/* Unit testing for outcomes
(C) 2013-2019 Niall Douglas <http://www.nedproductions.biz/> (30 commits)


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

Permission is hereby granted, free of charge, to any person or organization
obtaining a copy of the software and accompanying documentation covered by
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the above license grant, this restriction and the following disclaimer,
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*/

#ifdef TESTING_WG21_EXPERIMENTAL_RESULT
#include <boost/outcome/experimental/result.hpp>
#define BOOST_OUTCOME_AUTO_TEST_CASE(...) BOOST_AUTO_TEST_CASE(__VA_ARGS__)
#else
#include <boost/outcome/result.hpp>
#endif
#include <boost/test/unit_test.hpp>
#include <boost/test/unit_test_monitor.hpp>

#include <iostream>

#ifndef BOOST_NO_EXCEPTIONS
// Custom error type with payload
struct payload
{
  boost::system::error_code ec;
  const char *str{nullptr};
  payload() = default;
  payload(boost::system::errc::errc_t _ec, const char *_str)
      : ec(make_error_code(_ec))
      , str(_str)
  {
  }
};
struct payload_exception : std::runtime_error
{
  explicit payload_exception(const char *what)
      : std::runtime_error(what)
  {
  }
};
inline const boost::system::error_code &make_error_code(const payload &p)
{
  return p.ec;
}
inline void outcome_throw_as_system_error_with_payload(const payload &p)
{
  throw payload_exception(p.str);
}
#endif

BOOST_OUTCOME_AUTO_TEST_CASE(works_result, "Tests that the result works as intended")
{
#ifdef TESTING_WG21_EXPERIMENTAL_RESULT
  using namespace std::experimental;
  using std::in_place_type;
#else
  using namespace BOOST_OUTCOME_V2_NAMESPACE;
#endif

  static_assert(std::is_constructible<result<long>, int>::value, "Sanity check that monad can be constructed from a value_type");
  static_assert(!std::is_constructible<result<result<long>>, int>::value, "Sanity check that outer monad can be constructed from an inner monad's value_type");
  static_assert(!std::is_constructible<result<result<result<long>>>, int>::value, "Sanity check that outer monad can be constructed from an inner inner monad's value_type");
  static_assert(!std::is_constructible<result<result<result<result<long>>>>, int>::value, "Sanity check that outer monad can be constructed from an inner inner monad's value_type");

  static_assert(std::is_constructible<result<int>, result<long>>::value, "Sanity check that compatible monads can be constructed from one another");
  static_assert(std::is_constructible<result<result<int>>, result<long>>::value, "Sanity check that outer monad can be constructed from a compatible monad");
  static_assert(!std::is_constructible<result<result<result<int>>>, result<long>>::value, "Sanity check that outer monad can be constructed from a compatible monad up to two nestings deep");
  static_assert(!std::is_constructible<result<result<result<result<int>>>>, result<long>>::value, "Sanity check that outer monad can be constructed from a compatible monad three or more nestings deep");
  static_assert(!std::is_constructible<result<std::string>, result<int>>::value, "Sanity check that incompatible monads cannot be constructed from one another");

#ifndef TESTING_WG21_EXPERIMENTAL_RESULT
  static_assert(std::is_constructible<result<int>, result<void>>::value, "Sanity check that all monads can be constructed from a void monad");
  static_assert(std::is_constructible<result<result<int>>, result<void>>::value, "Sanity check that outer monad can be constructed from a compatible monad");
  static_assert(std::is_constructible<result<result<result<int>>>, result<void>>::value, "Sanity check that outer monad can be constructed from a compatible monad up to two nestings deep");
  static_assert(!std::is_constructible<result<void>, result<int>>::value, "Sanity check that incompatible monads cannot be constructed from one another");
#endif
  static_assert(std::is_void<result<void>::value_type>::value, "Sanity check that result<void> has a void value_type");
#ifndef TESTING_WG21_EXPERIMENTAL_RESULT
  static_assert(std::is_void<result<void, void>::error_type>::value, "Sanity check that result<void, void> has a void error_type");
#endif

  static_assert(std::is_same<result<int>::value_type, int>::value, "Sanity check that result<int> has a int value_type");
  static_assert(std::is_same<result<int>::error_type, boost::system::error_code>::value, "Sanity check that result<int> has a error_code error_type");


