% ===== Arabic RTL customizations for AI Agents in Depth =====
% Accent color comes from ElegantBook's cyan theme: \structurecolor = RGB(31,186,190)

% ── Text & math fonts: Palatino look, matching the author's papers ──
% The papers' preprint style (arxiv.sty) uses mathpazo (Palatino body +
% matching math) with helvet[scaled=.90] sans. These are the XeLaTeX-native
% equivalents: TeX Gyre Pagella (Palatino) text + TeX Gyre Pagella Math,
% and TeX Gyre Heros (Helvetica clone) sans. Must be set here rather than
% relying on the class: pandoc's template resets the fonts to Latin Modern
% after the class runs, so only preamble-level settings take effect.
% Loaded by filename (like the class's own setup): macOS fontconfig doesn't
% index texmf-dist, so family-name lookup would fail.
\usepackage{unicode-math}
\usepackage{polyglossia}
\setdefaultlanguage{arabic}
\setotherlanguage{english}
% Pandoc does not wrap every structural element in an explicit Arabic
% environment. Keep Arabic coverage in the global body/sans families; forcing
% Latin-only language families here makes unwrapped headings and captions lose
% their Arabic glyphs. The language-specific monospace families are defined
% with the selected true mono font below.
\IfFontExistsTF{Noto Naskh Arabic}{%
  \setmainfont[Script=Arabic,Scale=1.08]{Noto Naskh Arabic}%
  \newfontfamily\arabicfont[Script=Arabic,Scale=1.08]{Noto Naskh Arabic}%
}{\IfFontExistsTF{Amiri}{%
  \setmainfont[Script=Arabic,Scale=1.08]{Amiri}%
  \newfontfamily\arabicfont[Script=Arabic,Scale=1.08]{Amiri}%
}{%
  \setmainfont[Script=Arabic,Scale=1.08]{Geeza Pro}%
  \newfontfamily\arabicfont[Script=Arabic,Scale=1.08]{Geeza Pro}%
}}
\IfFontExistsTF{Noto Sans Arabic}{%
  \setsansfont[Script=Arabic,Scale=1.0]{Noto Sans Arabic}%
  \newfontfamily\arabicfontsf[Script=Arabic,Scale=1.0]{Noto Sans Arabic}%
}{%
  \setsansfont[Script=Arabic,Scale=1.0]{Arial}%
  \newfontfamily\arabicfontsf[Script=Arabic,Scale=1.0]{Arial}%
}
\setmathfont{texgyrepagella-math}[Extension = .otf]
\hypersetup{pdflang={ar}}

