using System;
using System.Data.SqlClient;
using System.IO;
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;

namespace MyDatabase
{
    public partial class frmDefault : Form
    {
        public frmDefault()
        {
            InitializeComponent();
        }

        //Global variables
        private string fileName = "MyDatabase";
        private string fileDirectory = AppDomain.CurrentDomain.BaseDirectory;

        //Checking if the database file already exists
        public static bool doesFileExist(string directory, string fileName)
        {
            if (File.Exists(directory + fileName))
            {
                return true;
            }
            return false;
        }

        //Verifying the login credentials
        private bool loginVerification(string username, string password)
        {
            if (!doesFileExist(fileDirectory, fileName + ".mdf"))
            {
                //SQL Variables
                String sql;
                SqlConnection databaseConnection = new SqlConnection("Server=localhost;Integrated security=SSPI;database=master");

                //Create database
                try
                {
                    databaseConnection.Open();
                    sql = "CREATE DATABASE " + fileName + " ON PRIMARY " +
                    "(NAME = " + fileName + "_Data, " +
                    "FILENAME = '" + fileDirectory + fileName + "Data.mdf', " +
                    "SIZE = 2MB, MAXSIZE = 10MB, FILEGROWTH = 10%) " +
                    "LOG ON (NAME = " + fileName + "_Log, " +
                    "FILENAME = '" + fileDirectory + fileName + "Log.ldf', " +
                    "SIZE = 1MB, " +
                    "MAXSIZE = 5MB, " +
                    "FILEGROWTH = 10%)";

                    SqlCommand nonqueryCommand = new SqlCommand(sql, databaseConnection);

                    nonqueryCommand.ExecuteNonQuery();

                    //Create table for login
                    nonqueryCommand.CommandText = "CREATE TABLE Users (username CHAR PRIMARY KEY, password CHAR)";

                    //Insert default login credentials
                    nonqueryCommand.CommandText = "INSERT INTO Users VALUES ('admin', 'password')";
                }
                catch (SqlException ex)
                {
                    Console.WriteLine(ex.ToString());
                }
                finally
                {
                    if (databaseConnection.State == ConnectionState.Open)
                    {
                        databaseConnection.Close();
                    }
                }

                //Login
                try
                {
                    SqlConnection loginConnection = new SqlConnection("Server=localhost;Integrated security=SSPI;database=master");
                    loginConnection.Open();
                    if (loginConnection.State == ConnectionState.Open)
                    {
                        SqlCommand cmd = new SqlCommand("SELECT Count(*) FROM Users WHERE username=" + username + " and password=" + password, loginConnection);
                        SqlDataReader dr = cmd.ExecuteReader();
                        if (dr.HasRows)
                        {
                            return true;
                        }
                        else
                        {
                            MessageBox.Show("Invalid credentials.");
                        }
                    }
                }
                catch (Exception ex)
                {
                    MessageBox.Show(ex.Message);
                }
            }
            else
            {
                MessageBox.Show("File exists?");
            }
            return false;
        }

        private void btnLoginPressed(object sender, EventArgs e)
        {
            String userUsername = txtUsername.Text;
            String userPassword = txtPassword.Text;

            if (loginVerification(userUsername, userPassword))
            {
                this.Hide();
                frmControlPanel controlPanel = new frmControlPanel();
                controlPanel.Show();
            }
        }
    }
}