% -*- coding: utf-8 -*-
% ----------------------------------------------------------------------------
% Author:  Jianrui Lyu <tolvjr@163.com>
% License: The LaTeX Project Public License 1.3c
% ----------------------------------------------------------------------------
% This package started as a fork of mediummath code of nccmath package,
% aiming to provide more stable and flexible medium-size math commands.

\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{medmath}[2024-01-20 v2024E Better medium-size math commands]

\RequirePackage{array}
\RequirePackage{etoolbox}

\newbool{mdm@bare}     \boolfalse{mdm@bare}    % don't define any public commands
\newbool{mdm@base}     \boolfalse{mdm@base}    % define only basic public commands

\DeclareKeys{
  bare         .if = mdm@bare,
  base         .if = mdm@base,
  all          .ifnot = mdm@base,
}

\ProcessKeyOptions

\RequirePackage{amsmath}

%%% --------------------------------------------------------
%%> \section{Define medium-size math commands with base option}
%%% --------------------------------------------------------

%% The |\mdm@select@msize| command prepares dimensions for medium-size math:
%% \begin{itemize}
%% \item In |\mdm@fracrulewidth| --- a rule width in fractions;
%% \item In |@tempdima| --- a raising value; and
%% \item In |@tempdimb| --- a font size to be used in medium fractions
%%       and matrices.
%% \end{itemize}

\newdimen\mdm@fracrulewidth
\def\mdm@select@msize{\relax
% |\@tempdima| contains the current font size
  \@tempdima \f@size\p@
% Calculate in |\@tempdimb| a text font size in medium fraction
  \ifdim\@tempdima>11.5\p@
    \@tempdimb .83\@tempdima
  \else
    \@tempdimb .8\@tempdima
    \ifdim\@tempdimb<5\p@ \@tempdimb 5\p@\fi
  \fi
% Calculate in |\mdm@fracrulewidth| the rule width and in
% |\@tempdima| --- the raising value
  \mdm@fracrulewidth .04\@tempdima
  \@tempdima 1.25\mdm@fracrulewidth
  \ifdim\mdm@fracrulewidth>.45\p@ \else
    \ifdim\mdm@fracrulewidth>.34\p@ \mdm@fracrulewidth .4\p@
    \else \mdm@fracrulewidth .3\p@
    \fi
  \fi
}

%% The |\mdm@innerfrac|\marg{style} prepares a fraction with a
%% special width in the given style:

\def\mdm@innerfrac#1{\genfrac{}{}\mdm@fracrulewidth{#1}}

%% Select a font by rounding its pt-size to the nearest integer
%% and redefine fractions to have the given rule width. The |\binom|
%% command is redefined also to its original value because it can be
%% changed when the |mediummath| option is applied.

\def\mdm@prepare@msize{%
  \@tempdima 1.2\@tempdimb
  \advance\@tempdimb .5\p@
  \edef\@tempa{\strip@pt\@tempdimb}%
  \expandafter\mdm@floor\expandafter\@tempa\@tempa.\@nil
  \fontsize\@tempa\@tempdima\selectfont
  \def\frac{\protect\mdm@innerfrac{}}%
  \def\dfrac{\mdm@innerfrac\z@}%
  \def\tfrac{\mdm@innerfrac\@ne}%
  \def\binom{\protect\genfrac()\z@{}}%
}
\def\mdm@floor#1#2.#3\@nil{\def#1{#2}}

%% Fix fractions and subfractions in superscripts/subscripts
%% Always use current style size to typeset the fractions

