enc/dec files

string caesar_encrypt(string plaintext, int shift) {
    string ciphertext = "";
    for (char& c : plaintext) {
        if (isalpha(c)) {
            // Convert to uppercase
            char upper_c = toupper(c);
            // Get the position of the character in the alphabet
            int char_pos = upper_c - 'A';
            // Apply the shift and wrap around the alphabet
            int shifted_pos = (char_pos + shift) % 26;
            // Convert the shifted position back to a character
            char shifted_char = shifted_pos + 'A';
            // Convert back to original case
            if (islower(c)) {
                shifted_char = tolower(shifted_char);
            }
            // Add the shifted character to the ciphertext
            ciphertext += shifted_char;
        }
        else if (isdigit(c)) {
            cout << "is difit " << c << endl;
            // Get the value of the digit
            int digit_val = c - '0';
            // Apply the shift and wrap around the digits
            int shifted_val = (digit_val + shift) % 10;
            // Convert the shifted value back to a character
            char shifted_char = shifted_val + '0';
            cout << "shifted " << shifted_char;
            // Add the shifted character to the ciphertext
            ciphertext += shifted_char;
        }
        else {
            // Non-alphabetic characters are left unchanged
            ciphertext += c;
        }
    }
    return ciphertext;
}

string caesar_decrypt(string ciphertext, int shift) {
    string plaintext = "";
    for (char& c : ciphertext) {
        if (isalpha(c)) {
            // Convert to uppercase
            char upper_c = toupper(c);
            // Get the position of the character in the alphabet
            int char_pos = upper_c - 'A';
            // Apply the reverse shift and wrap around the alphabet
            int shifted_pos = (char_pos - shift + 26) % 26;
            // Convert the shifted position back to a character
            char shifted_char = shifted_pos + 'A';
            // Convert back to original case
            if (islower(c)) {
                shifted_char = tolower(shifted_char);
            }
            // Add the shifted character to the plaintext
            plaintext += shifted_char;
        }
        else if (isdigit(c)) {
            // Get the value of the digit
            int digit_val = c - '0';
            // Apply the reverse shift and wrap around the digits
            int shifted_val = (digit_val - shift + 10) % 10;
            // Convert the shifted value back to a character
            char shifted_char = shifted_val + '0';
            // Add the shifted character to the plaintext
            plaintext += shifted_char;
        }
        else {
            // Non-alphabetic characters are left unchanged
            plaintext += c;
        }
    }
    return plaintext;
}

vector<string> split_ecrypted(const string& s) {
    vector<string> tokens;
    size_t start = 0, end = 0;
    while ((end = s.find('⋉', start)) != string::npos) {
        tokens.push_back(s.substr(start, end - start));
        start = end + 1;
    }
    tokens.push_back(s.substr(start));
    return tokens;
}

void encrypt_file(string file_name) {
    int lines_at_the_end = 0;
    int start_empty_lines_index = -1;
    ifstream file_lines(file_name);
    if (file_lines.is_open()) {
        string line;
        int curr = 0;
        while (!file_lines.eof()) {
            getline(file_lines, line);
            if (line != "") {
                lines_at_the_end = 0;
                start_empty_lines_index = -1;
            }
            else {
                lines_at_the_end++;
                if (start_empty_lines_index == -1) start_empty_lines_index = curr;
            }
            cout << "line is " << line << endl;
            curr++;
        }
    }

    cout << "at the end is " << lines_at_the_end << endl;
    cout << "empty starts from " << start_empty_lines_index << endl;

    ifstream file_r(file_name);
    if (file_r.is_open()) {
        string encrypted_line = "";
        string line;
        int all_lines = 0;
        int curr_2 = 0;
        while (getline(file_r, line)) {
            if (line == "" && start_empty_lines_index != -1 && curr_2 >= start_empty_lines_index) break;
            all_lines++;
            line = caesar_encrypt(line, KEY * 2);
            encrypted_line = encrypted_line + line + "⋉";
            curr_2++;
        }
        file_r.close();

        cout << "enc line is " << encrypted_line << endl;
        vector<string> enc = split_ecrypted(encrypted_line);

        file_r.close();

        ofstream file2(file_name, ofstream::trunc);
        file2.close();

        ofstream origfile(file_name, std::ios::app);

        int curr = 0;
        for (const string& e : enc) {
            origfile << e;
            if (curr + 1 < all_lines) origfile << "\n";
            curr++;
        }

        for (int i = 0; i < lines_at_the_end; i++) {
            origfile << "\n";
        }

        origfile.close();
    }
}

void decrypt_file(string file_name) {
    int lines_at_the_end = 0;
    int start_empty_lines_index = -1;
    ifstream file_lines(file_name);
    if (file_lines.is_open()) {
        string line;
        int curr = 0;
        while (!file_lines.eof()) {
            getline(file_lines, line);
            if (line != "") {
                lines_at_the_end = 0;
                start_empty_lines_index = -1;
            }
            else {
                lines_at_the_end++;
                if (start_empty_lines_index == -1) start_empty_lines_index = curr;
            }
            cout << "line is " << line << endl;
            curr++;
        }
    }

    cout << "at the end is " << lines_at_the_end << endl;
    cout << "empty starts from " << start_empty_lines_index << endl;

    ifstream file_r(file_name);
    int all_lines = 0;
    if (file_r.is_open()) {
        string decrypted_line = "";
        string line;
        int curr_2 = 0;
        while (getline(file_r, line)) {
            if (line == "" && start_empty_lines_index != -1 && curr_2 >= start_empty_lines_index) break;
            all_lines++;
            line = caesar_decrypt(line, KEY * 2);
            decrypted_line = decrypted_line + line + "⋉";
            curr_2++;
        }
        file_r.close();

        cout << "dec line is " << decrypted_line << endl;
        vector<string> enc = split_ecrypted(decrypted_line);

        file_r.close();

        ofstream file2(file_name, ofstream::trunc);
        file2.close();

        ofstream origfile(file_name, std::ios::app);

        cout << "all lines " << all_lines << endl;
        int curr = 0;
        for (const string& e : enc) {
            cout << "curr " << curr << " e is " << e << endl;
            origfile << e;
            if (curr + 1 < all_lines) origfile << "\n";
            curr++;
        }

        for (int i = 0; i < lines_at_the_end; i++) {
            origfile << "\n";
        }

        origfile.close();
    }
}