is_path_valid_service.hpp

// Copyright (c) 2025 Dexory
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
 
#ifndef NAV2_PLANNER__IS_PATH_VALID_SERVICE_HPP_
#define NAV2_PLANNER__IS_PATH_VALID_SERVICE_HPP_
 
#include <memory>
#include <limits>
#include <string>
 
#include "rclcpp/rclcpp.hpp"
#include "rclcpp_lifecycle/lifecycle_node.hpp"
#include "nav2_msgs/srv/is_path_valid.hpp"
#include "nav2_costmap_2d/costmap_2d_ros.hpp"
#include "nav2_costmap_2d/footprint_collision_checker.hpp"
#include "nav2_costmap_2d/cost_values.hpp"
#include "nav2_costmap_2d/costmap_layer.hpp"
#include "nav2_util/geometry_utils.hpp"
#include "nav2_ros_common/service_server.hpp"
#include "tf2/utils.hpp"
 
namespace nav2_planner
{
 
class IsPathValidService
{
public:
  IsPathValidService(
    nav2::LifecycleNode::WeakPtr node,
    std::shared_ptr<nav2_costmap_2d::Costmap2DROS> costmap_ros,
    const rclcpp::Duration & costmap_update_timeout)
  : node_(node), costmap_ros_(costmap_ros), logger_(rclcpp::get_logger("is_path_valid_service")),
    costmap_update_timeout_(costmap_update_timeout)
  {
  }
 
  void initialize()
  {
    auto node = node_.lock();
    if (!node) {
      throw std::runtime_error("Failed to lock node in initialize");
    }
 
    costmap_ = costmap_ros_->getCostmap();
 
    service_ = node->create_service<nav2_msgs::srv::IsPathValid>(
      "is_path_valid",
      std::bind(
        &IsPathValidService::callback, this,
        std::placeholders::_1, std::placeholders::_2, std::placeholders::_3));
  }
 
  void reset()
  {
    service_.reset();
    costmap_ = nullptr;
  }
 
private:
  nav2_costmap_2d::Costmap2D * getCostmapToCheck(const std::string & layer_name)
  {
    if (layer_name.empty()) {
      return costmap_;
    }
 
    auto layers = costmap_ros_->getLayeredCostmap()->getPlugins();
    for (auto & layer : *layers) {
      if (layer->getName() == layer_name) {
        auto * costmap_layer = dynamic_cast<nav2_costmap_2d::CostmapLayer *>(layer.get());
        if (costmap_layer != nullptr) {
          return static_cast<nav2_costmap_2d::Costmap2D *>(costmap_layer);
        }
      }
    }
 
    RCLCPP_ERROR(
      logger_, "Requested layer '%s' not found or does not provide a costmap.",
      layer_name.c_str());
    return nullptr;
  }
 
  bool getFootprintToUse(
    const std::string & footprint_string,
    nav2_costmap_2d::Footprint & footprint,
    bool & use_radius)
  {
    use_radius = costmap_ros_->getUseRadius();
 
    if (!footprint_string.empty()) {
      if (!nav2_costmap_2d::makeFootprintFromString(footprint_string, footprint)) {
        RCLCPP_ERROR(
          logger_, "Invalid footprint string '%s'. Cannot validate path.",
          footprint_string.c_str());
        return false;
      }
      use_radius = false;
    } else if (!use_radius) {
      footprint = costmap_ros_->getRobotFootprint();
    }
 
    return true;
  }
 
  unsigned int findClosestPointIndex(
    const geometry_msgs::msg::PoseStamped & current_pose,
    const nav_msgs::msg::Path & path)
  {
    unsigned int closest_point_index = 0;
    float closest_distance = std::numeric_limits<float>::max();
    const auto & current_point = current_pose.pose.position;
 
    for (unsigned int i = 0; i < path.poses.size(); ++i) {
      const auto & path_point = path.poses[i].pose.position;
      float distance = nav2_util::geometry_utils::euclidean_distance(current_point, path_point);
 
      if (distance < closest_distance) {
        closest_point_index = i;
        closest_distance = distance;
      }
    }
 
    return closest_point_index;
  }
 
  void callback(
    const std::shared_ptr<rmw_request_id_t>/*request_header*/,
    const std::shared_ptr<nav2_msgs::srv::IsPathValid::Request> request,
    std::shared_ptr<nav2_msgs::srv::IsPathValid::Response> response)
  {
    response->success = true;
    response->is_valid = true;
 
    if (request->path.poses.empty()) {
      RCLCPP_ERROR(logger_, "Received empty path. Cannot validate path.");
      response->success = false;
      response->is_valid = false;
      return;
    }
 
