/*

 * Copyright (C) 2007 Apple Inc.  All rights reserved.

 * Copyright (C) 2007 Staikos Computing Services Inc. <info@staikos.net>

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 *

 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY

 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR

 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,

 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR

 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY

 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

#include "config.h"

#include "PlatformScrollBar.h"

#include "EventHandler.h"

#include "FrameView.h"

#include "Frame.h"

#include "GraphicsContext.h"

#include "IntRect.h"

#include "PlatformMouseEvent.h"

#include <QApplication>

#include <QDebug>

#include <QPainter>

#include <QStyle>

using namespace std;

namespace WebCore {

const double cInitialTimerDelay = 0.25;

const double cNormalTimerDelay = 0.05;

PlatformScrollbar::PlatformScrollbar(ScrollbarClient* client, ScrollbarOrientation orientation, ScrollbarControlSize size)

    : Scrollbar(client, orientation, size), m_pressedPos(0),

      m_pressedPart(QStyle::SC_None),

      m_hoveredPart(QStyle::SC_None),

      m_scrollTimer(this, &PlatformScrollbar::autoscrollTimerFired)

{

    QStyle *s = QApplication::style();

    m_opt.state = QStyle::State_Active | QStyle::State_Enabled;

    m_opt.sliderValue = m_opt.sliderPosition = 0;

    m_opt.upsideDown = false;

    setEnabled(true);

    if (size != RegularScrollbar)

        m_opt.state |= QStyle::State_Mini;

    if (orientation == HorizontalScrollbar) {

        m_opt.rect.setHeight(horizontalScrollbarHeight(size));

        m_opt.orientation = Qt::Horizontal;

        m_opt.state |= QStyle::State_Horizontal;

    } else {

        m_opt.rect.setWidth(verticalScrollbarWidth(size));

        m_opt.orientation = Qt::Vertical;

        m_opt.state &= ~QStyle::State_Horizontal;

    }

}

PlatformScrollbar::~PlatformScrollbar()

{

    stopTimerIfNeeded();

}

void PlatformScrollbar::updateThumbPosition()

{

    invalidate();

}

void PlatformScrollbar::updateThumbProportion()

{

    invalidate();

}

int PlatformScrollbar::width() const

{

    return m_opt.rect.width();

}

int PlatformScrollbar::height() const

{

    return m_opt.rect.height();

}

void PlatformScrollbar::setRect(const IntRect& rect)

{

    setFrameGeometry(rect);

}

IntRect PlatformScrollbar::frameGeometry() const

{

    return m_opt.rect;

}

void PlatformScrollbar::setFrameGeometry(const IntRect& rect)

{

    m_opt.rect = rect;

}

bool PlatformScrollbar::isEnabled() const

{

    return m_opt.state & QStyle::State_Enabled;

}

void PlatformScrollbar::setEnabled(bool enabled)

{

    if (enabled != isEnabled()) {

        if (enabled) {

            m_opt.state |= QStyle::State_Enabled;

        } else {

            m_opt.state &= ~QStyle::State_Enabled;

        }

        invalidate();

    }

}

void PlatformScrollbar::paint(GraphicsContext* graphicsContext, const IntRect& damageRect)

{

    if (controlSize() != RegularScrollbar) {

        m_opt.state |= QStyle::State_Mini;

    } else {

        m_opt.state &= ~QStyle::State_Mini;

    }

    m_opt.orientation = (orientation() == VerticalScrollbar) ? Qt::Vertical : Qt::Horizontal;

    QStyle *s = QApplication::style();

    if (orientation() == HorizontalScrollbar) {

        m_opt.rect.setHeight(horizontalScrollbarHeight(controlSize()));

        m_opt.state |= QStyle::State_Horizontal;

    } else {

        m_opt.rect.setWidth(verticalScrollbarWidth(controlSize()));

        m_opt.state &= ~QStyle::State_Horizontal;

    }

    if (graphicsContext->paintingDisabled() || !m_opt.rect.isValid())

        return;

    // Don't paint anything if the scrollbar doesn't intersect the damage rect.

    if (!m_opt.rect.intersects(damageRect))

        return;

    QPainter *p = graphicsContext->platformContext();

    m_opt.sliderValue = value();

    m_opt.sliderPosition = value();

    m_opt.pageStep = m_visibleSize;

    m_opt.singleStep = m_lineStep;

    m_opt.minimum = 0;

    m_opt.maximum = qMax(0, m_totalSize - m_visibleSize);

    if (m_pressedPart != QStyle::SC_None) {

        m_opt.activeSubControls = m_pressedPart;

    } else {

        m_opt.activeSubControls = m_hoveredPart;

    }

    const QPoint topLeft = m_opt.rect.topLeft();

    p->translate(topLeft);

    m_opt.rect.moveTo(QPoint(0, 0));

    QApplication::style()->drawComplexControl(QStyle::CC_ScrollBar, &m_opt, p, 0);

    m_opt.rect.moveTo(topLeft);

    p->translate(-topLeft);

