#include "QtFlowLayout.h"

QtFlowLayout::QtFlowLayout(QWidget *parent, int margin, int hSpacing, int vSpacing)
    : QLayout(parent), m_hSpace(hSpacing), m_vSpace(vSpacing)
{
    setContentsMargins(margin, margin, margin, margin);
}

QtFlowLayout::QtFlowLayout(int margin, int hSpacing, int vSpacing)
    : m_hSpace(hSpacing), m_vSpace(vSpacing)
{
    setContentsMargins(margin, margin, margin, margin);
}

QtFlowLayout::~QtFlowLayout()
{
    QLayoutItem *item;
    while ((item = takeAt(0)))
        delete item;
}

void QtFlowLayout::addItem(QLayoutItem *item)
{
    itemList.append(item);
}

int QtFlowLayout::horizontalSpacing() const
{
    if (m_hSpace >= 0) {
        return m_hSpace;
    } else {
        return smartSpacing(QStyle::PM_LayoutHorizontalSpacing);
    }
}

int QtFlowLayout::verticalSpacing() const
{
    if (m_vSpace >= 0) {
        return m_vSpace;
    } else {
        return smartSpacing(QStyle::PM_LayoutVerticalSpacing);
    }
}

int QtFlowLayout::count() const
{
    return itemList.size();
}

QLayoutItem *QtFlowLayout::itemAt(int index) const
{
    return itemList.value(index);
}

QLayoutItem *QtFlowLayout::takeAt(int index)
{
    if (index >= 0 && index < itemList.size())
        return itemList.takeAt(index);
    else
        return 0;
}

Qt::Orientations QtFlowLayout::expandingDirections() const
{
    return Qt::Orientations();
}

bool QtFlowLayout::hasHeightForWidth() const
{
    return true;
}

int QtFlowLayout::heightForWidth(int width) const
{
    int height = doLayout(QRect(0, 0, width, 0), true);
    return height;
}

void QtFlowLayout::setGeometry(const QRect &rect)
{
    QLayout::setGeometry(rect);
    doLayout(rect, false);
}

QSize QtFlowLayout::sizeHint() const
{
    return minimumSize();
}

QSize QtFlowLayout::minimumSize() const
{
    QSize size;
    QLayoutItem *item;
    foreach (item, itemList)
        size = size.expandedTo(item->minimumSize());

    auto m = this->contentsMargins();
    size += QSize(m.left() + m.right(), m.top() + m.bottom());
    return size;
}


int QtFlowLayout::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;

  QLayoutItem *item;
  foreach (item, itemList) {
    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;
}

int QtFlowLayout::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, 0, pw);
    } else {
        return static_cast<QLayout *>(parent)->spacing();
    }
}
