% Section designs using memoir's public formatting hooks.
% Copyright 2026 Adib Hasan. Part of BOOKbangla; LPPL 1.3c or later.

% Restore the loaded memoir defaults when selecting default or switching styles.
\NewCommandCopy\bookbangla@memoirsecheadstyle\secheadstyle
\NewCommandCopy\bookbangla@memoirsecnumformat\@seccntformat
\newcommand*\bookbangla@sectionstyle[1]{%
  \let\secheadstyle\bookbangla@memoirsecheadstyle
  \let\@seccntformat\bookbangla@memoirsecnumformat
  \csname bookbangla@section@#1\endcsname}

% Keep section titles at memoir's Large size and leave lower heading levels alone.
% Decorate only section headings; references, contents and lower levels retain
% their ordinary numbers. The format is expanded by memoir before typesetting.
\newcommand*\bookbangla@sectionnumber[1]{%
  \setsecnumformat{%
    \ifstrequal{##1}{section}{#1}%
      {\bookbangla@memoirsecnumformat{##1}}}}
\newcommand*\bookbangla@section@classic{%
  \setsecheadstyle{\raggedright\Large\bfseries}%
  \bookbangla@sectionnumber{\S\,\thesection\hspace{.5em}}}
% Hanging numerals and a fine divider give modern a clear textbook hierarchy.
\newcommand*\bookbangla@section@modern{%
  \setsecheadstyle{\raggedright\Large\bfseries}%
  \bookbangla@sectionnumber{\bookbangla@modernsectionnumber}}
\DeclareRobustCommand\bookbangla@modernsectionnumber{%
  {\color{bookbanglaaccent}\Large\bfseries
    % Enlarge only the chapter component, keeping the author's numbering format.
    \let\bookbangla@sectionchapter\thechapter
    \renewcommand*\thechapter{\scalebox{1.4}{\bookbangla@sectionchapter}}%
    \thesection}%
  \hspace{.65em}{\color{bookbanglaaccent}\vrule width.6pt height1.1em depth.25em}%
  \hspace{.65em}}

% Centered crossheads follow the tradition represented by memoir's crosshead
% and Dowding styles. Use ordinary Bangla letterforms rather than small caps.
\newcommand*\bookbangla@section@minimal{%
  \setsecheadstyle{\centering\Large\mdseries\bookbangla@centeredsection}%
  \bookbangla@sectionnumber{\bookbangla@centeredsectionnumber}}
\DeclareRobustCommand\bookbangla@centeredsectionnumber{%
  {\color{bookbanglaaccent}\thesection}\nobreak\hspace{.65em}}
\newcommand\bookbangla@centeredsection[1]{%
  \sethangfrom{\noindent##1}%
  #1}

% A short heavy lead-in joins a hairline above the title. This uses the same
% rule-and-type vocabulary as titlesec's examples, through memoir's own hooks.
\newcommand*\bookbangla@section@ruled{%
  \setsecheadstyle{\raggedright\Large\bfseries\bookbangla@ruledsection}}
\newcommand\bookbangla@ruledsection[1]{%
  \noindent\hbox to\linewidth{\color{bookbanglaaccent}%
    \vrule width2em height1.6pt depth0pt\leaders\hrule height.4pt\hfill}%
  \par\nobreak\vskip6pt
  #1}
\newcommand*\bookbangla@section@default{}
\bookbangla@sectionstyle{classic}
\endinput