% Specify the class of the document.
% This is a Chinese BOOK (hence "ctexbook");
% this uses UTF8;
% this uses fonts to be specified (hence fontset=none);
% this uses the size of "小四" (hence zihao=-4);
% the numbers of equations will be displayed in the inner side
% (the left side on odd pages) (hence leqno).
% this uses A4 paper.
% Punctuation style: narrow some punctuation symbols.
\documentclass[%
    UTF8,%
    fontset=none,%
    punct=kaiming,%
    zihao=-4,%
    a4paper,%
    leqno%
]{ctexbook}

% Specify the fonts used by the document.
\setmainfont{XITS}
\setsansfont{Fira Sans}[
    UprightFont = * Light,
    BoldFont = * SemiBold,
    ItalicFont = * Light Italic,
    BoldItalicFont = * SemiBold Italic
]
\setmonofont{Sarasa Mono SC}[
    UprightFont = * Light,
    BoldFont = * Semibold,
    ItalicFont = * Light Italic,
    BoldItalicFont = * Semibold Italic
]
\setCJKmainfont{Source Han Serif CN}[
    UprightFont = * Light,
    BoldFont = Sarasa Mono SC Semibold,
    ItalicFont = Sarasa Mono SC Light Italic,
    BoldItalicFont = Sarasa Mono SC Semibold Italic
]
\setCJKsansfont{Sarasa Mono SC}[
    UprightFont = * Light,
    BoldFont = * Semibold,
    ItalicFont = * Light Italic,
    BoldItalicFont = * Semibold Italic
]
\setCJKmonofont{Sarasa Mono SC}[
    UprightFont = * Light,
    BoldFont = * Semibold,
    ItalicFont = * Light Italic,
    BoldItalicFont = * Semibold Italic
]

% If you do not want to use external fonts mentioned above,
% consider commenting lines 27--50
% and uncommenting lines 55--72.
% \setCJKmainfont{FandolSong}[
%     UprightFont = *,
%     BoldFont = FandolHei,
%     ItalicFont = FandolKai,
%     BoldItalicFont = FandolHei,
% ]
% \setCJKsansfont{FandolHei}[
%     UprightFont = *,
%     BoldFont = *,
%     ItalicFont = FandolKai,
%     BoldItalicFont = *,
% ]
% \setCJKmonofont{FandolFang}[
%     UprightFont = *,
%     BoldFont = FandolHei,
%     ItalicFont = FandolKai,
%     BoldItalicFont = FandolHei,
% ]

% Redefine the emphasis style.
\let\emph\relax
\DeclareTextFontCommand{\emph}{\bfseries}

% Add "pass" to retain the old page margin settings.
% \usepackage[pass]{geometry}

% Allow easier imports.
\usepackage{import}

% Make aliases.
\makeatletter
\providecommand*{\thetitle}{\@title}
\providecommand*{\theauthor}{\@author}
\providecommand*{\thedate}{\@date}
\makeatother

% This package makes modifications to existing commands easier.
\usepackage{xpatch}
% unnumbered sections, subsections, subsubsections etc.
% (parts are still numbered)
\xapptocmd{\frontmatter}{\setcounter{secnumdepth}{0}}{}{}
% numbered parts, chapters, sections,
% subsections, subsubsections etc.
\xapptocmd{\mainmatter}{\setcounter{secnumdepth}{2}}{}{}
% unnumbered sections, subsections, subsubsections etc.
% (Parts are still numbered.)
\xapptocmd{\backmatter}{\setcounter{secnumdepth}{0}}{}{}
% Modify how margin notes look.
\makeatletter
\xapptocmd{\@marginparreset}{%
    \footnotesize\raggedright\sffamily\itshape%
}{}{}
\makeatother

% This is a package which makes indices.
% Load "imakeidx" (or "makeidx") before "hyperref".
\usepackage[quiet]{imakeidx}
\makeindex[intoc]
\makeindex[
    name=testing,
    title={List of Vegetables, Fruits and Spices},
    intoc
]

% This is a package which includes a lot of logos about TeX.
\usepackage{hologo}

% This is a package which makes it possible
% to typeset numbers correctly and easily.
\usepackage[group-minimum-digits=4]{siunitx}

