// Example program
#include <iostream>
#include <string>
#include <bitset>

using namespace std;

uint8_t lookupLeft[] = {11,8,3,14,10,12,1,4,9,6,2,13,15,5,0,7};
uint8_t lookupRight[] = {8,14,4,11,1,6,0,3,10,12,5,9,7,15,2,13};

uint8_t keys[] = {
    0xde, 0xad, 0xbe, 0xef
};

uint16_t feistel(uint16_t input, uint8_t key)
{
    uint8_t leftIn, rightIn;
    uint8_t leftOut, rightOut;
    uint8_t temp, temp1;
    uint16_t output;

    leftIn = (input & 0b1111111100000000) >> 8;
    rightIn = input & 0b0000000011111111;

    cout << "input "<< bitset<8>(leftIn) << ' ' << bitset<8>(rightIn) << endl;

    temp = rightIn ^ key;

    cout << "1xor " << bitset<8>(temp) << endl;

    temp1 = (lookupLeft[(temp & 0b11110000) >> 4] << 4) | lookupRight[temp & 0b00001111];
    temp = (lookupLeft[(temp & 0b11110000) >> 4] ) | lookupRight[temp & 0b00001111] << 4;

    cout << "lookup " << bitset<8>(temp1) << endl;
    cout << "reverse " << bitset<8>(temp) << endl;

    leftOut = rightIn;
    rightOut = temp ^ leftIn;

    output =  (leftOut << 8) | (rightOut);

    cout << "output " << bitset<8>(output >> 8) << ' ' << bitset<8>(output) << endl;

    return output;
}

int main()
{
    uint16_t input = 0b0101100100000010;
    uint16_t ret, temp;

    cout << "1 stage" << endl;
    ret = feistel(input, keys[0]);
    cout << endl << "2 stage" << endl;
    ret = feistel(ret, keys[1]);
    cout << endl << "3 stage" << endl;
    ret = feistel(ret, keys[2]);
    cout << endl << "4 stage" << endl;
    ret = feistel(ret, keys[3]);

    temp = ret >> 8;
    ret = (ret << 8) | temp;

    cout <<endl<<endl << "1 stage" << endl;
    ret = feistel(ret, keys[3]);
    cout << endl << "2 stage" << endl;
    ret = feistel(ret, keys[2]);
    cout << endl << "3 stage" << endl;
    ret = feistel(ret, keys[1]);
    cout << endl << "4 stage" << endl;
    ret = feistel(ret, keys[0]);

}