#include<stdio.h>
#include<unistd.h>
#include<stdlib.h>
#include<string.h>
#include<fcntl.h>

#define FIFO_1 "./fifo1to2"
#define FIFO_2 "./fifo2to1"
#define MAX_RBUF 80


int FIFO_f1, FIFO_f2;

int main(int argc, char *argv[])
{
    int child, nbyte;
    char rbuf[MAX_RBUF]= " ";

    if(argc != 2) //check argc
    {
        fprintf(stderr,"Please Use : %s <[1,2]>\n", *argv);
        exit(EXIT_FAILURE);
    }

    if(access(FIFO_1,F_OK)== -1)
    {
        FIFO_FD1 = mkfifo(FIFO_1, 0777); //สร้างFIFO เซตPermission rwx
        if(FIFO_FD1)
        {
            fprintf(stderr,"Create fifo error %s\n",FIFO_1);
            exit(EXIT_FAILURE);
        }
    }

    if(access(FIFO_2,F_OK)== -1)
    {
        FIFO_FD2 = mkfifo(FIFO_2, 0777); //สร้างFIFO เซตPermission rwx
        if(FIFO_FD2)
        {
            fprintf(stderr,"Create fifo error %s\n",FIFO_2);
            exit(EXIT_FAILURE);
        }
    }

    //-----------------------------------------------------------//

FIFO_FD1 = open(FIFO_1, O_WRONLY);
FIFO_FD2 = open(FIFO_2, O_RDONLY);

argv++;

if(strcmp(*argv, "1")==0) //Process ที่1
{
    child = fork();
    switch(child)
    {
        case -1 : perror("Forking failed"); exit(EXIT_FAILURE);
        case 0 : while(strncmp(rbuf,"end chat",8)) //ให้child อ่านค่าจากท่อ2 และแสดงผลออกterminal
        {
            read(FIFO_f1,buffer,sizeof(rbuf));
            printf("%s\n",buffer);
        }
        break;
        default : while(strncmp(buffer,"end chat",8)) //Parent รับค่าจากkeyboardส่งเข้าท่อที่1
        {
            memset(rbuf,'\0',sizeof(rbuf));
            fgets(rbuf,MAX_RBUF,stdin);
            write(FIFO_1,rbuf,strlen(buffer)+1);
        }
    }

}

if(strcmp(*argv,"2")==0) //Process ที่2
{
    child = fork();
    switch(child)
    {
        case -1 : perror("Forking failed"); exit(EXIT_FAILURE);
        case 0 : while(strncmp(buffer,"end chat",8)) //ให้child อ่านค่าจากท่อ1 และแสดงผลออกterminal
        {
            read(FIFO_f2,buffer,sizeof(buffer));
            printf("%s\n",buffer);
        }
        default : while(strncmp(buffer,"end chat",8)) //ให้Parentรับค่าจากkeyboard แล้วส่งเข้าท่อที่2
        {
            memset(buffer,'\0',sizeof(buffer));
            fgets(buffer,MAX_RBUF,stdin);
            write(FIFO_2,buffer,strlen(buffer)+1);
        }
    }

}


if (FIFO_f1 !=-1) close(FIFO_f1);
if (FIFO_f2 !=-1) close(FIFO_f2);

exit(EXIT_SUCCESS);
}