% Babelbidi: Bidi extensions for Babel.
%
% Copyright (C) 2026 Amer Amikhteh
%
% This file is part of the Babelbidi package.
%
% This work is free software: you may redistribute it and/or modify
% it under the terms of the LaTeX Project Public License as published
% by the LaTeX Project, either version 1.3c of the License, or
% (at your option) any later version.
%
% This work is distributed in the hope that it will be useful,
% but WITHOUT ANY WARRANTY; without even the implied warranty of
% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
%
% The full license text is available at:
% https://www.latex-project.org/lppl/
%
% This work is "maintained" by Amer Amikhteh.
%
% The current maintainer of this work is Amer Amikhteh.

\ProvidesFile{babelbidi-api-extrafootnotes.def}[2026/11/08 v0.1.0 Extra footnote layouts for Babelbidi]

\makeatletter

% The widths, direction-separated streams and successive vertical splits
% follow extrafootnotefeatures-xetex-bidi.def (Vafa Khalighi, LPPL 1.3c+).
% Reuse the existing insertion commands instead of replacing their language,
% label and hyperlink handling. XeTeX loads bidi's implementation directly.

\newinsert\bbd@extra@ltr
\newinsert\bbd@extra@rtl
\newinsert\bbd@extra@mpltr
\newinsert\bbd@extra@mprtl
\newbox\bbd@extra@rest
\newbox\bbd@extra@piece
\newbox\bbd@extra@row
\newbox\bbd@extra@note
\newcount\bbd@extra@remaining
\newdimen\bbd@extra@gap
\newdimen\bbd@extra@width
\newdimen\bbd@extra@height
\newdimen\bbd@extra@fullwidth

\def\bbd@extra@mode{1}
\def\bbd@extra@layout{2}
\newdimen\bbd@extra@markwidth
\bbd@extra@markwidth1em
\def\bbd@extra@fraction{.45}

\skip\bbd@extra@ltr\skip\footins
\skip\bbd@extra@rtl\skip\footins
\skip\bbd@extra@mpltr\skip\@mpfootins
\skip\bbd@extra@mprtl\skip\@mpfootins

\def\bbd@extra@select#1#2{%
    \def\bbd@extra@mode{#1}%
    \IfBooleanTF{#2}%
    {\bbd@extra@markwidth\z@}%
    {\bbd@extra@markwidth1em}%
    \ifnum#1=\@ne\else
        \def\bbd@extra@layout{#1}%
        \skip\bbd@extra@ltr\skip\footins
        \skip\bbd@extra@rtl\skip\footins
        \ifnum#1=\z@
            \begingroup
            \footnotesize
            \@tempdima\footnotesep
            \advance\@tempdima by -\ht\strutbox
            \ifdim\@tempdima<\z@\@tempdima\z@\fi
            \advance\@tempdima by .5\normalbaselineskip
            \xdef\bbd@extra@paraskip{\the\@tempdima}%
            \endgroup
            \advance\skip\bbd@extra@ltr by \bbd@extra@paraskip
            \advance\skip\bbd@extra@rtl by \bbd@extra@paraskip
            \count@=1000
            \@tempdima\dimen\footins
        \else
            \count@=1000 \divide\count@ by #1\relax
            \@tempdima\dimen\footins \multiply\@tempdima by #1\relax
            \edef\bbd@extra@fraction{\ifcase#1\or1\or.45\or.3\or.25\or.2\or.16\or.142\or.125\or.1\or.1\fi}%
        \fi
        \count\bbd@extra@ltr\count@
        \count\bbd@extra@rtl\count@
        \dimen\bbd@extra@ltr\@tempdima
        \dimen\bbd@extra@rtl\@tempdima
    \fi
}

\ProvideDocumentCommand{\normalfootnotes}{s}{\bbd@extra@select{1}{#1}}
\ProvideDocumentCommand{\twocolumnfootnotes}{s}{\bbd@extra@select{2}{#1}}
\ProvideDocumentCommand{\threecolumnfootnotes}{s}{\bbd@extra@select{3}{#1}}
\ProvideDocumentCommand{\fourcolumnfootnotes}{s}{\bbd@extra@select{4}{#1}}
\ProvideDocumentCommand{\fivecolumnfootnotes}{s}{\bbd@extra@select{5}{#1}}
\ProvideDocumentCommand{\sixcolumnfootnotes}{s}{\bbd@extra@select{6}{#1}}
\ProvideDocumentCommand{\sevencolumnfootnotes}{s}{\bbd@extra@select{7}{#1}}
\ProvideDocumentCommand{\eightcolumnfootnotes}{s}{\bbd@extra@select{8}{#1}}
\ProvideDocumentCommand{\ninecolumnfootnotes}{s}{\bbd@extra@select{9}{#1}}
\ProvideDocumentCommand{\tencolumnfootnotes}{s}{\bbd@extra@select{10}{#1}}
\ProvideDocumentCommand{\paragraphfootnotes}{s}{\bbd@extra@select{0}{#1}}

