#include <knob>

Knob::Knob(int minimum, int maximum) {
	Knob::minimum = minimum;
	Knob::maximum = maximum;
	Knob::A = false;
	Knob::B = false;
	Knob::rotPlusOnePrev = false;
	Knob::rotMinOnePrev = false;
	Knob::rotation = 0;
}

int Knob::getRotation() {
	return Knob::rotation;
};

void Knob::updateRotation(bool ANew, bool BNew) {
	bool rotPlusOneNew = (!B && !A && !BNew && ANew) ||
						 (!B && A && BNew && ANew) ||
						 (B && !A && !BNew && !ANew) ||
						 (B && A && BNew && !ANew);

	bool rotMinOneNew = (!B && !A && BNew && !ANew) ||
						(!B && A && !BNew && !ANew) ||
						(B && !A && BNew && ANew) ||
						(B && A && !BNew && ANew);

	bool impossibleState = (!B && !A && BNew && ANew) ||
						   (!B && A && BNew && !ANew) ||
						   (B && !A && !BNew && ANew) ||
						   (B && A && !BNew && !ANew);

	if (rotPlusOneNew || (impossibleState && rotPlusOnePrev))
		rotation += 2;
	if (rotMinOneNew || (impossibleState && rotMinOnePrev))
		rotation -= 2;
	if (rotation < minimum)
		rotation = minimum;
	if (rotation > maximum)
		rotation = maximum;

	A = ANew;
	B = BNew;
	if (!impossibleState) {
		rotPlusOnePrev = rotPlusOneNew;
		rotMinOnePrev = rotMinOneNew;
	}
}