#include <iostream>
#include <fstream>
#include <string>
#include <cmath>
//#include <windows.h>;
#include <clocale>

using namespace std;

int getKey(int v, string key) {
	int startPos = (key.length() + (v*v + 1)) % key.length();
	int res = 0;
	for (int i = 0; i < 3; i++) {
		res = res * 256;
		res += key[(startPos + i) % key.length()] + 0;
	}
	return res;
}

int ceil2(int n) {
	if (n % 8 == 0) {
		return (n / 8);
	}
	else {
		return (n / 8) + 1;
	}
}

int main() {
	setlocale(LC_ALL, "Russian");
	int Number; // Кол-во кругов
	//SetConsoleCP(1251);
	//SetConsoleOutputCP(1251);
	string str, strres, strres2, key, tempstr;
	int n; // Кол-во строк по 8 символов
	int q;
	do {
		printf("1) Шифратор \n");
		printf("2) Дешафратор \n");
		printf("0) Выход \n");
		scanf_s("%i", &q);
		switch (q)
		{
		case 1:
		{
				  cout << "Введите ключ шифрования: ";
				  cin >> key;
				  cout << "Введите кол-во кругов: ";
				  cin >> Number;
				  ifstream file("source.txt", ios_base::in);
				  ofstream file2("encrypt.txt", ios_base::trunc);
				  while (!file.eof()){
					  str += file.get();
				  }
				  str = str.substr(0, str.length() - 1);
				  cout << str << endl;
				  n = ceil2(str.length());
				  cout << "Кол-во блоков по 8 символов: " << n << endl;
				  cout << str.length() << endl;
				  while ((int)str.length() < n * 8) {
					  str += '\0';
				  }
				  cout << str.length() << endl;
				  for (int i = 0; i < n; i++) {
					  int l = 0,
						  r = 0;
					  for (int j = 0; j < 8; j++) {
						  if (j < 4) {
							  l = l * 256;
							  l += (str[j + (i * 8)] + 0);
						  }
						  else {
							  r = r * 256;
							  r += (str[j + (i * 8)] + 0);
						  }
					  }
					  cout << "left: " << l << endl;
					  cout << "right: " << r << endl;
					  for (int k = 0; k < Number; k++) {
						  if (k != Number - 1) {
							  int l0 = l;
							  l = l ^ getKey(k, key);
							  l ^= r;
							  r = l0;
						  }
						  else {
							  int l0 = l;
							  l = l ^ getKey(k, key);
							  r = l ^ r;
							  l = l0;
						  }
					  }
					  cout << "left after: " << l << endl;
					  cout << "right after: " << r << endl;
					  for (int b = 0; b < 4; b++) {
						  strres += (int)(l / (pow(256, (3 - b))));
						  l = (l % (int)(pow(256, (3 - b))));
					  }
					  for (int b = 0; b < 4; b++) {
						  strres += (int)(r / (pow(256, (3 - b))));
						  r = (r % (int)(pow(256, (3 - b))));
					  }
					  //strres = strres + c;
				  }
				  file2 << strres;
				  file2.close();
				  file.close();
				  break;
		}
		case 2:
		{
				  cout << "Введите ключ шифрования: ";
				  cin >> key;
				  cout << "Введите кол-во кругов: ";
				  cin >> Number;
				  ifstream file("encrypt.txt", ios_base::in);
				  ofstream file2("decrypt.txt", ios_base::trunc);
				  strres = "";
				  while (!file.eof()){
					  strres += file.get();
				  }
				 strres = strres.substr(0, strres.length() - 1);
				  //while (getline(file, tempstr, '\n')) {
					 // cout << strres << endl;
					 // strres += tempstr + '\n';
				 // }
				  cout << strres << endl;
				  n = (strres.length() / 8);
				  cout << "Кол-во блоков по 8 символов: " << n << endl;
				  for (int i = 0; i < n; i++) {
					  int l = 0,
						  r = 0;
					  for (int j = 0; j < 8; j++) {
						  if (j < 4) {
							  l = l * 256;
							  l += (strres[j + (i * 8)] + 0);
						  }
						  else {
							  r = r * 256;
							  r += (strres[j + (i * 8)] + 0);
						  }
					  }
					  cout << "left: " << l << endl;
					  cout << "right: " << r << endl;
					  for (int k = 1; k <= Number; k++) {
						  if (k != Number) {
							  int l0 = l;
							  l = l ^ getKey(Number - k, key);
							  l ^= r;
							  r = l0;
						  }
						  else {
							  int l0 = l;
							  l = l ^ getKey(Number - k, key);
							  r = l ^ r;
							  l = l0;
						  }
					  }
					  cout << "left after: " << l << endl;
					  cout << "right after: " << r << endl;
					  for (int b = 0; b < 4; b++) {
						  strres2 += (int)(l / (pow(256, (3 - b))));
						  l = (l % (int)(pow(256, (3 - b))));
					  }
					  for (int b = 0; b < 4; b++) {
						  strres2 += (int)(r / (pow(256, (3 - b))));
						  r = (r % (int)(pow(256, (3 - b))));
					  }
				  }
				  file2 << strres2;
				  file.close();
				  file2.close();
				  break;
		}
		}
	} while (q != 0);
	system("pause");
	return 0;
}