#include "BigIntegerLibrary.hh"
#include <vector>
#include <math.h>
#include <time.h>
#include <iostream>
#include <sstream>

using namespace std;

BigInteger BigIntPow(const BigInteger &base, const BigInteger &exponent)
{
    BigInteger zero(0);
    BigInteger result(1);

    if(exponent == zero)
        return result;

    for (BigInteger power(0); power < exponent; power++)
        result *= base;

    return result;
}

BigInteger generatePrime()
{
    srand ( time(NULL) );

    int q = rand() % 16 + 11;
    int notDivisible, i, n = 1;

    vector <int> knownPrimes;

    knownPrimes.push_back(2);

    while(knownPrimes.size() < q)
    {
        n += 2;
        notDivisible = 0;
        i = 0;

        while(knownPrimes[i] <= sqrt((float)n))
        {
            if(n % knownPrimes[i] != 0)
                notDivisible++;

            i++;
        }

        if(i == notDivisible)
            knownPrimes.push_back(n);
    }

    BigInteger prime(knownPrimes[knownPrimes.size()-1]);
    return prime;
}

BigInteger encrypt()
{
    BigInteger p = 29;
    BigInteger q = generatePrime();
    BigInteger N = p*q;
    BigInteger fi = (p-1)*(q-1);

    cout << "p = " << p << endl;
    cout << "q = " << q << endl;
    cout << "N = " << N << endl;
    cout << "fi = " << fi << endl << endl;

    int intE;

    cout << "Adjuk meg 'e'-t: ";
    cin >> intE;
    cout << endl;

    BigInteger e(intE);
    BigInteger d = 0;

    while((e*d)%fi != 1)
        d++;

    cout << "d = " << d << endl << endl;

    char text[50];
    int ascii;
    BigInteger c;

    cout << "Type the text and press 'enter' to encrypt: ";
    cin >> text;
    cout << endl << "Encrypted text: " << endl;

    for(unsigned int i = 0; i<strlen(text); i++)
    {
        ascii = (int)text[i];
        BigInteger m(ascii);
        c = BigIntPow(m,e)%N;

        cout << c << " ";
    }

    cout << endl << endl;
    return 0;
}

BigInteger decrypt()
{
    string str;

    cout << "Type the encrypted text" << endl;
    cin.ignore(1024,'\n');
    getline(cin,str);
    cout << endl;

    stringstream ss;
    ss.str(str);

    int code;
    int secretKey;
    int modulus;
    char text;

    cout << "Type the value of 'd' (secret key): ";
    cin >> secretKey;

    cout << "Type the value of 'N' (modulus): ";
    cin >> modulus;
    cout << endl;

    BigInteger d(secretKey);
    BigInteger N(modulus);

    cout << "The decrypted text" << endl;

    while(!ss.eof())
    {
        ss >> code;
        BigInteger c(code);
        BigInteger m = BigIntPow(c,d)%N;

        text = (char)m.toInt();
        cout << text;
    }

    cout << endl << endl;
    return 0;
}