/* Reflow Oven Controller
 *
 * Copyright (C) 2020  Mario Hüttel <mario.huettel@gmx.net>
 *
 * This file is part of the reflow Oven Controller Project.
 *
 * The reflow oven controller is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * GDSII-Converter is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with GDSII-Converter. If not, see <http://www.gnu.org/licenses/>.
 */

#include <reflow-controller/calibration.h>
#include <reflow-controller/adc-meas.h>
#include <helper-macros/helper-macros.h>
#include <arm_math.h>
#include <stdlib.h>

void calibration_calculate(float low_measured, float low_setpoint, float high_measured, float high_setpoint,
			   float *sens_deviation, float *sens_corrected_offset)
{
	if (!sens_deviation || !sens_corrected_offset)
		return;

	float delta_y;
	float delta_x;
	float sens_corr_mult;

	delta_y = high_measured - low_measured;
	delta_x = high_setpoint - low_setpoint;

	sens_corr_mult = delta_x / delta_y;
	*sens_deviation = sens_corr_mult - 1.0f;

	*sens_corrected_offset = low_setpoint - low_measured * sens_corr_mult;
}



int calibration_acquire_data(float *mu, float *sigma, uint32_t count)
{
	int status;
	float *stream_mem;

	static volatile int flag = 0;

	if (!mu || !sigma || !count)
		return -1000;

	stream_mem = (float *)calloc(count, sizeof(float));
	if (!stream_mem)
		return -2;

	/* Clear errors of PT1000 reading */
	adc_pt1000_clear_error();

	status = adc_pt1000_stream_raw_value_to_memory(stream_mem, count, &flag);
	if (status)
		return status;

	/* Wait for data to be transferred */
	while (flag == 0);

	if (flag != 1) {
		/* Error */
		return -1;
	}

	/* Convert the stream memory to Ohm readings */
	adc_pt1000_convert_raw_value_array_to_resistance(NULL, stream_mem, count);

	/* Do not compute std-deviation. Too imprecise
	 * arm_std_f32(stream_mem, count, sigma);
	 */
	*sigma = 0;
	arm_mean_f32(stream_mem, count, mu);

	free(stream_mem);

	return 0;
}