/*
 * Copyright (c) 2010-2022 Belledonne Communications SARL.
 *
 * This file is part of Liblinphone
 * (see https://gitlab.linphone.org/BC/public/liblinphone).
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */

// =============================================================================
// Tools to get/set private data of Cpp objects.
//
// See: https://bloglitb.blogspot.fr/2011/12/access-to-private-members-safer.html
// See: http://en.cppreference.com/w/cpp/language/adl
// See: http://en.cppreference.com/w/cpp/language/friend
// =============================================================================

#ifndef _L_PRIVATE_ACCESS_H_
#define _L_PRIVATE_ACCESS_H_

#include <type_traits>

#include "linphone/utils/utils.h"

#define L_INTERNAL_STRUCT_L_ATTR_GET(CLASS, ATTR_NAME) AttrGet##_##CLASS##_##ATTR_NAME
#define L_INTERNAL_STRUCT_ATTR_SPY(ATTR_NAME) AttrSpy##_##ATTR_NAME

#define L_ENABLE_ATTR_ACCESS(CLASS, ATTR_TYPE, ATTR_NAME)                                                              \
	template <typename AttrSpy, ATTR_TYPE CLASS::*Attr>                                                                \
	struct L_INTERNAL_STRUCT_L_ATTR_GET(CLASS, ATTR_NAME) {                                                            \
		friend constexpr ATTR_TYPE CLASS::*get(AttrSpy *) {                                                            \
			return Attr;                                                                                               \
		}                                                                                                              \
	};                                                                                                                 \
	template <typename T>                                                                                              \
	struct L_INTERNAL_STRUCT_ATTR_SPY(ATTR_NAME);                                                                      \
	template <>                                                                                                        \
	struct L_INTERNAL_STRUCT_ATTR_SPY(ATTR_NAME)<CLASS> {                                                              \
		friend constexpr ATTR_TYPE CLASS::*get(L_INTERNAL_STRUCT_ATTR_SPY(ATTR_NAME) < CLASS > *);                     \
	};                                                                                                                 \
	template struct L_INTERNAL_STRUCT_L_ATTR_GET(CLASS, ATTR_NAME)<L_INTERNAL_STRUCT_ATTR_SPY(ATTR_NAME) < CLASS>,     \
	    &CLASS::ATTR_NAME > ;

// Warning: Allow to modify const data.
// Returns a ref to `ATTR_NAME`.
#define L_ATTR_GET(OBJECT, ATTR_NAME)                                                                                  \
	(const_cast<std::remove_pointer<std::decay<decltype(OBJECT)>::type>::type *>(                                      \
	     LinphonePrivate::Utils::getPtr(OBJECT)))                                                                      \
	        ->*get(static_cast<L_INTERNAL_STRUCT_ATTR_SPY(ATTR_NAME) <                                                 \
	                           std::remove_pointer<std::decay<decltype(OBJECT)>::type>::type> * > (nullptr))

#endif // ifndef _L_PRIVATE_ACCESS_H_
