#ifndef LOCALMAXIMA_H
#define LOCALMAXIMA_H

class LocalMaxima {

	static constexpr float MAX = 1e40;

	size_t everyNth;

	size_t cnt = 0;
	float s0;
	float s1;		// center value
	float s2;


public:

	struct Res {
		bool isMax;
		float val;
		Res(bool isMax, float val) : isMax(isMax), val(val) {;}
	};

	/** ctor. use only every n-th sample */
	LocalMaxima(const size_t everyNth) : everyNth(everyNth) {
		reset();
	}

	/** is the given value a local maxima? */
	Res add(const float s) {

		if		(cnt == 0*everyNth) {s0 = s;}	// set, wait some time
		else if (cnt == 1*everyNth) {s1 = s;}	// set, wait some time
		else if (cnt == 2*everyNth) {s2 = s;}	// set
		else if (cnt  > 2*everyNth) {			// now shift values for every time step, until max is found
			s0 = s1;
			s1 = s2;
			s2 = s;
		}

		++cnt;

		if ((s1 > s0) && (s1 > s2)) {
			Res res(true, s1);
			reset();
			return res;
		}

		return Res(false, 0);

	}

private:

	void reset() {
		s0 = MAX;
		s1 = MAX;
		s2 = MAX;
		cnt = 0;
	}

};

#endif // LOCALMAXIMA_H