/*************************************************************************/
/*  navigation_mesh_instance.cpp                                         */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
/*                      https://godotengine.org                          */
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/* Copyright (c) 2007-2022 Juan Linietsky, Ariel Manzur.                 */
/* Copyright (c) 2014-2022 Godot Engine contributors (cf. AUTHORS.md).   */
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/*************************************************************************/

#include "navigation_mesh_instance.h"

#include "core/os/os.h"
#include "mesh_instance.h"
#include "navigation.h"
#include "scene/resources/mesh.h"
#include "scene/resources/navigation_mesh.h"
#include "servers/navigation_server.h"

void NavigationMeshInstance::set_enabled(bool p_enabled) {
	if (enabled == p_enabled) {
		return;
	}
	enabled = p_enabled;

	if (!is_inside_tree()) {
		return;
	}

	if (!enabled) {
		NavigationServer::get_singleton()->region_set_map(region, RID());
	} else {
		if (navigation) {
			NavigationServer::get_singleton()->region_set_map(region, navigation->get_rid());
		}
	}

	if (debug_view) {
		MeshInstance *dm = Object::cast_to<MeshInstance>(debug_view);
		if (is_enabled()) {
			dm->set_material_override(get_tree()->get_debug_navigation_material());
		} else {
			dm->set_material_override(get_tree()->get_debug_navigation_disabled_material());
		}
	}

	update_gizmo();
}

bool NavigationMeshInstance::is_enabled() const {
	return enabled;
}

RID NavigationMeshInstance::get_region_rid() const {
	return region;
}

/////////////////////////////

void NavigationMeshInstance::_notification(int p_what) {
	switch (p_what) {
		case NOTIFICATION_ENTER_TREE: {
			Spatial *c = this;
			while (c) {
				navigation = Object::cast_to<Navigation>(c);
				if (navigation) {
					if (enabled) {
						NavigationServer::get_singleton()->region_set_map(region, navigation->get_rid());
					}
					break;
				}

				c = c->get_parent_spatial();
			}

			if (navmesh.is_valid() && get_tree()->is_debugging_navigation_hint()) {
				MeshInstance *dm = memnew(MeshInstance);
				dm->set_mesh(navmesh->get_debug_mesh());
				if (is_enabled()) {
					dm->set_material_override(get_tree()->get_debug_navigation_material());
				} else {
					dm->set_material_override(get_tree()->get_debug_navigation_disabled_material());
				}
				add_child(dm);
				debug_view = dm;
			}

		} break;
		case NOTIFICATION_TRANSFORM_CHANGED: {
			NavigationServer::get_singleton()->region_set_transform(region, get_global_transform());

		} break;
		case NOTIFICATION_EXIT_TREE: {
			if (navigation) {
				NavigationServer::get_singleton()->region_set_map(region, RID());
			}

			if (debug_view) {
				debug_view->queue_delete();
				debug_view = nullptr;
			}
			navigation = nullptr;
		} break;
	}
}

void NavigationMeshInstance::set_navigation_mesh(const Ref<NavigationMesh> &p_navmesh) {
	if (p_navmesh == navmesh)
		return;

	if (navmesh.is_valid()) {
		navmesh->remove_change_receptor(this);
	}

	navmesh = p_navmesh;

	if (navmesh.is_valid()) {
		navmesh->add_change_receptor(this);
	}

	NavigationServer::get_singleton()->region_set_navmesh(region, p_navmesh);

	if (debug_view && navmesh.is_valid()) {
		Object::cast_to<MeshInstance>(debug_view)->set_mesh(navmesh->get_debug_mesh());
	}

	emit_signal("navigation_mesh_changed");

	update_gizmo();
	update_configuration_warning();
}

Ref<NavigationMesh> NavigationMeshInstance::get_navigation_mesh() const {
	return navmesh;
}

struct BakeThreadsArgs {
	NavigationMeshInstance *nav_region;
};

void _bake_navigation_mesh(void *p_user_data) {
	BakeThreadsArgs *args = static_cast<BakeThreadsArgs *>(p_user_data);

	if (args->nav_region->get_navigation_mesh().is_valid()) {
		Ref<NavigationMesh> nav_mesh = args->nav_region->get_navigation_mesh()->duplicate();

