#include "DragAndDrop/DragDropHelper.h"
#include "DragAndDrop/DragDropScroller.h"
#include "DragAndDrop/DragDropTabSwitcher.h"
#include "SqpApplication.h"
#include "Visualization/VisualizationDragDropContainer.h"
#include "Visualization/VisualizationDragWidget.h"
#include "Visualization/VisualizationWidget.h"
#include "Visualization/operations/FindVariableOperation.h"

#include "Variable/Variable.h"
#include "Variable/VariableController.h"

#include "Common/MimeTypesDef.h"
#include "Common/VisualizationDef.h"

#include <QDir>
#include <QLabel>
#include <QUrl>
#include <QVBoxLayout>


Q_LOGGING_CATEGORY(LOG_DragDropHelper, "DragDropHelper")


struct DragDropHelper::DragDropHelperPrivate {

    VisualizationDragWidget *m_CurrentDragWidget = nullptr;
    std::unique_ptr<QWidget> m_PlaceHolder = nullptr;
    QLabel *m_PlaceHolderLabel;
    QWidget *m_PlaceBackground;
    std::unique_ptr<DragDropScroller> m_DragDropScroller = nullptr;
    std::unique_ptr<DragDropTabSwitcher> m_DragDropTabSwitcher = 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.

    VisualizationDragWidget *m_HighlightedDragWidget = nullptr;

    QMetaObject::Connection m_DragWidgetDestroyedConnection;
    QMetaObject::Connection m_HighlightedWidgetDestroyedConnection;

    QList<QWidget *> m_WidgetToClose;

    explicit DragDropHelperPrivate()
            : m_PlaceHolder{std::make_unique<QWidget>()},
              m_DragDropScroller{std::make_unique<DragDropScroller>()},
              m_DragDropTabSwitcher{std::make_unique<DragDropTabSwitcher>()}
    {

        auto layout = new QVBoxLayout{m_PlaceHolder.get()};
        layout->setSpacing(0);
        layout->setContentsMargins(0, 0, 0, 0);

        m_PlaceHolderLabel = new QLabel{"", m_PlaceHolder.get()};
        m_PlaceHolderLabel->setMinimumHeight(25);
        layout->addWidget(m_PlaceHolderLabel);

        m_PlaceBackground = new QWidget{m_PlaceHolder.get()};
        m_PlaceBackground->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
        layout->addWidget(m_PlaceBackground);

        sqpApp->installEventFilter(m_DragDropScroller.get());
        sqpApp->installEventFilter(m_DragDropTabSwitcher.get());

        m_ImageTempUrl = QDir::temp().absoluteFilePath("Sciqlop_graph.png");
    }

    void preparePlaceHolder(DragDropHelper::PlaceHolderType type, const QString &topLabelText) const
    {
        if (m_CurrentDragWidget) {
            m_PlaceHolder->setMinimumSize(m_CurrentDragWidget->size());
            m_PlaceHolder->setSizePolicy(m_CurrentDragWidget->sizePolicy());
        }
        else {
            // Configuration of the placeHolder when there is no dragWidget
            // (for instance with a drag from a variable)

            m_PlaceHolder->setMinimumSize(0, GRAPH_MINIMUM_HEIGHT);
            m_PlaceHolder->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
        }

        switch (type) {
            case DragDropHelper::PlaceHolderType::Graph:
                m_PlaceBackground->setStyleSheet(
                    "background-color: #BBD5EE; border: 1px solid #2A7FD4");
                break;
            case DragDropHelper::PlaceHolderType::Zone:
            case DragDropHelper::PlaceHolderType::Default:
                m_PlaceBackground->setStyleSheet(
                    "background-color: #BBD5EE; border: 2px solid #2A7FD4");
                m_PlaceHolderLabel->setStyleSheet("color: #2A7FD4");
                break;
        }

        m_PlaceHolderLabel->setText(topLabelText);
        m_PlaceHolderLabel->setVisible(!topLabelText.isEmpty());
    }
};


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

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

void DragDropHelper::resetDragAndDrop()
{
    setCurrentDragWidget(nullptr);
    impl->m_HighlightedDragWidget = nullptr;
}

void DragDropHelper::setCurrentDragWidget(VisualizationDragWidget *dragWidget)
{
    if (impl->m_CurrentDragWidget) {

