#include "DragDropHelper.h"
#include "Visualization/VisualizationDragWidget.h"
#include "SqpApplication.h"

#include <QDragMoveEvent>
#include <QDragEnterEvent>
#include <QScrollBar>
#include <QScrollArea>
#include <QVBoxLayout>
#include <QTimer>
#include <QDir>

const QString DragDropHelper::MIME_TYPE_GRAPH = "scqlop/graph";
const QString DragDropHelper::MIME_TYPE_ZONE = "scqlop/zone";


struct DragDropHelper::DragDropHelperPrivate {

    VisualizationDragWidget* m_currentDragWidget = nullptr;
    std::unique_ptr<QWidget> m_placeHolder = nullptr;
    std::unique_ptr<DragDropScroller> m_dragDropScroller = nullptr;
    QString m_imageTempUrl; //Temporary file for image url generated by the drag & drop. Not using QTemporaryFile to have a name which is not generated.

    explicit DragDropHelperPrivate()
        : m_placeHolder{std::make_unique<QWidget>()},
          m_dragDropScroller{std::make_unique<DragDropScroller>()}
    {
         m_placeHolder->setStyleSheet("background-color: #BBD5EE; border:2px solid #2A7FD4");
         sqpApp->installEventFilter(m_dragDropScroller.get());


         m_imageTempUrl = QDir::temp().absoluteFilePath("Scqlop_graph.png");
    }

    void preparePlaceHolder() const
    {
        if (m_currentDragWidget)
        {
            m_placeHolder->setMinimumSize(m_currentDragWidget->size());
            m_placeHolder->setSizePolicy(m_currentDragWidget->sizePolicy());
        }
        else
        {
            m_placeHolder->setMinimumSize(200, 200);
        }
    }
};


DragDropHelper::DragDropHelper() :
    impl{spimpl::make_unique_impl<DragDropHelperPrivate>()}
{
}

DragDropHelper::~DragDropHelper()
{
    QFile::remove(impl->m_imageTempUrl);
}

void DragDropHelper::setCurrentDragWidget(VisualizationDragWidget *dragWidget)
{
    impl->m_currentDragWidget = dragWidget;
}

VisualizationDragWidget *DragDropHelper::getCurrentDragWidget() const
{
    return impl->m_currentDragWidget;
}


QWidget& DragDropHelper::placeHolder() const
{
    return *impl->m_placeHolder;
}

void DragDropHelper::insertPlaceHolder(QVBoxLayout *layout, int index)
{
    removePlaceHolder();
    impl->preparePlaceHolder();
    layout->insertWidget(index, impl->m_placeHolder.get());
    impl->m_placeHolder->show();
}

void DragDropHelper::removePlaceHolder()
{
    auto parentWidget = impl->m_placeHolder->parentWidget();
    if (parentWidget)
    {
        parentWidget->layout()->removeWidget(impl->m_placeHolder.get());
        impl->m_placeHolder->setParent(nullptr);
        impl->m_placeHolder->hide();
    }
}

bool DragDropHelper::isPlaceHolderSet() const
{
    return impl->m_placeHolder->parentWidget();
}

QUrl DragDropHelper::imageTemporaryUrl(const QImage& image) const
{
    image.save(impl->m_imageTempUrl);
    return QUrl::fromLocalFile(impl->m_imageTempUrl);
}