#pragma once

#include "cell_helper.hpp"

#include <memory>
#include <range/v3/action/insert.hpp>
#include <range/v3/action/sort.hpp>
#include <range/v3/action/unique.hpp>
#include <range/v3/algorithm/count_if.hpp>
#include <range/v3/algorithm/fold_left.hpp>
#include <range/v3/range/conversion.hpp>
#include <range/v3/view/filter.hpp>
#include <utility>

template <typename MatrixElement>
CellHelper<MatrixElement>::CellHelper(
	std::shared_ptr<IMatrix<MatrixElement>> matrix) noexcept
	: _matrix(std::move(matrix))
{
}

template <typename MatrixElement>
auto CellHelper<MatrixElement>::compute_is_cell_dying(
	const Vector2 &cell_pos) const noexcept -> bool
{
	int64_t neighbour_cell_cnt = ranges::count_if(
		_get_valid_pos_neighbours(cell_pos),
		[this](const Vector2 &pos)
		{
			return _matrix->get(pos) == 'x';
		});

	return neighbour_cell_cnt < 2 || neighbour_cell_cnt >= 4;
}

template <typename MatrixElement>
auto CellHelper<MatrixElement>::compute_birth_cell_positions(
	const std::vector<Vector2> &cell_positions) const noexcept -> std::vector<Vector2>
{
	std::vector<Vector2> empty_neighbour_positions =
		ranges::fold_left(
			cell_positions,
			std::vector<Vector2>(),
			[this](std::vector<Vector2> acc, const Vector2 &pos)
			{
				std::vector<Vector2> neighbours = _get_valid_pos_neighbours(pos);

				auto empty_neighbours =
					neighbours | ranges::views::filter(
									 [this](const Vector2 &neighbour_pos)
									 {
										 return _matrix->get(neighbour_pos) == ' ';
									 });

				ranges::actions::insert(acc, acc.end(), empty_neighbours);

				return acc;
			}) |
		ranges::actions::sort | ranges::actions::unique;

	auto birth_cell_positions = empty_neighbour_positions |
								ranges::views::filter(
									[this](const Vector2 &cell_pos)
									{
										auto neighbours =
											_get_valid_pos_neighbours(cell_pos);

										int64_t neighbour_cell_cnt = ranges::count_if(
											neighbours,
											[this](const Vector2 &neighbour_pos)
											{
												return _matrix->get(neighbour_pos) == 'x';
											});

										return neighbour_cell_cnt == 3;
									});

	return birth_cell_positions | ranges::to<std::vector>();
}

template <typename MatrixElement>
auto CellHelper<MatrixElement>::_get_valid_pos_neighbours(
	const Vector2 &position) const noexcept -> std::vector<Vector2>
{
	const auto neighbours = {
		position + Vector2::up(),
		position + Vector2::down(),
		position + Vector2::left(),
		position + Vector2::right(),
		position + Vector2::up() + Vector2::left(),
		position + Vector2::up() + Vector2::right(),
		position + Vector2::down() + Vector2::left(),
		position + Vector2::down() + Vector2::right()};

	const auto matrix_size = _matrix->get_size();

	return neighbours |
		   ranges::views::filter(
			   [&matrix_size](const Vector2 &neighbour_pos)
			   {
				   return matrix_size.validate_coords(neighbour_pos) ==
						  CoordsValidation::VALID;
			   }) |
		   ranges::to<std::vector>();
}