        QObject::disconnect(impl->m_DragWidgetDestroyedConnection);
    }

    if (dragWidget) {
        // ensures the impl->m_CurrentDragWidget is reset when the widget is destroyed
        impl->m_DragWidgetDestroyedConnection
            = QObject::connect(dragWidget, &VisualizationDragWidget::destroyed,
                               [this]() { impl->m_CurrentDragWidget = nullptr; });
    }

    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, PlaceHolderType type,
                                       const QString &topLabelText)
{
    removePlaceHolder();
    impl->preparePlaceHolder(type, topLabelText);
    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();
}

void DragDropHelper::addDragDropScrollArea(QScrollArea *scrollArea)
{
    impl->m_DragDropScroller->addScrollArea(scrollArea);
}

void DragDropHelper::removeDragDropScrollArea(QScrollArea *scrollArea)
{
    impl->m_DragDropScroller->removeScrollArea(scrollArea);
}

void DragDropHelper::addDragDropTabBar(QTabBar *tabBar)
{
    impl->m_DragDropTabSwitcher->addTabBar(tabBar);
}

void DragDropHelper::removeDragDropTabBar(QTabBar *tabBar)
{
    impl->m_DragDropTabSwitcher->removeTabBar(tabBar);
}

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

void DragDropHelper::setHightlightedDragWidget(VisualizationDragWidget *dragWidget)
{
    if (impl->m_HighlightedDragWidget) {
        impl->m_HighlightedDragWidget->highlightForMerge(false);
        QObject::disconnect(impl->m_HighlightedWidgetDestroyedConnection);
    }

    if (dragWidget) {
        dragWidget->highlightForMerge(true);

        // ensures the impl->m_HighlightedDragWidget is reset when the widget is destroyed
        impl->m_DragWidgetDestroyedConnection
            = QObject::connect(dragWidget, &VisualizationDragWidget::destroyed,
                               [this]() { impl->m_HighlightedDragWidget = nullptr; });
    }

    impl->m_HighlightedDragWidget = dragWidget;
}

VisualizationDragWidget *DragDropHelper::getHightlightedDragWidget() const
{
    return impl->m_HighlightedDragWidget;
}

void DragDropHelper::delayedCloseWidget(QWidget *widget)
{
    widget->hide();
    impl->m_WidgetToClose << widget;
}

void DragDropHelper::doCloseWidgets()
{
    for (auto widget : impl->m_WidgetToClose) {
        widget->close();
    }

    impl->m_WidgetToClose.clear();
}

bool DragDropHelper::checkMimeDataForVisualization(const QMimeData *mimeData,
                                                   VisualizationDragDropContainer *dropContainer)
{
    if (!mimeData || !dropContainer) {
        qCWarning(LOG_DragDropHelper()) << QObject::tr(
            "DragDropHelper::checkMimeDataForVisualization, invalid input parameters.");
        Q_ASSERT(false);
        return false;
    }

    auto result = false;

    if (mimeData->hasFormat(MIME_TYPE_VARIABLE_LIST)) {
        auto variables = sqpApp->variableController().variablesForMimeData(
            mimeData->data(MIME_TYPE_VARIABLE_LIST));

        if (variables.count() == 1) {

            auto variable = variables.first();
            if (variable->dataSeries() != nullptr) {

                // Check that the variable is not already in a graph

                auto parent = dropContainer->parentWidget();
                while (parent && qobject_cast<VisualizationWidget *>(parent) == nullptr) {
                    parent = parent->parentWidget(); // Search for the top level VisualizationWidget
                }

                if (parent) {
                    auto visualizationWidget = static_cast<VisualizationWidget *>(parent);

                    FindVariableOperation findVariableOperation{variable};
                    visualizationWidget->accept(&findVariableOperation);
                    auto variableContainers = findVariableOperation.result();
                    if (variableContainers.empty()) {
                        result = true;
                    }
                    else {
                        // result = false: the variable already exist in the visualisation
                    }
                }
                else {
                    qCWarning(LOG_DragDropHelper()) << QObject::tr(
                        "DragDropHelper::checkMimeDataForVisualization, the parent "
                        "VisualizationWidget cannot be found. Cannot check if the variable is "
                        "already used or not.");
                }
            }
            else {
                // result = false: the variable is not fully loaded
            }
        }
        else {
            // result = false: cannot drop multiple variables in the visualisation
        }
    }
    else {
        // Other MIME data
        // no special rules, accepted by default
        result = true;
    }

    return result;
}