% -*- coding: utf-8 -*-
% SPDX-License-Identifier: GPL-2.0
%
% LaTeX preamble for "make latexdocs" or "make pdfdocs" including:
%   - TOC width settings
%   - Setting of tabulary (\tymin)
%   - Headheight setting for fancyhdr
%   - Fontfamily settings for CJK (Chinese, Japanese, and Korean) translations
%
% Note on the suffix of .sty:
%   This is not implemented as a LaTeX style file, but as a file containing
%   plain LaTeX code to be included into preamble.
%   ".sty" is chosen because ".tex" would cause the build scripts to confuse
%   this file with a LaTeX main file.
%
% Copyright (C) 2022  Akira Yokosawa

% Custom width parameters for TOC
%  - Redefine low-level commands defined in report.cls.
%  - Indent of 2 chars is preserved for ease of comparison.
% Summary of changes from default params:
%   Width of page number (\@pnumwidth): 1.55em -> 2.7em
%   Width of chapter number:            1.5em  -> 2.4em
%   Indent of section number:           1.5em  -> 2.4em
%   Width of section number:            2.6em  -> 3.2em
%   Indent of subsection number:        4.1em  -> 5.6em
%   Width of subsection number:         3.5em  -> 4.3em
%
% These params can have 4 digit page counts, 3 digit chapter counts,
% section counts of 4 digits + 1 period (e.g., 18.10), and subsection counts
% of 5 digits + 2 periods (e.g., 18.7.13).
\makeatletter
%% Redefine \@pnumwidth (page number width)
\renewcommand*\@pnumwidth{2.7em}
%% Redefine \l@chapter (chapter list entry)
\renewcommand*\l@chapter[2]{%
  \ifnum \c@tocdepth >\m@ne
    \addpenalty{-\@highpenalty}%
    \vskip 1.0em \@plus\p@
    \setlength\@tempdima{2.4em}%
    \begingroup
      \parindent \z@ \rightskip \@pnumwidth
      \parfillskip -\@pnumwidth
      \leavevmode \bfseries
      \advance\leftskip\@tempdima
      \hskip -\leftskip
      #1\nobreak\hfil
      \nobreak\hb@xt@\@pnumwidth{\hss #2%
                                 \kern-\p@\kern\p@}\par
      \penalty\@highpenalty
    \endgroup
  \fi}
%% Redefine \l@section and \l@subsection
\renewcommand*\l@section{\@dottedtocline{1}{2.4em}{3.2em}}
\renewcommand*\l@subsection{\@dottedtocline{2}{5.6em}{4.3em}}
\makeatother
%% Prevent default \sphinxtableofcontentshook from overwriting above tweaks.
\renewcommand{\sphinxtableofcontentshook}{} % Empty the hook

% Prevent column squeezing of tabulary.  \tymin is set by Sphinx as:
%   \setlength{\tymin}{3\fontcharwd\font`0 }
% , which is too short.
\setlength{\tymin}{20em}

% Adjust \headheight for fancyhdr
\addtolength{\headheight}{1.6pt}
\addtolength{\topmargin}{-1.6pt}

