text: /****************************************************************************
   *
   *   Copyright (c) 2021 PX4 Development Team. All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in
   *    the documentation and/or other materials provided with the
   *    distribution.
   * 3. Neither the name PX4 nor the names of its contributors may be
   *    used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
   * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
   * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
   * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
   * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
   * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
   * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
   * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGE.
   *
   ****************************************************************************/
  
  /**
   * @file DynamicPortSubscriber.hpp
   *
   * Defines basic functionality of UAVCAN v1 subscriber class with Non-fixed unregulated port identifier
   *
   * @author Jacob Crabill <jacob@flyvoly.com>
   */
  
  #pragma once
  
  #include <px4_platform_common/px4_config.h>
  
  #include <lib/parameters/param.h>
  
  #include <uavcan/_register/Access_1_0.h>
  
  #include "DynamicPortSubscriber.hpp"
  #include "../CanardInterface.hpp"
  #include "../ParamManager.hpp"
  
  class UavcanDynamicPortSubscriber : public UavcanBaseSubscriber
  {
  public:
  	UavcanDynamicPortSubscriber(CanardInstance &ins, UavcanParamManager &pmgr, const char *subject_name,
  				    uint8_t instance = 0) :
  		UavcanBaseSubscriber(ins, subject_name, instance), _param_manager(pmgr) { };
  
  	void updateParam()
  	{
  		char uavcan_param[90];
  		sprintf(uavcan_param, "uavcan.sub.%s.%d.id", _subject_name, _instance);
  
  		// Set _port_id from _uavcan_param
  		uavcan_register_Value_1_0 value;
  		_param_manager.GetParamByName(uavcan_param, value);
  		int32_t new_id = value.integer32.value.elements[0];
  
  		if (_port_id != new_id) {
  			if (new_id == CANARD_PORT_ID_UNSET) {
  				// Cancel subscription
  				unsubscribe();
  
  			} else {
  				if (_port_id != CANARD_PORT_ID_UNSET) {
  					// Already active; unsubscribe first
  					unsubscribe();
  				}
  
  				// Subscribe on the new port ID
  				_port_id = (CanardPortID)new_id;
  				PX4_INFO("Subscribing %s.%d on port %d", _subject_name, _instance, _port_id);
  				subscribe();
  			}
  		}
  	};
  
  protected:
  	UavcanParamManager &_param_manager;
  };
  