/****************************************************************************
**
** Copyright (C) 2015 The Qt Company Ltd.
** Contact: http://www.qt.io/licensing/
**
** This file is part of the Qt Quick Controls module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL3$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see http://www.qt.io/terms-conditions. For further
** information use the contact form at http://www.qt.io/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 3 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPLv3 included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 3 requirements
** will be met: https://www.gnu.org/licenses/lgpl.html.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 2.0 or later 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 2.0 requirements will be
** met: http://www.gnu.org/licenses/gpl-2.0.html.
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include "qquickswitch_p.h"
#include "qquickcheckable_p_p.h"

#include <QtQuick/private/qquickwindow_p.h>

QT_BEGIN_NAMESPACE

/*!
    \qmltype Switch
    \inherits Checkable
    \instantiates QQuickSwitch
    \inqmlmodule QtQuick.Controls
    \ingroup buttons
    \brief A switch control.

    Switch is an option button that can be dragged or toggled on (checked) or
    off (unchecked). Switches are typically used to select between two states.

    \table
    \row \li \image qtquickcontrols2-switch-normal.png
         \li A switch in its normal state.
    \row \li \image qtquickcontrols2-switch-checked.png
         \li A switch that is checked.
    \row \li \image qtquickcontrols2-switch-focused.png
         \li A switch that has active focus.
    \row \li \image qtquickcontrols2-switch-disabled.png
         \li A switch that is disabled.
    \endtable

    \code
    ColumnLayout {
        Switch {
            text: qsTr("Wi-Fi")
        }
        Switch {
            text: qsTr("Bluetooth")
        }
    }
    \endcode

    \sa {Customizing Switch}
*/

class QQuickSwitchPrivate : public QQuickCheckablePrivate
{
    Q_DECLARE_PUBLIC(QQuickSwitch)

public:
    QQuickSwitchPrivate() : position(0) { }

    void updatePosition();

    qreal position;
    QPoint pressPoint;
};

void QQuickSwitchPrivate::updatePosition()
{
    Q_Q(QQuickSwitch);
    q->setPosition(checked ? 1.0 : 0.0);
}

QQuickSwitch::QQuickSwitch(QQuickItem *parent) :
    QQuickCheckable(*(new QQuickSwitchPrivate), parent)
{
    setFiltersChildMouseEvents(true);
    QObjectPrivate::connect(this, &QQuickCheckable::checkedChanged, d_func(), &QQuickSwitchPrivate::updatePosition);
}

/*!
    \qmlproperty real QtQuickControls2::Switch::position

    This property holds the logical position of the thumb indicator.

    The position is defined as a percentage of the control's size, scaled to
    \c 0.0 - \c 1.0. The position can be used for example to determine whether
    the thumb has been dragged past the halfway. For visualizing a thumb
    indicator, the right-to-left aware \l visualPosition should be used instead.

    \sa visualPosition
*/
qreal QQuickSwitch::position() const
{
    Q_D(const QQuickSwitch);
    return d->position;
}

void QQuickSwitch::setPosition(qreal position)
{
    Q_D(QQuickSwitch);
    position = qBound(0.0, position, 1.0);
    if (d->position != position) {
        d->position = position;
        emit positionChanged();
        emit visualPositionChanged();
    }
}

/*!
    \qmlproperty real QtQuickControls2::Switch::visualPosition

    This property holds the visual position of the thumb indicator.

    The position is defined as a percentage of the control's size, scaled to
    \c 0.0 - \c 1.0. When the control is \l mirrored, the value is equal to
    \c {1.0 - position}. This makes the value suitable for visualizing the
    thumb indicator taking right-to-left support into account. In order to
    for example determine whether the thumb has been dragged past the halfway,
    the logical \l position should be used instead.

    \sa position
*/
qreal QQuickSwitch::visualPosition() const
{
    Q_D(const QQuickSwitch);
    if (isMirrored())
        return 1.0 - d->position;
    return d->position;
}

void QQuickSwitch::mirrorChange()
{
    QQuickCheckable::mirrorChange();
    emit visualPositionChanged();
}

bool QQuickSwitch::childMouseEventFilter(QQuickItem *child, QEvent *event)
{
    if (child == indicator()) {
        switch (event->type()) {
        case QEvent::MouseButtonPress:
            return handleMousePressEvent(child, static_cast<QMouseEvent *>(event));
        case QEvent::MouseMove:
            return handleMouseMoveEvent(child, static_cast<QMouseEvent *>(event));
        case QEvent::MouseButtonRelease:
            return handleMouseReleaseEvent(child, static_cast<QMouseEvent *>(event));
        case QEvent::UngrabMouse:
            return handleMouseUngrabEvent(child);
        default:
            return false;
        }
    }
    return false;
}

bool QQuickSwitch::handleMousePressEvent(QQuickItem *child, QMouseEvent *event)
{
    Q_D(QQuickSwitch);
    Q_UNUSED(child);
    d->pressPoint = event->pos();
    setPressed(true);
    event->accept();
    return true;
}

bool QQuickSwitch::handleMouseMoveEvent(QQuickItem *child, QMouseEvent *event)
{
    Q_D(QQuickSwitch);
    if (!child->keepMouseGrab())
        child->setKeepMouseGrab(QQuickWindowPrivate::dragOverThreshold(event->pos().x() - d->pressPoint.x(), Qt::XAxis, event));
    if (child->keepMouseGrab()) {
        setPosition(positionAt(event->pos()));
        event->accept();
    }
    return true;
}

bool QQuickSwitch::handleMouseReleaseEvent(QQuickItem *child, QMouseEvent *event)
{
    Q_D(QQuickSwitch);
    d->pressPoint = QPoint();
    setPressed(false);
    if (child->keepMouseGrab()) {
        setChecked(position() > 0.5);
        setPosition(isChecked() ? 1.0 : 0.0);
        child->setKeepMouseGrab(false);
    } else {
        emit clicked();
        toggle();
    }
    event->accept();
    return true;
}

bool QQuickSwitch::handleMouseUngrabEvent(QQuickItem *child)
{
    Q_D(QQuickSwitch);
    Q_UNUSED(child);
    d->pressPoint = QPoint();
    setChecked(position() > 0.5);
    setPosition(isChecked() ? 1.0 : 0.0);
    setPressed(false);
    return true;
}

qreal QQuickSwitch::positionAt(const QPoint &point) const
{
    qreal pos = point.x() / indicator()->width();
    if (isMirrored())
        return 1.0 - pos;
    return pos;
}

QT_END_NAMESPACE