% ── Unicode glyph fallback (the text/mono fonts lack these) ──────
\usepackage{newunicodechar}
% macOS has Arial Unicode MS / Heiti SC; on Linux those Apple fonts are absent,
% so fall back to broad-coverage libre fonts to keep the build working.
\IfFontExistsTF{Arial Unicode MS}{\newfontfamily\fallbackfont{Arial Unicode MS}}{\newfontfamily\fallbackfont{DejaVu Sans}}
\IfFontExistsTF{Heiti SC}{\newunicodechar{★}{{\fontspec{Heiti SC}★}}}{\newunicodechar{★}{{\fontspec{Noto Sans CJK SC}★}}}
\newunicodechar{✓}{{\fallbackfont ✓}}
\newunicodechar{✗}{{\fallbackfont ✗}}
\newunicodechar{₀}{{\fallbackfont ₀}}
\newunicodechar{₁}{{\fallbackfont ₁}}
\newunicodechar{₂}{{\fallbackfont ₂}}
\newunicodechar{₃}{{\fallbackfont ₃}}
\newunicodechar{₄}{{\fallbackfont ₄}}
\newunicodechar{₅}{{\fallbackfont ₅}}
\newunicodechar{₆}{{\fallbackfont ₆}}
\newunicodechar{₇}{{\fallbackfont ₇}}
\newunicodechar{₈}{{\fallbackfont ₈}}
\newunicodechar{₉}{{\fallbackfont ₉}}
\newunicodechar{ⓐ}{{\fallbackfont ⓐ}}
\newunicodechar{ⓑ}{{\fallbackfont ⓑ}}
\newunicodechar{ⓒ}{{\fallbackfont ⓒ}}
\newunicodechar{ⓓ}{{\fallbackfont ⓓ}}
\newunicodechar{ⓔ}{{\fallbackfont ⓔ}}
% Math / symbols absent from the Latin text font
\newunicodechar{≈}{{\fallbackfont ≈}}
\newunicodechar{±}{{\fallbackfont ±}}
\newunicodechar{²}{{\fallbackfont ²}}
\newunicodechar{→}{{\fallbackfont →}}
\newunicodechar{←}{{\fallbackfont ←}}
\newunicodechar{↓}{{\fallbackfont ↓}}
\newunicodechar{─}{{\fallbackfont ─}}
\newunicodechar{－}{{\fallbackfont －}}
\newunicodechar{♠}{{\fallbackfont ♠}}
\newunicodechar{♣}{{\fallbackfont ♣}}
\newunicodechar{♥}{{\fallbackfont ♥}}
\newunicodechar{♦}{{\fallbackfont ♦}}
\newunicodechar{ư}{{\fallbackfont ư}}
% Greek letters used inline in body text (Latin Modern lacks them here)
\newunicodechar{Σ}{{\fallbackfont Σ}}
\newunicodechar{Φ}{{\fallbackfont Φ}}
\newunicodechar{α}{{\fallbackfont α}}
\newunicodechar{β}{{\fallbackfont β}}
\newunicodechar{γ}{{\fallbackfont γ}}
\newunicodechar{δ}{{\fallbackfont δ}}
\newunicodechar{ε}{{\fallbackfont ε}}
\newunicodechar{η}{{\fallbackfont η}}
\newunicodechar{θ}{{\fallbackfont θ}}
\newunicodechar{κ}{{\fallbackfont κ}}
\newunicodechar{λ}{{\fallbackfont λ}}
\newunicodechar{μ}{{\fallbackfont μ}}
\newunicodechar{π}{{\fallbackfont π}}
\newunicodechar{ρ}{{\fallbackfont ρ}}
\newunicodechar{σ}{{\fallbackfont σ}}
\newunicodechar{τ}{{\fallbackfont τ}}
\newunicodechar{φ}{{\fallbackfont φ}}
\newunicodechar{ω}{{\fallbackfont ω}}

% ── Residual CJK glyphs ──────────────────────────────────────────
% This is an English book, but a handful of Han characters still appear as
% inline examples (Chinese tokenization / translation / speech-recognition
% cases). Route just those code points to a CJK font so they render, without
% pulling in the whole ctex/xeCJK Chinese-typesetting stack. macOS: Heiti SC;
% Linux: Noto Sans CJK SC.
\IfFontExistsTF{Heiti SC}{\newfontfamily\cjkfallback{Heiti SC}}{\newfontfamily\cjkfallback{Noto Sans CJK SC}}
\newunicodechar{医}{{\cjkfallback 医}}
\newunicodechar{图}{{\cjkfallback 图}}
\newunicodechar{型}{{\cjkfallback 型}}
\newunicodechar{模}{{\cjkfallback 模}}
\newunicodechar{生}{{\cjkfallback 生}}
\newunicodechar{解}{{\cjkfallback 解}}
\newunicodechar{陈}{{\cjkfallback 陈}}
\newunicodechar{两}{{\cjkfallback 两}}
\newunicodechar{么}{{\cjkfallback 么}}
\newunicodechar{了}{{\cjkfallback 了}}
\newunicodechar{京}{{\cjkfallback 京}}
\newunicodechar{代}{{\cjkfallback 代}}
\newunicodechar{体}{{\cjkfallback 体}}
\newunicodechar{北}{{\cjkfallback 北}}
\newunicodechar{右}{{\cjkfallback 右}}
\newunicodechar{大}{{\cjkfallback 大}}
\newunicodechar{天}{{\cjkfallback 天}}
\newunicodechar{左}{{\cjkfallback 左}}
\newunicodechar{怎}{{\cjkfallback 怎}}
\newunicodechar{思}{{\cjkfallback 思}}
\newunicodechar{推}{{\cjkfallback 推}}
\newunicodechar{智}{{\cjkfallback 智}}
\newunicodechar{样}{{\cjkfallback 样}}
\newunicodechar{概}{{\cjkfallback 概}}
\newunicodechar{气}{{\cjkfallback 气}}
\newunicodechar{点}{{\cjkfallback 点}}
\newunicodechar{理}{{\cjkfallback 理}}
\newunicodechar{的}{{\cjkfallback 的}}
\newunicodechar{考}{{\cjkfallback 考}}
\newunicodechar{能}{{\cjkfallback 能}}
\newunicodechar{零}{{\cjkfallback 零}}

