Automatically switch between \theenumi, \theenumii, and \theenumiii based on \@enumdepth

Question

I am trying to reformat an enumerated value depending on whether I am "grading" or not, and I have a working solution, but I would like to know would be how to automatically switch between \theenumi, \theenumii, and \theenumiii based on \@enumdepth in the minimum working example that I have posted below:

\documentclass{article}
\usepackage{ifthen, amsmath, tikz, enumerate}

\newif\ifgrading
\gradingtrue

\newcommand*\circleAns[1]{\tikz[baseline=(char.base)]{
            \node[shape=circle,draw,inner sep=2pt,color=blue] (char) {#1};}}

\makeatletter        
\newcommand{\itemAns}{
    \ifgrading
        \stepcounter{enum\romannumeral\@enumdepth}
        \item[\circleAns{\textcolor{blue}{\theenumi)}}]
    \else \item
    \fi
}
\makeatother

\begin{document}

\begin{enumerate}[a)]
    \item 
    \itemAns
    \item
\end{enumerate}

\end{document}

I tried using \theenum\romannumeral\@enumdepth instead of \theenumii, similar to what I did with \stepcounter{enum\romannumeral\@enumdepth}, which didn't work though I think I understand why. If anyone has any suggestions for how to implement this solution better and update based on the level, I am very open to suggestions.

--------------------------- EDIT

Using Donald Arseneau's solution as a basis, I've modified my implementation to also include the label automatically: \textcolor{ForestGreen}{\@nameuse{label\@enumctr}} So the code

\begin{enumerate}[a)]
    \item 
    \itemAns
    \item 
\end{enumerate}
\begin{enumerate}[a.]
    \item 
    \item 
    \itemAns
\end{enumerate}

produces So it has the functionality I need it to. If anyone knows a simple way of recentering the circled items, let me know but otherwise I'm very happy with the result!

Answer 1

Use \@nameuse{ } or \csname \endcsname.

\textcolor{blue}{\@nameuse{theenum\romannumeral\@enumdepth})}

But since you already know about \@enumdepth and use it, you probably have seen \@enumctr which will simplify usage

\textcolor{blue}{\@nameuse{the\@enumctr})}