% bidi uses a full-width rule with this option and disables rule selectors.
\def\footnoterule{\kern-3\p@\hrule\@width\columnwidth\kern2.6\p@}
\RenewDocumentCommand{\autofootnoterule}{}{}
\RenewDocumentCommand{\leftfootnoterule}{}{}
\RenewDocumentCommand{\rightfootnoterule}{}{}
\RenewDocumentCommand{\textwidthfootnoterule}{}{}
\DeclareCommandCopy{\LRfootnoterule}{\leftfootnoterule}
\DeclareCommandCopy{\RLfootnoterule}{\rightfootnoterule}

\def\bbd@extra@direction{%
    \ifnum\bbd@fn@explicit<\z@
        \ifnum\bbd@fn@policy<\z@
            \the\bbl@thetextdir
        \else
            \bbd@fn@policy
        \fi
    \else
        \bbd@fn@explicit
    \fi
}

\long\def\bbd@extra@insert#1#2#3{%
    \begingroup
    \edef\bbd@extra@dir{\bbd@extra@direction}%
    \bbd@extra@fullwidth\columnwidth
    \ifnum\bbd@extra@mode=\@ne\else
        \ifnum#1=\z@
            \ifnum\bbd@extra@dir=\z@
                \let\footins\bbd@extra@ltr
            \else
                \let\footins\bbd@extra@rtl
            \fi
        \else
            \ifnum\bbd@extra@dir=\z@
                \let\@mpfootins\bbd@extra@mpltr
            \else
                \let\@mpfootins\bbd@extra@mprtl
            \fi
        \fi
        \ifnum\bbd@extra@mode>\@ne
            \columnwidth\bbd@extra@fraction\columnwidth
        \fi
    \fi
    \let\@makefntext\bbd@extra@format
    #2{#3}%
    \endgroup
}

\def\bbd@extra@mark{%
    \ifdim\bbd@extra@markwidth=\z@
        \hboxL{\@makefnmark}%
    \else
        \hboxL to \bbd@extra@markwidth{%
            \ifnum\bbd@extra@dir=\z@\hss\fi
            \@makefnmark
            \ifnum\bbd@extra@dir>\z@\hss\fi
        }%
    \fi%
}

\long\def\bbd@extra@format#1{%
    \bbd@footnote@dir{\bbd@extra@dir}%
    \parindent\z@
    \tolerance5000
    \ifnum\bbd@extra@mode=\z@
        \bbd@extra@paranote{#1}%
    \else
        \ifnum\bbd@extra@mode=\@ne\parindent1em\fi
        \noindent\bbd@extra@mark#1\par
        \ifnum\bbd@extra@mode>\@ne\allowbreak\fi
    \fi
}

% Store paragraph notes as breakable horizontal material. TeX reserves an
% estimated height for each note, then the output routine reflows the stream.
\long\def\bbd@extra@paranote#1{%
    \setbox\bbd@extra@note\hbox{%
        \bbl@textdir{\bbd@extra@dir}%
        \def\@finalstrut##1{\strut}%
        \bbd@extra@mark\strut#1%
        \penalty-10
        \hskip1em plus.3em minus.3em
    }%
    \@tempdima\baselineskip
    \multiply\@tempdima by 256
    \@tempdimb\bbd@extra@fullwidth
    \divide\@tempdimb by 256
    \divide\@tempdima by \@tempdimb
    \ht\bbd@extra@note=\strip@pt\@tempdima\wd\bbd@extra@note
    \dp\bbd@extra@note\z@
    \box\bbd@extra@note
    \penalty\z@
}

% Join the two extra insertion classes before LaTeX builds its footnote area.
% Mixed directions follow bidi's order: normal notes, RTL group, LTR group.
\def\bbd@extra@join{%
    \bbd@extra@append\footins\bbd@extra@rtl{1}%
    \bbd@extra@append\footins\bbd@extra@ltr{0}%
}
\def\bbd@extra@joinmp{%
    \bbd@extra@append\@mpfootins\bbd@extra@mprtl{1}%
    \bbd@extra@append\@mpfootins\bbd@extra@mpltr{0}%
}

