/* gcc -o coordinator coordinator.c OR make */
/* CS540 assgn 1 */
/* Martian (Adam Smyth) */
/* martian@midgard.org */
/* I never comment my code. (It's bad for job security. ;;) */

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

int numkids;
pid_t *kids;

void killexit()
{
  int i;
  printf("Killing related processes:");
  for(i=0; i<numkids; i++)
  {
    printf(" %d", kids[i]); 
    kill(kids[i], SIGKILL);
  }
  printf("\nExiting.\n\n");
  exit(-1);
}

void sigalarm(int signum)
{
  killexit();
}

main(int argc, char *args[])
{
  int *values;
  int numvalues, i, ret;
  pid_t pid;
  char a[5], b[5];

  numvalues = (argc-1) + ((argc-1) % 2);

  values = (int*)malloc(numvalues*sizeof(int));
  kids = (pid_t*)malloc(numvalues*sizeof(pid_t));

  for(i=0; i<numvalues; i++)
    values[i] = 0;


  for(i=1; i<argc; i++)
    values[i-1] = atoi(args[i]);

  signal(SIGALRM, sigalarm);
  alarm(10);

  while(numvalues > 1)
  {

    numkids = numvalues/2;

    for(i=0; i<numkids; i++)
    {
      sprintf(a, "%d", values[(i*2)]);
      sprintf(b, "%d", values[(i*2)+1]);
      pid = fork();
      if(pid==0) {
        execlp("./worker", "worker", a, b, NULL);
      } else if(pid<0) {
        printf("FORK ERROR. TERMINATING.\n");
        killexit();
      } else {
        kids[i] = pid;
      }
    }

    numvalues = numkids + (numkids % 2);

    for(i=0; i<numvalues; i++)
      values[i] = 0;

    for(i=0; i<numkids; i++)
    {
      pid = wait(&ret);
      if(!WIFEXITED(ret)) {
        printf("ERROR FROM CHILD. TERMINATING.\n");
        killexit();
      }
      printf("%s %d: %d\n", args[0], pid, values[i]=WEXITSTATUS(ret));
    }

    if(numkids == 1)
    {
      printf("\nSum: %d\n\n", values[0]);
      exit(0);
    }
  }
}