/**************************************************************************/
/*  a_star_grid_2d.cpp                                                    */
/**************************************************************************/
/*                         This file is part of:                          */
/*                             GODOT ENGINE                               */
/*                        https://godotengine.org                         */
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/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur.                  */
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/* Permission is hereby granted, free of charge, to any person obtaining  */
/* a copy of this software and associated documentation files (the        */
/* "Software"), to deal in the Software without restriction, including    */
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/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,        */
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/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY   */
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#include "a_star_grid_2d.h"
#include "a_star_grid_2d.compat.inc"

#include "core/variant/typed_array.h"

static real_t heuristic_euclidean(const Vector2i &p_from, const Vector2i &p_to) {
	real_t dx = (real_t)ABS(p_to.x - p_from.x);
	real_t dy = (real_t)ABS(p_to.y - p_from.y);
	return (real_t)Math::sqrt(dx * dx + dy * dy);
}

static real_t heuristic_manhattan(const Vector2i &p_from, const Vector2i &p_to) {
	real_t dx = (real_t)ABS(p_to.x - p_from.x);
	real_t dy = (real_t)ABS(p_to.y - p_from.y);
	return dx + dy;
}

static real_t heuristic_octile(const Vector2i &p_from, const Vector2i &p_to) {
	real_t dx = (real_t)ABS(p_to.x - p_from.x);
	real_t dy = (real_t)ABS(p_to.y - p_from.y);
	real_t F = Math_SQRT2 - 1;
	return (dx < dy) ? F * dx + dy : F * dy + dx;
}

static real_t heuristic_chebyshev(const Vector2i &p_from, const Vector2i &p_to) {
	real_t dx = (real_t)ABS(p_to.x - p_from.x);
	real_t dy = (real_t)ABS(p_to.y - p_from.y);
	return MAX(dx, dy);
}

static real_t (*heuristics[AStarGrid2D::HEURISTIC_MAX])(const Vector2i &, const Vector2i &) = { heuristic_euclidean, heuristic_manhattan, heuristic_octile, heuristic_chebyshev };

void AStarGrid2D::set_region(const Rect2i &p_region) {
	ERR_FAIL_COND(p_region.size.x < 0 || p_region.size.y < 0);
	if (p_region != region) {
		region = p_region;
		dirty = true;
	}
}

Rect2i AStarGrid2D::get_region() const {
	return region;
}

void AStarGrid2D::set_size(const Size2i &p_size) {
	WARN_DEPRECATED_MSG(R"(The "size" property is deprecated, use "region" instead.)");
	ERR_FAIL_COND(p_size.x < 0 || p_size.y < 0);
	if (p_size != region.size) {
		region.size = p_size;
		dirty = true;
	}
}

Size2i AStarGrid2D::get_size() const {
	return region.size;
}

void AStarGrid2D::set_offset(const Vector2 &p_offset) {
	if (!offset.is_equal_approx(p_offset)) {
		offset = p_offset;
		dirty = true;
	}
}

Vector2 AStarGrid2D::get_offset() const {
	return offset;
}

void AStarGrid2D::set_cell_size(const Size2 &p_cell_size) {
	if (!cell_size.is_equal_approx(p_cell_size)) {
		cell_size = p_cell_size;
		dirty = true;
	}
}

Size2 AStarGrid2D::get_cell_size() const {
	return cell_size;
}

void AStarGrid2D::set_cell_shape(CellShape p_cell_shape) {
	if (cell_shape == p_cell_shape) {
		return;
	}

	ERR_FAIL_INDEX(p_cell_shape, CellShape::CELL_SHAPE_MAX);
	cell_shape = p_cell_shape;
	dirty = true;
}

