FString ObjectToJsonString(const UObject* Obj);
FString StructToJsonString(const UStruct* Struct, const void* StructData);
FString PropertyValueToJsonString(const UProperty* Prop, const void* ValuePtr);

FString ObjectToJsonString(const UObject* Obj)
{
    FString ObjJsonString;
    ObjJsonString += TEXT("{ ");

    bool bIsFirst = true;
    for (TFieldIterator<const UProperty> PropIt(Obj->GetClass(), EFieldIteratorFlags::IncludeSuper, EFieldIteratorFlags::ExcludeDeprecated, EFieldIteratorFlags::IncludeInterfaces); PropIt; ++PropIt)
    {
        if (!bIsFirst)
        {
            ObjJsonString += TEXT(", ");
        }
        bIsFirst = false;

        ObjJsonString += PropIt->GetName();
        ObjJsonString += TEXT(": ");
        ObjJsonString += PropertyValueToJsonString(*PropIt, PropIt->ContainerPtrToValuePtr<void>(Obj));
    }

    ObjJsonString += TEXT(" }");
    return ObjJsonString;
}

FString StructToJsonString(const UStruct* Struct, const void* StructData)
{
    FString StructJsonString;
    StructJsonString += TEXT("{ ");

    bool bIsFirst = true;
    for (TFieldIterator<const UProperty> PropIt(Struct, EFieldIteratorFlags::IncludeSuper, EFieldIteratorFlags::ExcludeDeprecated, EFieldIteratorFlags::IncludeInterfaces); PropIt; ++PropIt)
    {
        if (!bIsFirst)
        {
            StructJsonString += TEXT(", ");
        }
        bIsFirst = false;

        StructJsonString += PropIt->GetName();
        StructJsonString += TEXT(": ");
        StructJsonString += PropertyValueToJsonString(*PropIt, PropIt->ContainerPtrToValuePtr<void>(StructData));
    }

    StructJsonString += TEXT(" }");
    return StructJsonString;
}

FString PropertyValueToJsonString(const UProperty* Prop, const void* ValuePtr)
{
    FString PropJsonString;

    if (Prop->ArrayDim > 1)
    {
        PropJsonString += TEXT("[ ");
    }

    for (int32 i = 0; i < Prop->ArrayDim; ++i)
    {
        const void* const ElementValueAddress = reinterpret_cast<const uint8*>(ValuePtr) + (Prop->ElementSize * i);

        if (i > 0)
        {
            PropJsonString += TEXT(", ");
        }

        if (const UArrayProperty* const ArrayProp = Cast<const UArrayProperty>(Prop))
        {
            PropJsonString += TEXT("[ ");

            FScriptArrayHelper ScriptArrayHelper(ArrayProp, ElementValueAddress);
            const int32 ElementCount = ScriptArrayHelper.Num();
            for (int32 j = 0; j < ElementCount; ++j)
            {
                if (j > 0)
                {
                    PropJsonString += TEXT(", ");
                }

                PropJsonString += PropertyValueToJsonString(ArrayProp->Inner, ScriptArrayHelper.GetRawPtr(j));
            }

            PropJsonString += TEXT(" ]");
        }
        else if (const UMapProperty* const MapProp = Cast<const UMapProperty>(Prop))
        {
            PropJsonString += TEXT("{ ");

            bool bIsFirstMapEntry = true;
            FScriptMapHelper ScriptMapHelper(MapProp, ElementValueAddress);
            const int32 ElementCount = ScriptMapHelper.Num();
            for (int32 j = 0; j < ElementCount; ++j)
            {
                if (!ScriptMapHelper.IsValidIndex(j))
                {
                    continue;
                }

                if (!bIsFirstMapEntry)
                {
                    PropJsonString += TEXT(", ");
                }
                bIsFirstMapEntry = false;

                const uint8* MapPairPtr = ScriptMapHelper.GetPairPtr(j);
                PropJsonString += PropertyValueToJsonString(MapProp->KeyProp, MapPairPtr + MapProp->MapLayout.KeyOffset);
                PropJsonString += TEXT(": ");
                PropJsonString += PropertyValueToJsonString(MapProp->ValueProp, MapPairPtr + MapProp->MapLayout.ValueOffset);
            }

            PropJsonString += TEXT(" }");
        }
        else if (const UStructProperty* const StructProp = Cast<const UStructProperty>(Prop))
        {
            PropJsonString += StructToJsonString(StructProp->Struct, ElementValueAddress);
        }
        else if (const UObjectPropertyBase* const ObjectProp = Cast<const UObjectPropertyBase>(Prop))
        {
            // note: need to detect loops
            const UObject* InnerObject = ObjectProp->GetObjectPropertyValue(ElementValueAddress);
            if (InnerObject)
            {
                PropJsonString += ObjectToJsonString(InnerObject);
            }
        }
        else
        {
            Prop->ExportText_Direct(PropJsonString, ElementValueAddress, ElementValueAddress, nullptr, PPF_Delimited);
        }
    }

    if (Prop->ArrayDim > 1)
    {
        PropJsonString += TEXT(" ]");
    }

    return PropJsonString;
}