#pragma once
// Support for the generated platform skeleton (platform_stub.py, docs/PORT-PLAN.md 2A). A function whose
// body still starts with MT_PLATFORM_STUB() has no platform implementation yet; it does nothing and
// returns a default value. With MT_PLATFORM_STUB_TRACE set in the environment, the first call of each
// one is reported on stderr.

#include <cstdlib>
#include <type_traits>

void mt_platform_stub_called(const char* function, bool* reported);

#define MT_PLATFORM_STUB()                                    \
	do                                                        \
	{                                                         \
		static bool mt_platform_stub_reported = false;        \
		mt_platform_stub_called(__func__, &mt_platform_stub_reported); \
	} while (0)

template <class T>
T mt_platform_stub_return()
{
	if constexpr (std::is_reference_v<T>)
	{
		using U = std::remove_cv_t<std::remove_reference_t<T>>;
		if constexpr (std::is_default_constructible_v<U> && !std::is_abstract_v<U>)
		{
			static U value{};
			return static_cast<T>(value);
		}
		else
		{
			// Never constructed: a caller that uses the referent of an unimplemented platform function
			// is a bug the stub cannot hide.
			alignas(U) static unsigned char storage[sizeof(U)];
			return static_cast<T>(*reinterpret_cast<U*>(storage));
		}
	}
	else if constexpr (std::is_same_v<T, const char*>)
	{
		// Callers strcmp/strlen/format the names these return (CPythonPlayer::GetName in RecvGuild); a
		// null string would crash where the real function never returns one.
		return "";
	}
	else if constexpr (std::is_default_constructible_v<T>)
	{
		return T{};
	}
	else
	{
		std::abort();
	}
}