/*
This file is part of Telegram Desktop,
the official desktop version of Telegram messaging app, see https://telegram.org

Telegram Desktop is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

It 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 General Public License for more details.

In addition, as a special exception, the copyright holders give permission
to link the code of portions of this program with the OpenSSL library.

Full license: https://github.com/telegramdesktop/tdesktop/blob/master/LICENSE
Copyright (c) 2014-2017 John Preston, https://desktop.telegram.org
*/
#pragma once

namespace Ui {

class FocusPersister {
public:
	FocusPersister(QWidget *parent, QWidget *steal = nullptr)
	: _weak(GrabFocused(parent)) {
		if (steal) {
			steal->setFocus();
		}
	}

	~FocusPersister() {
		if (auto strong = _weak.data()) {
			if (auto window = strong->window()) {
				if (window->focusWidget() != strong) {
					strong->setFocus();
				}
			}
		}
	}

private:
	static QWidget *GrabFocused(QWidget *parent) {
		if (auto window = parent ? parent->window() : nullptr) {
			return window->focusWidget();
		}
		return nullptr;
	}
	QPointer<QWidget> _weak;

};

} // namespace Ui