\newcommand{\mdm@larger@frac}[2]{%
  \mathchoice{\genfrac{}{}{}{0}{#1}{#2}}{\genfrac{}{}{}{0}{#1}{#2}}%
             {\genfrac{}{}{}{1}{#1}{#2}}{\genfrac{}{}{}{2}{#1}{#2}}%
}
\def\mdm@prepare@msize{%
  \@tempdima 1.2\@tempdimb
  \advance\@tempdimb .5\p@
  \edef\@tempa{\strip@pt\@tempdimb}%
  \expandafter\mdm@floor\expandafter\@tempa\@tempa.\@nil
  \fontsize\@tempa\@tempdima\selectfont
  \let\frac=\mdm@larger@frac
  \def\dfrac{\mdm@innerfrac\z@}%
  \def\tfrac{\mdm@innerfrac\@ne}%
  \def\binom{\protect\genfrac()\z@{}}%
}

%% |\mdm@op@prepare|\marg{integral}
%% command prepares an integral. It looks forward, extracts indices
%% and limits-change commands, and puts the integral with required kerning
%% of indices. The |\mdm@op@print| driver is a command to print the integral.
%% Its default value is |\mdm@op@printm|. The driver uses the following hooks:
%% |\mdm@op| contains an integral command, |\mdm@op@lim| contains
%% the selected limits-style, |\mdm@op@sb| contains a subscript,
%% |\mdm@op@sp| contains a superscript, |mdm@op@kern| contains the
%% kerning value for medium-size integrals. If subscript or superscript
%% is omitted, the corresponding hook is equal to |\relax|.

\DeclareRobustCommand*\mdm@op@prepare[1]{%
  \def\mdm@op{#1}%
  \let\mdm@op@print\mdm@op@printm
  \mdm@op@prepare@
}
\def\mdm@op@prepare@{%
  \let\mdm@op@lim\ilimits@
  \let\mdm@op@sp\relax
  \let\mdm@op@sb\relax
  \mdm@op@next
}
\def\mdm@op@next{\futurelet\@let@token\mdm@op@getnext}
% Test the next token and get it if necessary:
\def\mdm@op@getnext{%
  \let\@tempa\mdm@op@skip
  \ifx\@let@token\limits
   \let\mdm@op@lim\limits \else
    \ifx\@let@token\nolimits
     \let\mdm@op@lim\nolimits \else
      \ifx\@let@token\displaylimits
       \let\mdm@op@lim\displaylimits \else
        \ifx\@let@token\sp
         \mdm@op@test\mdm@op@sp
         \def\@tempa{\mdm@op@get\mdm@op@sp}\else
          \ifx\@let@token\sb
           \mdm@op@test\mdm@op@sb
           \def\@tempa{\mdm@op@get\mdm@op@sb}\else
            \ifx\@let@token\@sptoken
             \let\@tempa\mdm@op@skipsp \else
             \let\@tempa\mdm@op@print
            \fi
          \fi
        \fi
      \fi
    \fi
  \fi
  \@tempa
}
% Skip |\limits|-like token:
\def\mdm@op@skip#1{\mdm@op@next}
% Skip a space token. A space token is skipped within |\@ifnextchar|
% before comparing it with the first parameter. So, it does not important
% what char to test for:
\def\mdm@op@skipsp{%
  \@ifnextchar0{\mdm@op@next}{\mdm@op@next}%
}
% Test subscript or superscript to be already defined:
\def\mdm@op@test#1{%
  \ifx#1\relax \else
    \PackageError{nccmath}{Double index in math operator}{}
  \fi
}
% Get a subscript or superscript:
\def\mdm@op@get#1#2#3{\def#1{#3}\mdm@op@next}

%% Driver for printing the medium-size integral with indices:

\def\mdm@op@printm{%
  \ifx\mdm@op@lim\nolimits \mdm@op@printm@\@ne \else
    \ifx\mdm@op@lim\limits \mdm@op@printm@\z@ \else
      \mathchoice{\displaystyle\mdm@op@printm@\z@}%
                 {\textstyle\mdm@op@printm@\@ne}%
                 {\scriptstyle\mdm@op@printm@\@ne}%
                 {\scriptscriptstyle\mdm@op@printm@\@ne}%
    \fi
  \fi
}
\def\mdm@op@printm@{\mdm@op@print@\mdm@op\mdm@op@kern}

