#include "icon_view_delegate.h"

#include <QGraphicsDropShadowEffect>
#include <QGraphicsScene>
#include <QGraphicsPixmapItem>
#include <QPainter>
#include <QDebug>


namespace LtsDataView
{
static constexpr int s_shadowRadius = 22;

void IconViewDelegate::setDisplayWidgetCreator(const std::function<AbstractDisplayWidget*()> &customDisplayWidgetCreator)
{
  m_customDisplayWidgetCreator = customDisplayWidgetCreator;

  QScopedPointer<AbstractDisplayWidget> dw(m_customDisplayWidgetCreator());
  if (!dw)
  {
    qWarning() << "IconViewDelegate::setDisplayWidgetCreator: delegate is not a base of AbstractDisplayWidget!";
    Q_ASSERT(false);
    return;
  }

  m_displayWidgetSize = dw->size() + QSize(s_shadowRadius * 2, s_shadowRadius * 2);
}


QSize IconViewDelegate::sizeHint(const QStyleOptionViewItem &, const QModelIndex &) const
{
  return m_displayWidgetSize;
}

void IconViewDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
  QScopedPointer<AbstractDisplayWidget> dw(m_customDisplayWidgetCreator());

  if (!dw)
  {
    qWarning() << "IconViewDelegate::paint: delegate is not a base of AbstractDisplayWidget!";
    Q_ASSERT(false);
    return;
  }

  if (!dw->init(index))
  {
    qWarning() << "IconViewDelegate::paint: delegate could not create ui";
    return;
  }

  const auto dpr = dw->devicePixelRatioF();
  QPixmap p(dw->size() * dpr);
  p.setDevicePixelRatio(dpr);
  QPainter myPainter(&p);
  dw->render(&myPainter);
  myPainter.end();

  // drop shadow
  QGraphicsDropShadowEffect *shadowEffect = new QGraphicsDropShadowEffect();
  shadowEffect->setBlurRadius(s_shadowRadius);
  shadowEffect->setOffset(0, 0); // center (shadow on all sides)

  if (option.state & QStyle::State_Selected)
    shadowEffect->setColor(dw->palette().light().color());
  else
    shadowEffect->setColor(dw->palette().shadow().color());

  // draw pixmap & shadow
  QGraphicsPixmapItem *item = new QGraphicsPixmapItem(p);
  item->setGraphicsEffect(shadowEffect);

  // TODO: avoid creating a QGraphicsScene by using QGraphicsItem::paint()
  QGraphicsScene scene;
  scene.addItem(item);
  scene.render(painter, option.rect, QRectF(-s_shadowRadius, -s_shadowRadius, option.rect.width(), option.rect.height()));
}
} // namespace LtsDataView