clear;

% Functions
function r = myXor(a, b)
  if(a == b)
    r = 0;
  else
    r = 1;
  end
end

function randomSignal = generateRandomSignal(length)
  randomSignal = rand(length, 1);

  for i = 1:numel(randomSignal)

    if(randomSignal(i) < 0.5)
      randomSignal(i) = 0;
    else
      randomSignal(i) = 1;
    end

  end

end

function scrambledSignal = scrambleSignal(signal)
  register = [1, 0, 0, 1, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0];
  registerLength = numel(register);
  scrambledSignal = [];

  for z = 1:numel(signal)
    xoredLastRegisterNumbers = myXor(register(registerLength - 1), register(registerLength));

    %rotate register to the right
    for i = registerLength:-1:2
      register(i) = register(i - 1);
    end
    register(1) = xoredLastRegisterNumbers; # asign first value
    %

    newOutBit = myXor(xoredLastRegisterNumbers, signal(z));

    scrambledSignal = [scrambledSignal, newOutBit];
  end

end

function subsequenceMap = countSubsequences(singal, digit)

  subsequenceMap = [];

  counter = 0;
  signalLength = numel(singal);
  for i = 1:numel(singal)
    if(singal(i) == digit)
      counter++;
     else
        if(counter != 0)
          subsequenceMap = [subsequenceMap, counter];
        end
        counter = 0;
     end
  end

  if(counter != 0)
    subsequenceMap = [subsequenceMap, counter];
  end

end

function scrambledSignal = scrambleSignalV34(signal)
  register = [1, 0, 0, 1, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0 ,0 ,0 ,0 ,0 ,0 ,0];
  registerLength = numel(register);
  scrambledSignal = [];

  for z = 1:numel(signal)
    xoredLastRegisterNumbers = myXor(register(registerLength - 5), register(registerLength));

    %rotate register to the right
    for i = registerLength:-1:2
      register(i) = register(i - 1);
    end
    %

    newOutBit = myXor(xoredLastRegisterNumbers, signal(z));

    register(1) = newOutBit; # asign first value

    scrambledSignal = [scrambledSignal, newOutBit];
  end

end

function descrambledSignal = descrambleSignalV34(signal)
  register = [1, 0, 0, 1, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0 ,0 ,0 ,0 ,0 ,0 ,0];
  registerLength = numel(register);
  descrambledSignal = [];

  for z = 1:numel(signal)
    xoredLastRegisterNumbers = myXor(register(registerLength - 5), register(registerLength));

    %rotate register to the right
    for i = registerLength:-1:2
      register(i) = register(i - 1);
    end
    %

    newOutBit = myXor(xoredLastRegisterNumbers, signal(z));

    register(1) = signal(z); # asign first value

    descrambledSignal = [descrambledSignal, newOutBit];
  end

end

function monitorScrambler(signalLength)
  zerosSignal = zeros(signalLength, 1); # same 0
  onesSignal = ones(signalLength, 1); # same 1
  randomSignal = generateRandomSignal(signalLength); # randomowe 0 i 1

  zerosSignal = scrambleSignal(zerosSignal);
  onesSignal = scrambleSignal(onesSignal);
  randomSignal = scrambleSignal(randomSignal);

  % a)
  subplot(2,2,1);
  hist(countSubsequences(zerosSignal, 0));
  title('Same 0');
  ylabel('Ilosc wystapien');
  xlabel('Dlugosc cykli 0');

  % b)
  subplot(2,2,2);
  hist(countSubsequences(onesSignal, 1));
  title('Same 1');
  ylabel('Ilosc wystapien');
  xlabel('Dlugosc cykli 1');

  % c)
  subplot(2,2,3);
  hist(countSubsequences(randomSignal, 0));
  title('Losowe');
  ylabel('Ilosc wystapien');
  xlabel('Dlugosc cykli 0');

  subplot(2,2,4);
  hist(countSubsequences(randomSignal, 1));
  title('Losowe');
  ylabel('Ilosc wystapien');
  xlabel('Dlugosc cykli 1');

end

function areEqual = compareArrays(a, b)
  areEqual = true;

  for z = 1:numel(a)
    if(a(z) != b(z))
      areEqual = false;
      return
    end
  end

end

function monitorScramblerV34(signalLength)
  zerosSignal = zeros(signalLength, 1); # same 0
  onesSignal = ones(signalLength, 1); # same 1
  randomSignal = generateRandomSignal(signalLength); # randomowe 0 i 1

  scrambledZerosSignal = scrambleSignalV34(zerosSignal);
  scrambledOnesSignal = scrambleSignalV34(onesSignal);
  scrambledRandomSignal = scrambleSignalV34(randomSignal);

  descrambledZeros = descrambleSignalV34(scrambledZerosSignal);
  descrambledOnes = descrambleSignalV34(scrambledOnesSignal);
  descrambledRandom = descrambleSignalV34(scrambledRandomSignal);

  disp(compareArrays(descrambledZeros, zerosSignal));
  disp(compareArrays(descrambledOnes, onesSignal));
  disp(compareArrays(descrambledRandom, randomSignal));

  % a)
  subplot(2,2,1);
  hist(countSubsequences(scrambledZerosSignal, 0));
  title('Same 0');
  ylabel('Ilosc wystapien');
  xlabel('Dlugosc cykli 0');

  % b)
  subplot(2,2,2);
  hist(countSubsequences(scrambledOnesSignal, 1));
  title('Same 1');
  ylabel('Ilosc wystapien');
  xlabel('Dlugosc cykli 1');

  % c)
  subplot(2,2,3);
  hist(countSubsequences(scrambledRandomSignal, 0));
  title('Losowe');
  ylabel('Ilosc wystapien');
  xlabel('Dlugosc cykli 0');

  subplot(2,2,4);
  hist(countSubsequences(scrambledRandomSignal, 1));
  title('Losowe');
  ylabel('Ilosc wystapien');
  xlabel('Dlugosc cykli 1');

end


% Settings
signalLength = 10*10;

% Main
%monitorScrambler(signalLength);
monitorScramblerV34(signalLength);