%% Fix sizes of integral operators in superscripts/subscripts

\newlength{\@mdm@em}
\setlength{\@mdm@em}{1em}
\newcommand{\mdm@style@unit}[1]{%
  \mathchoice{\setlength{\@mdm@em}{1em}#1}{\setlength{\@mdm@em}{1em}#1}
             {\setlength{\@mdm@em}{0.5em}#1}{\setlength{\@mdm@em}{0.3em}#1}%
}
\let\mdm@saved@op@printm=\mdm@op@printm
\def\mdm@op@printm{\mdm@style@unit{\mdm@saved@op@printm}}

%% |\mdm@op@print@|\marg{integral}\marg{kern}\marg{level} command
%% prints an \meta{integral} using the specified \meta{kern} in indices.
%% If \meta{level} = 0 use |\limits| else use |\nolimits|.

\def\mdm@op@print@#1#2#3{\mathop{#1}%
  \setlength\@tempdima{#2}%
  \@tempswatrue
  \ifx\mdm@op@sb\relax \else \ifnum#3>\z@ \@tempswafalse \fi \fi
  \ifx\mdm@op@sp\relax \else \ifnum#3>\z@ \@tempswafalse \fi \fi
  \edef\@tempa{%
    \ifnum#3=\z@ \noexpand\limits \else \noexpand\nolimits \fi
    \ifx\mdm@op@sb\relax \else
      \noexpand\sb{%
        \ifnum#3=\z@ \kern -\@tempdima\else \kern -.8\@tempdima \fi
        \noexpand\mdm@op@sb}%
    \fi
    \ifx\mdm@op@sp\relax \else
      \noexpand\sp{\ifnum#3=\z@ \kern \@tempdima\fi
        \noexpand\mdm@op@sp}%
    \fi
    \if@tempswa \kern -.2\@tempdima \fi
  }%
  \@tempa
}

%% The |\medmath|\marg{formula} prepares a medium-size formula
%% in display style:

\NewDocumentCommand\mdm@base@medmath{m}{\mdm@select@msize
  \mathord{\raise\@tempdima\hbox{\mdm@prepare@msize
    $\displaystyle#1$}}%
}

%% Fix sizes of non integral operators in superscripts/subscripts
%% We use the method in scalerel package for saving math styles
% big operator in normal text is 80% of the size of \displaystyle
% big operator in script is 80% of the size of \textstyle
% big operator in script script is 80% of the size of \scriptstyle

\def\@mdm@style@D{\displaystyle}
\def\@mdm@style@T{\displaystyle}
\def\@mdm@style@S{\textstyle}
\def\@mdm@style@s{\scriptstyle}
\def\mdm@style@saved{\csname @mdm@style@\@mdm@style@switch\endcsname}
\newcommand{\mdm@style@this}[1]{%
  \mathchoice{\def\@mdm@style@switch{D}#1}{\def\@mdm@style@switch{T}#1}
             {\def\@mdm@style@switch{S}#1}{\def\@mdm@style@switch{s}#1}%
}
\DeclareDocumentCommand\mdm@base@medmath{m}{\mdm@select@msize
  \mathord{\mdm@style@this{\raise\@tempdima\hbox{\mdm@prepare@msize$\mdm@style@saved #1$}}}%
}

%% The |\medop|\marg{operator} prepares an operator in the medium size:

\NewExpandableDocumentCommand\mdm@base@medop{m}{\DOTSB\mathop{\medmath{#1}}\slimits@}

%% The |\medintcorr|\marg{length} specifies an italic correction
%% for a medium integral:

\NewExpandableDocumentCommand\mdm@base@medintcorr{m}{\def\mdm@op@kern{#1}}
\mdm@base@medintcorr{0.5\@mdm@em}

%% The |\medint|\marg{integral} command prepares a medium integral:

\NewExpandableDocumentCommand\mdm@base@medint{m}{\DOTSI\mdm@op@prepare{\medmath{#1}}}

