#include "viewmarkingscrollbar.h"
#include "modelutils.h"
#include <QStyle>
#include <QStyleOptionSlider>
#include <QPainter>

using namespace MOShared;

ViewMarkingScrollBar::ViewMarkingScrollBar(QTreeView* view, int role)
  : QScrollBar(view)
  , m_view(view)
  , m_role(role)
{
  // not implemented for horizontal sliders
  Q_ASSERT(this->orientation() == Qt::Vertical);
}

void ViewMarkingScrollBar::paintEvent(QPaintEvent* event)
{
  if (m_view->model() == nullptr) {
    return;
  }
  QScrollBar::paintEvent(event);

  QStyleOptionSlider styleOption;
  initStyleOption(&styleOption);

  QPainter painter(this);

  QRect handleRect = style()->subControlRect(QStyle::CC_ScrollBar, &styleOption, QStyle::SC_ScrollBarSlider, this);
  QRect innerRect = style()->subControlRect(QStyle::CC_ScrollBar, &styleOption, QStyle::SC_ScrollBarGroove, this);

  auto indices = visibleIndex(m_view, 0);

  painter.translate(innerRect.topLeft() + QPoint(0, 3));
  qreal scale = static_cast<qreal>(innerRect.height() - 3) / static_cast<qreal>(indices.size());

  for (int i = 0; i < indices.size(); ++i) {
    QVariant data = indices[i].data(m_role);
    QColor color;

    if (data.canConvert<QColor>()) {
      color = data.value<QColor>();
    }

    auto childrenColor = MOShared::childrenColor(indices[i], m_view, m_role);
    if (childrenColor.isValid()) {
      color = childrenColor;
    }

    if (color.isValid()) {
      painter.setPen(color);
      painter.setBrush(color);
      painter.drawRect(QRect(2, i * scale - 2, handleRect.width() - 5, 3));
    }
  }
}