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

#pragma once

#include "CoreMinimal.h"
#include "UObject/ObjectMacros.h"
#include "Serialization/ArchiveUObject.h"

struct FTraceRouteRecord
{
    struct FObjectGraphNode* GraphNode;
    TArray<FProperty*> ReferencerProperties;

    FTraceRouteRecord(struct FObjectGraphNode* InGraphNode, FProperty* InReferencerProperty)
        : GraphNode(InGraphNode)
    {
        ReferencerProperties.Add(InReferencerProperty);
    }

    FTraceRouteRecord(struct FObjectGraphNode* InGraphNode, const TArray<FProperty*>& InReferencerProperties)
        : GraphNode(InGraphNode)
    {
        ReferencerProperties = InReferencerProperties;
    }

    void Add(FProperty* InReferencerProperty)
    {
        ReferencerProperties.Add(InReferencerProperty);
    }
};

struct FObjectGraphNode
{
    /** the object this node represents */
    UObject* NodeObject;

    /** Records for objects which reference this object */
    TMap<UObject*, FTraceRouteRecord> ReferencerRecords;

    /** Records for objects which are referenced by this object */
    TMap<UObject*, FTraceRouteRecord> ReferencedObjects;

    /** the number of links between NodeObject and the target object */
    int32 ReferenceDepth;

    /** Used during search - Visited or not */
    bool Visited;

    /**
     * The property that references NodeObject; only set on nodes which are part
     * of the calculated shortest route
     */
    TArray<FProperty*> ReferencerProperties;

    /** Default constructor */
    FObjectGraphNode(UObject* InNodeObject = NULL)
        : NodeObject(InNodeObject), ReferenceDepth(MAX_int32), Visited(false)
    {}
};

/*----------------------------------------------------------------------------
        FArchiveObjectGraph.
----------------------------------------------------------------------------*/
// This is from FArchiveTraceRoute -This only creates object graph of all objects
// This can be used by other classes such as FTraceReferences - trace references of one object
class FArchiveObjectGraph: public FArchiveUObject
{
    /** Handles serialization of UObject references */
    FArchive& operator<<(class UObject*& Obj);

    /**
     * The object currently being serialized; used by the overloaded serialization operator to determine the referencing object.
     */
    UObject* CurrentReferencer;
    /** The set of objects encountered while serializing CurrentReferencer */
    TArray<UObject*> ObjectsToSerialize;

    /** true if we should serialize objects marked RF_Transient */
    bool bIncludeTransients;

    /**
     * A bitmask of object flags which indicates which objects should be included in the group of initial objects to be serialized;
     * RF_RootSet will be automatically added to this bitmask, and OBJECTMARK_TagExp will automatically be removed.
     */
    EObjectFlags RequiredFlags;

public:
    UE_DEPRECATED(4.23, "This class is out of date and misses many references, replace with FReferenceChainSearch or FFindReferencersArchive")
    FArchiveObjectGraph(bool IncludeTransients, EObjectFlags KeepFlags);
    ~FArchiveObjectGraph();

    /**
     * Serializes the objects in the specified set; any objects encountered during serialization
     * of an object are added to the object set and processed until no new objects are added.
     * DO NOT MAKE THIS VIRTUAL - this is called by constructor. If you wish to do so, please change where be called
     * @param	Objects		the original set of objects to serialize; the original set will be preserved.
     */
    void GenerateObjectGraph(TArray<UObject*>& Objects);

    void ClearSearchFlags();

    /** A complete graph of all references between all objects in memory */
    TMap<UObject*, FObjectGraphNode*> ObjectGraph;
};