#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>
#include <sys/wait.h>
#include <unistd.h>
#include <stdio.h>
#include <fcntl.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h> //nu era nevoie de toate astea

int afisareReplicaTata();
int afisareReplicaFiu();
int fd1,fd2,flag;
int main(int argc,char*argv[])
{
  if(argc<4){perror("da 3 argumente: tata fiu si flag"); exit(0);}
  if(-1==(fd1=open(argv[1],O_RDONLY))){perror("nu pot citi tata"); exit(0);}
  if(-1==(fd2=open(argv[2],O_RDONLY))){perror("nu pot citi fiu"); exit(0);}
  if(-1==(flag=open(argv[3],O_RDWR | O_TRUNC))){perror("nu pot citi flag"); exit(0);}

  pid_t pid_fiu;
  if((pid_fiu=fork())==-1){perror("eroare la fork"); exit(1);}

  else if(pid_fiu==0) //fiu
  {
    char c='a';
    while(1) //cat timp nu e eof
    {
      lseek(flag,0,SEEK_SET);
      read(flag,&c,1);
      if(c=='2')
      {
        while(afisareReplicaFiu()!=1);
        break;
      }
      if(c=='1')
      {
        if(afisareReplicaFiu()==1)
          break;
      }
      sleep(1);
    }
  }

  else //tata
  {
    char c='a';
    afisareReplicaTata();
    while(1) //cat timp nu e eof
    {
      lseek(flag,0,SEEK_SET);
      read(flag,&c,1);
      if(c=='2')
      {
        while(afisareReplicaTata()!=1);
        break;
      }
      if(c=='0')
      {
        if(afisareReplicaTata()==1)
          break;
      }
      else if(c=='2') break;
      sleep(1);
    }
  }
  close(fd1);
  close(fd2);
  return 0;
}

int afisareReplicaTata()
{
  char c='a';
  char*replica=malloc(100);
  int i=0;
  while(1){
    read(fd1,&c,1);
    if(c=='\n'){break;}
    replica[i]=c; i++;
  }
  printf("%s \n", replica);

  int val=0;
  if(read(fd1,&c,1)==0)
   {c='2'; val=1;}
   else c='1';

  lseek(fd1,-1,SEEK_CUR);
  lseek(flag,0,SEEK_SET);
  write(flag,&c,1);

  return val;
}

int afisareReplicaFiu()
{
  char c='a';
  char*replica=malloc(100);
  int i=0;
  while(1){
    read(fd2,&c,1);
    if(c=='\n'){break;}
    replica[i]=c; i++;
  }
  printf("%s \n", replica);

  int val=0;
  if(read(fd2,&c,1)==0)
   {c='2'; val=1;}
  else c='0';

  lseek(fd2,-1,SEEK_CUR);
  lseek(flag,0,SEEK_SET);
  write(flag,&c,1);

  return val;
}