AStarGrid2D::CellShape AStarGrid2D::get_cell_shape() const {
	return cell_shape;
}

void AStarGrid2D::update() {
	if (!dirty) {
		return;
	}

	points.clear();

	const int32_t end_x = region.get_end().x;
	const int32_t end_y = region.get_end().y;
	const Vector2 half_cell_size = cell_size / 2;

	for (int32_t y = region.position.y; y < end_y; y++) {
		LocalVector<Point> line;
		for (int32_t x = region.position.x; x < end_x; x++) {
			Vector2 v = offset;
			switch (cell_shape) {
				case CELL_SHAPE_ISOMETRIC_RIGHT:
					v += half_cell_size + Vector2(x + y, y - x) * half_cell_size;
					break;
				case CELL_SHAPE_ISOMETRIC_DOWN:
					v += half_cell_size + Vector2(x - y, x + y) * half_cell_size;
					break;
				case CELL_SHAPE_SQUARE:
					v += Vector2(x, y) * cell_size;
					break;
				default:
					break;
			}
			line.push_back(Point(Vector2i(x, y), v));
		}
		points.push_back(line);
	}

	dirty = false;
}

bool AStarGrid2D::is_in_bounds(int32_t p_x, int32_t p_y) const {
	return region.has_point(Vector2i(p_x, p_y));
}

bool AStarGrid2D::is_in_boundsv(const Vector2i &p_id) const {
	return region.has_point(p_id);
}

bool AStarGrid2D::is_dirty() const {
	return dirty;
}

void AStarGrid2D::set_jumping_enabled(bool p_enabled) {
	jumping_enabled = p_enabled;
}

bool AStarGrid2D::is_jumping_enabled() const {
	return jumping_enabled;
}

void AStarGrid2D::set_diagonal_mode(DiagonalMode p_diagonal_mode) {
	ERR_FAIL_INDEX((int)p_diagonal_mode, (int)DIAGONAL_MODE_MAX);
	diagonal_mode = p_diagonal_mode;
}

AStarGrid2D::DiagonalMode AStarGrid2D::get_diagonal_mode() const {
	return diagonal_mode;
}

void AStarGrid2D::set_default_compute_heuristic(Heuristic p_heuristic) {
	ERR_FAIL_INDEX((int)p_heuristic, (int)HEURISTIC_MAX);
	default_compute_heuristic = p_heuristic;
}

AStarGrid2D::Heuristic AStarGrid2D::get_default_compute_heuristic() const {
	return default_compute_heuristic;
}

void AStarGrid2D::set_default_estimate_heuristic(Heuristic p_heuristic) {
	ERR_FAIL_INDEX((int)p_heuristic, (int)HEURISTIC_MAX);
	default_estimate_heuristic = p_heuristic;
}

AStarGrid2D::Heuristic AStarGrid2D::get_default_estimate_heuristic() const {
	return default_estimate_heuristic;
}

void AStarGrid2D::set_point_solid(const Vector2i &p_id, bool p_solid) {
	ERR_FAIL_COND_MSG(dirty, "Grid is not initialized. Call the update method.");
	ERR_FAIL_COND_MSG(!is_in_boundsv(p_id), vformat("Can't set if point is disabled. Point %s out of bounds %s.", p_id, region));
	_get_point_unchecked(p_id)->solid = p_solid;
}

bool AStarGrid2D::is_point_solid(const Vector2i &p_id) const {
	ERR_FAIL_COND_V_MSG(dirty, false, "Grid is not initialized. Call the update method.");
	ERR_FAIL_COND_V_MSG(!is_in_boundsv(p_id), false, vformat("Can't get if point is disabled. Point %s out of bounds %s.", p_id, region));
	return _get_point_unchecked(p_id)->solid;
}

void AStarGrid2D::set_point_weight_scale(const Vector2i &p_id, real_t p_weight_scale) {
	ERR_FAIL_COND_MSG(dirty, "Grid is not initialized. Call the update method.");
	ERR_FAIL_COND_MSG(!is_in_boundsv(p_id), vformat("Can't set point's weight scale. Point %s out of bounds %s.", p_id, region));
	ERR_FAIL_COND_MSG(p_weight_scale < 0.0, vformat("Can't set point's weight scale less than 0.0: %f.", p_weight_scale));
	_get_point_unchecked(p_id)->weight_scale = p_weight_scale;
}

real_t AStarGrid2D::get_point_weight_scale(const Vector2i &p_id) const {
	ERR_FAIL_COND_V_MSG(dirty, 0, "Grid is not initialized. Call the update method.");
	ERR_FAIL_COND_V_MSG(!is_in_boundsv(p_id), 0, vformat("Can't get point's weight scale. Point %s out of bounds %s.", p_id, region));
	return _get_point_unchecked(p_id)->weight_scale;
}

