#include <stdio.h>
#include <string.h> /* memset */
#include <math.h>   /* sin */
#include <labmaster.h>
#include "dac.h"

#define SIZE 500

static const int DAC = 1;
static const int DAC_LOWER = -2048;
static const int DAC_HIGHER = 2047;
static const int DAC_WARNING = 256;

static const int ADC = 1;

static const int TIME_LOWER = 40; /* us */
static const int ITER_LOWER = 1;

static const char *DATA = "experiment.data";
static const char *GNUP = "experiment.gnu";
static const char *GNU = "gnuplot -persist";

int plot() {
  FILE *fp_gnup;
  FILE *gnu;

  /* open .gnu */
  if(!(fp_gnup = fopen(GNUP, "w")))
    { perror(GNUP); return 0; }

  fprintf(fp_gnup, "set xlabel 'Time (s)'\n");
  fprintf(fp_gnup, "set ylabel 'Volts (V)'\n");
  fprintf(fp_gnup, "plot \\\n");
  fprintf(fp_gnup, "'%s' using 1:3 title 'Output' with points\n", DATA);

  /* close .gnu */
  if(!(fclose(fp_gnup)))
    { perror(GNUP); }

  /* open gnuplot */
  if(!(gnu = popen(GNU, "w")))
    { perror(GNU); return 0; }

  fprintf(gnu, "load '%s'\n", GNUP);

  /* close gnuplot */
  if(!(fclose(gnu)))
    { perror(GNU); }

  return -1;
}

int main(int argc, char **argv) {
  int i, iter;
  int T = 100, iterations = 8;
  int out[SIZE];
  double in[SIZE], adc;
  FILE *fp_data;

  /* command line: period */
  if(argc > 1) sscanf(argv[1], "%d", &T);
  if(T < TIME_LOWER) {
    fprintf(stderr, "Period lower bound: %d us corrected to %d us.\n", T, TIME_LOWER);
    T = TIME_LOWER;
  }

  /* command line: iterations */
  if(argc > 2) sscanf(argv[2], "%d", &iterations);
  if(iterations < ITER_LOWER) {
    fprintf(stderr, "Iterations lower bound: %d corrected to %d.\n", iterations, ITER_LOWER);
    iterations = ITER_LOWER;
  }

  /* open .data */
  if(!(fp_data = fopen(DATA, "w")))
    { perror(DATA); return 1; }

  /* set up LUT */
  /* for(i = 0; i < SIZE; i++)
     out[i] = (i & 1) ? DAC_LOWER : DAC_HIGHER; */
  for(i = 0; i < SIZE; i++)
    out[i] = ((double)(256 + 128) * sin((i / (double)SIZE) * 2 * M_PI)) - 570;

  fprintf(stderr, "Initalising LabMaster!\n");
  labmaster_initialize();

  fprintf(stderr, "Writing %dus to the timeout function.\n", T);
  write_am9513_command(DISARM_COUNTERS | COUNTER_5);
  mode_D(5, SOURCE_F1, OUTPUT_TC_PULSE_HIGH, COUNT_DOWN);
  write_counter_load(5, T);
  write_am9513_command(LOAD_AND_ARM_COUNTERS | COUNTER_5);

  fprintf(stderr, "ADC enabling external start.\n");
  adc_enable_external_start();

  /* the DAC lags when starting up one, maybe two times, no idea why */
  fprintf(stderr, "Clearing the DAC.\n");
  for(iter = 0; iter < 4; iter++) {
    out_dac(DAC, out[0]);
    adc = in_adc(ADC);
  }

  fprintf(stderr, "Doing experiment %d times: <", iterations);
  for(iter = 0; iter < iterations; iter++) {
    fprintf(stderr, "|"); /* clear */
    for(i = 0; i < SIZE; i++) {
      out_dac(DAC, out[i]);

      adc = in_adc(ADC); /* DEBUG: crash and burn */

      /* actually, we do'n't really care where it came from */
      /* if(out[i] < adc - DAC_WARNING || out[i] > adc + DAC_WARNING)
	 fprintf(stderr, "%d: %g (%d) ", i, adc, out[i]); */

      in[i] = in[i] * (iter / (double)(iter + 1)) + adc * (1 / (double)(iter + 1));
    }
  }
  fprintf(stderr, ">.\n");

  fprintf(stderr, "ADC disabling external start.\n");
  adc_disable_external_start();

  fprintf(stderr, "Terminating LabMaster.\n");
  labmaster_terminate();

  /* open .data */
  if(!(fp_data = fopen(DATA, "w")))
    { perror(DATA); return 1; }

  fprintf(fp_data, "# Caibration of DAC/ADC\n");
  fprintf(fp_data, "# <SIZE %d> * <T %dus> = %dus, iterations %d\n", SIZE, T, SIZE * T, iterations);
  fprintf(fp_data, "# time (s)\tout (V)\tin (s)\n");
  for(i = 0; i < SIZE; i++)
    fprintf(fp_data, "%g\t%g\t%g\n", i * T * 1e-6, a[1] + b[1] * (double)out[i], a[1] + b[1] * in[i]);

  /* close .data */
  if(!fclose(fp_data))
    { perror(DATA); }

  plot();

  return 0;
}