  {  // errored int
    result<int> m(boost::system::errc::bad_address);
    BOOST_CHECK(!m);
    BOOST_CHECK(!m.has_value());
    BOOST_CHECK(m.has_error());
    // BOOST_CHECK(!m.has_exception());
    BOOST_CHECK_THROW(m.value(), boost::system::system_error);
    BOOST_CHECK_NO_THROW(m.error());
  }
  {  // errored void
    result<void> m(boost::system::errc::bad_address);
    BOOST_CHECK(!m);
    BOOST_CHECK(!m.has_value());
    BOOST_CHECK(m.has_error());
// BOOST_CHECK(!m.has_exception());
#ifndef TESTING_WG21_EXPERIMENTAL_RESULT
    BOOST_CHECK_THROW(([&m]() -> void { return m.value(); }()), boost::system::system_error);
#endif
    BOOST_CHECK_NO_THROW(m.error());
  }
  {  // valued int
    result<int> m(5);
    BOOST_CHECK(m);
    BOOST_CHECK(m.has_value());
    BOOST_CHECK(!m.has_error());
    // BOOST_CHECK(!m.has_exception());
    BOOST_CHECK(m.value() == 5);
    m.value() = 6;
    BOOST_CHECK(m.value() == 6);
    BOOST_CHECK_THROW(m.error(), bad_result_access);
  }
  {  // valued bool
    result<bool> m(false);
    BOOST_CHECK(m);
    BOOST_CHECK(m.has_value());
    BOOST_CHECK(!m.has_error());
    // BOOST_CHECK(!m.has_exception());
    BOOST_CHECK(m.value() == false);
    m.value() = true;
    BOOST_CHECK(m.value() == true);
    BOOST_CHECK_THROW(m.error(), bad_result_access);
  }
  {  // moves do not clear state
    result<std::string> m("niall");
    BOOST_CHECK(m);
    BOOST_CHECK(m.has_value());
    BOOST_CHECK(!m.has_error());
    // BOOST_CHECK(!m.has_exception());
    BOOST_CHECK(m.value() == "niall");
    m.value() = "NIALL";
    BOOST_CHECK(m.value() == "NIALL");
    auto temp(std::move(m).value());
    BOOST_CHECK(temp == "NIALL");
    BOOST_CHECK(m.value().empty());  // NOLINT
  }
  {  // valued void
    result<void> m(in_place_type<void>);
    BOOST_CHECK(m);
    BOOST_CHECK(m.has_value());
    BOOST_CHECK(!m.has_error());
    // BOOST_CHECK(!m.has_exception());
    BOOST_CHECK_NO_THROW(m.value());  // works, but type returned is unusable
    BOOST_CHECK_THROW(m.error(), bad_result_access);
  }
  {  // errored
    boost::system::error_code ec(5, boost::system::system_category());
    result<int> m(ec);
    BOOST_CHECK(!m);
    BOOST_CHECK(!m.has_value());
    BOOST_CHECK(m.has_error());
    // BOOST_CHECK(!m.has_exception());
    BOOST_CHECK_THROW(m.value(), boost::system::system_error);
    BOOST_CHECK(m.error() == ec);
  }
#if !defined(__APPLE__) || defined(__cpp_exceptions)
  {  // errored, custom
    boost::system::error_code ec(5, boost::system::system_category());
    auto e = boost::copy_exception(boost::system::system_error(ec));  // NOLINT
    result<int, boost::exception_ptr> m(e);
    BOOST_CHECK(!m);
    BOOST_CHECK(!m.has_value());
    BOOST_CHECK(m.has_error());
    // BOOST_CHECK(!m.has_exception());
    BOOST_CHECK_THROW(m.value(), boost::system::system_error);
    BOOST_CHECK(m.error() == e);
  }
#endif
#ifndef TESTING_WG21_EXPERIMENTAL_RESULT
  {  // custom error type
    struct Foo
    {
    };
    result<int, Foo> m(in_place_type<Foo>);
    BOOST_CHECK(!m);
    BOOST_CHECK(!m.has_value());
    BOOST_CHECK(m.has_error());
    // BOOST_CHECK(!m.has_exception());
    // BOOST_CHECK_NO_THROW(m.value());
    // BOOST_CHECK_NO_THROW(m.error());
  }
  if(false)  // NOLINT
  {          // void, void is permitted, but is not constructible
    result<void, void> *m = nullptr;
    m->value();
    m->error();
  }
#endif

  {
    // Deliberately define non-trivial operations
    struct udt
    {
      int _v{0};
      udt() = default;
      udt(udt &&o) noexcept : _v(o._v) {}
      udt(const udt &o)  // NOLINT
      : _v(o._v)
      {
      }
      udt &operator=(udt &&o) noexcept
      {
        _v = o._v;
        return *this;
      }
      udt &operator=(const udt &o)  // NOLINT
      {
        _v = o._v;
        return *this;
      }
      ~udt() { _v = 0; }
    };
    // No default construction, no copy nor move
    struct udt2
    {
      udt2() = delete;
      udt2(udt2 &&) = delete;
      udt2(const udt2 &) = delete;
      udt2 &operator=(udt2 &&) = delete;
      udt2 &operator=(const udt2 &) = delete;
      explicit udt2(int /*unused*/) {}
      ~udt2() = default;
    };
    // Can only be constructed via multiple args
    struct udt3
    {
      udt3() = delete;
      udt3(udt3 &&) = delete;
      udt3(const udt3 &) = delete;
      udt3 &operator=(udt3 &&) = delete;
      udt3 &operator=(const udt3 &) = delete;
      explicit udt3(int /*unused*/, const char * /*unused*/, std::nullptr_t /*unused*/) {}
      ~udt3() = default;
    };