%% The |\mfrac|\marg{numerator}\marg{denominator} prepares
%% a medium-size fraction:

\NewDocumentCommand\mdm@base@mfrac{mm}{\medmath{\frac{#1}{#2}}}

%% The |\mbinom|\marg{numerator}\marg{denominator} prepares
%% a medium-size binomial expression:

\NewDocumentCommand\mdm@base@mbinom{mm}{%
  \Bigl(\medmath{\genfrac{}{}{\z@}{}{#1}{#2}}\Bigr)%
}

%% The |medsize| environment is useful for preparing medium-size arrays:

\NewDocumentEnvironment{mdm@base@medsize}{}{\mdm@select@msize
  \mathord\bgroup
    \raise\@tempdima\hbox\bgroup\mdm@prepare@msize
      \arraycolsep .8\arraycolsep $}{$\egroup\egroup}

%% The |mmatrix| environment prepares a medium-size matrix:

\NewDocumentEnvironment{mdm@base@mmatrix}{}{\medsize\begin{matrix}}{\end{matrix}\endmedsize}

%% Improve the |\MultiIntegral| kerning method on the base of
%% |\mdm@op@prepare@| hook. The original method from |amsmath| works
%% bad if a multi-integral is an argument of the |\medint| command.

\NewDocumentCommand\mdm@base@MultiIntegral{m}{%
  \edef\mdm@op{\noexpand\intop
    \ifnum#1=\z@\noexpand\intdots@\else\noexpand\intkern@\fi
    \ifnum#1>\tw@\noexpand\intop\noexpand\intkern@\fi
    \ifnum#1>\thr@@\noexpand\intop\noexpand\intkern@\fi
    \noexpand\intop
  }%
  \let\mdm@op@print\mdm@op@printd
  \mdm@op@prepare@
}
\def\mdm@op@printd{%
  \setlength\@tempdima{\mdm@op@kern}%
  \ifx\mdm@op@lim\nolimits \@tempcnta\@ne \else
    \ifx\mdm@op@lim\limits \@tempcnta\z@ \else
      \@tempcnta\m@ne
    \fi
  \fi
  \mathchoice{\mdm@op@printd@{\displaystyle}{1.2\@tempdima}}%
             {\mdm@op@printd@{\textstyle}{.8\@tempdima}}%
             {\mdm@op@printd@{\scriptstyle}{.8\@tempdima}}%
             {\mdm@op@printd@{\scriptscriptstyle}{.8\@tempdima}}%
}
\def\mdm@op@printd@#1#2{#1%
  \ifnum\@tempcnta>\m@ne
    \mdm@op@print@{\hbox{$#1\mdm@op$}}{#2}\@tempcnta
  \else
    \ifx#1\displaystyle
      \mdm@op@print@{\hbox{$#1\mdm@op$}}{#2}\z@
    \else
      \mdm@op@print@{\hbox{$#1\mdm@op$}}{#2}\@ne
    \fi
  \fi
}

%%% --------------------------------------------------------
%%> \section{Redefine existing math commands with all option}
%%% --------------------------------------------------------

%% Redifine fractions and binoms.

\NewDocumentCommand\mdm@all@frac{}{\mdm@op@select\mfrac{\genfrac{}{}{}{}}}
\NewDocumentCommand\mdm@all@binom{}{\mdm@op@select\mbinom{\genfrac()\z@{}}}
\def\mdm@op@select#1#2#3#4{%
  \mathchoice{#1{#3}{#4}}{#1{#3}{#4}}%
             {\scriptstyle#2{#3}{#4}}{\scriptscriptstyle#2{#3}{#4}}%
}

%% Fix fractions and subfractions in superscripts/subscripts
%% Always use current style size to typeset the fractions

\DeclareDocumentCommand\mdm@all@frac{mm}{%
  \mathchoice{\mfrac{#1}{#2}}{\mfrac{#1}{#2}}%
             {\mdm@larger@frac{#1}{#2}}{\mdm@larger@frac{#1}{#2}}%
}

