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/**
 * @file AerotennaULanding.hpp
 * @author Jessica Stockham <jessica@aerotenna.com>
 * @author Roman Bapst <roman@uaventure.com>
 *
 * Driver for the uLanding radar from Aerotenna
 */

#pragma once

#include <fcntl.h>
#include <poll.h>
#include <termios.h>
#include <unistd.h>

#include <drivers/drv_hrt.h>
#include <lib/perf/perf_counter.h>
#include <lib/drivers/rangefinder/PX4Rangefinder.hpp>
#include <px4_platform_common/px4_config.h>
#include <px4_platform_common/defines.h>
#include <px4_platform_common/px4_work_queue/ScheduledWorkItem.hpp>
#include <lib/perf/perf_counter.h>

using namespace time_literals;

#define ULANDING_MEASURE_INTERVAL       10_ms
#define ULANDING_MAX_DISTANCE	        50.0f
#define ULANDING_MIN_DISTANCE	        0.315f
#define ULANDING_VERSION	        1

#if ULANDING_VERSION == 1
#define ULANDING_PACKET_HDR     254
#define ULANDING_BUFFER_LENGTH  18
#else
#define ULANDING_PACKET_HDR     72
#define ULANDING_BUFFER_LENGTH  9
#endif

/**
 * Assume standard deviation to be equal to sensor resolution.
 * Static bench tests have shown that the sensor ouput does
 * not vary if the unit is not moved.
 */
#define SENS_VARIANCE           0.045f * 0.045f

class AerotennaULanding : public px4::ScheduledWorkItem
{
public:
	/**
	 * Default Constructor
	 * @param port The serial port to open for communicating with the sensor.
	 * @param rotation The sensor rotation relative to the vehicle body.
	 */
	AerotennaULanding(const char *port, uint8_t rotation = distance_sensor_s::ROTATION_DOWNWARD_FACING);
	~AerotennaULanding() override;

	int init();
	void print_info();

private:

	/**
	 * Reads data from serial UART and places it into a buffer.
	 */
	int collect();

	/**
	 * Opens and configures the UART serial communications port.
	 * @param speed The baudrate (speed) to configure the serial UART port.
	 */
	int open_serial_port(const speed_t speed = B115200);

	void Run() override;
	void start();
	void stop();

	PX4Rangefinder _px4_rangefinder;

	char _port[20] {};

	int _file_descriptor{-1};

	uint8_t _buffer[ULANDING_BUFFER_LENGTH] {};

	perf_counter_t _comms_errors{perf_alloc(PC_COUNT, MODULE_NAME": com_err")};
	perf_counter_t _sample_perf{perf_alloc(PC_ELAPSED, MODULE_NAME": read")};

};
