/**************************************************************************/
/*  nav_region_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        */
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#include "nav_region_2d.h"

#include "nav_map_2d.h"

#include "2d/nav_mesh_queries_2d.h"
#include "2d/nav_region_builder_2d.h"
#include "2d/nav_region_iteration_2d.h"
#include "core/config/project_settings.h"

using namespace Nav2D;

void NavRegion2D::set_map(NavMap2D *p_map) {
	if (map == p_map) {
		return;
	}

	cancel_async_thread_join();
	cancel_sync_request();

	if (map) {
		map->remove_region(this);
	}

	map = p_map;
	iteration_dirty = true;

	if (map) {
		map->add_region(this);
		request_sync();
		if (iteration_build_thread_task_id != WorkerThreadPool::INVALID_TASK_ID) {
			request_async_thread_join();
		}
	}
}

void NavRegion2D::set_enabled(bool p_enabled) {
	if (enabled == p_enabled) {
		return;
	}
	enabled = p_enabled;
	iteration_dirty = true;

	request_sync();
}

void NavRegion2D::set_use_edge_connections(bool p_enabled) {
	if (use_edge_connections != p_enabled) {
		use_edge_connections = p_enabled;
		iteration_dirty = true;
	}

	request_sync();
}

void NavRegion2D::set_transform(Transform2D p_transform) {
	if (transform == p_transform) {
		return;
	}
	transform = p_transform;
	iteration_dirty = true;

	request_sync();
}

void NavRegion2D::set_navigation_mesh(Ref<NavigationPolygon> p_navigation_mesh) {
#ifdef DEBUG_ENABLED
	if (map && p_navigation_mesh.is_valid() && !Math::is_equal_approx(double(map->get_cell_size()), double(p_navigation_mesh->get_cell_size()))) {
		ERR_PRINT_ONCE(vformat("Attempted to update a navigation region with a navigation mesh that uses a `cell_size` of %s while assigned to a navigation map set to a `cell_size` of %s. The cell size for navigation maps can be changed by using the NavigationServer map_set_cell_size() function. The cell size for default navigation maps can also be changed in the ProjectSettings.", double(p_navigation_mesh->get_cell_size()), double(map->get_cell_size())));
	}
#endif // DEBUG_ENABLED

	navmesh = p_navigation_mesh;

	iteration_dirty = true;

	request_sync();
}

ClosestPointQueryResult NavRegion2D::get_closest_point_info(const Vector2 &p_point) const {
	RWLockRead read_lock(region_rwlock);

	return NavMeshQueries2D::polygons_get_closest_point_info(get_polygons(), p_point);
}

Vector2 NavRegion2D::get_random_point(uint32_t p_navigation_layers, bool p_uniformly) const {
	RWLockRead read_lock(region_rwlock);

	if (!get_enabled()) {
		return Vector2();
	}

	return NavMeshQueries2D::polygons_get_random_point(get_polygons(), p_navigation_layers, p_uniformly);
}

void NavRegion2D::set_navigation_layers(uint32_t p_navigation_layers) {
	if (navigation_layers == p_navigation_layers) {
		return;
	}
	navigation_layers = p_navigation_layers;
	iteration_dirty = true;

	request_sync();
}

void NavRegion2D::set_enter_cost(real_t p_enter_cost) {
	real_t new_enter_cost = MAX(p_enter_cost, 0.0);
	if (enter_cost == new_enter_cost) {
		return;
	}
	enter_cost = new_enter_cost;
	iteration_dirty = true;

	request_sync();
}

void NavRegion2D::set_travel_cost(real_t p_travel_cost) {
	real_t new_travel_cost = MAX(p_travel_cost, 0.0);
	if (travel_cost == new_travel_cost) {
		return;
	}
	travel_cost = new_travel_cost;
	iteration_dirty = true;

	request_sync();
}

void NavRegion2D::set_owner_id(ObjectID p_owner_id) {
	if (owner_id == p_owner_id) {
		return;
	}
	owner_id = p_owner_id;
	iteration_dirty = true;

	request_sync();
}

void NavRegion2D::scratch_polygons() {
	iteration_dirty = true;

	request_sync();
}

real_t NavRegion2D::get_surface_area() const {
	RWLockRead read_lock(iteration_rwlock);
	return iteration->get_surface_area();
}

Rect2 NavRegion2D::get_bounds() const {
	RWLockRead read_lock(iteration_rwlock);
	return iteration->get_bounds();
}

LocalVector<Nav2D::Polygon> const &NavRegion2D::get_polygons() const {
	RWLockRead read_lock(iteration_rwlock);
	return iteration->get_navmesh_polygons();
}

bool NavRegion2D::sync() {
	bool requires_map_update = false;
	if (!map) {
		return requires_map_update;
	}

	if (iteration_dirty && !iteration_building && !iteration_ready) {
		_build_iteration();
	}

	if (iteration_ready) {
		_sync_iteration();
		requires_map_update = true;
	}

	return requires_map_update;
}

void NavRegion2D::sync_async_tasks() {
	if (iteration_build_thread_task_id != WorkerThreadPool::INVALID_TASK_ID) {
		if (WorkerThreadPool::get_singleton()->is_task_completed(iteration_build_thread_task_id)) {
			WorkerThreadPool::get_singleton()->wait_for_task_completion(iteration_build_thread_task_id);

			iteration_build_thread_task_id = WorkerThreadPool::INVALID_TASK_ID;
			iteration_building = false;
			iteration_ready = true;
			request_sync();
		}
	}
}

void NavRegion2D::_build_iteration() {
	if (!iteration_dirty || iteration_building || iteration_ready) {
		return;
	}

	iteration_dirty = false;
	iteration_building = true;
	iteration_ready = false;

	iteration_build.reset();

	if (navmesh.is_valid()) {
		navmesh->get_data(iteration_build.navmesh_data.vertices, iteration_build.navmesh_data.polygons);
	}

	iteration_build.map_cell_size = map->get_merge_rasterizer_cell_size();