% ── Code/monospace font (covers Arabic comments + box drawing) ───
% Menlo and SF Mono omit Arabic, which turns translated code comments into
% empty squares. Courier New is monospaced and includes Arabic on macOS;
% DejaVu Sans Mono provides the same coverage on Linux.
\IfFontExistsTF{Courier New}{%
  \setmonofont[Scale=0.86]{Courier New}%
  \newfontfamily\englishfonttt[Scale=0.86]{Courier New}%
  \newfontfamily\arabicfonttt[Script=Arabic,Scale=0.86]{Courier New}%
}{%
  \setmonofont[Scale=0.86]{DejaVu Sans Mono}%
  \newfontfamily\englishfonttt[Scale=0.86]{DejaVu Sans Mono}%
  \newfontfamily\arabicfonttt[Script=Arabic,Scale=0.86]{DejaVu Sans Mono}%
}

% Pandoc's highlighted-code environments process text under the English
% language and a verbatim scanner. Even with an Arabic-capable mono font,
% unmarked Arabic runs are therefore laid out left-to-right. Detect Arabic in
% the token classes that can carry prose and hand just those runs back to
% Polyglossia so they are shaped and ordered correctly.
\ExplSyntaxOn
\cs_new_protected:Npn \arabic_code_wrap:n #1
  {
    \regex_match:nnTF { [\x{0600}-\x{06FF}] } { #1 }
      { \textarabic{#1} }
      { #1 }
  }
\NewDocumentCommand{\arabiccodewrap}{m}{\arabic_code_wrap:n{#1}}
\ExplSyntaxOff
\makeatletter
\@ifundefined{CommentTok}{}{%
  \let\arabiccodeoriginalcomment\CommentTok
  \renewcommand{\CommentTok}[1]{\arabiccodeoriginalcomment{\arabiccodewrap{#1}}}%
}
\@ifundefined{NormalTok}{}{%
  \let\arabiccodeoriginalnormal\NormalTok
  \renewcommand{\NormalTok}[1]{\arabiccodeoriginalnormal{\arabiccodewrap{#1}}}%
}
\@ifundefined{StringTok}{}{%
  \let\arabiccodeoriginalstring\StringTok
  \renewcommand{\StringTok}[1]{\arabiccodeoriginalstring{\arabiccodewrap{#1}}}%
}
\makeatother

% ── tcolorbox (ElegantBook already loads it; just add libraries) ──
\tcbuselibrary{skins,breakable}

% ── TikZ (for the full-bleed image cover in cover.tex) ───────────
\usepackage{tikz}
\usetikzlibrary{fadings}
% Vertical fade: invisible at the top, solid at the bottom — lets the cover
% art melt smoothly into the navy title band.
\tikzfading[name=titlefade, top color=transparent!100, bottom color=transparent!0]

% Theme accent color: override ElegantBook's bright cyan with a deep navy
% (classic, authoritative technical-book tone). Drives headings, rules, links,
% code chrome and the cover. Tweak this one line to restyle the whole book.
\definecolor{structurecolor}{RGB}{30,58,107}

% Accent shade for code/figure chrome (follows the theme color above)
\colorlet{accent}{structurecolor}

% Internal cross-reference links (图N-M / 第N章) — clickable + subtle teal,
% independent of the document class's global linkcolor. Used by crossref.lua.
\newcommand{\crossreflink}[2]{\hyperref[#1]{\textcolor{structurecolor}{#2}}}
\colorlet{accentbg}{structurecolor!6}
\colorlet{accentrule}{structurecolor!35}

% ── Wrap long lines in code blocks ───────────────────────────────
% pandoc emits fancyvrb's Verbatim (via `Highlighting` for ```lang blocks
% and plain `verbatim` for un-tagged blocks); neither wraps by default, so
% long lines overflow the page. fvextra adds breaklines; re-define both
% environments to wrap, breaking mid-token when a chunk has no spaces (URLs,
% long identifiers, CJK comments). A teal ↳ marks each continued line.
\usepackage{fvextra}
\fvset{breaklines=true,breakanywhere=true,%
  breaksymbolleft={\footnotesize\textcolor{accentrule}{$\hookrightarrow$}\,}}
\DefineVerbatimEnvironment{Highlighting}{Verbatim}{%
  commandchars=\\\{\},breaklines,breakanywhere}

