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#include <QtWidgets>
#include <QtGlobal>

#include "FlowLayout.h"

//-----------------------------------------------------------------------------
// Function: FlowLayout::FlowLayout()
//-----------------------------------------------------------------------------
FlowLayout::FlowLayout(QWidget *parent, int margin, int hSpacing, int vSpacing):
QLayout(parent),
m_hSpace_(hSpacing),
m_vSpace_(vSpacing)
{
    setContentsMargins(margin, margin, margin, margin);
}

//-----------------------------------------------------------------------------
// Function: FlowLayout::FlowLayout()
//-----------------------------------------------------------------------------
FlowLayout::FlowLayout(int margin, int hSpacing, int vSpacing):
m_hSpace_(hSpacing),
m_vSpace_(vSpacing)
{
    setContentsMargins(margin, margin, margin, margin);
}

//-----------------------------------------------------------------------------
// Function: FlowLayout::~FlowLayout()
//-----------------------------------------------------------------------------
FlowLayout::~FlowLayout()
{
    QLayoutItem *item;
    while ((item = takeAt(0)))
    {
        delete item;
    }
}

//-----------------------------------------------------------------------------
// Function: FlowLayout::addItem()
//-----------------------------------------------------------------------------
void FlowLayout::addItem(QLayoutItem *item)
{
    itemList_.append(item);
}

//-----------------------------------------------------------------------------
// Function: FlowLayout::horizontalSpacing()
//-----------------------------------------------------------------------------
int FlowLayout::horizontalSpacing() const
{
    if (m_hSpace_ >= 0)
    {
        return m_hSpace_;
    }
    else
    {
        return smartSpacing(QStyle::PM_LayoutHorizontalSpacing);
    }
}

//-----------------------------------------------------------------------------
// Function: FlowLayout::verticalSpacing()
//-----------------------------------------------------------------------------
int FlowLayout::verticalSpacing() const
{
    if (m_vSpace_ >= 0)
    {
        return m_vSpace_;
    }
    else
    {
        return smartSpacing(QStyle::PM_LayoutVerticalSpacing);
    }
}

//-----------------------------------------------------------------------------
// Function: FlowLayout::count()
//-----------------------------------------------------------------------------
int FlowLayout::count() const
{
    return itemList_.size();
}

//-----------------------------------------------------------------------------
// Function: FlowLayout::itemAt()
//-----------------------------------------------------------------------------
QLayoutItem *FlowLayout::itemAt(int index) const
{
    return itemList_.value(index);
}

//-----------------------------------------------------------------------------
// Function: FlowLayout::takeAt()
//-----------------------------------------------------------------------------
QLayoutItem *FlowLayout::takeAt(int index)
{
    if (index >= 0 && index < itemList_.size())
    {
        return itemList_.takeAt(index);
    }

    return nullptr;
}

//-----------------------------------------------------------------------------
// Function: FlowLayout::expandingDirections()
//-----------------------------------------------------------------------------
Qt::Orientations FlowLayout::expandingDirections() const
{
    return Qt::Orientations();
}

//-----------------------------------------------------------------------------
// Function: FlowLayout::hasHeightForWidth()
//-----------------------------------------------------------------------------
bool FlowLayout::hasHeightForWidth() const
{
    return true;
}

//-----------------------------------------------------------------------------
// Function: FlowLayout::heightForWidth()
//-----------------------------------------------------------------------------
int FlowLayout::heightForWidth(int width) const
{
    int height = doLayout(QRect(0, 0, width, 0), true);
    return height;
}

//-----------------------------------------------------------------------------
// Function: FlowLayout::setGeometry()
//-----------------------------------------------------------------------------
void FlowLayout::setGeometry(const QRect &rect)
{
    QLayout::setGeometry(rect);
    doLayout(rect, false);
}

//-----------------------------------------------------------------------------
// Function: FlowLayout::sizeHint()
//-----------------------------------------------------------------------------
QSize FlowLayout::sizeHint() const
{
    return minimumSize();
}

//-----------------------------------------------------------------------------
// Function: FlowLayout::minimumSize()
//-----------------------------------------------------------------------------
QSize FlowLayout::minimumSize() const
{
    QSize size;
    for (const QLayoutItem *item : itemList_)
    {
        size = size.expandedTo(item->minimumSize());
    }

    const QMargins margins = contentsMargins();
    size += QSize(margins.left() + margins.right(), margins.top() + margins.bottom());
    return size;
}

//-----------------------------------------------------------------------------
// Function: FlowLayout::doLayout()
//-----------------------------------------------------------------------------
int FlowLayout::doLayout(const QRect &rect, bool testOnly) const
{
    int left, top, right, bottom;
    getContentsMargins(&left, &top, &right, &bottom);
    QRect effectiveRect = rect.adjusted(+left, +top, -right, -bottom);
    int x = effectiveRect.x();
    int y = effectiveRect.y();
    int lineHeight = 0;

    for (QLayoutItem *item : itemList_)
    {
        const QWidget *wid = item->widget();
        int spaceX = horizontalSpacing();
        if (spaceX == -1)
        {
            spaceX = wid->style()->layoutSpacing(QSizePolicy::PushButton, QSizePolicy::PushButton, Qt::Horizontal);
        }
        int spaceY = verticalSpacing();
        if (spaceY == -1)
        {
            spaceY = wid->style()->layoutSpacing(QSizePolicy::PushButton, QSizePolicy::PushButton, Qt::Vertical);
        }

        int nextX = x + item->sizeHint().width() + spaceX;
        if (nextX - spaceX > effectiveRect.right() && lineHeight > 0)
        {
            x = effectiveRect.x();
            y = y + lineHeight + spaceY;
            nextX = x + item->sizeHint().width() + spaceX;
            lineHeight = 0;
        }

        if (!testOnly)
        {
            item->setGeometry(QRect(QPoint(x, y), item->sizeHint()));
        }

        x = nextX;
        lineHeight = qMax(lineHeight, item->sizeHint().height());
    }
    return y + lineHeight - rect.y() + bottom;
}

//-----------------------------------------------------------------------------
// Function: FlowLayout::smartSpacing()
//-----------------------------------------------------------------------------
int FlowLayout::smartSpacing(QStyle::PixelMetric pm) const
{
    QObject *parent = this->parent();
    if (!parent)
    {
        return -1;
    }
    else if (parent->isWidgetType())
    {
        QWidget *pw = static_cast<QWidget *>(parent);
        return pw->style()->pixelMetric(pm, nullptr, pw);
    }
    else
    {
        return static_cast<QLayout *>(parent)->spacing();
    }
}