void AStarGrid2D::fill_solid_region(const Rect2i &p_region, bool p_solid) {
	ERR_FAIL_COND_MSG(dirty, "Grid is not initialized. Call the update method.");

	const Rect2i safe_region = p_region.intersection(region);
	const int32_t end_x = safe_region.get_end().x;
	const int32_t end_y = safe_region.get_end().y;

	for (int32_t y = safe_region.position.y; y < end_y; y++) {
		for (int32_t x = safe_region.position.x; x < end_x; x++) {
			_get_point_unchecked(x, y)->solid = p_solid;
		}
	}
}

void AStarGrid2D::fill_weight_scale_region(const Rect2i &p_region, real_t p_weight_scale) {
	ERR_FAIL_COND_MSG(dirty, "Grid is not initialized. Call the update method.");
	ERR_FAIL_COND_MSG(p_weight_scale < 0.0, vformat("Can't set point's weight scale less than 0.0: %f.", p_weight_scale));

	const Rect2i safe_region = p_region.intersection(region);
	const int32_t end_x = safe_region.get_end().x;
	const int32_t end_y = safe_region.get_end().y;

	for (int32_t y = safe_region.position.y; y < end_y; y++) {
		for (int32_t x = safe_region.position.x; x < end_x; x++) {
			_get_point_unchecked(x, y)->weight_scale = p_weight_scale;
		}
	}
}

AStarGrid2D::Point *AStarGrid2D::_jump(Point *p_from, Point *p_to) {
	if (!p_to || p_to->solid) {
		return nullptr;
	}
	if (p_to == end) {
		return p_to;
	}

	int32_t from_x = p_from->id.x;
	int32_t from_y = p_from->id.y;

	int32_t to_x = p_to->id.x;
	int32_t to_y = p_to->id.y;

	int32_t dx = to_x - from_x;
	int32_t dy = to_y - from_y;

	if (diagonal_mode == DIAGONAL_MODE_ALWAYS || diagonal_mode == DIAGONAL_MODE_AT_LEAST_ONE_WALKABLE) {
		if (dx != 0 && dy != 0) {
			if ((_is_walkable(to_x - dx, to_y + dy) && !_is_walkable(to_x - dx, to_y)) || (_is_walkable(to_x + dx, to_y - dy) && !_is_walkable(to_x, to_y - dy))) {
				return p_to;
			}
			if (_jump(p_to, _get_point(to_x + dx, to_y)) != nullptr) {
				return p_to;
			}
			if (_jump(p_to, _get_point(to_x, to_y + dy)) != nullptr) {
				return p_to;
			}
		} else {
			if (dx != 0) {
				if ((_is_walkable(to_x + dx, to_y + 1) && !_is_walkable(to_x, to_y + 1)) || (_is_walkable(to_x + dx, to_y - 1) && !_is_walkable(to_x, to_y - 1))) {
					return p_to;
				}
			} else {
				if ((_is_walkable(to_x + 1, to_y + dy) && !_is_walkable(to_x + 1, to_y)) || (_is_walkable(to_x - 1, to_y + dy) && !_is_walkable(to_x - 1, to_y))) {
					return p_to;
				}
			}
		}
		if (_is_walkable(to_x + dx, to_y + dy) && (diagonal_mode == DIAGONAL_MODE_ALWAYS || (_is_walkable(to_x + dx, to_y) || _is_walkable(to_x, to_y + dy)))) {
			return _jump(p_to, _get_point(to_x + dx, to_y + dy));
		}
	} else if (diagonal_mode == DIAGONAL_MODE_ONLY_IF_NO_OBSTACLES) {
		if (dx != 0 && dy != 0) {
			if ((_is_walkable(to_x + dx, to_y + dy) && !_is_walkable(to_x, to_y + dy)) || !_is_walkable(to_x + dx, to_y)) {
				return p_to;
			}
			if (_jump(p_to, _get_point(to_x + dx, to_y)) != nullptr) {
				return p_to;
			}
			if (_jump(p_to, _get_point(to_x, to_y + dy)) != nullptr) {
				return p_to;
			}
		} else {
			if (dx != 0) {
				if ((_is_walkable(to_x, to_y + 1) && !_is_walkable(to_x - dx, to_y + 1)) || (_is_walkable(to_x, to_y - 1) && !_is_walkable(to_x - dx, to_y - 1))) {
					return p_to;
				}
			} else {
				if ((_is_walkable(to_x + 1, to_y) && !_is_walkable(to_x + 1, to_y - dy)) || (_is_walkable(to_x - 1, to_y) && !_is_walkable(to_x - 1, to_y - dy))) {
					return p_to;
				}
			}
		}
		if (_is_walkable(to_x + dx, to_y + dy) && _is_walkable(to_x + dx, to_y) && _is_walkable(to_x, to_y + dy)) {
			return _jump(p_to, _get_point(to_x + dx, to_y + dy));
		}
	} else { // DIAGONAL_MODE_NEVER
		if (dx != 0) {
			if ((_is_walkable(to_x, to_y - 1) && !_is_walkable(to_x - dx, to_y - 1)) || (_is_walkable(to_x, to_y + 1) && !_is_walkable(to_x - dx, to_y + 1))) {
				return p_to;
			}
		} else if (dy != 0) {
			if ((_is_walkable(to_x - 1, to_y) && !_is_walkable(to_x - 1, to_y - dy)) || (_is_walkable(to_x + 1, to_y) && !_is_walkable(to_x + 1, to_y - dy))) {
				return p_to;
			}
			if (_jump(p_to, _get_point(to_x + 1, to_y)) != nullptr) {
				return p_to;
			}
			if (_jump(p_to, _get_point(to_x - 1, to_y)) != nullptr) {
				return p_to;
			}
		}
		return _jump(p_to, _get_point(to_x + dx, to_y + dy));
	}
	return nullptr;
}

