/****************************************************************************
**
** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the demonstration applications of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** GNU Lesser General Public License Usage
** This file may be used under the terms of the GNU Lesser General Public
** License version 2.1 as published by the Free Software Foundation and
** appearing in the file LICENSE.LGPL included in the packaging of this
** file. Please review the following information to ensure the GNU Lesser
** General Public License version 2.1 requirements will be met:
** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain additional
** rights. These rights are described in the Nokia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU General
** Public License version 3.0 as published by the Free Software Foundation
** and appearing in the file LICENSE.GPL included in the packaging of this
** file. Please review the following information to ensure the GNU General
** Public License version 3.0 requirements will be met:
** http://www.gnu.org/copyleft/gpl.html.
**
** Other Usage
** Alternatively, this file may be used in accordance with the terms and
** conditions contained in a signed written agreement between you and Nokia.
**
**
**
**
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include "autosaver.h"

#include <QtCore/QDir>
#include <QtCore/QCoreApplication>
#include <QtCore/QMetaObject>
#include <QtDebug>

#define AUTOSAVE_IN  1000 * 3  // seconds
#define MAXWAIT      1000 * 15 // seconds

AutoSaver::AutoSaver(QObject *parent) : QObject(parent)
{
    Q_ASSERT(parent);
}

AutoSaver::~AutoSaver()
{
    if (m_timer.isActive())
        qWarning() << "AutoSaver: still active when destroyed, changes not saved.";
}

void AutoSaver::changeOccurred()
{
    if (m_firstChange.isNull())
        m_firstChange.start();

    if (m_firstChange.elapsed() > MAXWAIT) {
        saveIfNeccessary();
    } else {
        m_timer.start(AUTOSAVE_IN, this);
    }
}

void AutoSaver::timerEvent(QTimerEvent *event)
{
    if (event->timerId() == m_timer.timerId()) {
        saveIfNeccessary();
    } else {
        QObject::timerEvent(event);
    }
}

void AutoSaver::saveIfNeccessary()
{
    if (!m_timer.isActive())
        return;
    m_timer.stop();
    m_firstChange = QTime();
    if (!QMetaObject::invokeMethod(parent(), "save", Qt::DirectConnection)) {
        qWarning() << "AutoSaver: error invoking slot save() on parent";
    }
}