/*
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */

#define CAML_NAME_SPACE
#include <caml/alloc.h>
#include <caml/memory.h>
#include <caml/mlvalues.h>
#include <limits.h>
#include <stdlib.h>

#define Val_none Val_int(0)

static value Val_some(value v) {
  CAMLparam1(v);
  CAMLlocal1(some);
  some = caml_alloc(1, 0);
  Store_field(some, 0, v);
  CAMLreturn(some);
}

CAMLprim value hh_realpath(value v) {
  const char* input;
#ifndef _WIN32
  char output[PATH_MAX];
#else
  char output[_MAX_PATH];
#endif
  char* result;

  CAMLparam1(v);

  input = String_val(v);
#ifndef _WIN32
  result = realpath(input, output);
#else
  result = _fullpath(output, input, _MAX_PATH);
#endif
  if (result == NULL) {
    CAMLreturn(Val_none);
  } else {
    CAMLreturn(Val_some(caml_copy_string(output)));
  }
}
