#include <string.h>
#include <stdlib.h>

#include "fileutils.h"

// direction is either false=input or true=output and used to overload parameter '-'
FILE *fd_magic(char *str, bool direction) {
  static bool usedDir[2] = { false, false };

  // check if stdin/-out is wanted
  if (strcmp(str, "-") == 0) {
    // check if we already used this
    if (usedDir[direction]) {
      fprintf(stderr, "stdin/-out cannot be used twice\n");
      exit(-1);
    }

    // mark that we used it and return in
    usedDir[direction] = true;
    return direction ? stdout : stdin;
  }

  // check if stdout is wanted
  if (strcmp(str, "0") == 0) {
    // replace filename and proceed
    str = "/dev/null";
  }

  // open file traditionally
  FILE *fd = fopen(str, direction ? "w" : "r" );
  if (fd == NULL) {
    fprintf(stderr, "Failed to open %s\n", str);
    exit(-1);
  }

  return fd;
}