using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace KRY_0x01_ng
{
    public partial class main_form : Form
    {
        public main_form()
        {
            InitializeComponent();
        }

        char[,] arrayTable = new char[5, 5];
        char[] alphabet = "ABCDEFGHIJKLMNOPQRSTUVXYZ".ToCharArray(); // no W
        char[] nualphabet = new char[25];



        public string restore_order(string str)
        {
            string alpha_str = Regex.Replace(str, "SPACEBRO", " ");
            return alpha_str;
        }

        public string pad(string str)
        {
            string padded_str = "";
            if (str.Length > 0)
            {
                int i = 0;
                while (i < str.Length)
                {
                    char first_char = str[i];
                    i++;
                    char second_char;
                    if ((i == str.Length || str[i] == first_char) && (first_char != 'X'))
                    {
                        second_char = 'X';
                    }
                    else if ((i == str.Length || str[i] == first_char) && (first_char != 'Q'))
                    {
                        second_char = 'Q';
                    }
                    else if ((i == str.Length || str[i] == first_char) && (first_char != 'W'))
                    {
                        second_char = 'W';
                    }
                    else
                    {
                        second_char = str[i];
                        i++;
                    }
                    padded_str += first_char;
                    padded_str += second_char;
                }
            }
            return padded_str;
        }


        void check_key(TextBox tb_k)
        {
            if (tb_k.Text.Length == 0)
            {
                MessageBox.Show("Empty key.", "Warning");
                return;
            }
            
            string str_to_check = str_to_check = String.Join("", tb_k.Text.ToUpper().Distinct());
            if (str_to_check.Length < 9)
            {
                MessageBox.Show($"The key is too short ({str_to_check.Length} characters).\nKey requirements: 9-25 unique alphabetic characters", "Error");
                return;
            }
            else if (str_to_check.Length > 25)
            {
                MessageBox.Show("The key is too long", "Warning");
                return;
            }

            Match match = Regex.Match(str_to_check, @"\d|\s+");
            if (match.Success)
            {
                MessageBox.Show("Only alphabetic characters and spaces are allowed.\nCheck the key for numbers, symbols or tab whitespace and remove them before continuing.", "Error");
                return;
            }
            TextBox tb_pruned_k = textBox2;
            tb_pruned_k.Text = str_to_check;
            return;
        }

        void check_message(TextBox tb_m)
        {
            if (tb_m.Text.Length == 0)
            {
                MessageBox.Show("Empty message, nothing to do.", "Warning");
                return;
            }
            string msg = Regex.Replace(tb_m.Text.ToUpper(), " ", "SPACEBRO");
            Match match = Regex.Match(msg, @"\d|\s+");
            if (match.Success)
            {
                MessageBox.Show("Only alphabetic characters and spaces are allowed.\nCheck the message for numbers, symbols or tab whitespace and remove them before continuing.\nAlso, \"W\" will be replaced by \"V\".", "Error");
                return;
            }
            msg = msg.Replace("W", "V");
            textBox5.Text = msg;
            return;
        }
        void prep_message(TextBox tb_m)
        {
            string msg = tb_m.Text;
            if (msg.Length % 2 != 0)
            {
                if (! msg.EndsWith("X"))
                {
                    msg += "X";
                }
                else if (! msg.EndsWith("Q"))
                {
                    msg += "Q";
                }
                else if (! msg.EndsWith("Z"))
                {
                    msg += "Z";
                }
            }
            textBox6.Text = pad(msg);
            return;
        }


        void encrypt()
        {
            check_message(textBox4);
            prep_message(textBox5);
            string cryptmessage = "";
            textBox7.Text = cryptmessage;
            return;
        }



        private void button1_Click(object sender, EventArgs e)
        {
            /* encrypt button */
            encrypt();
        }

        private void button2_Click(object sender, EventArgs e)
        {
            /* check key button */
            check_key(textBox1);
        }
    }
}