#include <iostream>
#include <fstream>

using namespace std;

//
//
//
string StringEncryptorDecryptor(char encryptionKey, string stringToEncrypt);

//
//
//
void GetFileInfo(string& fileName, ifstream& inData);

//
//
//
string ChangeFileExtension(string fileName);

int main()
{
    string secretMessage{};
    string decryptMessage{};
    char encryptionKey{};
    string fileName{};
    ifstream inData{};
    ofstream outData{};

    cout << "Choose a single character to encrypt your file. " << endl;
    cin.get(encryptionKey);
    encryptionKey = toupper(encryptionKey);
    cin.ignore(INT_MAX,'\n');


    GetFileInfo(fileName, inData);

    outData.open(fileName.substr(0, fileName.find_last_of('.'))+".xor");

    inData >> secretMessage;
    while(!inData.eof()){
        inData >> secretMessage;
        outData << StringEncryptorDecryptor(encryptionKey, secretMessage) <<" ";
    }

    cout << "Your program has now been encrypted." << endl;
    cout << "The Encrypted filename is: " << ChangeFileExtension(fileName) << endl;

    outData.close();
    inData.close();

    cout <<"\nWould you like to decrypt a file?" << endl;
    cin >> decryptMessage;

    if(decryptMessage == "Yes" ||decryptMessage == "yes"||decryptMessage == "y" ){
        GetFileInfo(fileName, inData);
        cout <<"Your file has been decrypted and is as follows : " << endl;
        inData >> secretMessage;
        while(!inData.eof()){
            cout << StringEncryptorDecryptor(encryptionKey, secretMessage) <<" ";
            inData >> secretMessage;
        }
    }
    else{
        cout <<"Goodbye." << endl;
    }

  return 0;
}

string StringEncryptorDecryptor(char encryptionKey, string stringToEncrypt){
    string word = stringToEncrypt;
    for (int i{0};i < stringToEncrypt.size() ; i++){
        word[i] = stringToEncrypt[i] ^ encryptionKey;
    }
    return word;
};

void GetFileInfo(string& fileName, ifstream& inData){
    do {
        // Prompt user for file name and open file
        cout << "Enter file containing input values: ";

        cin >> fileName;
        inData.open(fileName.c_str());
        if (!inData){
            cout << "Invalid file!\n\n";
            }
    } while (!inData); // Loop until valid file name provided
};

string ChangeFileExtension(string fileName){
    string changedExtension{};
    changedExtension = fileName.substr(0, fileName.find_last_of('.'))+".xor";

    return changedExtension;
};