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;

namespace XOR
{
    public partial class Form1 : Form
    {
        string text, gamma;
        public Form1()
        {
            InitializeComponent();
        }
        public const string alphabet = "абвгдеёжзийклмнопрстуфхцчшщъыьэюяАБВГДЕЁЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯ 0123456789.,-:;!?=+-";
        class Encryption
        {
            public int[] TpluseG;
            string C, G1;
            public Encryption(string _T, string _G)
            {
                int[] T, G, modN;
                int count = 0, k = 0;
                T = new int [_T.Length];
                G = new int[_T.Length];
                TpluseG = new int[_T.Length];
                modN = new int[_T.Length];
                for (int i = 0; i < _T.Length; i++)
                {
                    for (int j = 0; j < alphabet.Length; j++)
                    {
                        if (_T[i]==alphabet[j])
                        {
                            T[i] = j + 1;
                        }
                    }
                }
                while (count != _T.Length)
                {
                    G1 += _G[k];
                    k++;
                    count++;
                    if (k == _G.Length)
                    {
                        k = 0;
                    }
                }
                for (int i = 0; i < _T.Length; i++)
                {
                    for (int j = 0; j < alphabet.Length; j++)
                    {
                        if (G1[i] == alphabet[j])
                        {
                            G[i] = j + 1;
                        }
                    }
                }
                for (int i = 0; i < _T.Length; i++)
                {
                    TpluseG[i] = T[i] + G[i];
                }
                for (int i = 0; i < _T.Length; i++)
                {
                    modN[i] = TpluseG[i] % alphabet.Length;
                }
                for (int i = 0; i < _T.Length; i++)
                {
                    if (modN[i] == 0)
                    {
                        modN[i] = alphabet.Length;
                    }
                }
                for (int i = 0; i < _T.Length; i++)
                {
                    modN[i] -= 1;
                }
                for (int i = 0; i < _T.Length; i++)
                {
                    C += alphabet[modN[i]];
                }
            }
            public string output()
            {
                return C;
            }
        }
        class Decryption
        {
            int[] CminusG, CminusGpluseN, C, G, modN;
            string T, G1;
            public Decryption(string _C, string _G)
            {
                int count = 0, k = 0;
                C = new int[_C.Length];
                G = new int[_C.Length];
                CminusG = new int[_C.Length];
                modN = new int[_C.Length];
                CminusGpluseN = new int[_C.Length];
                for (int i = 0; i < _C.Length; i++)
                {
                    for (int j = 0; j < alphabet.Length; j++)
                    {
                        if (_C[i] == alphabet[j])
                        {
                            C[i] = j + 1;
                        }
                    }
                }
                while (count != _C.Length)
                {
                    G1 += _G[k];
                    k++;
                    count++;
                    if (k == _G.Length)
                    {
                        k = 0;
                    }
                }
                for (int i = 0; i < _C.Length; i++)
                {
                    for (int j = 0; j < alphabet.Length; j++)
                    {
                        if (G1[i] == alphabet[j])
                        {
                            G[i] = j + 1;
                        }
                    }
                }
                for (int i = 0; i < _C.Length; i++)
                {
                    CminusG[i] = C[i] - G[i];
                }
                for (int i = 0; i < _C.Length; i++)
                {
                    CminusGpluseN[i] = CminusG[i] + alphabet.Length;
                }
                for (int i = 0; i < _C.Length; i++)
                {
                    modN[i] = CminusGpluseN[i] % alphabet.Length;
                }
                for (int i = 0; i < _C.Length; i++)
                {
                    if (modN[i] == 0)
                    {
                        modN[i] = alphabet.Length;
                    }
                }
                for (int i = 0; i < _C.Length; i++)
                {
                    modN[i] -= 1;
                }
                for (int i = 0; i < _C.Length; i++)
                {
                    T += alphabet[modN[i]];
                }
            }
            public string output()
            {
                return T;
            }
        }

        private void button1_Click(object sender, EventArgs e)
        {
            richTextBox2.Text = "";
            text = richTextBox1.Text;
            gamma = textBox1.Text;
            Encryption line = new Encryption(text, gamma);
            richTextBox2.Text += "" + line.output();
        }

        private void button2_Click(object sender, EventArgs e)
        {
            richTextBox2.Text = "";
            text = richTextBox1.Text;
            gamma = textBox1.Text;
            Decryption line = new Decryption(text, gamma);
            richTextBox2.Text += "" + line.output();
        }

        private void button3_Click(object sender, EventArgs e)
        {
            richTextBox1.Text = "";
        }

        private void button4_Click(object sender, EventArgs e)
        {
            richTextBox2.Text = "";
        }

        private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
        {
            char ch=e.KeyChar;
            if (ch >= 'а' && ch <= 'я' || Char.IsControl(e.KeyChar))
            {
                return;
            }
            else
            {
                e.Handled = true;
            }
        }
    }
}