/****************************************************************************
**
** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
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** This file is part of the demonstration applications of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL21$
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** accordance with the commercial license agreement provided with the
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** use the contact form at http://qt.digia.com/contact-us.
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** Alternatively, this file may be used under the terms of the GNU Lesser
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** LICENSE.LGPLv3 included in the packaging of this file. Please review the
** following information to ensure the GNU Lesser General Public License
** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
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**
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** rights. These rights are described in the Digia Qt LGPL Exception
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****************************************************************************/

#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";
    }
}