% ── Code blocks: subtle O'Reilly-style framed box ────────────────
% One shared box style for ALL code blocks so highlighted (```lang → Shaded)
% and plain (``` → verbatim) blocks look identical. The plain verbatim nests
% a fvextra Verbatim inside the box; \VerbatimEnvironment makes it end at
% \end{verbatim} (the outer env name) rather than \end{Verbatim}.
\newtcolorbox{codebox}{%
  breakable, enhanced,
  colback=black!3, colframe=accentrule,
  boxrule=0.5pt, leftrule=2.5pt,
  left=0.7em, right=0.6em, top=0.4em, bottom=0.4em,
  arc=0.6mm,
  before skip=0.7em, after skip=0.7em
}
\makeatletter
\@ifundefined{Shaded}{\newenvironment{Shaded}{}{}}{}
\makeatother
\renewenvironment{Shaded}{\begin{english}\begin{codebox}}{\end{codebox}\end{english}}
\renewenvironment{verbatim}%
  {\VerbatimEnvironment\begin{english}\begin{codebox}\begin{Verbatim}}%
  {\end{Verbatim}\end{codebox}\end{english}}

% ── Experiment & question callouts (used by experiment_box.lua) ───
\newtcolorbox{experimentbox}{
  breakable, enhanced,
  colback=accentbg, colframe=accent,
  boxrule=0.6pt, left=0.8em, right=0.8em, top=0.6em, bottom=0.6em,
  arc=1mm, before skip=0.9em, after skip=0.9em
}

\newtcolorbox{questionbox}{
  breakable, enhanced,
  colback=accentbg, colframe=accent,
  boxrule=0.8pt, left=0.9em, right=0.9em, top=0.9em, bottom=0.7em,
  arc=1.2mm, before skip=0.9em, after skip=0.9em,
  title={\sffamily\bfseries للتفكير المتعمق},
  fonttitle=\normalsize\color{white},
  coltitle=white,
  attach boxed title to top left={xshift=1em, yshift=-\tcboxedtitleheight/2},
  boxed title style={colback=accent, colframe=accent, arc=0.8mm, outer arc=0.8mm}
}

% ── Figures: force [H] so they can sit inside callout/quote boxes ─
\usepackage{float}
\let\origfigure\figure
\let\origendfigure\endfigure
\renewenvironment{figure}[1][htbp]{\origfigure[H]}{\origendfigure}
\setkeys{Gin}{width=\linewidth,height=0.38\textheight,keepaspectratio}

% ── Captions: manual numbering in text, so suppress auto labels ──
\usepackage{caption}
% Sans, bold, centered. Figure numbers live in the image caption itself, and
% table numbers are likewise written immediately above each table as
% "جدول N-M ...". Suppress labels globally; limiting this to figures would
% duplicate every manual table number with an automatic "الجدول N:" prefix.
\captionsetup{font={normalsize,sf,bf}, labelformat=empty, skip=4pt, justification=centering}

% ── Blockquotes: teal left bar (experiments render as quotes) ────
\renewenvironment{quote}{%
  \begin{tcolorbox}[
    blanker, breakable,
    borderline east={2.5pt}{0pt}{accent},
    colback=accent!4,
    left=1em, right=0.6em, top=0.5em, bottom=0.5em,
    before skip=0.6em, after skip=0.6em
  ]%
}{%
  \end{tcolorbox}%
}

% ── Inline code: keep it tight ───────────────────────────────────
\setlength{\parindent}{2em}

% Arabic structural labels and document direction.
\AtBeginDocument{%
  \renewcommand{\contentsname}{المحتويات}%
  \renewcommand{\chaptername}{الفصل}%
  \renewcommand{\figurename}{الشكل}%
  \renewcommand{\tablename}{الجدول}%
}

% A long code block may cross a page while English is the active language.
% Force stored Arabic chapter/section marks back through the Arabic font so
% running headers never lose glyphs on those pages.
\makeatletter
\if@twoside
  \fancyhead[EL]{\color{structurecolor}\cnormal\textarabic{\leftmark}}
  \fancyhead[OR]{\color{structurecolor}\cnormal\textarabic{\rightmark}}
\else
  \fancyhead[R]{\color{structurecolor}\cnormal\textarabic{\rightmark}}
\fi
\makeatother

% ElegantBook empties the `plain` page style used on chapter-opening pages.
% Keep those pages numbered, matching the centered footer on regular pages.
\fancypagestyle{plain}{%
  \fancyhf{}%
  \fancyfoot[C]{\color{structurecolor}\small\thepage}%
  \renewcommand{\headrulewidth}{0pt}%
  \renewcommand{\footrulewidth}{0pt}%
}