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

void verifSig(int sig)
{
    if(sig == SIGUSR1)
    {
        printf("C\n");
    }
    if(sig == SIGALRM)
    {
        printf("1\n");

    }
    alarm(1);
}

void handler(int sig)
{
	if (sig==SIGCHLD)
    {
		pid_t pid;
        pid = wait(NULL);
        printf("Pid %d exited.\n", pid);
	}
}

int main(int argc, char* argv[])
{
    if(argc != 3)
    {
        perror("nr gresit de arg");
        exit(1);
    }

    int pfd1[2], pfd2[2];
    int pid1, pid2, pid3;
    int fd1=open(argv[1],O_RDONLY);
    int fd2=open(argv[2],O_RDONLY);

    struct sigaction sigActAlarm;
    sigActAlarm.sa_handler = verifSig;
    sigActAlarm.sa_flags = 0;

    int rez;
    if((rez = sigaction(SIGALRM, &sigActAlarm, NULL)) < 0)
    {
        perror("eroare la sigalrm");
        exit(2);
    }
    if((rez = sigaction(SIGUSR1, &sigActAlarm, NULL)) < 0)
    {
        perror("eroare la sigusr1");
        exit(2);
    }

    struct sigaction sigActChld;
    sigActChld.sa_handler = handler;
    sigActChld.sa_flags = 0;


    if((fd1 < 0) || (fd2 < 0))
    {
        perror("eroare la deschidere fisiere");
        exit(2);
    }

    if((pipe(pfd1) < 0) || (pipe(pfd2) < 0))
    {
        perror("eroare la unul din pipes");
        exit(3);
    }

    //COPIL 1
    if((pid1 = fork()) < 0)
    {
        perror("nu s-a creat primul copil");
        exit(-1);
    }
    else if(pid1 == 0)
    {
        close(pfd1[0]);
        close(pfd2[1]);
        close(pfd2[0]);

        dup2(pfd1[1],1);
        execlp("cat", "cat", argv[1], NULL);
        printf("daca ajung aici, e eroare");
        exit(71);
    }

    //COPIL 2
    if((pid2 = fork()) < 0)
    {
        perror("nu s-a creat al doilea copil");
        exit(2);
    }
    else if(pid2 == 0)
    {
        close(pfd1[0]);
        close(pfd1[1]);
        close(pfd2[0]);

        dup2(pfd2[1],1);
        execlp("cat", "cat", argv[2], NULL);
        printf("daca ajung aici, e eroare");
        exit(72);
    }

    //COPIL 3
    if((pid3 = fork()) < 0)
    {
        perror("nu s-a creat al treilea copil");
        exit(2);
    }
    else if(pid3 == 0)
    {
        close(pfd1[1]);
        close(pfd2[1]);

        int nrc = 0;
        char buf1,buf2;
        printf("\n");
        while(read(pfd1[0], &buf1, 1) > 0)
        {
            if(buf1 >= '0' && buf1 <= '9')
            {
                nrc ++;
                kill(getppid(), SIGUSR1);
            }
            printf("%c", buf1);
        }
        printf("\n");
        while(read(pfd2[0], &buf2, 1) > 0)
        {
            if(buf2 >= '0' && buf2 <= '9')
            {
                nrc ++;
                kill(getppid(), SIGUSR1);
            }
            printf("%c", buf2);
        }
        printf("\n");
        exit(nrc);
    }

    if((rez = sigaction(SIGCHLD, &sigActChld, NULL)) > 0)
    {
        perror("eroare la sigchld");
        exit(2);
    }
    kill(getpid(),SIGCHLD);

    alarm(1);

    close(pfd1[0]);
    close(pfd1[1]);
    close(pfd2[0]);
    close(pfd2[1]);

    while(1);
    return 0;
}