#include <stdio.h>
#include <signal.h>
#include <unistd.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/sysctl.h>

void updateClock(int sig){

  int life, state;
  size_t len = sizeof(int);
  sysctlbyname("hw.acpi.battery.life",&life,&len,NULL,0);
  sysctlbyname("hw.acpi.battery.state",&state,&len,NULL,0);

  char* color;
  if(state != 1){
    // AC online

    color = "0;32m"; //

  }else{
    // Battery

    color = (life < 30) ? "0;41m" : "0;42m";
  }
  
  time_t now = time(NULL);
  printf("\x1b[0;0H\x1b[0;%s%3d\x1b[0m %s", color,life, ctime(&now));

}

int main(int argc, char** args){
  printf("\x1b[2J\x1b[0;0H"); // clear screen


  struct itimerval timer = {{1,0}, {1,0}};
  int err = setitimer(ITIMER_REAL, &timer, NULL);
  if(err < 0){
    printf("%d: %s\n",err,"Can not set itimer");
    return err;
  }

  signal(SIGALRM, updateClock);

  for(;;)pause();
}