#pragma once

#include <array>
#include <cstdint>

namespace kel {
namespace impl {
struct ico_surface_helper {
	/**
	 * On each triangle we assume a ccw order and we start on the top-left part of the
	 * triangle. The orientation of the triangle is determined by the horizontal line
	 * (on the 2D foldout of the icosahedron) which is the down direction.  
	 */
	static constexpr std::array<std::array<uint8_t,3u>, 20u> neighbour_map {
		{1,4,5},//0
		{2,0,6},//1
		{3,1,7},//2
		{4,2,8},//3
		{0,3,9},//4
		{14,10,0},//5
		{10,11,1},//6
		{11,12,2},//7
		{12,13,3},//8
		{13,14,4},//9
		{6,5,15},//10
		{7,6,16},//11
		{8,7,17},//12
		{9,8,18},//13
		{5,9,19},//14
		{19,16,10},//15
		{15,17,11},//16
		{16,18,12},//17
		{17,19,13},//18
		{18,15,14} //19
	};
};
}

template<uint64_t SubD>
class ico_addr {
private:
	std::array<uint8_t, SubD+1u> vals_;
public:
	template<uint64_t Div = 1u>
	ico_addr<Div> slice() const {
		return {};
	}
};

template<typename T, uint64_t D>
class ico_triangle {
private:
	std::array<ico_triangle<T,D-1u>> subdivs_;
public:
};

template<typename T>
class ico_triangle<T,0u> final {
private:
	T val_;
public:
};

template<typename T, uint64_t SubD>
class icosahedron final {
private:
	std::array<ico_triangle<T,SubD>,20u> surfaces_;
public:
};
}