// Copyright Epic Games, Inc. All Rights Reserved.
#pragma once

#include "CoreMinimal.h"
#include "Input/DragAndDrop.h"
#include "Widgets/DeclarativeSyntaxSupport.h"
#include "Widgets/SBoxPanel.h"
#include "Widgets/Text/STextBlock.h"
#include "EditorStyleSet.h"
#include "Widgets/Layout/SBorder.h"
#include "Widgets/Images/SImage.h"
#include "Styling/SlateIconFinder.h"

class FClassDragDropOp: public FDragDropOperation
{
public:
    DRAG_DROP_OPERATOR_TYPE(FClassDragDropOp, FDragDropOperation)

    /** The classes to be dropped. */
    TArray<TWeakObjectPtr<UClass>> ClassesToDrop;

    /** The widget decorator to use */
    virtual TSharedPtr<SWidget> GetDefaultDecorator() const override
    {
        // Just use the first class for the cursor decorator.
        const FSlateBrush* ClassIcon = FSlateIconFinder::FindIconBrushForClass(ClassesToDrop[0].Get());

        // If the class icon is the default brush, do not put it in the cursor decoration window.
        if (ClassIcon)
        {
            return SNew(SBorder)
                .BorderImage(FEditorStyle::GetBrush("Graph.ConnectorFeedback.Border"))
                .Content()
                    [SNew(SHorizontalBox)

                     + SHorizontalBox::Slot()
                           .AutoWidth()
                               [SNew(SImage)
                                    .Image(ClassIcon)]

                     + SHorizontalBox::Slot()
                           .AutoWidth()
                               [SNew(STextBlock)
                                    .Text(FText::FromString(ClassesToDrop[0]->GetName()))]];
        }

        return SNew(SBorder)
            .BorderImage(FEditorStyle::GetBrush("Graph.ConnectorFeedback.Border"))
            .Content()
                [SNew(SHorizontalBox) + SHorizontalBox::Slot()
                                            .AutoWidth()
                                                [SNew(STextBlock)
                                                     .Text(FText::FromString(ClassesToDrop[0]->GetName()))]];
    }

    static TSharedRef<FClassDragDropOp> New(TWeakObjectPtr<UClass> ClassToDrop)
    {
        TSharedRef<FClassDragDropOp> Operation = MakeShareable(new FClassDragDropOp);
        Operation->ClassesToDrop.Add(ClassToDrop);
        Operation->Construct();
        return Operation;
    }

protected:
    /** Adding hint text to all drag drop operations that drop locations could set, and the decorator could report. */
    FText HintText;
};