#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include "meas.h"

struct meas meas[4];
float lin_a, lin_b, lin_a2, lin_b2;
float dac_min, dac_max, dac_init;
float Psi_sta, Psi_st;

write_output(filename)
	char *filename;
{
	FILE *outf;

	if (filename) {
		outf = fopen(filename, "w");
		if (!outf) {
			perror(filename);
			exit(1);
		}
	} else
		outf = stdout;

	fputs("rf_table afcparams\n\n", outf);
	/* Psi parameters */
	fprintf(outf, "%10u\t# Psi_sta_inv\n", (unsigned)(1.0f / Psi_sta));
	fprintf(outf, "%10u\t# Psi_st\n", (unsigned)(Psi_st * 65536.0f));
	fprintf(outf, "%10u\t# Psi_st_32\n",
		(unsigned)(Psi_st * 65536.0f * 65536.0f));
	fprintf(outf, "%10u\t# Psi_st_inv\n\n", (unsigned)(1.0f / Psi_st));
	/* DAC settings */
	fprintf(outf, "%10d\t# DAC_INIT * 8\n", (int)(dac_init * 8.0f));
	fprintf(outf, "%10d\t# DAC_MIN * 8\n", (int)(dac_min * 8.0f));
	fprintf(outf, "%10d\t# DAC_MAX * 8\n", (int)(dac_max * 8.0f));
	fprintf(outf, "%10d\t# snr_thr\n", 2560);
	/* rfpw 10 setting in a comment line */
	fprintf(outf, "\n# DAC_INIT: rfpw 10 %d\n", (int)dac_init);

	if (filename)
		fclose(outf);
}

main(argc, argv)
	char **argv;
{
	float pi;

	if (argc < 2 || argc > 3) {
		fprintf(stderr, "usage: %s meas-file [outfile]\n", argv[0]);
		exit(1);
	}
	read_meas_file(argv[1], meas, 4);

	/* first linear approximation */
	lin_a = (float)(meas[1].freq_offset - meas[0].freq_offset) /
		(float)(meas[1].dac_value - meas[0].dac_value);
	lin_b = (float)meas[1].freq_offset - lin_a * meas[1].dac_value;

	/* second linear approximation */
	lin_a2 = (float)(meas[3].freq_offset - meas[2].freq_offset) /
		(float)(meas[3].dac_value - meas[2].dac_value);
	lin_b2 = (float)meas[3].freq_offset - lin_a2 * meas[3].dac_value;

	/* DAC settings */
	dac_min = (-13500.0f - lin_b) / lin_a;
	dac_max = (13500.0f - lin_b) / lin_a;
	dac_init = -lin_b2 / lin_a2;

	/* Psi computations */
	pi = acos(-1.0);
	Psi_sta = 2.0f * pi * (float)(meas[1].freq_offset - meas[0].freq_offset)
		/ ((float)(meas[1].dac_value - meas[0].dac_value) * 270833.0f);
	Psi_st = Psi_sta * 0.8f;

	/* spit it all out */
	write_output(argv[2]);
	exit(0);
}