#include <unistd.h>
#include <stdio.h>
#include <X11/Xlib.h>
#include <time.h>
#include <string.h>

#define INTERVAL 10

int main(void) {
  Display *display = XOpenDisplay(NULL);
  if (display == NULL) {
    fprintf(stderr, "dwmst: cannot open display.\n");
  }

  /* time */
  char tbuffer[128] = { 0 };
  time_t currentTime;
  struct tm *timeinfo;

  /* battery */
  char bbuffer[6] = { 0 };
  FILE *f;

  /* status */
  char status[256] = { 0 };

  for (;;sleep(INTERVAL)) {
    /* get current time */
    time(&currentTime);
    timeinfo = localtime(&currentTime);
    
    strftime(tbuffer, sizeof(tbuffer), "%a %b %d %H:%M", timeinfo);

    if (OPTION_BATTERY) {
      /* battery status */
      f = fopen("/sys/class/power_supply/BAT0/capacity", "r");
      if (f == NULL) {
	fprintf(stderr, "dwmst: cannot access battery.\n");
      } else {
	fgets(bbuffer, 4, f);
	strtok(bbuffer, "\n"); /* remove trailing white space */
	strcat(bbuffer, "%");
	fclose(f);
      }

      f = fopen("/sys/class/power_supply/BAT0/status", "r");
      if (f == NULL) {
	fprintf(stderr, "dwmst: cannot access battery.\n");
      } else {
	switch(getc(f)) {
	case 'D': /* Discharging */
	  strcat(bbuffer, "-");
	  break;
	case 'C': /* Charging */
	  strcat(bbuffer, "+");
	  break;
	case 'F': /* Full */
	  strcat(bbuffer, "=");
	}
	fclose(f);
      }
    }

    /* build status */
    if (OPTION_BATTERY)
      sprintf(status, "%s | %s", tbuffer, bbuffer);
    else
      sprintf(status, "%s", tbuffer);

    /* store root window name */
    XStoreName(display, DefaultRootWindow(display), status);
    XSync(display, False);
  }
}