namespace Luax
{

	///
	/// 注册工厂，注册class table，以type name为键设置在名称空间上。在注册阶段不会设置元表，等到New方法调用的时候才会。
	/// 
	template<typename T>
	void LuaxState::RegisterFactory()
	{
		lua_State* L = mState;
		LuaxState& state = *this;

		int top = lua_gettop(L); // namespace table
		assert(lua_istable(L, top));

		// class table
		lua_newtable(L);
		LuaxClass<T>::RegisterLuaxClass(state);
		LuaxClass<T>::RegisterLuaxFactoryClass(state);
		T::RegisterLuaxClass(state);

		// 检测T里面是否没有注册必须的方法
	#define _assertmethod(I, NAME) \
		GetField(I, NAME); \
		assert(IsType(-1, LUA_TFUNCTION)); \
		Pop();

		_assertmethod(-1, "New");

	#undef _assertmethod

		// .Extend()
		lua_pushvalue(state, -1); // class table
		lua_pushcclosure(state, LuaxClass<T>::l_ExtendFactory, 1);
		lua_setfield(state, -2, "Extend");

		// class["__index"] = class
		lua_pushvalue(state, -1); // class table
		lua_setfield(state, -2, "__index");

		LuaxClass<T>::SetLuaxClassTableRef(state, -1);

		cc8* type = T::GetLuaxFactoryName();
		SetField(top, type);

		// reset top
		lua_settop(L, top);

		// 后处理
		T::RegisterLuaxPostprocess(state);
	}

	///
	/// Singleton
	///
	template<typename T>
	void LuaxState::RegisterSingleton()
	{
		lua_State* L = mState;
		LuaxState& state = *this;

		int top = lua_gettop(L); // namespace table
		assert(lua_istable(L, top));

		// class table.
		lua_newtable(L);
		LuaxClass<T>::RegisterLuaxClass(state);
		LuaxClass<T>::RegisterLuaxFactoryClass(state);
		T::RegisterLuaxClass(state);

		LuaxClass<T>::SetLuaxClassTableRef(state, -1);

		// class table的__index和__newindex指向自身
		lua_pushvalue(state, -1);
		lua_setfield(state, -2, "__index");
		lua_pushvalue(state, -1);
		lua_setfield(state, -2, "__newindex");

		cc8* type = T::GetLuaxSingletonName();
		SetField(top, type);

		// reset top
		lua_settop(L, top);

		// 后处理
		T::RegisterLuaxPostprocess(state);
	}

	template<typename T>
	void LuaxState::SetField(int idx, cc8* key, T value)
	{
		if (IsTableOrUserdata(idx))
		{
			idx = AbsIndex(idx);
			this->Push(value);
			lua_setfield(mState, idx, key);
		}
	}

	template<typename T>
	T LuaxState::GetField(int idx, cc8* key, T value)
	{
		GetField(idx, key);
		T result = GetValue < T >(-1, value);
		this->Pop();

		return result;
	}

	template<typename T>
	T LuaxState::GetField(int idx, int key, T value)
	{
		GetField(idx, key);
		T result = GetValue < T >(-1, value);
		Pop();

		return result;
	}

	template<typename T>
	T* LuaxState::GetLuaUserdata(int idx)
	{
		void* p = nullptr;

		if (IsType(idx, LUA_TUSERDATA))
		{
			p = *(void**)lua_touserdata(mState, idx);
		}

		return static_cast<T*>(p);
	}

}