From 7307815e99a79dac42f2a9c06b0fe6171ea11ba0 Mon Sep 17 00:00:00 2001
From: HampusM <hampus@hampusmat.com>
Date: Fri, 1 Jul 2022 16:01:04 +0200
Subject: refactor: use ranges

---
 src/game/cell_helper_impl.hpp | 121 ++++++++++++++++++++++--------------------
 1 file changed, 63 insertions(+), 58 deletions(-)

(limited to 'src/game/cell_helper_impl.hpp')

diff --git a/src/game/cell_helper_impl.hpp b/src/game/cell_helper_impl.hpp
index bd40794..c03b80c 100644
--- a/src/game/cell_helper_impl.hpp
+++ b/src/game/cell_helper_impl.hpp
@@ -2,18 +2,15 @@
 
 #include "cell_helper.hpp"
 
-#include "util/algorithm.hpp"
-
-template <typename MatrixElement>
-constexpr auto has_matrix_value(
-	const std::shared_ptr<IMatrix<MatrixElement>> &matrix,
-	const MatrixElement &value) noexcept
-{
-	return [&matrix, &value](const Vector2 &pos)
-	{
-		return matrix->get(pos) == value;
-	};
-}
+#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(
@@ -26,74 +23,82 @@ template <typename MatrixElement>
 auto CellHelper<MatrixElement>::is_cell_dying(const Vector2 &cell_pos) const noexcept
 	-> bool
 {
-	const auto neighbour_cell_positions =
-		container_filter(find_neighbours(cell_pos), has_matrix_value(_matrix, 'x'));
-
-	const auto neighbour_cell_cnt = neighbour_cell_positions.size();
+	int64_t neighbour_cell_cnt = ranges::count_if(
+		find_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>::get_birth_cell_positions(
-	const std::list<Vector2> &cell_positions) const noexcept -> std::list<Vector2>
+	const std::vector<Vector2> &cell_positions) const noexcept -> std::vector<Vector2>
 {
-	auto all_empty_neighbour_positions = std::list<Vector2>();
-
-	for (const auto &cell_pos : cell_positions)
-	{
-		const std::vector<Vector2> empty_neighbour_positions =
-			container_filter(find_neighbours(cell_pos), has_matrix_value(_matrix, ' '));
-
-		all_empty_neighbour_positions.insert(
-			all_empty_neighbour_positions.end(),
-			empty_neighbour_positions.begin(),
-			empty_neighbour_positions.end());
-	}
-
-	// Remove duplicates
-	all_empty_neighbour_positions.sort();
-	all_empty_neighbour_positions.unique();
-
-	auto birth_cell_positions = container_filter(
-		all_empty_neighbour_positions,
-		[this](const Vector2 &cell_pos)
-		{
-			const auto neighbour_cell_positions = container_filter(
-				find_neighbours(cell_pos),
-				has_matrix_value(_matrix, 'x'));
-
-			return neighbour_cell_positions.size() == 3;
-		});
-
-	return birth_cell_positions;
+	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 = find_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 = find_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>::find_neighbours(const Vector2 &cell_pos) const noexcept
 	-> std::vector<Vector2>
 {
-	std::vector<Vector2> cell_positions = {};
-
 	const auto matrix_size =
 		Bounds({.width = _matrix->get_column_cnt(), .height = _matrix->get_row_cnt()});
 
 	const auto neighbours = _get_position_neighbours(cell_pos);
 
-	for (const auto &neighbour_pos : neighbours)
-	{
-		if (matrix_size.validate_coords(neighbour_pos) == CoordsValidation::VALID)
-		{
-			cell_positions.push_back(neighbour_pos);
-		}
-	}
-
-	return cell_positions;
+	return neighbours |
+		   ranges::views::filter(
+			   [&matrix_size](const Vector2 &neighbour_pos)
+			   {
+				   return matrix_size.validate_coords(neighbour_pos) ==
+						  CoordsValidation::VALID;
+			   }) |
+		   ranges::to<std::vector>();
 }
 
 template <typename MatrixElement>
 auto CellHelper<MatrixElement>::_get_position_neighbours(const Vector2 &position) noexcept
-	-> std::list<Vector2>
+	-> std::vector<Vector2>
 {
 	return {
 		position + Vector2::up(),
-- 
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