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

#pragma once

#include "UObject/UnrealType.h"

/** Reference collector that will purge (null) any references to the given set of objects (as if they'd been marked PendingKill) */
class FPurgingReferenceCollector: public FReferenceCollector
{
public:
    bool HasObjectToPurge() const
    {
        return ObjectsToPurge.Num() > 0;
    }

    void AddObjectToPurge(const UObject* Object)
    {
        ObjectsToPurge.Add(Object);
    }

    virtual bool IsIgnoringArchetypeRef() const override
    {
        return false;
    }

    virtual bool IsIgnoringTransient() const override
    {
        return false;
    }

protected:
    virtual void HandleObjectReference(UObject*& Object, const UObject* ReferencingObject, const FProperty* ReferencingProperty) override
    {
        ConditionalPurgeObject(Object);
    }

    virtual void HandleObjectReferences(UObject** InObjects, const int32 ObjectNum, const UObject* InReferencingObject, const FProperty* InReferencingProperty) override
    {
        for (int32 ObjectIndex = 0; ObjectIndex < ObjectNum; ++ObjectIndex)
        {
            UObject*& Object = InObjects[ObjectIndex];
            ConditionalPurgeObject(Object);
        }
    }

    void ConditionalPurgeObject(UObject*& Object)
    {
        if (ObjectsToPurge.Contains(Object))
        {
            Object = nullptr;
        }
    }

    TSet<const UObject*> ObjectsToPurge;
};