% Translations have Asian (CJK) characters which are only displayed if
% xeCJK is used
\usepackage{ifthen}
\newboolean{enablecjk}
\setboolean{enablecjk}{false}
\IfFontExistsTF{Noto Sans CJK SC}{
    \IfFileExists{xeCJK.sty}{
	\setboolean{enablecjk}{true}
    }{}
}{}
\ifthenelse{\boolean{enablecjk}}{
    % Load xeCJK when both the Noto Sans CJK font and xeCJK.sty are available.
    \usepackage{xeCJK}
    % Noto CJK fonts don't provide slant shape. [AutoFakeSlant] permits
    % its emulation.
    % Select KR variant at the beginning of each document so that quotation
    % and apostorph symbols of half-width is used in TOC of Latin documents.
    \IfFontExistsTF{Noto Serif CJK KR}{
	\setCJKmainfont{Noto Serif CJK KR}[AutoFakeSlant]
    }{
	\setCJKmainfont{Noto Sans CJK KR}[AutoFakeSlant]
    }
    \setCJKsansfont{Noto Sans CJK KR}[AutoFakeSlant]
    \setCJKmonofont{Noto Sans Mono CJK KR}[AutoFakeSlant]
    % Teach xeCJK of half-width symbols
    \xeCJKDeclareCharClass{HalfLeft}{`“,`‘}
    \xeCJKDeclareCharClass{HalfRight}{`”,`’}
    % CJK Language-specific font choices
    %% for Simplified Chinese
    \IfFontExistsTF{Noto Serif CJK SC}{
	\newCJKfontfamily[SCmain]\scmain{Noto Serif CJK SC}[AutoFakeSlant]
	\newCJKfontfamily[SCserif]\scserif{Noto Serif CJK SC}[AutoFakeSlant]
    }{
	\newCJKfontfamily[SCmain]\scmain{Noto Sans CJK SC}[AutoFakeSlant]
	\newCJKfontfamily[SCserif]\scserif{Noto Sans CJK SC}[AutoFakeSlant]
    }
    \newCJKfontfamily[SCsans]\scsans{Noto Sans CJK SC}[AutoFakeSlant]
    \newCJKfontfamily[SCmono]\scmono{Noto Sans Mono CJK SC}[AutoFakeSlant]
    %% for Traditional Chinese
    \IfFontExistsTF{Noto Serif CJK TC}{
	\newCJKfontfamily[TCmain]\tcmain{Noto Serif CJK TC}[AutoFakeSlant]
	\newCJKfontfamily[TCserif]\tcserif{Noto Serif CJK TC}[AutoFakeSlant]
    }{
	\newCJKfontfamily[TCmain]\tcmain{Noto Sans CJK TC}[AutoFakeSlant]
	\newCJKfontfamily[TCserif]\tcserif{Noto Sans CJK TC}[AutoFakeSlant]
    }
    \newCJKfontfamily[TCsans]\tcsans{Noto Sans CJK TC}[AutoFakeSlant]
    \newCJKfontfamily[TCmono]\tcmono{Noto Sans Mono CJK TC}[AutoFakeSlant]
    %% for Korean
    \IfFontExistsTF{Noto Serif CJK KR}{
	\newCJKfontfamily[KRmain]\krmain{Noto Serif CJK KR}[AutoFakeSlant]
	\newCJKfontfamily[KRserif]\krserif{Noto Serif CJK KR}[AutoFakeSlant]
    }{
	\newCJKfontfamily[KRmain]\krmain{Noto Sans CJK KR}[AutoFakeSlant]
	\newCJKfontfamily[KRserif]\krserif{Noto Sans CJK KR}[AutoFakeSlant]
    }
    \newCJKfontfamily[KRsans]\krsans{Noto Sans CJK KR}[AutoFakeSlant]
    \newCJKfontfamily[KRmono]\krmono{Noto Sans Mono CJK KR}[AutoFakeSlant]
    %% for Japanese
    \IfFontExistsTF{Noto Serif CJK JP}{
	\newCJKfontfamily[JPmain]\jpmain{Noto Serif CJK JP}[AutoFakeSlant]
	\newCJKfontfamily[JPserif]\jpserif{Noto Serif CJK JP}[AutoFakeSlant]
    }{
	\newCJKfontfamily[JPmain]\jpmain{Noto Sans CJK JP}[AutoFakeSlant]
	\newCJKfontfamily[JPserif]\jpserif{Noto Sans CJK JP}[AutoFakeSlant]
    }
    \newCJKfontfamily[JPsans]\jpsans{Noto Sans CJK JP}[AutoFakeSlant]
    \newCJKfontfamily[JPmono]\jpmono{Noto Sans Mono CJK JP}[AutoFakeSlant]
    % Define custom macros to on/off CJK
    %% One and half spacing for CJK contents
    \newcommand{\kerneldocCJKon}{\makexeCJKactive\onehalfspacing}
    \newcommand{\kerneldocCJKoff}{\makexeCJKinactive\singlespacing}
    % Define custom macros for switching CJK font setting
    %% for Simplified Chinese
    \newcommand{\kerneldocBeginSC}{%
	\begingroup%
	\scmain%
	\xeCJKDeclareCharClass{FullLeft}{`“,`‘}% Full-width in SC
	\xeCJKDeclareCharClass{FullRight}{`”,`’}% Full-width in SC
	\renewcommand{\CJKrmdefault}{SCserif}%
	\renewcommand{\CJKsfdefault}{SCsans}%
	\renewcommand{\CJKttdefault}{SCmono}%
	\xeCJKsetup{CJKspace = false}% gobble white spaces by ' '
	% For CJK ascii-art alignment
	\setmonofont{Noto Sans Mono CJK SC}[AutoFakeSlant]%
    }
    \newcommand{\kerneldocEndSC}{\endgroup}
    %% for Traditional Chinese
    \newcommand{\kerneldocBeginTC}{%
	\begingroup%
	\tcmain%
	\xeCJKDeclareCharClass{FullLeft}{`“,`‘}% Full-width in TC
	\xeCJKDeclareCharClass{FullRight}{`”,`’}% Full-width in TC
	\renewcommand{\CJKrmdefault}{TCserif}%
	\renewcommand{\CJKsfdefault}{TCsans}%
	\renewcommand{\CJKttdefault}{TCmono}%
	\xeCJKsetup{CJKspace = false}% gobble white spaces by ' '
	% For CJK ascii-art alignment
	\setmonofont{Noto Sans Mono CJK TC}[AutoFakeSlant]%
    }
    \newcommand{\kerneldocEndTC}{\endgroup}
    %% for Korean
    \newcommand{\kerneldocBeginKR}{%
	\begingroup%
	\krmain%
	\renewcommand{\CJKrmdefault}{KRserif}%
	\renewcommand{\CJKsfdefault}{KRsans}%
	\renewcommand{\CJKttdefault}{KRmono}%
	% \xeCJKsetup{CJKspace = true} % true by default
	% For CJK ascii-art alignment (still misaligned for Hangul)
	\setmonofont{Noto Sans Mono CJK KR}[AutoFakeSlant]%
    }
    \newcommand{\kerneldocEndKR}{\endgroup}
    %% for Japanese
    \newcommand{\kerneldocBeginJP}{%
	\begingroup%
	\jpmain%
	\renewcommand{\CJKrmdefault}{JPserif}%
	\renewcommand{\CJKsfdefault}{JPsans}%
	\renewcommand{\CJKttdefault}{JPmono}%
	\xeCJKsetup{CJKspace = false}% gobble white space by ' '
	% For CJK ascii-art alignment
	\setmonofont{Noto Sans Mono CJK JP}[AutoFakeSlant]%
    }
    \newcommand{\kerneldocEndJP}{\endgroup}