void AStarGrid2D::_get_nbors(Point *p_point, LocalVector<Point *> &r_nbors) {
	bool ts0 = false, td0 = false,
		 ts1 = false, td1 = false,
		 ts2 = false, td2 = false,
		 ts3 = false, td3 = false;

	Point *left = nullptr;
	Point *right = nullptr;
	Point *top = nullptr;
	Point *bottom = nullptr;

	Point *top_left = nullptr;
	Point *top_right = nullptr;
	Point *bottom_left = nullptr;
	Point *bottom_right = nullptr;

	{
		bool has_left = false;
		bool has_right = false;

		if (p_point->id.x - 1 >= region.position.x) {
			left = _get_point_unchecked(p_point->id.x - 1, p_point->id.y);
			has_left = true;
		}
		if (p_point->id.x + 1 < region.position.x + region.size.width) {
			right = _get_point_unchecked(p_point->id.x + 1, p_point->id.y);
			has_right = true;
		}
		if (p_point->id.y - 1 >= region.position.y) {
			top = _get_point_unchecked(p_point->id.x, p_point->id.y - 1);
			if (has_left) {
				top_left = _get_point_unchecked(p_point->id.x - 1, p_point->id.y - 1);
			}
			if (has_right) {
				top_right = _get_point_unchecked(p_point->id.x + 1, p_point->id.y - 1);
			}
		}
		if (p_point->id.y + 1 < region.position.y + region.size.height) {
			bottom = _get_point_unchecked(p_point->id.x, p_point->id.y + 1);
			if (has_left) {
				bottom_left = _get_point_unchecked(p_point->id.x - 1, p_point->id.y + 1);
			}
			if (has_right) {
				bottom_right = _get_point_unchecked(p_point->id.x + 1, p_point->id.y + 1);
			}
		}
	}

	if (top && !top->solid) {
		r_nbors.push_back(top);
		ts0 = true;
	}
	if (right && !right->solid) {
		r_nbors.push_back(right);
		ts1 = true;
	}
	if (bottom && !bottom->solid) {
		r_nbors.push_back(bottom);
		ts2 = true;
	}
	if (left && !left->solid) {
		r_nbors.push_back(left);
		ts3 = true;
	}

