#ifndef LUT_H
#define LUT_H

#include <vector>
#include "../Math.h"

namespace Distribution {

	template <typename Scalar> class LUT {

	private:

		Scalar min;
		Scalar max;
		Scalar diff;

		/** number of samples between min and max */
		int numSamples;

		/** the look-up-table */
		std::vector<Scalar> samples;


	public:

		/** ctor */
		template <typename Distribution> LUT(const Distribution dist, const Scalar min, const Scalar max, const int numSamples) :
			min(min), max(max), diff(max-min), numSamples(numSamples) {

			buildLUT(dist);

		}

		/** get the probability of val from the LUT */
		Scalar getProbability(const Scalar val) const {
			int idx = ((val - min) * numSamples / diff);
			idx = Math::clamp(0, numSamples-1, idx);
			return samples[idx];
		}

	private:

		/** build the look-up-table */
		template <typename Distribution> void buildLUT(const Distribution dist) {

			samples.resize(numSamples);
			for (int idx = 0; idx < numSamples; ++idx) {
				const Scalar val = min + (idx * diff / numSamples);
				samples[idx] = dist.getProbability(val);
			}

		}

	};

}

#endif // LUT_H