% These are packages which deal with mathematical formulae.
\usepackage{amsmath}
\usepackage{mathtools}
\usepackage[
    math-style=ISO,
    bold-style=ISO,
    mathrm=sym,
    mathbf=sym,
    partial=upright,
    warnings-off={mathtools-colon,mathtools-overbracket}
]{unicode-math}
\allowdisplaybreaks[3]
% Standing-up-straight integral symbol (For XITS Math).
\setmathfont{XITS Math}[StylisticSet=8]
\setmathfont{TeX Gyre Termes Math}[range=bb/{latin,Latin}]
\setmathfont{STIX Two Math}[range={"2218-"2218}]

% These are packages which deal with theorem environments.
\usepackage{amsthm}
\usepackage{thmtools}
\usepackage{thm-restate}
\declaretheoremstyle[%
    spaceabove=2ex,%
    spacebelow=2ex,%
    headfont=\normalfont\bfseries,%
    notefont=\normalfont,%
    notebraces={(}{)},%
    bodyfont=\normalfont,%
    headindent=\parindent,%
    headpunct={},%
    postheadspace=1em%
]{TheoremStyle}
\declaretheoremstyle[%
    spaceabove=2ex,%
    spacebelow=2ex,%
    headfont=\normalfont\bfseries,%
    notefont=\normalfont,%
    notebraces={(}{)},%
    bodyfont=\normalfont,%
    headindent=\parindent,%
    headpunct={},%
    postheadspace=1em,%
    qed=\qedsymbol%
]{ProofStyle}
\declaretheorem[%
    style=TheoremStyle,%
    name=定理,%
    numberwithin=chapter%
]{theorem}
\declaretheorem[%
    style=TheoremStyle,%
    name=定义,%
    sibling=theorem%
]{definition}
\declaretheorem[%
    style=TheoremStyle,%
    name=定义,%
    numbered=no%
]{definition*}
\declaretheorem[%
    style=TheoremStyle,%
    name=命题,%
    sibling=theorem%
]{proposition}
\declaretheorem[%
    style=TheoremStyle,%
    name=引理,%
    sibling=theorem%
]{lemma}
\declaretheorem[%
    style=TheoremStyle,%
    name=公理,%
    sibling=theorem%
]{axiom}
\declaretheorem[%
    style=TheoremStyle,%
    name=推论,%
    sibling=theorem%
]{corollary}
\declaretheorem[%
    style=TheoremStyle,%
    name=例,%
    sibling=theorem%
]{example}
\declaretheorem[%
    style=TheoremStyle,%
    name=注,%
    sibling=theorem%
]{remark}
\declaretheorem[%
    style=TheoremStyle,%
    name=注,%
    numbered=no%
]{remark*}
\declaretheorem[%
    style=TheoremStyle,%
    name=猜想,%
    sibling=theorem%
]{conjecture}
% Undefine the proof environment provided by `amsthm`
\let\proof\relax
\let\endproof\relax
\declaretheorem[%
    style=ProofStyle,%
    name=证,
    numbered=no%
]{proof}
\renewcommand*{\qedsymbol}{证毕.}

% These are packages which deal with hyperlinks.
\usepackage[hidelinks,hyperindex,breaklinks]{hyperref}
% Add hyperlinks to the table of contents.
\usepackage{bookmark}

% This package deals with footnotes.
% Slightly modify the style of the footnotes.
\usepackage[perpage,multiple,symbol*]{footmisc}

% This package deals with headers and footers.
\usepackage{fancyhdr}
\pagestyle{fancy}
\fancyhf{}
\setlength{\headheight}{15pt}
\fancyhead[LO]{\sffamily\nouppercase{\rightmark}}
\fancyhead[RO]{\sffamily\thepage}
\fancyhead[RE]{\sffamily\nouppercase{\leftmark}}
\fancyhead[LE]{\sffamily\thepage}
\renewcommand*{\headrulewidth}{0pt}
\renewcommand*{\footrulewidth}{0pt}
\fancypagestyle{plain}{%
    \fancyhf{}
    \fancyfoot[C]{\sffamily\thepage}
    \renewcommand*{\headrulewidth}{0pt}
    \renewcommand*{\footrulewidth}{0pt}
}