    % Single spacing in literal blocks
    \fvset{baselinestretch=1}
    % To customize \sphinxtableofcontents
    \usepackage{etoolbox}
    % Inactivate CJK after tableofcontents
    \apptocmd{\sphinxtableofcontents}{\kerneldocCJKoff}{}{}
    \xeCJKsetup{CJKspace = true}% For inter-phrase space of Korean TOC
    % Suppress extra white space at latin .. non-latin in literal blocks
    \AtBeginEnvironment{sphinxVerbatim}{\CJKsetecglue{}}
}{ % Don't enable CJK
    % Custom macros to on/off CJK and switch CJK fonts (Dummy)
    \newcommand{\kerneldocCJKon}{}
    \newcommand{\kerneldocCJKoff}{}
    %% By defining \kerneldocBegin(SC|TC|KR|JP) as commands with an argument
    %% and ignore the argument (#1) in their definitions, whole contents of
    %% CJK chapters can be ignored.
    \newcommand{\kerneldocBeginSC}[1]{%
	%% Put a note on missing CJK fonts or the xecjk package in place of
	%% zh_CN translation.
	\begin{sphinxadmonition}{note}{Note on missing fonts and a package:}
	    Translations of Simplified Chinese (zh\_CN), Traditional Chinese
	    (zh\_TW), Korean (ko\_KR), and Japanese (ja\_JP) were skipped
	    due to the lack of suitable font families and/or the texlive-xecjk
	    package.

	    If you want them, please install non-variable ``Noto Sans CJK''
	    font families along with the texlive-xecjk package by following
	    instructions from
	    \sphinxcode{./tools/docs/sphinx-pre-install}.
	    Having optional non-variable ``Noto Serif CJK'' font families will
	    improve the looks of those translations.
	\end{sphinxadmonition}}
    \newcommand{\kerneldocEndSC}{}
    \newcommand{\kerneldocBeginTC}[1]{}
    \newcommand{\kerneldocEndTC}{}
    \newcommand{\kerneldocBeginKR}[1]{}
    \newcommand{\kerneldocEndKR}{}
    \newcommand{\kerneldocBeginJP}[1]{}
    \newcommand{\kerneldocEndJP}{}
}
