SafetyChannelMonitor.hpp

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// Copyright 2026 Intelligent Robotics Lab
//
// 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 EASYNAV_SYSTEM__SAFETY__SAFETYCHANNELMONITOR_HPP_
#define EASYNAV_SYSTEM__SAFETY__SAFETYCHANNELMONITOR_HPP_
 
#include <chrono>
#include <cstdint>
#include <mutex>
#include <optional>
#include <string>
 
#include "easynav_interfaces/msg/safety_status.hpp"
 
#include "easynav_core/SafetyChannel.hpp"
 
namespace easynav::safety
{

class SafetyChannelMonitor
{
public:
  using Clock = std::chrono::steady_clock;
  using Status = easynav_interfaces::msg::SafetyStatus;

  enum class Condition : uint8_t {VALID, NO_STATUS, STALE, INVALID};
 
  struct Evaluation
  {
    SafetyChannelState state;
    Condition condition {Condition::NO_STATUS};
    bool operator==(const Evaluation & other) const
    {
      return state == other.state && condition == other.condition;
    }
  };

  void configure(double timeout);

  void received(const Status & msg, Clock::time_point now);

  Evaluation evaluate(Clock::time_point now) const;

  std::optional<Status> last_status() const;

  static std::string invalid_reason(const Status & msg);
 
private:
  Clock::duration timeout_ {};
  mutable std::mutex mutex_;
  std::optional<Status> last_;
  Clock::time_point last_time_ {};
  bool last_valid_ {false};
};
 
}  // namespace easynav::safety
 
#endif  // EASYNAV_SYSTEM__SAFETY__SAFETYCHANNELMONITOR_HPP_