%% Redefine all math operators except integrals:

\NewDocumentCommand\mdm@redef@operators{mmm}{%
  \ifx#2\@undefined \let#2#1\fi
  \def#3{\DOTSB\medop{#2}}%
}
\mdm@redef@operators \coprod    \coprod@    \mdm@all@coprod
\mdm@redef@operators \bigvee    \bigvee@    \mdm@all@bigvee
\mdm@redef@operators \bigwedge  \bigwedge@  \mdm@all@bigwedge
\mdm@redef@operators \biguplus  \biguplus@  \mdm@all@biguplus
\mdm@redef@operators \bigcap    \bigcap@    \mdm@all@bigcap
\mdm@redef@operators \bigcup    \bigcup@    \mdm@all@bigcup
\mdm@redef@operators \prod      \prod@      \mdm@all@prod
\mdm@redef@operators \sum       \sum@       \mdm@all@sum
\mdm@redef@operators \bigotimes \bigotimes@ \mdm@all@bigotimes
\mdm@redef@operators \bigoplus  \bigoplus@  \mdm@all@bigoplus
\mdm@redef@operators \bigodot   \bigodot@   \mdm@all@bigodot
\mdm@redef@operators \bigsqcup  \bigsqcup@  \mdm@all@bigsqcup

%% Redefine integrals:

\@ifundefined{NCC@op}{\let\mdm@op@int=\intop}{\let\mdm@op@int=\NCC@op@int}
\NewDocumentCommand\mdm@all@intop{}{\mathop{\medmath{\mdm@op@int}}}
\newcommand*\mdm@all@int{\DOTSI\mdm@op@prepare{\mdm@all@intop}}

\@ifundefined{NCC@op}{\let\mdm@op@oint=\ointop}{\let\mdm@op@oint=\NCC@op@oint}
\NewDocumentCommand\mdm@all@ointop{}{\mathop{\medmath{\mdm@op@oint}}}
\newcommand*\mdm@all@oint{\DOTSI\mdm@op@prepare{\mdm@all@ointop}}

%% Adjust \oiint operator.

\ifdef{\oiint}{%
  \let\mdm@op@oiint=\oiint
  \NewDocumentCommand\mdm@all@oiintop{}{\mathop{\medmath{\mdm@op@oiint}}}%
  \newcommand*\mdm@all@oiint{\DOTSI\mdm@op@prepare{\mdm@all@oiintop}}%
}{}%

%% Redefine multiple integrals:

\NewDocumentCommand\mdm@all@MultiIntegral{m}{%
  \edef\mdm@op{\noexpand\intop
    \ifnum#1=\z@\noexpand\intdots@\else\noexpand\intkern@\fi
    \ifnum#1>\tw@\noexpand\intop\noexpand\intkern@\fi
    \ifnum#1>\thr@@\noexpand\intop\noexpand\intkern@\fi
    \noexpand\intop
  }%
  \let\mdm@op@print\mdm@op@printm
  \mdm@op@prepare@
}
\NewDocumentCommand\mdm@all@intkern@{}{\kern-\mdm@op@kern}
\NewDocumentCommand\mdm@all@intdots@{}{\setlength\@tempdima{\mdm@op@kern}%
  \kern-.4\@tempdima{\cdotp}\mkern1.5mu{\cdotp}%
  \mkern1.5mu{\cdotp}\kern-.4\@tempdima}

%% The definite integrals in cases environment may cause infinite loops
%% Our redefinition moves \quad to the beginning of the second columns
%% Therefore removing extra spaces when there is only one column in it

\NewDocumentEnvironment{mdm@all@cases}{}{%
  \left\{\linespread{1.0}\selectfont\def\arraystretch{1.2}%
  \begin{array}{@{}l@{}>{\quad}l@{}}%
}{%
  \end{array}\right.%
}

%%% --------------------------------------------------------
%%> \section{Activate definitions at the beginning of the document}
%%% --------------------------------------------------------

%% Current largesymbols font of math version normal is stored in \mv@normal:
%% ... \getanddefine@fonts \symlargesymbols \OMX/cmex/m/n ...

