#pragma once

#include <cstdlib>
#include <cstdio>
#include <string>

#define TF_OS_LINUX 0
#define TF_OS_DRAGONFLY 0
#define TF_OS_FREEBSD 0
#define TF_OS_NETBSD 0
#define TF_OS_OPENBSD 0
#define TF_OS_DARWIN 0
#define TF_OS_WINDOWS 0
#define TF_OS_CNK 0
#define TF_OS_HURD 0
#define TF_OS_SOLARIS 0
#define TF_OS_UNIX 0 /* disjunction of TF_OS_LINUX, TF_OS_DARWIN etc. */

#ifdef _WIN32
#undef TF_OS_WINDOWS
#define TF_OS_WINDOWS 1
#endif

#if (defined __APPLE__ && defined __MACH__)
#undef TF_OS_DARWIN
#define TF_OS_DARWIN 1
#endif

// in some ppc64 linux installations, only the second condition is met
#if (defined __linux)
#undef TF_OS_LINUX
#define TF_OS_LINUX 1
#elif (defined __linux__)
#undef TF_OS_LINUX
#define TF_OS_LINUX 1
#else
#endif

#if (defined __DragonFly__)
#undef TF_OS_DRAGONFLY
#define TF_OS_DRAGONFLY 1
#endif

#if (defined __FreeBSD__)
#undef TF_OS_FREEBSD
#define TF_OS_FREEBSD 1
#endif

#if (defined __NetBSD__)
#undef TF_OS_NETBSD
#define TF_OS_NETBSD 1
#endif

#if (defined __OpenBSD__)
#undef TF_OS_OPENBSD
#define TF_OS_OPENBSD 1
#endif

#if (defined __bgq__)
#undef TF_OS_CNK
#define TF_OS_CNK 1
#endif

#if (defined __GNU__)
#undef TF_OS_HURD
#define TF_OS_HURD 1
#endif

#if (defined __sun)
#undef TF_OS_SOLARIS
#define TF_OS_SOLARIS 1
#endif

#if (1 !=                                                                  \
     TF_OS_LINUX + TF_OS_DRAGONFLY + TF_OS_FREEBSD + TF_OS_NETBSD +        \
     TF_OS_OPENBSD + TF_OS_DARWIN + TF_OS_WINDOWS + TF_OS_HURD +           \
     TF_OS_SOLARIS)
#error Unknown OS
#endif

#if TF_OS_LINUX || TF_OS_DRAGONFLY || TF_OS_FREEBSD || TF_OS_NETBSD ||     \
    TF_OS_OPENBSD || TF_OS_DARWIN || TF_OS_HURD || TF_OS_SOLARIS
#undef TF_OS_UNIX
#define TF_OS_UNIX 1
#endif

namespace tf {

// Function: get_env
inline std::string get_env(const std::string& str) {
#ifdef _MSC_VER
  char *ptr = nullptr;
  size_t len = 0;
  
  if(_dupenv_s(&ptr, &len, str.c_str()) == 0 && ptr != nullptr) {
    std::string res(ptr, len);
    free(ptr);
    return res;
  }
  return "";

#else
  auto ptr = std::getenv(str.c_str());
  return ptr ? ptr : "";
#endif
}


}  // end of namespace tf -----------------------------------------------------