		NavigationServer::get_singleton()->region_bake_navmesh(nav_mesh, args->nav_region);
		args->nav_region->call_deferred("_bake_finished", nav_mesh);
		memdelete(args);
	} else {
		ERR_PRINT("Can't bake the navigation mesh if the `NavigationMesh` resource doesn't exist");
		args->nav_region->call_deferred("_bake_finished", Ref<NavigationMesh>());
		memdelete(args);
	}
}

void NavigationMeshInstance::bake_navigation_mesh(bool p_on_thread) {
	ERR_FAIL_COND_MSG(bake_thread.is_started(), "Navigation Mesh Bake thread is already baking a Navigation Mesh. Unable to start another bake request.");

	BakeThreadsArgs *args = memnew(BakeThreadsArgs);
	args->nav_region = this;

	if (p_on_thread && !OS::get_singleton()->can_use_threads()) {
		WARN_PRINT("NavigationMesh bake 'on_thread' will be disabled as the current OS does not support multiple threads."
				   "\nAs a fallback the navigation mesh will bake on the main thread which can cause framerate issues.");
	}

	if (p_on_thread && OS::get_singleton()->can_use_threads()) {
		bake_thread.start(_bake_navigation_mesh, args);
	} else {
		_bake_navigation_mesh(args);
	}
}

void NavigationMeshInstance::_bake_finished(Ref<NavigationMesh> p_nav_mesh) {
	set_navigation_mesh(p_nav_mesh);
	bake_thread.wait_to_finish();
	emit_signal("bake_finished");
}

String NavigationMeshInstance::get_configuration_warning() const {
	if (!is_visible_in_tree() || !is_inside_tree()) {
		return String();
	}

	if (!navmesh.is_valid()) {
		return TTR("A NavigationMesh resource must be set or created for this node to work.");
	}
	const Spatial *c = this;
	while (c) {
		if (Object::cast_to<Navigation>(c)) {
			return String();
		}

		c = Object::cast_to<Spatial>(c->get_parent());
	}

	return TTR("NavigationMeshInstance must be a child or grandchild to a Navigation node. It only provides navigation data.");
}

void NavigationMeshInstance::_bind_methods() {
	ClassDB::bind_method(D_METHOD("set_navigation_mesh", "navmesh"), &NavigationMeshInstance::set_navigation_mesh);
	ClassDB::bind_method(D_METHOD("get_navigation_mesh"), &NavigationMeshInstance::get_navigation_mesh);

	ClassDB::bind_method(D_METHOD("set_enabled", "enabled"), &NavigationMeshInstance::set_enabled);
	ClassDB::bind_method(D_METHOD("is_enabled"), &NavigationMeshInstance::is_enabled);

	ClassDB::bind_method(D_METHOD("get_region_rid"), &NavigationMeshInstance::get_region_rid);

	ClassDB::bind_method(D_METHOD("bake_navigation_mesh", "on_thread"), &NavigationMeshInstance::bake_navigation_mesh, DEFVAL(true));
	ClassDB::bind_method(D_METHOD("_bake_finished", "nav_mesh"), &NavigationMeshInstance::_bake_finished);

	ADD_PROPERTY(PropertyInfo(Variant::OBJECT, "navmesh", PROPERTY_HINT_RESOURCE_TYPE, "NavigationMesh"), "set_navigation_mesh", "get_navigation_mesh");
	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "enabled"), "set_enabled", "is_enabled");

	ADD_SIGNAL(MethodInfo("navigation_mesh_changed"));
	ADD_SIGNAL(MethodInfo("bake_finished"));
}

void NavigationMeshInstance::_changed_callback(Object *p_changed, const char *p_prop) {
	update_gizmo();
	update_configuration_warning();
}

NavigationMeshInstance::NavigationMeshInstance() {
	set_notify_transform(true);
	region = NavigationServer::get_singleton()->region_create();
	enabled = true;
}

NavigationMeshInstance::~NavigationMeshInstance() {
	if (navmesh.is_valid()) {
		navmesh->remove_change_receptor(this);
	}
	NavigationServer::get_singleton()->free(region);
}