\def\mdm@get@font@cmd#1\getanddefine@fonts\symlargesymbols#2#3\@mdm@scan@stop{%
  \expandafter\mdm@get@font@name\string#2\@mdm@scan@stop
}

\def\mdm@get@font@name#1#2/#3/#4/#5\@mdm@scan@stop{%
  \def\@mdm@font@name{#3}%
}

\def\@mdm@intcorr@factor@cmex{0.5}  % default largesymbols font
\def\@mdm@intcorr@factor@mdput{0.3} % [utopia]{mathdesign}
\def\@mdm@intcorr@factor@mdbch{0.3} % [charter]{mathdesign}, {arevmath}

\NewDocumentCommand\mdm@adjust@intcorr{}{%
  \expandafter\mdm@get@font@cmd\mv@normal\@mdm@scan@stop
  \ifcsdef{@mdm@intcorr@factor@\@mdm@font@name}{%
    \edef\@mdm@intcorr@factor{\csuse{@mdm@intcorr@factor@\@mdm@font@name}}%
  }{%
    \def\@mdm@intcorr@factor{0.5}% default value
  }%
  \ExpandArgs{No}\def\mdm@op@kern{\@mdm@intcorr@factor\@mdm@em}%
}

\NewDocumentCommand\mdm@activate@base{}{%
  \mdm@adjust@intcorr
  \let \medmath       = \mdm@base@medmath
  \let \medop         = \mdm@base@medop
  \let \medintcorr    = \mdm@base@medintcorr
  \let \medint        = \mdm@base@medint
  \let \mfrac         = \mdm@base@mfrac
  \let \mbinom        = \mdm@base@mbinom
  \let \medsize       = \mdm@base@medsize
  \let \endmedsize    = \endmdm@base@medsize
  \let \mmatrix       = \mdm@base@mmatrix
  \let \endmmatrix    = \endmdm@base@mmatrix
  \let \MultiIntegral = \mdm@base@MultiIntegral
}

\NewDocumentCommand\mdm@activate@all{}{%
  \mdm@activate@base
  \let \frac          = \mdm@all@frac
  \let \binom         = \mdm@all@binom
  \let \coprod        = \mdm@all@coprod
  \let \bigvee        = \mdm@all@bigvee
  \let \bigwedge      = \mdm@all@bigwedge
  \let \biguplus      = \mdm@all@biguplus
  \let \bigcap        = \mdm@all@bigcap
  \let \bigcup        = \mdm@all@bigcup
  \let \prod          = \mdm@all@prod
  \let \sum           = \mdm@all@sum
  \let \bigotimes     = \mdm@all@bigotimes
  \let \bigoplus      = \mdm@all@bigoplus
  \let \bigodot       = \mdm@all@bigodot
  \let \bigsqcup      = \mdm@all@bigsqcup
  \let \intop         = \mdm@all@intop
  \let \int           = \mdm@all@int
  \let \ointop        = \mdm@all@ointop
  \let \oint          = \mdm@all@oint
  \ifdef{\oiint}{%
    \let \oiintop     = \mdm@all@oiintop
    \let \oiint       = \mdm@all@oiint
  }{}%
  \let \MultiIntegral = \mdm@all@MultiIntegral
  \let \intkern@      = \mdm@all@intkern@
  \let \intdots@      = \mdm@all@intdots@
  \let \cases         = \mdm@all@cases
  \let \endcases      = \endmdm@all@cases
}

\AtBeginDocument{%
  \ifbool{mdm@bare}{}{%
    \ifbool{mdm@base}{\mdm@activate@base}{\mdm@activate@all}%
  }%
}