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/**
 * @file Publisher.hpp
 *
 * Defines basic functionality of UAVCAN v1 publisher class
 *
 * @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 "../CanardInterface.hpp"
#include "../ParamManager.hpp"

/* This is a default baseline timeout for publishers
 * Still it's recommended for implementers to check if their publisher
 * has timing requirements and if it should drop messages that are too old in favour of newer messages
 */
#define PUBLISHER_DEFAULT_TIMEOUT_USEC 100000UL

class UavcanPublisher
{
public:
	static constexpr uint16_t CANARD_PORT_ID_UNSET = 65535U;
	static constexpr uint16_t CANARD_PORT_ID_MAX   = 32767U;

	UavcanPublisher(CanardInstance &ins, UavcanParamManager &pmgr, const char *subject_name, uint8_t instance = 0) :
		_canard_instance(ins), _param_manager(pmgr), _subject_name(subject_name), _instance(instance) { };

	// Update the uORB Subscription and broadcast a UAVCAN message
	virtual void update() = 0;

	bool isValidPortId(int32_t id) const { return id >= 0 && id <= CANARD_PORT_ID_MAX; }

	CanardPortID id() { return _port_id; };

	void updateParam()
	{
		char uavcan_param[256];
		snprintf(uavcan_param, sizeof(uavcan_param), "uavcan.pub.%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];

		// Allow, for example, a default PX4 param value of '-1' to disable publication
		if (!isValidPortId(new_id)) {
			// but always use the standard 'unset' value for comparison
			new_id = CANARD_PORT_ID_UNSET;
		}

		if (_port_id != new_id) {
			if (new_id == CANARD_PORT_ID_UNSET) {
				PX4_INFO("Disabling publication of subject %s.%d", _subject_name, _instance);
				_port_id = CANARD_PORT_ID_UNSET;

			} else {
				_port_id = (CanardPortID)new_id;
				PX4_INFO("Enabling subject %s.%d on port %d", _subject_name, _instance, _port_id);
			}
		}
	};

	void printInfo()
	{
		if (_port_id != CANARD_PORT_ID_UNSET) {
			PX4_INFO("Enabled subject %s.%d on port %d", _subject_name, _instance, _port_id);
		}
	}

protected:
	CanardInstance &_canard_instance;
	UavcanParamManager &_param_manager;
	const char *_subject_name;
	uint8_t _instance {0};

	CanardPortID _port_id {CANARD_PORT_ID_UNSET};
	CanardTransferID _transfer_id {0};
};
