#include <iostream>
#include <vector>
#include <thread>
#include <string>
#include <fstream>

using namespace std;
typedef vector<char>::iterator it;

vector<char>readFile(const char* fileName){
    int NumberOfBits;
    vector<char> vecReadBits;
    ifstream file(fileName, ios::in | ios::binary | ios::ate);
    if(file.is_open()){
        NumberOfBits = file.tellg();
        char* MemBlock = new char[NumberOfBits];
        file.seekg(0, ios::beg);
        file.read(MemBlock, NumberOfBits);
        file.close();
        vecReadBits.resize(NumberOfBits-4);
        for(int i = 0; i<NumberOfBits-4; i++){
            vecReadBits.push_back(MemBlock[i]);
        }
        cout<<"This file [" << fileName <<"] contains "<< NumberOfBits-4<<" bits."<<endl;
        delete [] MemBlock;
        cout << "SUCCESSFULLY DONE - readFile - " << fileName << endl;
    }else cout<<"ERROR - readFile."<<endl;
    return vecReadBits;
}

void writeInFile(string fileName, vector<char> vec){
    it vecIt=vec.begin();
    char* MemBlock = new char[vec.size()];
    ofstream file(fileName, ios::out | ios::binary);
    for(int i=0; vecIt != vec.end(); vecIt++, i++)
        MemBlock[i] = *vecIt;
    file.write(MemBlock,vec.size());
       file.close();
        cout << "SUCCESSFULLY DONE - writeInFile - " << fileName << endl;
}

void XOR(it inputBegin, it inputEnd, it keyBegin, it keyEnd, it outBegin){

    it inputIt  = inputBegin;
    it keyIt    = keyBegin;
    it outIt    = outBegin;

    for(;inputIt!=inputEnd; inputIt++, keyIt++, outIt++){
        if(keyIt >= keyEnd)
            keyIt = keyBegin;
        *outIt = *inputIt ^ *keyIt;
    }
}

int main(int argc, char* argv[])
{
    vector<char> vecInput   = readFile(argv[1]);
    vector<char> vecKey     = readFile(argv[2]);
    vector<char> vecOut(vecInput.size());

    int threadNum  = stoi(argv[4]);
    int threadSize = vecInput.size() / threadNum;
    thread threadList[threadNum];

    int i;
    bool TheLastThreadIsDifferent = (vecInput.size() % threadNum != 0);
    int NumberOfForLoops = threadNum;
    if(TheLastThreadIsDifferent) NumberOfForLoops--;
    for(i=0; i<NumberOfForLoops; i++){

       // vector<char>::iterator  inItBegin  = vecInput.begin() + i*threadSize;
       // vector<char>::iterator  inItEnd    = inItBegin        + i*threadSize;
       // vector<char>::iterator  keyItBegin = vecKey.begin()   + i*threadSize;
       // vector<char>::iterator  outItBegin = vecOut.begin()   + i*threadSize;

//         if(keyItBegin >= vecKey.end())
  //          keyItBegin = vecKey.begin();

        threadList[i] = thread(XOR, vecInput.begin()+ i*threadSize,
                                    vecInput.begin()+ (i+1)*threadSize,
                                    vecKey.begin()  + i*threadSize,
                                    vecKey.begin()  + (i+1)*threadSize,
                                    vecOut.begin()  + i*threadSize);
    }
    if(TheLastThreadIsDifferent){
        i++;
        threadList[i] = thread(XOR, vecInput.begin()+ i*threadSize,
                                    vecInput.end(),
                                    vecKey.begin()  + i*threadSize,
                                    vecKey.begin()  + (i+1)*threadSize,
                                    vecOut.begin()  + i*threadSize);
    }

    for(int i=0; i<threadNum; i++)
        threadList[i].join();

    cout << "SUCCESSFULLY DONE - XOR with threads" << endl;
    writeInFile(argv[3],vecOut);
    cout << "SUCCSSFULLY DONE - THE WHOLE PROGRAM" << endl;
    return 0;
}