	switch (diagonal_mode) {
		case DIAGONAL_MODE_ALWAYS: {
			td0 = true;
			td1 = true;
			td2 = true;
			td3 = true;
		} break;
		case DIAGONAL_MODE_NEVER: {
		} break;
		case DIAGONAL_MODE_AT_LEAST_ONE_WALKABLE: {
			td0 = ts3 || ts0;
			td1 = ts0 || ts1;
			td2 = ts1 || ts2;
			td3 = ts2 || ts3;
		} break;
		case DIAGONAL_MODE_ONLY_IF_NO_OBSTACLES: {
			td0 = ts3 && ts0;
			td1 = ts0 && ts1;
			td2 = ts1 && ts2;
			td3 = ts2 && ts3;
		} break;
		default:
			break;
	}

	if (td0 && (top_left && !top_left->solid)) {
		r_nbors.push_back(top_left);
	}
	if (td1 && (top_right && !top_right->solid)) {
		r_nbors.push_back(top_right);
	}
	if (td2 && (bottom_right && !bottom_right->solid)) {
		r_nbors.push_back(bottom_right);
	}
	if (td3 && (bottom_left && !bottom_left->solid)) {
		r_nbors.push_back(bottom_left);
	}
}

bool AStarGrid2D::_solve(Point *p_begin_point, Point *p_end_point) {
	last_closest_point = nullptr;
	pass++;

	if (p_end_point->solid) {
		return false;
	}

	bool found_route = false;

	LocalVector<Point *> open_list;
	SortArray<Point *, SortPoints> sorter;

	p_begin_point->g_score = 0;
	p_begin_point->f_score = _estimate_cost(p_begin_point->id, p_end_point->id);
	p_begin_point->abs_g_score = 0;
	p_begin_point->abs_f_score = _estimate_cost(p_begin_point->id, p_end_point->id);
	open_list.push_back(p_begin_point);
	end = p_end_point;

	while (!open_list.is_empty()) {
		Point *p = open_list[0]; // The currently processed point.

		// Find point closer to end_point, or same distance to end_point but closer to begin_point.
		if (last_closest_point == nullptr || last_closest_point->abs_f_score > p->abs_f_score || (last_closest_point->abs_f_score >= p->abs_f_score && last_closest_point->abs_g_score > p->abs_g_score)) {
			last_closest_point = p;
		}

		if (p == p_end_point) {
			found_route = true;
			break;
		}

		sorter.pop_heap(0, open_list.size(), open_list.ptr()); // Remove the current point from the open list.
		open_list.remove_at(open_list.size() - 1);
		p->closed_pass = pass; // Mark the point as closed.

		LocalVector<Point *> nbors;
		_get_nbors(p, nbors);

		for (Point *e : nbors) {
			real_t weight_scale = 1.0;

			if (jumping_enabled) {
				// TODO: Make it works with weight_scale.
				e = _jump(p, e);
				if (!e || e->closed_pass == pass) {
					continue;
				}
			} else {
				if (e->solid || e->closed_pass == pass) {
					continue;
				}
				weight_scale = e->weight_scale;
			}

			real_t tentative_g_score = p->g_score + _compute_cost(p->id, e->id) * weight_scale;
			bool new_point = false;

			if (e->open_pass != pass) { // The point wasn't inside the open list.
				e->open_pass = pass;
				open_list.push_back(e);
				new_point = true;
			} else if (tentative_g_score >= e->g_score) { // The new path is worse than the previous.
				continue;
			}

			e->prev_point = p;
			e->g_score = tentative_g_score;
			e->f_score = e->g_score + _estimate_cost(e->id, p_end_point->id);

			e->abs_g_score = tentative_g_score;
			e->abs_f_score = e->f_score - e->g_score;

			if (new_point) { // The position of the new points is already known.
				sorter.push_heap(0, open_list.size() - 1, 0, e, open_list.ptr());
			} else {
				sorter.push_heap(0, open_list.find(e), 0, e, open_list.ptr());
			}
		}
	}

	return found_route;
}

real_t AStarGrid2D::_estimate_cost(const Vector2i &p_from_id, const Vector2i &p_end_id) {
	real_t scost;
	if (GDVIRTUAL_CALL(_estimate_cost, p_from_id, p_end_id, scost)) {
		return scost;
	}
	return heuristics[default_estimate_heuristic](p_from_id, p_end_id);
}

