostgreSQL"].ConnectionString;
        public Auth()
        {
            InitializeComponent();
        }

        private void Auth_Load(object sender, EventArgs e)
        {

        }
        private string HashPassword(string password, string salt)
        {
            var plainTextWithSaltBytes = Encoding.UTF8.GetBytes(password + salt);
            using (SHA256 sha256Hash = SHA256.Create())
            {
                return Convert.ToBase64String(sha256Hash.ComputeHash(plainTextWithSaltBytes));
            }
        }

        private bool VerifyPassword(string enteredPassword, string storedSalt, string storedHash)
        {
            var computedHash = HashPassword(enteredPassword, storedSalt);
            return computedHash == storedHash;
        }

        private void Button2_Click(object sender, EventArgs e)
        {
            using (NpgsqlConnection connection = new NpgsqlConnection(connStr))
            {
                try
                {
                    connection.Open();
                    string Query = "SELECT * FROM authenticate_user(@login)";
                    using (var command = new NpgsqlCommand(Query, connection))
                    {
                        command.Parameters.AddWithValue("@login", textBox5.Text);
                        using (var reader = command.ExecuteReader())
                        {
                            if (reader.Read())
                            {
                                int userId = reader.GetInt32(0);
                                string dbRoleName = reader.GetString(1);
                                string dbPasswordHash = reader.GetString(2);
                                string dbSalt = reader.GetString(3);
                                string fullname = reader.GetString(4);      
                    if (VerifyPassword(textBox1.Text, dbSalt, dbPasswordHash))
                                {
                                    Session.UserId = userId;
                                    Session.UserRole = dbRoleName;
                                    Session.UserFullName = reader.GetString(4); 


                                    reader.Close();

                                    string getLibId = "SELECT library_id FROM users WHERE id = @userId";
                                    using (var cmdLib = new NpgsqlCommand(getLibId, connection))
                                    {
                                        cmdLib.Parameters.AddWithValue("userId", userId);
                                        var libIdResult = cmdLib.ExecuteScalar();
                                        Session.LibraryId = libIdResult != DBNull.Value ? Convert.ToInt32(libIdResult) : (int?)null;
                                    }

                                    switch (dbRoleName)
                                    {
                                        case "reader":
                                            ReaderMainForm casualForm = new ReaderMainForm();
                                            casualForm.FormClosed += (s, args) => this.Close();
                                            casualForm.Show();
                                            this.Hide();
                                            break;
                                        case "employe":
                                            bibliot bibliotForm = new bibliot();
                                            bibliotForm.FormClosed += (s, args) => this.Close();
                                            bibliotForm.Show();
                                            this.Hide();
                                            break;
                                        case "admin":
                                            AdminMainForm adminForm = new AdminMainForm();
                                            adminForm.FormClosed += (s, args) => this.Close();
                                            adminForm.Show();
                                            this.Hide();
                                            break;
                                        default:
                                            MessageBox.Show("Ошибка: Неизвестная роль пользователя.");
                                            break;
                                    }
                                }
                                else
                                {
                                    MessageBox.Show("Ошибка: Неверный пароль.");
                                }
                            }
                            else
                            {
                                MessageBox.Show("Ошибка: Запись не найдена");
                            }
                        }
                    }
                }
                catch (Exception ex)
                {
                    MessageBox.Show("Ошибка подключения: " + ex.Message);
                }
            }
        }

        private void textBox5_TextChanged(object sender, EventArgs e)
        {

        }

        private void headerLabel_Click(object sender, EventArgs e)
        {

        }
    }
}