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/**
 * @file gyro_calibration.cpp
 *
 * Gyroscope calibration routine
 */

#include "gyro_calibration.h"
#include "calibration_messages.h"
#include "commander_helper.h"

#include <stdio.h>
#include <fcntl.h>
#include <poll.h>
#include <math.h>
#include <string.h>
#include <drivers/drv_hrt.h>
#include <uORB/topics/sensor_combined.h>
#include <drivers/drv_gyro.h>
#include <mavlink/mavlink_log.h>
#include <systemlib/param/param.h>
#include <systemlib/err.h>
#include <systemlib/mcu_version.h>

/* oddly, ERROR is not defined for c++ */
#ifdef ERROR
# undef ERROR
#endif
static const int ERROR = -1;

static const char *sensor_name = "gyro";

int do_gyro_calibration(int mavlink_fd)
{
	const unsigned max_gyros = 3;

	int32_t device_id[3];
	mavlink_log_info(mavlink_fd, CAL_STARTED_MSG, sensor_name);
	mavlink_log_info(mavlink_fd, "HOLD STILL");

	/* wait for the user to respond */
	sleep(2);

	struct gyro_scale gyro_scale[max_gyros] = { {
		0.0f,
		1.0f,
		0.0f,
		1.0f,
		0.0f,
		1.0f,
	}
	};

	int res = OK;

	/* store board ID */
	uint32_t mcu_id[3];
	mcu_unique_id(&mcu_id[0]);

	/* store last 32bit number - not unique, but unique in a given set */
	(void)param_set(param_find("CAL_BOARD_ID"), &mcu_id[2]);

	char str[30];

	for (unsigned s = 0; s < max_gyros; s++) {

		/* ensure all scale fields are initialized tha same as the first struct */
		(void)memcpy(&gyro_scale[s], &gyro_scale[0], sizeof(gyro_scale[0]));

		sprintf(str, "%s%u", GYRO_BASE_DEVICE_PATH, s);
		/* reset all offsets to zero and all scales to one */
		int fd = open(str, 0);

		if (fd < 0) {
			continue;
		}

		device_id[s] = ioctl(fd, DEVIOCGDEVICEID, 0);

		res = ioctl(fd, GYROIOCSSCALE, (long unsigned int)&gyro_scale);
		close(fd);

		if (res != OK) {
			mavlink_log_critical(mavlink_fd, CAL_FAILED_RESET_CAL_MSG);
		}
	}

	unsigned calibration_counter[max_gyros] = { 0 };
	const unsigned calibration_count = 5000;

	if (res == OK) {
		/* determine gyro mean values */
		unsigned poll_errcount = 0;

		/* subscribe to gyro sensor topic */
		int sub_sensor_gyro[max_gyros];
		struct pollfd fds[max_gyros];

		for (unsigned s = 0; s < max_gyros; s++) {
			sub_sensor_gyro[s] = orb_subscribe_multi(ORB_ID(sensor_gyro), s);
			fds[s].fd = sub_sensor_gyro[s];
			fds[s].events = POLLIN;
		}

		struct gyro_report gyro_report;

		/* use first gyro to pace, but count correctly per-gyro for statistics */
		while (calibration_counter[0] < calibration_count) {
			/* wait blocking for new data */

			int poll_ret = poll(fds, 1, 1000);

			if (poll_ret > 0) {

				for (unsigned s = 0; s < max_gyros; s++) {
					bool changed;
					orb_check(sub_sensor_gyro[s], &changed);

					if (changed) {
						orb_copy(ORB_ID(sensor_gyro), sub_sensor_gyro[s], &gyro_report);
						gyro_scale[s].x_offset += gyro_report.x;
						gyro_scale[s].y_offset += gyro_report.y;
						gyro_scale[s].z_offset += gyro_report.z;
						calibration_counter[s]++;
					}

					if (s == 0 && calibration_counter[0] % (calibration_count / 20) == 0) {
						mavlink_log_info(mavlink_fd, CAL_PROGRESS_MSG, sensor_name, (calibration_counter[0] * 100) / calibration_count);
					}
				}