real_t AStarGrid2D::_compute_cost(const Vector2i &p_from_id, const Vector2i &p_to_id) {
	real_t scost;
	if (GDVIRTUAL_CALL(_compute_cost, p_from_id, p_to_id, scost)) {
		return scost;
	}
	return heuristics[default_compute_heuristic](p_from_id, p_to_id);
}

void AStarGrid2D::clear() {
	points.clear();
	region = Rect2i();
}

Vector2 AStarGrid2D::get_point_position(const Vector2i &p_id) const {
	ERR_FAIL_COND_V_MSG(dirty, Vector2(), "Grid is not initialized. Call the update method.");
	ERR_FAIL_COND_V_MSG(!is_in_boundsv(p_id), Vector2(), vformat("Can't get point's position. Point %s out of bounds %s.", p_id, region));
	return _get_point_unchecked(p_id)->pos;
}

TypedArray<Dictionary> AStarGrid2D::get_point_data_in_region(const Rect2i &p_region) const {
	ERR_FAIL_COND_V_MSG(dirty, TypedArray<Dictionary>(), "Grid is not initialized. Call the update method.");
	const Rect2i inter_region = region.intersection(p_region);

	const int32_t start_x = inter_region.position.x - region.position.x;
	const int32_t start_y = inter_region.position.y - region.position.y;
	const int32_t end_x = inter_region.get_end().x - region.position.x;
	const int32_t end_y = inter_region.get_end().y - region.position.y;

	TypedArray<Dictionary> data;

	for (int32_t y = start_y; y < end_y; y++) {
		for (int32_t x = start_x; x < end_x; x++) {
			const Point &p = points[y][x];

			Dictionary dict;
			dict["id"] = p.id;
			dict["position"] = p.pos;
			dict["solid"] = p.solid;
			dict["weight_scale"] = p.weight_scale;
			data.push_back(dict);
		}
	}

	return data;
}

Vector<Vector2> AStarGrid2D::get_point_path(const Vector2i &p_from_id, const Vector2i &p_to_id, bool p_allow_partial_path) {
	ERR_FAIL_COND_V_MSG(dirty, Vector<Vector2>(), "Grid is not initialized. Call the update method.");
	ERR_FAIL_COND_V_MSG(!is_in_boundsv(p_from_id), Vector<Vector2>(), vformat("Can't get id path. Point %s out of bounds %s.", p_from_id, region));
	ERR_FAIL_COND_V_MSG(!is_in_boundsv(p_to_id), Vector<Vector2>(), vformat("Can't get id path. Point %s out of bounds %s.", p_to_id, region));

	Point *a = _get_point(p_from_id.x, p_from_id.y);
	Point *b = _get_point(p_to_id.x, p_to_id.y);

	if (a == b) {
		Vector<Vector2> ret;
		ret.push_back(a->pos);
		return ret;
	}

	Point *begin_point = a;
	Point *end_point = b;

	bool found_route = _solve(begin_point, end_point);
	if (!found_route) {
		if (!p_allow_partial_path || last_closest_point == nullptr) {
			return Vector<Vector2>();
		}

		// Use closest point instead.
		end_point = last_closest_point;
	}

	Point *p = end_point;
	int32_t pc = 1;
	while (p != begin_point) {
		pc++;
		p = p->prev_point;
	}

	Vector<Vector2> path;
	path.resize(pc);

	{
		Vector2 *w = path.ptrw();

		p = end_point;
		int32_t idx = pc - 1;
		while (p != begin_point) {
			w[idx--] = p->pos;
			p = p->prev_point;
		}

		w[0] = p->pos;
	}

	return path;
}

TypedArray<Vector2i> AStarGrid2D::get_id_path(const Vector2i &p_from_id, const Vector2i &p_to_id, bool p_allow_partial_path) {
	ERR_FAIL_COND_V_MSG(dirty, TypedArray<Vector2i>(), "Grid is not initialized. Call the update method.");
	ERR_FAIL_COND_V_MSG(!is_in_boundsv(p_from_id), TypedArray<Vector2i>(), vformat("Can't get id path. Point %s out of bounds %s.", p_from_id, region));
	ERR_FAIL_COND_V_MSG(!is_in_boundsv(p_to_id), TypedArray<Vector2i>(), vformat("Can't get id path. Point %s out of bounds %s.", p_to_id, region));

