/*
 * CHAT utilizando pipes con procesos emparentados
 * Excelente maestro es aquel que, enseņando poco, hace nacer   
 * en el alumno un deseo grande de aprender.
 * Arturo Graf (1848-1913) Escritor y poeta italiano.
 */

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

int main(int argc, char **argv) {
	int pipe1[2];  // pipe1[0] -> lectura  pipe1[1] -> escritura
	int pipe2[2];  // pipe2[0] -> lectura  pipe2[1] -> escritura
	pipe(pipe1);
	pipe(pipe2);
	
	if ( fork() ) {
		// padre! P
		if ( fork() ) {
			// padre! P
			close(pipe1[0]);
			close(pipe1[1]);
			close(pipe2[0]);
			close(pipe2[1]);
			printf("P pid=%d\n",getpid());
			while(wait(NULL) != -1);
			printf("P:fin!\n");
		} else {
			// hijo! H2
			if ( fork() ) {
				// hijo! H2
				printf("--------------------------------H2 pid=%d\n",getpid());
				close(pipe2[0]);
				close(pipe2[1]);
				close(pipe1[0]);
				char linea[255];
				while(strncmp(linea,"chau",4) != 0) {
                        		printf("--------------------------------Ingrese mensaje\n"); 
                                        gets(linea);
					printf("--------------------------------H2 [%d] envio [%s]\n",getpid(),linea);
					write(pipe1[1],linea,strlen(linea));
                                        sleep(1) ;
					}
				close(pipe1[1]);
				printf("----------------------------------------H2 fin!\n");
			} else {
				// nieto! N2
				printf("--------------------------------N2 pid=%d\n",getpid());
				close(pipe1[0]);
				close(pipe1[1]);
				close(pipe2[1]);
				char linea[255];
				int n;
				while(strncmp(linea,"chau",4) != 0) {
					n = read(pipe2[0],linea,255);
					linea[n]='\0';
					printf("--------------------------------N2 [%d] lei [%s]\n",getpid(),linea);
				}
				close(pipe2[0]);
				printf("N2 fin!\n");
			}
		}
	} else {
		// hijo! H1
		if ( fork() ) {
			// hijo! H1
			printf("H1 pid=%d\n",getpid());
			close(pipe2[0]);
			close(pipe1[1]);
			close(pipe1[0]);
			char linea[255];
			while(strncmp(linea,"chau",4) != 0) {
                      		printf("ingrese mensaje \n"); 
                                gets(linea);
				printf("H1 [%d] envio [%s]\n",getpid(),linea);
				write(pipe2[1],linea,strlen(linea));
                                sleep(1) ;
			}
			close(pipe2[1]);
			printf("H1 fin!\n");
 		} else {
			// nieto! N1
			printf("N1 pid=%d\n",getpid());
			close(pipe2[0]);
			close(pipe2[1]);
			close(pipe1[1]);
			char linea[255];
			int n;
			while(strncmp(linea,"chau",4) != 0) {
				n = read(pipe1[0],linea,255);
				linea[n]='\0';
				printf("N1 [%d] lei [%s]\n",getpid(),linea);
			}
			close(pipe1[0]);
			printf("N1 fin!\n");
		}
	}
	return 0;
}