			} else {
				poll_errcount++;
			}

			if (poll_errcount > 1000) {
				mavlink_log_critical(mavlink_fd, CAL_FAILED_SENSOR_MSG);
				res = ERROR;
				break;
			}
		}

		for (unsigned s = 0; s < max_gyros; s++) {
			close(sub_sensor_gyro[s]);

			gyro_scale[s].x_offset /= calibration_counter[s];
			gyro_scale[s].y_offset /= calibration_counter[s];
			gyro_scale[s].z_offset /= calibration_counter[s];
		}
	}

	if (res == OK) {
		/* check offsets */
		if (!isfinite(gyro_scale[0].x_offset) || !isfinite(gyro_scale[0].y_offset) || !isfinite(gyro_scale[0].z_offset)) {
			mavlink_log_critical(mavlink_fd, "ERROR: offset is NaN");
			res = ERROR;
		}
	}

	if (res == OK) {
		/* set offset parameters to new values */
		bool failed = false;

		for (unsigned s = 0; s < max_gyros; s++) {

			/* if any reasonable amount of data is missing, skip */
			if (calibration_counter[s] < calibration_count / 2) {
				continue;
			}

			(void)sprintf(str, "CAL_GYRO%u_XOFF", s);
			failed |= (OK != param_set(param_find(str), &(gyro_scale[s].x_offset)));
			(void)sprintf(str, "CAL_GYRO%u_YOFF", s);
			failed |= (OK != param_set(param_find(str), &(gyro_scale[s].y_offset)));
			(void)sprintf(str, "CAL_GYRO%u_ZOFF", s);
			failed |= (OK != param_set(param_find(str), &(gyro_scale[s].z_offset)));
			(void)sprintf(str, "CAL_GYRO%u_ID", s);
			failed |= (OK != param_set(param_find(str), &(device_id[s])));

			/* apply new scaling and offsets */
			(void)sprintf(str, "%s%u", GYRO_BASE_DEVICE_PATH, s);
			int fd = open(str, 0);

			if (fd < 0) {
				continue;
			}

			res = ioctl(fd, GYROIOCSSCALE, (long unsigned int)&gyro_scale[s]);
			close(fd);

			if (res != OK) {
				mavlink_log_critical(mavlink_fd, CAL_FAILED_APPLY_CAL_MSG);
			}
		}
		
		if (failed) {
			mavlink_log_critical(mavlink_fd, "ERROR: failed to set offset params");
			res = ERROR;
		}
	}

#if 0
	/* beep on offset calibration end */
	mavlink_log_info(mavlink_fd, "gyro offset calibration done");
	tune_neutral();

	/* scale calibration */
	/* this was only a proof of concept and is currently not working. scaling will be set to 1.0 for now. */

	mavlink_log_info(mavlink_fd, "offset done. Rotate for scale 30x or wait 5s to skip.");
	warnx("offset calibration finished. Rotate for scale 30x, or do not rotate and wait for 5 seconds to skip.");

	/* apply new offsets */
	fd = open(GYRO_DEVICE_PATH, 0);

	if (OK != ioctl(fd, GYROIOCSSCALE, (long unsigned int)&gyro_scale)) {
		warn("WARNING: failed to apply new offsets for gyro");
	}

	close(fd);


	unsigned rotations_count = 30;
	float gyro_integral = 0.0f;
	float baseline_integral = 0.0f;

	// XXX change to mag topic
	orb_copy(ORB_ID(sensor_combined), sub_sensor_combined, &raw);

	float mag_last = -atan2f(raw.magnetometer_ga[1], raw.magnetometer_ga[0]);

	if (mag_last > M_PI_F) { mag_last -= 2 * M_PI_F; }

	if (mag_last < -M_PI_F) { mag_last += 2 * M_PI_F; }


	uint64_t last_time = hrt_absolute_time();
	uint64_t start_time = hrt_absolute_time();

	while ((int)fabsf(baseline_integral / (2.0f * M_PI_F)) < rotations_count) {

		/* abort this loop if not rotated more than 180 degrees within 5 seconds */
		if ((fabsf(baseline_integral / (2.0f * M_PI_F)) < 0.6f)
		    && (hrt_absolute_time() - start_time > 5 * 1e6)) {
			mavlink_log_info(mavlink_fd, "scale skipped, gyro calibration done");
			close(sub_sensor_combined);
			return OK;
		}