	Point *a = _get_point(p_from_id.x, p_from_id.y);
	Point *b = _get_point(p_to_id.x, p_to_id.y);

	if (a == b) {
		TypedArray<Vector2i> ret;
		ret.push_back(a->id);
		return ret;
	}

	Point *begin_point = a;
	Point *end_point = b;

	bool found_route = _solve(begin_point, end_point);
	if (!found_route) {
		if (!p_allow_partial_path || last_closest_point == nullptr) {
			return TypedArray<Vector2i>();
		}

		// Use closest point instead.
		end_point = last_closest_point;
	}

	Point *p = end_point;
	int32_t pc = 1;
	while (p != begin_point) {
		pc++;
		p = p->prev_point;
	}

	TypedArray<Vector2i> path;
	path.resize(pc);

	{
		p = end_point;
		int32_t idx = pc - 1;
		while (p != begin_point) {
			path[idx--] = p->id;
			p = p->prev_point;
		}

		path[0] = p->id;
	}

	return path;
}

void AStarGrid2D::_bind_methods() {
	ClassDB::bind_method(D_METHOD("set_region", "region"), &AStarGrid2D::set_region);
	ClassDB::bind_method(D_METHOD("get_region"), &AStarGrid2D::get_region);
	ClassDB::bind_method(D_METHOD("set_size", "size"), &AStarGrid2D::set_size);
	ClassDB::bind_method(D_METHOD("get_size"), &AStarGrid2D::get_size);
	ClassDB::bind_method(D_METHOD("set_offset", "offset"), &AStarGrid2D::set_offset);
	ClassDB::bind_method(D_METHOD("get_offset"), &AStarGrid2D::get_offset);
	ClassDB::bind_method(D_METHOD("set_cell_size", "cell_size"), &AStarGrid2D::set_cell_size);
	ClassDB::bind_method(D_METHOD("get_cell_size"), &AStarGrid2D::get_cell_size);
	ClassDB::bind_method(D_METHOD("set_cell_shape", "cell_shape"), &AStarGrid2D::set_cell_shape);
	ClassDB::bind_method(D_METHOD("get_cell_shape"), &AStarGrid2D::get_cell_shape);
	ClassDB::bind_method(D_METHOD("is_in_bounds", "x", "y"), &AStarGrid2D::is_in_bounds);
	ClassDB::bind_method(D_METHOD("is_in_boundsv", "id"), &AStarGrid2D::is_in_boundsv);
	ClassDB::bind_method(D_METHOD("is_dirty"), &AStarGrid2D::is_dirty);
	ClassDB::bind_method(D_METHOD("update"), &AStarGrid2D::update);
	ClassDB::bind_method(D_METHOD("set_jumping_enabled", "enabled"), &AStarGrid2D::set_jumping_enabled);
	ClassDB::bind_method(D_METHOD("is_jumping_enabled"), &AStarGrid2D::is_jumping_enabled);
	ClassDB::bind_method(D_METHOD("set_diagonal_mode", "mode"), &AStarGrid2D::set_diagonal_mode);
	ClassDB::bind_method(D_METHOD("get_diagonal_mode"), &AStarGrid2D::get_diagonal_mode);
	ClassDB::bind_method(D_METHOD("set_default_compute_heuristic", "heuristic"), &AStarGrid2D::set_default_compute_heuristic);
	ClassDB::bind_method(D_METHOD("get_default_compute_heuristic"), &AStarGrid2D::get_default_compute_heuristic);
	ClassDB::bind_method(D_METHOD("set_default_estimate_heuristic", "heuristic"), &AStarGrid2D::set_default_estimate_heuristic);
	ClassDB::bind_method(D_METHOD("get_default_estimate_heuristic"), &AStarGrid2D::get_default_estimate_heuristic);
	ClassDB::bind_method(D_METHOD("set_point_solid", "id", "solid"), &AStarGrid2D::set_point_solid, DEFVAL(true));
	ClassDB::bind_method(D_METHOD("is_point_solid", "id"), &AStarGrid2D::is_point_solid);
	ClassDB::bind_method(D_METHOD("set_point_weight_scale", "id", "weight_scale"), &AStarGrid2D::set_point_weight_scale);
	ClassDB::bind_method(D_METHOD("get_point_weight_scale", "id"), &AStarGrid2D::get_point_weight_scale);
	ClassDB::bind_method(D_METHOD("fill_solid_region", "region", "solid"), &AStarGrid2D::fill_solid_region, DEFVAL(true));
	ClassDB::bind_method(D_METHOD("fill_weight_scale_region", "region", "weight_scale"), &AStarGrid2D::fill_weight_scale_region);
	ClassDB::bind_method(D_METHOD("clear"), &AStarGrid2D::clear);