	Ref<NavRegionIteration2D> new_iteration;
	new_iteration.instantiate();

	new_iteration->navigation_layers = get_navigation_layers();
	new_iteration->enter_cost = get_enter_cost();
	new_iteration->travel_cost = get_travel_cost();
	new_iteration->owner_object_id = get_owner_id();
	new_iteration->owner_type = get_type();
	new_iteration->owner_rid = get_self();
	new_iteration->enabled = get_enabled();
	new_iteration->transform = get_transform();
	new_iteration->owner_use_edge_connections = get_use_edge_connections();

	iteration_build.region_iteration = new_iteration;

	if (use_async_iterations) {
		iteration_build_thread_task_id = WorkerThreadPool::get_singleton()->add_native_task(&NavRegion2D::_build_iteration_threaded, &iteration_build, true, SNAME("NavRegionBuilder2D"));
		request_async_thread_join();
	} else {
		NavRegionBuilder2D::build_iteration(iteration_build);

		iteration_building = false;
		iteration_ready = true;
	}
}

void NavRegion2D::_build_iteration_threaded(void *p_arg) {
	NavRegionIterationBuild2D *_iteration_build = static_cast<NavRegionIterationBuild2D *>(p_arg);

	NavRegionBuilder2D::build_iteration(*_iteration_build);
}

void NavRegion2D::_sync_iteration() {
	if (iteration_building || !iteration_ready) {
		return;
	}

	performance_data.pm_polygon_count = iteration_build.performance_data.pm_polygon_count;
	performance_data.pm_edge_count = iteration_build.performance_data.pm_edge_count;
	performance_data.pm_edge_merge_count = iteration_build.performance_data.pm_edge_merge_count;

	RWLockWrite write_lock(iteration_rwlock);
	ERR_FAIL_COND(iteration.is_null());
	iteration = Ref<NavRegionIteration2D>();
	DEV_ASSERT(iteration.is_null());
	iteration = iteration_build.region_iteration;
	iteration_build.region_iteration = Ref<NavRegionIteration2D>();
	DEV_ASSERT(iteration_build.region_iteration.is_null());
	iteration_id = iteration_id % UINT32_MAX + 1;

	iteration_ready = false;

	cancel_async_thread_join();
}

Ref<NavRegionIteration2D> NavRegion2D::get_iteration() {
	RWLockRead read_lock(iteration_rwlock);
	return iteration;
}

void NavRegion2D::request_async_thread_join() {
	DEV_ASSERT(map);
	if (map && !async_list_element.in_list()) {
		map->add_region_async_thread_join_request(&async_list_element);
	}
}

void NavRegion2D::cancel_async_thread_join() {
	if (map && async_list_element.in_list()) {
		map->remove_region_async_thread_join_request(&async_list_element);
	}
}

void NavRegion2D::request_sync() {
	if (map && !sync_dirty_request_list_element.in_list()) {
		map->add_region_sync_dirty_request(&sync_dirty_request_list_element);
	}
}

void NavRegion2D::cancel_sync_request() {
	if (map && sync_dirty_request_list_element.in_list()) {
		map->remove_region_sync_dirty_request(&sync_dirty_request_list_element);
	}
}

void NavRegion2D::set_use_async_iterations(bool p_enabled) {
	if (use_async_iterations == p_enabled) {
		return;
	}
#ifdef THREADS_ENABLED
	use_async_iterations = p_enabled;
#endif
}

bool NavRegion2D::get_use_async_iterations() const {
	return use_async_iterations;
}

NavRegion2D::NavRegion2D() :
		sync_dirty_request_list_element(this), async_list_element(this) {
	type = NavigationUtilities::PathSegmentType::PATH_SEGMENT_TYPE_REGION;
	iteration_build.region = this;
	iteration.instantiate();

#ifdef THREADS_ENABLED
	use_async_iterations = GLOBAL_GET("navigation/world/region_use_async_iterations");
#else
	use_async_iterations = false;
#endif
}

NavRegion2D::~NavRegion2D() {
	cancel_async_thread_join();
	cancel_sync_request();

	if (iteration_build_thread_task_id != WorkerThreadPool::INVALID_TASK_ID) {
		WorkerThreadPool::get_singleton()->wait_for_task_completion(iteration_build_thread_task_id);
		iteration_build_thread_task_id = WorkerThreadPool::INVALID_TASK_ID;
	}

	iteration_build.region = nullptr;
	iteration_build.region_iteration = Ref<NavRegionIteration2D>();
	iteration = Ref<NavRegionIteration2D>();
}