}

int PlatformScrollbar::thumbPosition() const

{

    if (isEnabled())

        return (float)m_currentPos * (trackLength() - thumbLength()) / (m_totalSize - m_visibleSize);

    return 0;

}

int PlatformScrollbar::thumbLength() const

{

    IntRect thumb = QApplication::style()->subControlRect(QStyle::CC_ScrollBar, &m_opt, QStyle::SC_ScrollBarSlider, 0);

    return m_orientation == HorizontalScrollbar ? thumb.width() : thumb.height();

}

int PlatformScrollbar::trackLength() const

{

    IntRect track = QApplication::style()->subControlRect(QStyle::CC_ScrollBar, &m_opt, QStyle::SC_ScrollBarGroove, 0);

    return m_orientation == HorizontalScrollbar ? track.width() : track.height();

}

bool PlatformScrollbar::handleMouseMoveEvent(const PlatformMouseEvent& evt)

{

    const QPoint pos = parent()->convertFromContainingWindow(evt.pos());

    //qDebug() << "PlatformScrollbar::handleMouseMoveEvent" << m_opt.rect << pos << endl;

    m_opt.state |= QStyle::State_MouseOver;

    const QPoint ctlPt = m_opt.rect.topLeft();

    m_opt.rect.moveTo(0, 0);

    QStyle::SubControl sc = QApplication::style()->hitTestComplexControl(QStyle::CC_ScrollBar, &m_opt, QPoint(pos) - ctlPt, 0);

    m_opt.rect.moveTo(ctlPt);

    if (sc == m_pressedPart) {

        m_opt.state |= QStyle::State_Sunken;

    } else {

        m_opt.state &= ~QStyle::State_Sunken;

    }

    if (m_pressedPart == QStyle::SC_ScrollBarSlider) {

        // Drag the thumb.

        int thumbPos = thumbPosition();

        int thumbLen = thumbLength();

        int trackLen = trackLength();

        int maxPos = trackLen - thumbLen;

        int delta = 0;

        if (m_orientation == HorizontalScrollbar)

            delta = pos.x() - m_pressedPos;

        else

            delta = pos.y() - m_pressedPos;

        if (delta > 0)

            // The mouse moved down/right.

            delta = min(maxPos - thumbPos, delta);

        else if (delta < 0)

            // The mouse moved up/left.

            delta = max(-thumbPos, delta);

        if (delta != 0) {

            setValue((float)(thumbPos + delta) * (m_totalSize - m_visibleSize) / (trackLen - thumbLen));

            m_pressedPos += thumbPosition() - thumbPos;

        }

        return true;

    }

    if (m_pressedPart != QStyle::SC_None)

        m_pressedPos = m_orientation == HorizontalScrollbar ? pos.x() : pos.y();

    if (sc != m_hoveredPart) {

        if (m_pressedPart != QStyle::SC_None) {

            if (sc == m_pressedPart) {

                // The mouse is moving back over the pressed part.  We

                // need to start up the timer action again.

                startTimerIfNeeded(cNormalTimerDelay);

                invalidate();

            } else if (m_hoveredPart == m_pressedPart) {

                // The mouse is leaving the pressed part.  Kill our timer

                // if needed.

                stopTimerIfNeeded();

                invalidate();

            }

        } else {

            invalidate();

        }

        m_hoveredPart = sc;

    } 

    return true;

}

bool PlatformScrollbar::handleMouseOutEvent(const PlatformMouseEvent& evt)

{

    m_opt.state &= ~QStyle::State_MouseOver;

    m_opt.state &= ~QStyle::State_Sunken;

    invalidate();

    return true;

}

bool PlatformScrollbar::handleMousePressEvent(const PlatformMouseEvent& evt)

{

    const QPoint pos = parent()->convertFromContainingWindow(evt.pos());

    //qDebug() << "PlatformScrollbar::handleMousePressEvent" << m_opt.rect << pos << endl;

    const QPoint ctlPt = m_opt.rect.topLeft();

    m_opt.rect.moveTo(0, 0);

    QStyle::SubControl sc = QApplication::style()->hitTestComplexControl(QStyle::CC_ScrollBar, &m_opt, QPoint(pos) - ctlPt, 0);

    m_opt.rect.moveTo(ctlPt);

    switch (sc) {

        case QStyle::SC_ScrollBarAddLine:

        case QStyle::SC_ScrollBarSubLine:

        case QStyle::SC_ScrollBarSlider:

            m_opt.state |= QStyle::State_Sunken;

        case QStyle::SC_ScrollBarAddPage:

        case QStyle::SC_ScrollBarSubPage:

        case QStyle::SC_ScrollBarGroove:

            m_pressedPart = sc;

            break;

        default:

            m_pressedPart = QStyle::SC_None;

            return false;

    }

    m_pressedPos = m_orientation == HorizontalScrollbar ? pos.x() : pos.y();

    autoscrollPressedPart(cInitialTimerDelay);

    invalidate();

    return true;

