#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
int stop(char *, int);
int main(int argc, char **argv) {
  int pipeAlPadre[2], pipeAlFiglio[2];
  pid_t pid1, pid2;
  int readChar;
  if (argc != 3)
    perror("Insert 2 files"), exit(-1);
  if (pipe(pipeAlPadre) < 0)
    perror("Pipe 1"), exit(-1);
  pipe(pipeAlPadre);
  if ((pid1 = fork()) < 0)
    perror("Fork 1"), exit(-1);
  if (pid1 == 0) { /*figlio 1*/
    int fileDesc;
    char buffer[2];
    char stopSign = '*';
    if ((fileDesc = open(argv[1], O_RDONLY)) < 0)
      perror("File opening 1"), exit(-1);
    close(pipeAlPadre[0]);
    while ((readChar = read(fileDesc, buffer, 2))) {
      if (readChar == 2)
        write(pipeAlPadre[1], buffer, 2);
      else
        write(pipeAlPadre[1], &stopSign, sizeof(char));
    }
    close(pipeAlPadre[1]);
    close(fileDesc);
  } else {
    pipe(pipeAlFiglio);
    if ((pid2 = fork()) < 0)
      perror("Fork 2"), exit(-1);
    if (pid2 == 0) { /* figlio 2*/
      int fileDesc, readChar;
      char buffer[4];
      char bufferOut[2];
      close(pipeAlFiglioa[1]);
      if ((fileDesc = open(argv[2], O_WRONLY | O_CREAT, S_IRWXU | S_IRWXO)) < 0)
        perror("Open 2"), exit(-1);
      while ((readChar = read(pipeAlFiglio[0], buffer, 4))) {
        if (readChar == 4) {
          bufferOut[0] = buffer[0];
          bufferOut[1] = buffer[3];
          write(fileDesc, bufferOut, 2);
        }
      }
      close(pipeAlFiglio[0]);
      close(fileDesc);
    } else { /*padre*/
      char buffer[4];
      int readChar;

      close(pipeAlPadre[1]);
      close(pipeAlFiglio[0]);
      while ((readChar = read(pipeAlPadre[0], buffer, 4)) == 4) {
        if (stop(buffer, 4)) {
          break;
        } else {
          if (buffer[0] != buffer[3]) {
            printf("Inviato\n");
            write(pipeAlFiglio[1], buffer, 4);
          }
        }
      }
      close(pipeAlPadre[0]);
      close(pipeAlFiglio[1]);
    }
  }
  return 0;
}

int stop(char *String, int dim) {
  char c = '*';
  int index = 0;
  while (index < dim) {
    if (String[index] == c)
      return 1;
    index++;
  }
  return 0;
}