\def\bbd@extra@append#1#2#3{%
    \ifvoid#2\else
        \global\setbox#1\vbox{%
            \ifvoid#1\else
                \unvbox#1%
                \@tempskipa\skip#2%
                \ifnum\bbd@extra@layout=\z@
                    \advance\@tempskipa by -\bbd@extra@paraskip
                \fi
                \vskip\@tempskipa
            \fi
            \begingroup
            \bbd@setdir{#3}%
            \reset@font\footnotesize
            \@parboxrestore
            \hsize\columnwidth
            \ifnum\bbd@extra@layout=\z@
                \bbd@extra@paragraph#2%
            \else
                \bbd@extra@columns#2{#3}%
            \fi
            \endgroup
        }%
        \global\setbox#2\box\voidb@x
    \fi
}

% Split the remaining material by the number of columns still to fill, as
% bidi does. Keep each column's own direction; only reverse their order.
\def\bbd@extra@columns#1#2{%
    \setbox\bbd@extra@rest\box#1%
    \bbd@extra@remaining\bbd@extra@layout\relax
    \bbd@extra@width\bbd@extra@fraction\columnwidth
    \bbd@extra@gap\columnwidth
    \advance\bbd@extra@gap by -\bbd@extra@layout\bbd@extra@width
    \@tempcnta\bbd@extra@layout\relax \advance\@tempcnta\m@ne
    \divide\bbd@extra@gap by \@tempcnta
    \splittopskip\ht\strutbox
    \splitmaxdepth\dp\strutbox
    \vbadness\@M
    \setbox\bbd@extra@row\hboxL{}%
    \loop
    \bbd@extra@height\ht\bbd@extra@rest
    \divide\bbd@extra@height by \bbd@extra@remaining
    \advance\bbd@extra@height by \splittopskip
    \setbox\bbd@extra@piece\vsplit\bbd@extra@rest to \bbd@extra@height
    \setbox\bbd@extra@piece\vtop{%
        \hsize\bbd@extra@width
        \kern\z@
        \unvbox\bbd@extra@piece
    }%
    \wd\bbd@extra@piece\bbd@extra@width
    \setbox\bbd@extra@row\hboxL{%
        \ifnum#2=\z@
            \unhbox\bbd@extra@row
            \ifnum\bbd@extra@remaining<\bbd@extra@layout\relax
                \kern\bbd@extra@gap
            \fi
            \box\bbd@extra@piece
        \else
            \box\bbd@extra@piece
            \ifnum\bbd@extra@remaining<\bbd@extra@layout\relax
                \kern\bbd@extra@gap
            \fi
            \unhbox\bbd@extra@row
        \fi
    }%
    \advance\bbd@extra@remaining\m@ne
    \ifnum\bbd@extra@remaining>\z@\repeat
    \hboxL to \columnwidth{\unhbox\bbd@extra@row\hss}%
}

\def\bbd@extra@paragraph#1{%
    \setbox\bbd@extra@row\hbox{}%
    \setbox\bbd@extra@rest\vbox{%
        \unvbox#1%
        \bbd@extra@collect
    }%
    \parindent\z@
    \noindent\unhbox\bbd@extra@row\unskip\par
}
\def\bbd@extra@collect{%
    \unskip\unpenalty\unskip
    \setbox\bbd@extra@note\lastbox
    \ifhbox\bbd@extra@note
        \global\setbox\bbd@extra@row\hbox{%
            \unhbox\bbd@extra@note\unhbox\bbd@extra@row
        }%
        \expandafter\bbd@extra@collect
    \fi
}

\def\bbd@extra@reinsert#1{%
    \ifvoid#1\else\insert#1{\unvbox#1}\fi
}

\AddToHook{begindocument/before}[babelbidi/extrafootnotes]{%
    \DeclareCommandCopy{\bbd@extra@footnotetext}{\@footnotetext}%
    \DeclareCommandCopy{\bbd@extra@mpfootnotetext}{\@mpfootnotetext}%
    \long\def\@footnotetext#1{%
        \bbd@extra@insert{0}\bbd@extra@footnotetext{#1}%
    }%
    \long\def\@mpfootnotetext#1{%
        \bbd@extra@insert{1}\bbd@extra@mpfootnotetext{#1}%
    }%
    \bbl@sreplace\endminipage
    {\ifvoid\@mpfootins}{\bbd@extra@joinmp\ifvoid\@mpfootins}%
}
\DeclareHookRule{begindocument/before}{babelbidi/extrafootnotes}{after}{babelbidi/bidi-api}

\AddToHook{cmd/@makecol/before}{\bbd@extra@join}
\AddToHook{cmd/@doclearpage/before}{\bbd@extra@join}
\AddToHook{cmd/@reinserts/after}{%
    \bbd@extra@reinsert\bbd@extra@rtl
    \bbd@extra@reinsert\bbd@extra@ltr
}

\makeatother
\endinput