    result<int> a(5);
    result<int> b(make_error_code(boost::system::errc::invalid_argument));
    std::cout << sizeof(a) << std::endl;  // 32 bytes
    if(false)                             // NOLINT
    {
      b.assume_value();
      a.assume_error();
    }
#ifndef BOOST_NO_EXCEPTIONS
    try
    {
      b.value();
      std::cerr << "fail" << std::endl;
      std::terminate();
    }
    catch(const boost::system::system_error & /*unused*/)
    {
    }
#endif
    static_assert(!std::is_default_constructible<decltype(a)>::value, "");
    static_assert(!std::is_nothrow_default_constructible<decltype(a)>::value, "");
    static_assert(std::is_copy_constructible<decltype(a)>::value, "");
// Quality of implementation of std::optional is poor :(
#ifndef TESTING_WG21_EXPERIMENTAL_RESULT
    static_assert(std::is_trivially_copy_constructible<decltype(a)>::value, "");
    static_assert(std::is_nothrow_copy_constructible<decltype(a)>::value, "");
    static_assert(std::is_copy_assignable<decltype(a)>::value, "");
    static_assert(std::is_trivially_copy_assignable<decltype(a)>::value, "");
    static_assert(std::is_nothrow_copy_assignable<decltype(a)>::value, "");
#endif
    static_assert(std::is_trivially_destructible<decltype(a)>::value, "");
    static_assert(std::is_nothrow_destructible<decltype(a)>::value, "");

    // Test void compiles
    result<void> c(in_place_type<void>);
    result<void> c2(c);
    (void) c2;

    // Test a standard udt compiles
    result<udt> d(in_place_type<udt>);
    result<udt> d2(d);
    static_assert(!std::is_default_constructible<decltype(d)>::value, "");
    static_assert(!std::is_nothrow_default_constructible<decltype(d)>::value, "");
    static_assert(std::is_copy_constructible<decltype(d)>::value, "");
    static_assert(!std::is_trivially_copy_constructible<decltype(d)>::value, "");
    static_assert(!std::is_nothrow_copy_constructible<decltype(d)>::value, "");
    static_assert(std::is_copy_assignable<decltype(d)>::value, "");
    static_assert(!std::is_trivially_copy_assignable<decltype(d)>::value, "");
    static_assert(!std::is_nothrow_copy_assignable<decltype(d)>::value, "");
    static_assert(std::is_move_assignable<decltype(d)>::value, "");
    static_assert(!std::is_trivially_move_assignable<decltype(d)>::value, "");
    static_assert(std::is_nothrow_move_assignable<decltype(d)>::value, "");
    static_assert(!std::is_trivially_destructible<decltype(d)>::value, "");
    static_assert(std::is_nothrow_destructible<decltype(d)>::value, "");

    // Test a highly pathological udt compiles
    result<udt2> e(in_place_type<udt2>, 5);
    // result<udt2> e2(e);
    static_assert(!std::is_default_constructible<decltype(e)>::value, "");
    static_assert(!std::is_nothrow_default_constructible<decltype(e)>::value, "");
    static_assert(!std::is_copy_constructible<decltype(e)>::value, "");
    static_assert(!std::is_trivially_copy_constructible<decltype(e)>::value, "");
    static_assert(!std::is_nothrow_copy_constructible<decltype(e)>::value, "");
    static_assert(!std::is_copy_assignable<decltype(e)>::value, "");
    static_assert(!std::is_trivially_copy_assignable<decltype(e)>::value, "");
    static_assert(!std::is_nothrow_copy_assignable<decltype(e)>::value, "");
    static_assert(!std::is_move_assignable<decltype(e)>::value, "");
    static_assert(!std::is_trivially_move_assignable<decltype(e)>::value, "");
    static_assert(!std::is_nothrow_move_assignable<decltype(e)>::value, "");

    // Test a udt which can only be constructed in place compiles
    result<udt3> g(in_place_type<udt3>, 5, static_cast<const char *>("niall"), nullptr);
    // Does converting inplace construction also work?
    result<udt3> h(5, static_cast<const char *>("niall"), nullptr);
    result<udt3> i(ENOMEM, boost::system::generic_category());
    BOOST_CHECK(h.has_value());
    BOOST_CHECK(i.has_error());
  }

  // Test direct use of error code enum works
  {
    constexpr result<int, boost::system::errc::errc_t> a(5), b(boost::system::errc::invalid_argument);
    static_assert(a.value() == 5, "a is not 5");
    static_assert(b.error() == boost::system::errc::invalid_argument, "b is not errored");
    BOOST_CHECK_THROW(b.value(), boost::system::system_error);
  }

#ifndef TESTING_WG21_EXPERIMENTAL_RESULT
#ifndef BOOST_NO_EXCEPTIONS
  // Test payload facility
  {
    const char *niall = "niall";
    result<int, payload> b{boost::system::errc::invalid_argument, niall};
    try
    {
      b.value();
      BOOST_CHECK(false);
    }
    catch(const payload_exception &e)
    {
      BOOST_CHECK(!strcmp(e.what(), niall));
    }
    catch(...)
    {
      BOOST_CHECK(false);
    }
  }
#endif
#endif
}