		/* wait blocking for new data */
		struct pollfd fds[1];
		fds[0].fd = sub_sensor_combined;
		fds[0].events = POLLIN;

		int poll_ret = poll(fds, 1, 1000);

		if (poll_ret) {

			float dt_ms = (hrt_absolute_time() - last_time) / 1e3f;
			last_time = hrt_absolute_time();

			orb_copy(ORB_ID(sensor_combined), sub_sensor_combined, &raw);

			// XXX this is just a proof of concept and needs world / body
			// transformation and more

			//math::Vector2f magNav(raw.magnetometer_ga);

			// calculate error between estimate and measurement
			// apply declination correction for true heading as well.
			//float mag = -atan2f(magNav(1),magNav(0));
			float mag = -atan2f(raw.magnetometer_ga[1], raw.magnetometer_ga[0]);

			if (mag > M_PI_F) { mag -= 2 * M_PI_F; }

			if (mag < -M_PI_F) { mag += 2 * M_PI_F; }

			float diff = mag - mag_last;

			if (diff > M_PI_F) { diff -= 2 * M_PI_F; }

			if (diff < -M_PI_F) { diff += 2 * M_PI_F; }

			baseline_integral += diff;
			mag_last = mag;
			// Jump through some timing scale hoops to avoid
			// operating near the 1e6/1e8 max sane resolution of float.
			gyro_integral += (raw.gyro_rad_s[2] * dt_ms) / 1e3f;

//			warnx("dbg: b: %6.4f, g: %6.4f", (double)baseline_integral, (double)gyro_integral);

			// } else if (poll_ret == 0) {
			// 	/* any poll failure for 1s is a reason to abort */
			// 	mavlink_log_info(mavlink_fd, "gyro calibration aborted, retry");
			// 	return;
		}
	}

	float gyro_scale = baseline_integral / gyro_integral;

	warnx("gyro scale: yaw (z): %6.4f", (double)gyro_scale);
	mavlink_log_info(mavlink_fd, "gyro scale: yaw (z): %6.4f", (double)gyro_scale);


	if (!isfinite(gyro_scale.x_scale) || !isfinite(gyro_scale.y_scale) || !isfinite(gyro_scale.z_scale)) {
		mavlink_log_info(mavlink_fd, "gyro scale calibration FAILED (NaN)");
		close(sub_sensor_gyro);
		mavlink_log_critical(mavlink_fd, "gyro calibration failed");
		return ERROR;
	}

	/* beep on calibration end */
	mavlink_log_info(mavlink_fd, "gyro scale calibration done");
	tune_neutral();

	if (res == OK) {
		/* set scale parameters to new values */
		if (param_set(param_find("CAL_GYRO0_XSCALE"), &(gyro_scale.x_scale))
		    || param_set(param_find("CAL_GYRO0_YSCALE"), &(gyro_scale.y_scale))
		    || param_set(param_find("CAL_GYRO0_ZSCALE"), &(gyro_scale.z_scale))) {
			mavlink_log_critical(mavlink_fd, "ERROR: failed to set scale params");
			res = ERROR;
		}
	}

	#endif

	if (res == OK) {
		/* auto-save to EEPROM */
		res = param_save_default();

		if (res != OK) {
			mavlink_log_critical(mavlink_fd, CAL_FAILED_SAVE_PARAMS_MSG);
		}
	}

	if (res == OK) {
		mavlink_log_info(mavlink_fd, CAL_DONE_MSG, sensor_name);

	} else {
		mavlink_log_info(mavlink_fd, CAL_FAILED_MSG, sensor_name);
	}

	return res;
}