/* Example of Outcome try used with foreign object
(C) 2019-2020 Niall Douglas <http://www.nedproductions.biz/> (1 commit)


Boost Software License - Version 1.0 - August 17th, 2003

Permission is hereby granted, free of charge, to any person or organization
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*/

#include "../../../include/boost/outcome.hpp"

#include <iostream>

namespace outcome = BOOST_OUTCOME_V2_NAMESPACE;

//! [foreign_type]
enum Errc
{
  kBadValue
};
template <class T, class E = Errc> struct ForeignExpected
{
  T Value;
  E Error;
  int IsErrored;

  ForeignExpected(T v)
      : Value(v)
      , Error()
      , IsErrored(0)
  {
  }
  ForeignExpected(E e)
      : Value()
      , Error(e)
      , IsErrored(1)
  {
  }
};
//! [foreign_type]

//! [tell_outcome]
BOOST_OUTCOME_V2_NAMESPACE_BEGIN
template <class T, class E>  //
inline bool try_operation_has_value(const ForeignExpected<T, E> &v)
{
  return 0 == v.IsErrored;
}
template <class T, class E>  //
inline auto try_operation_return_as(const ForeignExpected<T, E> &v)
{
  switch(v.Error)
  {
  case kBadValue:
    return failure(make_error_code(std::errc::argument_out_of_domain));
  }
  abort();
}
template <class T, class E>  //
inline auto try_operation_extract_value(const ForeignExpected<T, E> &v)
{
  return v.Value;
}
BOOST_OUTCOME_V2_NAMESPACE_END
//! [tell_outcome]

//! [functions]
ForeignExpected<int> old_code(int a)  // old code
{
  if(0 == a)
    return kBadValue;
  return a;
}

outcome::result<int> new_code(int a)  // new code
{
  BOOST_OUTCOME_TRY(x, old_code(a));
  return x;
}
//! [functions]

int main()
{
  //! [example]
  auto printresult = [](const char *desc, auto x) {
    if(x)
    {
      std::cout << desc << " returns successful " << x.value() << std::endl;
    }
    else
    {
      std::cout << desc << " returns failure " << x.error().message() << std::endl;
    }
  };
  printresult("\nnew_code(5)", new_code(5));
  printresult("\nnew_code(0)", new_code(0));
  //! [example]
  return 0;
}