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 System.Text.RegularExpressions;


namespace exam2tsp
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        Regex reg = new Regex("[^a-z6-9]");

        private void button1_Click(object sender, EventArgs e)
        {
            string user = textBox1.Text;
            string pass = textBox2.Text;

            if (user.Length < 5 || user.Length >8)
            {
                MessageBox.Show("Username must be at least 5 characters long, up to 8");
                textBox1.Clear();
            }


            else if (Char.IsNumber(user[0]))
            {
                MessageBox.Show("Username should start with a small latin letter");
                textBox1.Clear();
            }

            else if(pass.Length != 4)
            {
                MessageBox.Show("Password must be exactly 4 symbols and end with a question mark (?).");
                textBox2.Clear();
            }

            else if (textBox2.Text[3] != '?')
            {
                MessageBox.Show("The password must always end with a question mark (?).");
                textBox2.Clear();
            }

            else if (reg.Matches(textBox1.Text).Count > 0 )
            {
                MessageBox.Show("The username must contain only digits from 6 to 9 and small latin letters! ");
                textBox1.Clear();
            }




            else
            {
                MessageBox.Show("success");
                /*
               this.Hide();
               Form2 Data = new Form2();
               form2.Show();
                 */
                //login is successful and leads to another menu which i haven't made yet

            }

        }