// Copyright Epic Games, Inc. All Rights Reserved.

#pragma once

#include "CoreMinimal.h"
#include "Serialization/ArchiveUObject.h"
#include "UObject/UObjectAnnotation.h"
#include "Serialization/DuplicatedObject.h"
#include "Serialization/LargeMemoryData.h"
#include "Templates/RefCounting.h"
#include "UObject/UObjectThreadContext.h"

struct FObjectInstancingGraph;

/*----------------------------------------------------------------------------
        FDuplicateDataWriter.
----------------------------------------------------------------------------*/
/**
 * Writes duplicated objects to a memory buffer, duplicating referenced inner objects and adding the duplicates to the DuplicatedObjects map.
 */
class FDuplicateDataWriter: public FArchiveUObject
{
private:
    class FUObjectAnnotationSparse<FDuplicatedObject, false>& DuplicatedObjectAnnotation;
    FLargeMemoryData& ObjectData;
    int64 Offset;
    EObjectFlags FlagMask;
    EObjectFlags ApplyFlags;
    EInternalObjectFlags InternalFlagMask;
    EInternalObjectFlags ApplyInternalFlags;
    bool bAssignExternalPackages;

    /**
     * This is used to prevent object & component instancing resulting from the calls to StaticConstructObject(); instancing subobjects and components is pointless,
     * since we do that manually and replace the current value with our manually created object anyway.
     */
    struct FObjectInstancingGraph* InstanceGraph;

    /** Context for duplication */
    TRefCountPtr<FUObjectSerializeContext> DuplicateContext;

    //~ Begin FArchive Interface.

    virtual FArchive& operator<<(FName& N) override;
    virtual FArchive& operator<<(UObject*& Object) override;
    virtual FArchive& operator<<(FLazyObjectPtr& LazyObjectPtr) override;
    virtual FArchive& operator<<(FField*& Field) override;

    virtual void Serialize(void* Data, int64 Num)
    {
        if (ObjectData.Write(Data, Offset, Num))
        {
            Offset += Num;
        }
    }

    virtual void Seek(int64 InPos)
    {
        Offset = InPos;
    }

    /**
     * Places a new duplicate in the DuplicatedObjects map as well as the UnserializedObjects list
     *
     * @param	SourceObject	the original version of the object
     * @param	DuplicateObject	the copy of the object
     */
    void AddDuplicate(UObject* SourceObject, UObject* DuplicateObject);

public:
    /**
     * Returns the name of the Archive.  Useful for getting the name of the package a struct or object
     * is in when a loading error occurs.
     *
     * This is overridden for the specific Archive Types
     **/
    virtual FString GetArchiveName() const { return TEXT("FDuplicateDataWriter"); }

    virtual int64 Tell()
    {
        return Offset;
    }

    virtual int64 TotalSize()
    {
        return ObjectData.GetSize();
    }

    virtual void SetSerializeContext(FUObjectSerializeContext* InLoadContext) override
    {
        DuplicateContext = InLoadContext;
    }

    virtual FUObjectSerializeContext* GetSerializeContext() override
    {
        return DuplicateContext;
    }

    TArray<UObject*> UnserializedObjects;

    /**
     * Returns a pointer to the duplicate of a given object, creating the duplicate object if necessary.
     *
     * @param	Object	the object to find a duplicate for
     * @param	bCreateIfMissing Create the duplicated object if it's missing.
     *
     * @return	a pointer to the duplicate of the specified object
     */
    UObject* GetDuplicatedObject(UObject* Object, bool bCreateIfMissing = true);

    /**
     * Constructor
     *
     * @param	InDuplicatedObjects		Annotation for storing a mapping from source to duplicated object
     * @param	InObjectData			will store the serialized data
     * @param	SourceObject			the object to copy
     * @param	DestObject				the object to copy to
     * @param	InFlagMask				the flags that should be copied when the object is duplicated
     * @param	InApplyFlags			the flags that should always be set on the duplicated objects (regardless of whether they're set on the source)
     * @param	InInstanceGraph			the instancing graph to use when creating the duplicate objects.
     */
    FDuplicateDataWriter(
        FUObjectAnnotationSparse<FDuplicatedObject, false>& InDuplicatedObjects,
        FLargeMemoryData& InObjectData,
        UObject* SourceObject,
        UObject* DestObject,
        EObjectFlags InFlagMask,
        EObjectFlags InApplyMask,
        EInternalObjectFlags InInternalFlagMask,
        EInternalObjectFlags InApplyInternalFlags,
        FObjectInstancingGraph* InInstanceGraph,
        uint32 InPortFlags,
        bool InAssignExternalPackages);
};