/*
 * Utility functions and structures
 */
#include "utility.h"
#include <unistd.h>
#include <stdio.h>

#define NUM_TIMESTAMPS 20
#define SZ_TIMESTAMP 40

static char ts_array[NUM_TIMESTAMPS][SZ_TIMESTAMP];
static int ts_index = -1;

char* make_timestamp(const struct timeval* tv)
{
  char *str;
  if (ts_index < 0 || ts_index >= NUM_TIMESTAMPS)
    ts_index = 0;
  str = ts_array[ts_index++];
  struct timeval now;
  if (tv == NULL)
  {
    tv = &now;
    gettimeofday(&now, NULL);
  }
  snprintf(str, SZ_TIMESTAMP, "%02d:%02d:%02d.%06d",
      (int) (tv->tv_sec / 3600 % 24),
      (int) (tv->tv_sec / 60 % 60),
      (int) (tv->tv_sec % 60),
      (int) (tv->tv_usec));
  return str;
}

double time_diff(struct timeval* later, struct timeval* earlier)
{
  double delta = 
    ((double) later->tv_sec - (double) earlier->tv_sec)
     + 0.000001 * ((double) later->tv_usec - (double) earlier->tv_usec);
  return delta;
}

/*
 * subtract the earlier time value from the later time value
 */
int time_sub(struct timeval* later, struct timeval* earlier)
{
  if (later->tv_sec < earlier->tv_sec ||
      (later->tv_sec == earlier->tv_sec &&
       later->tv_usec < earlier->tv_usec))
    return -1;
  later->tv_sec -= earlier->tv_sec;
  if (later->tv_usec < earlier->tv_usec)
  {
    later->tv_sec--;
    later->tv_usec = 1000000 + later->tv_usec - earlier->tv_usec;
  }
  else
  {
    later->tv_usec -= earlier->tv_usec;
  }
  return 0;
}

int time_cmp(struct timeval* later, struct timeval* earlier)
{
  double delta = (1.0 * later->tv_sec + 0.000001 * later->tv_usec) -
      (1.0 * earlier->tv_sec + 0.000001 * earlier->tv_usec);
  if (delta == 0.0)
    return 0;
  else if (delta > 0.0)
    return 1;
  else return -1;
}

/*
 * Advance the timer by <msec> milliseconds until it is in the future
 */
void time_adv(struct timeval* tmr, int msec)
{
  struct timeval now;
  gettimeofday(&now, NULL);
  while (tmr->tv_sec < now.tv_sec ||
      (tmr->tv_sec == now.tv_sec &&
       tmr->tv_usec <= now.tv_usec))
  {
    tmr->tv_sec += msec / 1000;
    tmr->tv_usec += (msec % 1000) * 1000;
    if (tmr->tv_usec >= 1000000)
    {
      tmr->tv_sec += tmr->tv_usec / 1000000;
      tmr->tv_usec = tmr->tv_usec % 1000000;
    }
  }
}

#define DEBUG_FILE "debug_file.txt"
#include <stdarg.h>
#ifndef dprintf
static int debug_level = -1;
int set_debug_level(int new_level)
{
  int temp = debug_level;
  debug_level = new_level;
  return temp;
}

int dprintf(int level, const char* format, ...)
{
  int result = 0;
  int iRet  = 0;
  va_list ap;

  if (level <= debug_level)
  {
    FILE* debug_file = fopen(DEBUG_FILE, "a");
    if (debug_file)
    {
      va_start(ap, format);
      iRet = fprintf(debug_file, "%s ", make_timestamp(NULL));
      result = iRet;
      iRet = vfprintf(debug_file, format, ap);
      result += iRet;
      va_end(ap);
      fclose(debug_file);
    }
  }
  return result;
}
#endif