Sort list of (biblatex)-keys by their citation number

Question

As this is a rather specific question and in lieu of a MWE some context:

I am working on a personalized version of the tufte-book class. In the process I am now at a point where I think I need a way to sort a list of biblatex-keys in order of the number they have. This is because I have extended the cite-command. (Note: tufte-book uses bibtex in the vanilla-version, I changed that to biblatex with biber backend, in case that is relevant)

In tufte-book when you call \cite{key1,key2,..} what really gets called is something like

% Normal \cite behavior
\newcounter{@tufte@num@bibkeys}%
\newcommand{\@tufte@normal@cite}[2][0pt]{%
  \hiddencite{#2}
  % Snag the last bibentry in the list for later comparison
  \let\@temp@last@bibkey\@empty%
  \@for\@temp@bibkey:=#2\do{\let\@temp@last@bibkey\@temp@bibkey}%
  \marginnote[#1]{%
    % Loop through all the bibentries, separating them with semicolons and spaces
    \normalsize\normalfont\@tufte@citation@font%
    \setcounter{@tufte@num@bibkeys}{0}%
    \@for\@temp@bibkeyx:=#2\do{%
      \ifthenelse{\equal{\@temp@last@bibkey}{\@temp@bibkeyx}}%
        {\ifthenelse{\equal{\value{@tufte@num@bibkeys}}{0}}{}{and\ }%
         \@tufte@trim@spaces\@temp@bibkeyx% trim spaces around bibkey
         \hiddencite{\@temp@bibkeyx}\bibentry{\@temp@bibkeyx}}%
        {\@tufte@trim@spaces\@temp@bibkeyx% trim spaces around bibkey
         \hiddencite{\@temp@bibkeyx}\bibentry{\@temp@bibkeyx};\ }%
      \stepcounter{@tufte@num@bibkeys}%
    }%
  }%
}

This already includes some changes from me (the goal is to have the full citation not as a footnote but as a marginnote with the citation number visible, see picture below). Hiddencite is nothing but the original cite which I stored because it gets changed from tufte-book. However, this does not work as good as the original cite command, because the list (#2) is not sorted.

here's an exemplary result to show my problem

generated by

some citations\cite{Tufte2001,Tufte1990,Tufte1997,Tufte2006}
same citations in different ordering \cite{Tufte2001,Tufte2006,Tufte1990,Tufte1997}

My goal is to find a way that both calls generate the same output (in the main text and the marginnote)

and now the actual question: How would I achieve a sorting of the list of citation keys I have? I want something that turns the argument key1,key3,key2,key4 into key1,key2,key3,key4. (Assuming that is the correct order).

What I did try is to look into the natbib and biblatex packages how they handle this, but I frankly failed to understand the code.

Final remark: I was asked how one would achieve such behaviour, this is not my idea (Personally I would be fine with a plain bibliography at the end)

Answer 1

moewe in the comments was right this can be achieved easily using biblatex only

 \usepackage[
  style=numeric-comp,
  backend=biber,
  sorting=none
  ]{biblatex}

\addbibresource{sample-handout.bib}
\let\truecite\cite
\DeclareCiteCommand{\footcite}[\marginnote]%
  {\usebibmacro{prenote}}
{\truecite{\thefield{entrykey}} \printnames{author},\
\printfield{title},\printfield{year}}
  {\multicitedelim}
  {\usebibmacro{postnote}}
\renewcommand{\cite}[1]{\truecite{#1}\footcite{#1}}

i will deal with citations in sidenotes separately (moved to an answer as suggested in the comments)