% If a chapter has no section,
% mark the header on the odd pages as well.
% Put the definition after fancyhdr.
\renewcommand*{\chaptermark}[1]{%
    \markboth{\CTEXifname{\CTEXthechapter\hspace{\ccwd}}{%
        }#1}{\CTEXifname{\CTEXthechapter\hspace{\ccwd}}{%
        }#1}%
}

% No page numbers or headers or footers on empty pages.
\usepackage{emptypage}

% Ensure that the number of pages is even.
\usepackage{evenpage}

% This package deals with lists,
% including numbered and unnumbered ones.
\usepackage{enumitem}
\setlist[1]{labelindent=\parindent}
\setlist[itemize]{leftmargin=*,nosep}
\setlist[enumerate]{leftmargin=*,nosep,align=left}
\setlist[enumerate,1]{label=(\arabic*),ref=(\arabic*)}
\setlist[description]{style=nextline,leftmargin=2\parindent}

% Insert the table of bibliography (and reference).
\usepackage[backend=biber,style=gb7714-2015]{biblatex}
% Multiple .bib files can also be added.
\addbibresource{data/bibliography.bib}
\addbibresource{data/less important references.bib}
\addbibresource{data/other references.bib}

% Trick: https://tex.stackexchange.com/questions/294362/use-fira-code-font-with-ligatures-in-code-listings
% Make the mono-space font look better.
\makeatletter
\def\verbatim@nolig@list{}
\makeatother

% Display the code more easily.
\usepackage[savemem]{listings}
\lstset{% general command to set parameter(s)
    basicstyle=\ttfamily,
    breaklines=true,
    columns=fullflexible,
    keepspaces=true,
    tabsize=4
}
\renewcommand*{\lstlistingname}{码}
\renewcommand*{\lstlistlistingname}{代码}

% Insert figures.
\usepackage{graphicx}
\graphicspath{{images/}}
% Insert and configure captions.
\usepackage{caption}
% Insert sub-figures.
\usepackage{subcaption}

% Make long tables.
\usepackage{longtable}
% Line break in a cell.
\providecommand*{\makecell}[2][c]{%
    \begin{tabular}[#1]{@{}l@{}}#2\end{tabular}}

% This package deals with arrays.
% The following code makes it easier to input a version number
% converging to 2pi.
%
% Usage: \ApproxToTwoPi[n], where n is a positive integer
% less than 1100.
\usepackage{readarray}
\readrecordarray{data/ApproximationsTo2Pi.txt}\ApproxToTwoPi

% This package deals with glossaries.
\usepackage[nonumberlist,nopostdot,toc=true]{glossaries-extra}
\newglossary*{lore}{List of Lores}
\makenoidxglossaries
\input{data/glossary entries}
\input{data/lores}
% Enable to print all entries without even referring to them.
\glsaddall

% This is something between \fussy and \sloopy.
% Source: memoir.
\makeatletter
\providecommand*{\midsloppy}{%
    \tolerance 5000%
    \hbadness 4000%
    \emergencystretch 1.5em%
    \hfuzz .1\p@%
    \vfuzz\hfuzz}
\makeatother

% Some xeCJK settings.
\xeCJKsetup{%
    xCJKecglue = true,%
    CheckSingle = true,%
}

% These are modifications which are
% to be inserted after \begin{document}.
\AtBeginDocument{%
    % A magic that kills as many overfull lines as possible.
    \midsloppy

    \renewcommand*{\UrlFont}{\ttfamily}

    \let\umathpi\pi
    \renewcommand*{\pi}{\symup\umathpi}
    \let\umathiota\iota
    \renewcommand*{\iota}{\symup\umathiota}

    \renewcommand*{\leq}{\leqslant}
    \renewcommand*{\geq}{\geqslant}
    \renewcommand*{\mathellipsis}{\cdots}

    \renewcommand*{\Re}{\operatorname{Re}}
    \renewcommand*{\Im}{\operatorname{Im}}
}