	ClassDB::bind_method(D_METHOD("get_point_position", "id"), &AStarGrid2D::get_point_position);
	ClassDB::bind_method(D_METHOD("get_point_data_in_region", "region"), &AStarGrid2D::get_point_data_in_region);
	ClassDB::bind_method(D_METHOD("get_point_path", "from_id", "to_id", "allow_partial_path"), &AStarGrid2D::get_point_path, DEFVAL(false));
	ClassDB::bind_method(D_METHOD("get_id_path", "from_id", "to_id", "allow_partial_path"), &AStarGrid2D::get_id_path, DEFVAL(false));

	GDVIRTUAL_BIND(_estimate_cost, "from_id", "end_id")
	GDVIRTUAL_BIND(_compute_cost, "from_id", "to_id")

	ADD_PROPERTY(PropertyInfo(Variant::RECT2I, "region"), "set_region", "get_region");
	ADD_PROPERTY(PropertyInfo(Variant::VECTOR2I, "size"), "set_size", "get_size");
	ADD_PROPERTY(PropertyInfo(Variant::VECTOR2, "offset"), "set_offset", "get_offset");
	ADD_PROPERTY(PropertyInfo(Variant::VECTOR2, "cell_size"), "set_cell_size", "get_cell_size");
	ADD_PROPERTY(PropertyInfo(Variant::INT, "cell_shape", PROPERTY_HINT_ENUM, "Square,IsometricRight,IsometricDown"), "set_cell_shape", "get_cell_shape");

	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "jumping_enabled"), "set_jumping_enabled", "is_jumping_enabled");
	ADD_PROPERTY(PropertyInfo(Variant::INT, "default_compute_heuristic", PROPERTY_HINT_ENUM, "Euclidean,Manhattan,Octile,Chebyshev"), "set_default_compute_heuristic", "get_default_compute_heuristic");
	ADD_PROPERTY(PropertyInfo(Variant::INT, "default_estimate_heuristic", PROPERTY_HINT_ENUM, "Euclidean,Manhattan,Octile,Chebyshev"), "set_default_estimate_heuristic", "get_default_estimate_heuristic");
	ADD_PROPERTY(PropertyInfo(Variant::INT, "diagonal_mode", PROPERTY_HINT_ENUM, "Never,Always,At Least One Walkable,Only If No Obstacles"), "set_diagonal_mode", "get_diagonal_mode");

	BIND_ENUM_CONSTANT(HEURISTIC_EUCLIDEAN);
	BIND_ENUM_CONSTANT(HEURISTIC_MANHATTAN);
	BIND_ENUM_CONSTANT(HEURISTIC_OCTILE);
	BIND_ENUM_CONSTANT(HEURISTIC_CHEBYSHEV);
	BIND_ENUM_CONSTANT(HEURISTIC_MAX);

	BIND_ENUM_CONSTANT(DIAGONAL_MODE_ALWAYS);
	BIND_ENUM_CONSTANT(DIAGONAL_MODE_NEVER);
	BIND_ENUM_CONSTANT(DIAGONAL_MODE_AT_LEAST_ONE_WALKABLE);
	BIND_ENUM_CONSTANT(DIAGONAL_MODE_ONLY_IF_NO_OBSTACLES);
	BIND_ENUM_CONSTANT(DIAGONAL_MODE_MAX);

	BIND_ENUM_CONSTANT(CELL_SHAPE_SQUARE);
	BIND_ENUM_CONSTANT(CELL_SHAPE_ISOMETRIC_RIGHT);
	BIND_ENUM_CONSTANT(CELL_SHAPE_ISOMETRIC_DOWN);
	BIND_ENUM_CONSTANT(CELL_SHAPE_MAX);
}