#include <stdio.h>
#include <stdlib.h>

#include <string.h>

#include <sys/types.h>

const char *icon[] = {
    "\uf58d",  /* 0% */

    "\uf579",

    "\uf57a",
    "\uf57b",

    "\uf57c",

    "\uf57d",  /* 50% */

    "\uf57e",

    "\uf57f",
    "\uf580",
    "\uf581",

    "\uf578",  /* 100% */

};

typedef enum {

  CHARGED = 0,
  DISCHARGING = 1,
  CHARGING = 2,
  DISCONNECTED = 7,
} State;

#if defined (__linux__)
void battery_state(int *nbats, int bat[], State state[]) {

  FILE *fd;

  int i=0;

  do {

    char filename[50], status[50];

    // get current capacity
    sprintf(filename, "/sys/class/power_supply/BAT%d/capacity", i);
    fd = fopen(filename, "rb");

    if (fd == NULL) 

      break;

    fscanf(fd, "%d", &bat[i]);
    fclose(fd);
    // battery status (charging...)

    sprintf(filename, "/sys/class/power_supply/BAT%d/status", i);

    fd = fopen(filename, "rb");
    fgets(status, 50, fd);
    // puts(status);
    fclose(fd);
    if (!strcmp(status, "Not charging\n"))
      state[i] = CHARGED;
    else if (!strcmp(status, "Discharging\n"))
      state[i] = DISCHARGING;
    else if (!strcmp(status, "Charging\n"))
      state[i] = CHARGING;

    // next
    i++;
  } while (1);
  *nbats = i;

}
#elif defined (__FreeBSD__)

#include <sys/sysctl.h>

void battery_state(int *nbats, int bat[], State state[]) {

  size_t len = sizeof(int);

  int state = -1, life = 0;

  if (sysctlbyname("hw.acpi.battery.state", &state, &len, NULL, 0) ||

      sysctlbyname("hw.acpi.battery.life", &life, &len, NULL, 0))

    state[0] = UNKNOWN;

  *nbats = 1;
  bat[0] = life;
  state[0] = state;
}
#endif

int main() {

  char *color;
  int life[2], nbats;

  State state[2];

  battery_state(&nbats, life, state);
  for (int i=0; i < nbats; i++) {

    if (life[i] >= 50) color = "colour028"; /* green */
    else if (life[i] >= 25) color = "colour172"; /* yellow */
    else color = "colour088"; /* red */

    switch (state[i]) {

    case CHARGED: /* fully charged */

      printf("%s %d%%  ", icon[life[i]/10], life[i]);
      break;

    case DISCHARGING: /* discharging */

      printf("#[fg=%s]%s#[fg=default] %d%%  ", color, icon[life[i]/10], life[i]);

      break;
    case CHARGING: /* charging */

      printf("#[fg=yellow]\uf583#[fg=default] %d%%\n  ", life[i]);
      break;

    case DISCONNECTED: /* disconnected */
      printf("\uf492  ");
      break;
    default: /* unknown code */
      printf("\uf590  ");

    }

  }

  return EXIT_SUCCESS;

}