    // Wait for costmap to become current (skip if timeout is zero or negative)
    if (costmap_update_timeout_ > rclcpp::Duration(0, 0)) {
      try {
        costmap_ros_->waitUntilCurrent(costmap_update_timeout_);
      } catch (const std::exception & ex) {
        RCLCPP_ERROR(logger_, "Failed to wait for costmap: %s", ex.what());
        response->success = false;
        response->is_valid = false;
        return;
      }
    }
 
    geometry_msgs::msg::PoseStamped current_pose;
    if (!costmap_ros_->getRobotPose(current_pose)) {
      RCLCPP_ERROR(logger_, "Failed to get robot pose. Cannot validate path.");
      response->success = false;
      response->is_valid = false;
      return;
    }
 
    unsigned int closest_point_index = findClosestPointIndex(current_pose, request->path);
 
    // Determine which costmap to use based on layer_name parameter
    nav2_costmap_2d::Costmap2D * costmap_to_check = getCostmapToCheck(request->layer_name);
 
    if (!costmap_to_check) {
      response->success = false;
      response->is_valid = false;
      return;
    }
 
    std::unique_lock<nav2_costmap_2d::Costmap2D::mutex_t> lock(
      *(costmap_to_check->getMutex()));
    unsigned int mx = 0;
    unsigned int my = 0;
 
    // Determine footprint to use
    nav2_costmap_2d::Footprint footprint;
    bool use_radius;
 
    if (!getFootprintToUse(request->footprint, footprint, use_radius)) {
      response->success = false;
      response->is_valid = false;
      return;
    }
 
    // Create collision checker for this request if needed
    std::unique_ptr<nav2_costmap_2d::FootprintCollisionChecker<nav2_costmap_2d::Costmap2D *>>
    collision_checker;
    if (!use_radius) {
      collision_checker =
        std::make_unique<nav2_costmap_2d::FootprintCollisionChecker<nav2_costmap_2d::Costmap2D *>>(
        costmap_to_check);
    }
 
    // Determine the end index for validation based on lookahead distance
    const auto & poses = request->path.poses;
    unsigned int end_index = poses.size();
    if (request->max_lookahead_distance > 0.0) {
      auto end_it = nav2_util::geometry_utils::first_after_integrated_distance(
        poses.begin() + closest_point_index, poses.end(),
        request->max_lookahead_distance);
      end_index = std::distance(poses.begin(), end_it);
    }
 
    unsigned int cost = nav2_costmap_2d::FREE_SPACE;
    for (unsigned int i = closest_point_index; i < end_index; ++i) {
      auto & position = request->path.poses[i].pose.position;
      if (use_radius) {
        if (costmap_to_check->worldToMap(position.x, position.y, mx, my)) {
          cost = costmap_to_check->getCost(mx, my);
        } else {
          cost = nav2_costmap_2d::LETHAL_OBSTACLE;
        }
      } else {
        auto theta = tf2::getYaw(request->path.poses[i].pose.orientation);
        cost = static_cast<unsigned int>(collision_checker->footprintCostAtPose(
            position.x, position.y, theta, footprint));
      }
 
      if (cost == nav2_costmap_2d::NO_INFORMATION && request->consider_unknown_as_obstacle) {
        cost = nav2_costmap_2d::LETHAL_OBSTACLE;
      } else if (cost == nav2_costmap_2d::NO_INFORMATION) {
        cost = nav2_costmap_2d::FREE_SPACE;
      }
 
      if (use_radius &&
        (cost >= request->max_cost || cost == nav2_costmap_2d::LETHAL_OBSTACLE ||
        cost == nav2_costmap_2d::INSCRIBED_INFLATED_OBSTACLE))
      {
        response->is_valid = false;
        response->invalid_pose_indices.push_back(i);
        if (request->stop_at_first_collision) {
          break;
        }
      } else if (cost == nav2_costmap_2d::LETHAL_OBSTACLE || cost >= request->max_cost) {
        response->is_valid = false;
        response->invalid_pose_indices.push_back(i);
        if (request->stop_at_first_collision) {
          break;
        }
      }
    }
  }
 
  nav2::LifecycleNode::WeakPtr node_;
  std::shared_ptr<nav2_costmap_2d::Costmap2DROS> costmap_ros_;
  nav2_costmap_2d::Costmap2D * costmap_;
  rclcpp::Logger logger_;
  rclcpp::Duration costmap_update_timeout_;
  nav2::ServiceServer<nav2_msgs::srv::IsPathValid>::SharedPtr service_;
};
 
}  // namespace nav2_planner
 
#endif  // NAV2_PLANNER__IS_PATH_VALID_SERVICE_HPP_