#pragma once

#include "population.h"
#include "propagation.h"

#include "cuboid.h"
#include "concepts.h"
#include "population.h"

#include <unistd.h>

namespace pattern {

template <concepts::Arithmetic T>
class SSS {
private:
	Cuboid _cuboid;

	T* _base;
	T* _buffer[population::q];
	T* _f[population::q];

public:
	using value_t = T;

	SSS(Cuboid cuboid):
		_cuboid(cuboid)
	{
		const std::size_t pagesize = sysconf(_SC_PAGESIZE);
		const std::ptrdiff_t padding = population::max_offset(_cuboid);
		_base = static_cast<T*>(
		  std::aligned_alloc(pagesize, population::q * (_cuboid.volume() + 2*padding) * sizeof(T)));
		for (unsigned iPop=0; iPop < population::q; ++iPop) {
			_buffer[iPop] = _base + iPop * (_cuboid.volume() + 2*padding);
			_f[iPop] = _buffer[iPop] + padding;
		}
	}

	~SSS() {
		delete [] _base;
	}

	T* get(unsigned iPop, stage::pre_collision) {
		return _f[iPop];
	}

	T* get(unsigned iPop, stage::post_collision) {
		return _f[population::opposite(iPop)];
	}

	void stream() {
		T* f_old[population::q];
		for (unsigned iPop=0; iPop < population::q; ++iPop) {
		  f_old[iPop] = _f[iPop];
		}
		for (unsigned iPop=0; iPop < population::q; ++iPop) {
		  _f[iPop] = f_old[population::opposite(iPop)] - population::offset(_cuboid, iPop);
		}
	}

};

}