}

bool PlatformScrollbar::handleMouseReleaseEvent(const PlatformMouseEvent& evt)

{

    const QPoint pos = parent()->convertFromContainingWindow(evt.pos());

    //qDebug() << "PlatformScrollbar::handleMouseReleaseEvent" << m_opt.rect << pos << endl;

    m_opt.state &= ~QStyle::State_Sunken;

    m_pressedPart = QStyle::SC_None;

    m_pressedPos = 0;

    stopTimerIfNeeded();

    invalidate();

    return true;

}

void PlatformScrollbar::startTimerIfNeeded(double delay)

{

    // Don't do anything for the thumb.

    if (m_pressedPart == QStyle::SC_ScrollBarSlider)

        return;

    // Handle the track.  We halt track scrolling once the thumb is level

    // with us.

    if (m_pressedPart == QStyle::SC_ScrollBarGroove && thumbUnderMouse()) {

        invalidate();

        m_hoveredPart = QStyle::SC_ScrollBarSlider;

        return;

    }

    // We can't scroll if we've hit the beginning or end.

    ScrollDirection dir = pressedPartScrollDirection();

    if (dir == ScrollUp || dir == ScrollLeft) {

        if (m_currentPos == 0)

            return;

    } else {

        if (m_currentPos == m_totalSize - m_visibleSize)

            return;

    }

    m_scrollTimer.startOneShot(delay);

}

void PlatformScrollbar::stopTimerIfNeeded()

{

    if (m_scrollTimer.isActive())

        m_scrollTimer.stop();

}

void PlatformScrollbar::autoscrollPressedPart(double delay)

{

    // Don't do anything for the thumb or if nothing was pressed.

    if (m_pressedPart == QStyle::SC_ScrollBarSlider || m_pressedPart == QStyle::SC_None)

        return;

    // Handle the track.

    if (m_pressedPart == QStyle::SC_ScrollBarGroove && thumbUnderMouse()) {

        invalidate();

        m_hoveredPart = QStyle::SC_ScrollBarSlider;

        return;

    }

    // Handle the arrows and track.

    if (scroll(pressedPartScrollDirection(), pressedPartScrollGranularity()))

        startTimerIfNeeded(delay);

}

void PlatformScrollbar::autoscrollTimerFired(Timer<PlatformScrollbar>*)

{

    autoscrollPressedPart(cNormalTimerDelay);

}

ScrollDirection PlatformScrollbar::pressedPartScrollDirection()

{

    if (m_orientation == HorizontalScrollbar) {

        if (m_pressedPart == QStyle::SC_ScrollBarSubLine || m_pressedPart == QStyle::SC_ScrollBarSubPage)

            return ScrollLeft;

        return ScrollRight;

    } else {

        if (m_pressedPart == QStyle::SC_ScrollBarSubLine || m_pressedPart == QStyle::SC_ScrollBarSubPage)

            return ScrollUp;

        return ScrollDown;

    }

}

ScrollGranularity PlatformScrollbar::pressedPartScrollGranularity()

{

    if (m_pressedPart == QStyle::SC_ScrollBarSubLine || m_pressedPart == QStyle::SC_ScrollBarAddLine)

        return ScrollByLine;

    return ScrollByPage;

}

bool PlatformScrollbar::thumbUnderMouse()

{

    // Construct a rect.

    IntRect thumb = QApplication::style()->subControlRect(QStyle::CC_ScrollBar, &m_opt, QStyle::SC_ScrollBarSlider, 0);

    thumb.move(-m_opt.rect.x(), -m_opt.rect.y());

    int begin = (m_orientation == HorizontalScrollbar) ? thumb.x() : thumb.y();

    int end = (m_orientation == HorizontalScrollbar) ? thumb.right() : thumb.bottom();

    return (begin <= m_pressedPos && m_pressedPos < end);

}

int PlatformScrollbar::horizontalScrollbarHeight(ScrollbarControlSize controlSize)

{

    QStyle *s = QApplication::style();

    QStyleOptionSlider o;

    o.orientation = Qt::Horizontal;

    o.state |= QStyle::State_Horizontal;

    if (controlSize != RegularScrollbar)

        o.state |= QStyle::State_Mini;

    return s->pixelMetric(QStyle::PM_ScrollBarExtent, &o, 0);

}

int PlatformScrollbar::verticalScrollbarWidth(ScrollbarControlSize controlSize)

{

    QStyle *s = QApplication::style();

    QStyleOptionSlider o;

    o.orientation = Qt::Vertical;

    o.state &= ~QStyle::State_Horizontal;

    if (controlSize != RegularScrollbar)

        o.state |= QStyle::State_Mini;

    return s->pixelMetric(QStyle::PM_ScrollBarExtent, &o, 0);

}

IntRect PlatformScrollbar::windowClipRect() const

{

    IntRect clipRect = m_opt.rect;

    if (m_client)

        clipRect.intersect(m_client->windowClipRect());

    return clipRect;

}

}

// vim: ts=4 sw=4 et