\NeedsTeXFormat{LaTeX2e}
\ProvidesClass{cccbform}[2024-11-08 In the Beginning, There Was Chaos]

\LoadClass{scrartcl}
\RequirePackage{geometry, calc, xparse, xcolor, hyperref, tikz,
		fontspec, changepage, letltxmacro, textpos}

% address
\newcommand{\address}{%
	Chaos Computer Club Berlin / CCC~(B)~e.~V.\\
	Marienstr.~11\\
	10117~Berlin
}

% page
\geometry{a4paper, margin=1.5cm, inner=2.5cm}
\pagestyle{empty}

% fonts
\setmainfont{Barlow}

% colors
\definecolor{fieldcolor}{gray}{0.94}
\definecolor{bordercolor}{gray}{0.5}

% lengths
\def\deflength#1#2{\newlength{#1}\setlength{#1}{#2}}
\setlength{\parindent}{0pt}
\setlength{\fboxsep}{0pt}
\deflength{\formfieldheight}{14pt}
\deflength{\formskip}{0.5em}
\deflength{\indentstep}{1cm}
\deflength{\borderwidth}{0.5pt}

% counters
\newcounter{fieldnum}
\def\@autofieldname{field\thefieldnum}

% abbreviations
\def\@formdefaults{%
	backgroundcolor=fieldcolor,bordercolor=fieldcolor,%
	borderwidth=0pt,charsize=\formfieldheight%
}

% address placement helper
\newcommand{\@dinaddress}{%
	\begin{tikzpicture}[remember picture, overlay]
		\node[anchor=north west] at (current page.north west) [xshift=2.35cm, yshift=-5cm] {%
		\begin{minipage}{10cm}
			\emph{an den} \par
			\vspace{\formskip}
			\noindent\address
		\end{minipage}
		};
	\end{tikzpicture}
}

% % % form@, fake@, and full@ variants of the form elements:
%
% (raw@: renamed / prefixed hyperref command)
% form@: PDF form element (some viewers don't print it)
% fake@: A colored box, non-interactive (but will be printed!)
% full@: a stack of fake@ and form@ on top of each other
%
% The general parameter convention here is: height, width multiplier
% - height is optional and defaults to \formfieldheight, giving the right size
%   for a single-line text field
% - width is "mandatory" but always used followed by \linewidth, so passing an
%   empty argument works and is effectively equivalent to passing 1

% rename commands to make nice names available
\LetLtxMacro\raw@TextField\TextField
\LetLtxMacro\raw@CheckBox\CheckBox
\let\CheckBox\relax

% wrapped form fields with defaults filled in
\NewDocumentCommand{\form@TextField}{O{\formfieldheight} m}{%
	\stepcounter{fieldnum}
	\expandafter\raw@TextField\expandafter[\@formdefaults,
		name=\@autofieldname,
		width=\dimexpr #2\linewidth - 4pt \relax,
		height=\dimexpr #1 - 3pt \relax
	]{}%
}

\NewDocumentCommand{\form@MultilineTextField}{O{\formfieldheight} m}{%
	\stepcounter{fieldnum}
	\expandafter\raw@TextField\expandafter[\@formdefaults,
		name=\@autofieldname,
		multiline=true,
		width=\dimexpr #2\linewidth - 4pt \relax,
		height=\dimexpr #1 - 3pt \relax
	]{}%
}

\NewDocumentCommand{\form@CheckBox}{}{%
	\stepcounter{fieldnum}
	\expandafter\raw@CheckBox\expandafter[\@formdefaults,
		name=\@autofieldname,
		width=\dimexpr \formfieldheight - 3pt \relax,
		height=\dimexpr \formfieldheight - 3pt \relax
	]{}%
}

% fake form fields to put *under* the PDF form fields
\NewDocumentCommand{\fake@TextField}{O{\formfieldheight} m}{%
	\begin{tikzpicture}[baseline=0.6ex]
		\fill[fieldcolor]
			(0,0) rectangle (#2\linewidth - 2\borderwidth,#1);
		\draw[dash pattern=on 0.5\borderwidth off 5\borderwidth,bordercolor,
				line width=\borderwidth, line cap=round]
			(0,0) -- (#2\linewidth - 2\borderwidth,0);
	\end{tikzpicture}
}

\LetLtxMacro\fake@MultilineTextField\fake@TextField

\NewDocumentCommand{\fake@CheckBox}{}{%
	\begin{tikzpicture}[baseline=0.6ex]
		\fill[fieldcolor]
			(0,0) rectangle (\formfieldheight,\formfieldheight);
		\draw[bordercolor,line width=\borderwidth]
			(0,0) rectangle (\formfieldheight,\formfieldheight);
	\end{tikzpicture}
}

% "full" stacked version of fake + actual form field
\NewDocumentCommand{\full@TextField}{O{\formfieldheight} m}{%
	\leavevmode\smash{\rlap{\fake@TextField[#1]{#2}}}%
	\raisebox{-1.5pt}{\kern-0.5pt\form@TextField[#1]{#2}}%
}

\NewDocumentCommand{\full@MultilineTextField}{O{\formfieldheight} m}{%
	\leavevmode\smash{\rlap{\fake@MultilineTextField[#1]{#2}}}%
	\raisebox{-1.5pt}{\kern-0.5pt\form@MultilineTextField[#1]{#2}}%
}

\NewDocumentCommand{\full@CheckBox}{}{%
	\leavevmode\smash{\rlap{\fake@CheckBox}}%
	\raisebox{-1.75pt}{\kern-0.5pt\form@CheckBox}%
}

% % % exposed form elements

% Text{text…} - just text, with proper spacing
\NewDocumentCommand{\Text}{m}{%
	\par#1\par\vspace{\formskip}
}

% TextField{label} - a single-line input
\RenewDocumentCommand{\TextField}{m}{%
	\par%
	{\small #1\strut}\\%
	\full@TextField{}%
	\par\vspace{\formskip}%
}

% ShortTextField[width]{label} - a single-line input that doesn't have full width
%                                (50% by default)
\NewDocumentCommand{\ShortTextField}{O{0.5} m}{%
	\par%
	{\small #2\strut}\\%
	\full@TextField{#1}%
	\par\vspace{\formskip}%
}

% MultilineTextField[height]{label} - a multi-line input
\NewDocumentCommand{\MultilineTextField}{O{} m}{%
	\par%
	{\small #2\strut}\\%
	\full@MultilineTextField[#1]{}%
	\par\vspace{\formskip}%
}

% Signature[label] - a field not fillable on the computer, big enough for a signature
\NewDocumentCommand{\Signature}{O{Datum, Unterschrift}}{%
	\par%
	{\small #1\strut}\\%
	\fake@MultilineTextField[1.0cm]{0.5}%
	\par\vspace{\formskip}%
}

% Notes[label] - a slightly taller fake field that fills the whole width
\NewDocumentCommand{\Notes}{O{Vermerke}}{%
	\par%
	{\small #1\strut}\\%
	\fake@MultilineTextField[1.5cm]{}%
	\par\vspace{\formskip}%
}

% Checkbox{label} - a checkbox; label can be long and will linebreak reasonably pretty
\NewDocumentCommand{\Checkbox}{m}{%
	\par%
	\full@CheckBox\quad%
	\begin{minipage}[t]{\dimexpr \linewidth - \formfieldheight - 1em \relax}%
		#1%
	\end{minipage}%
	\par\vspace{\formskip}%
}

% CheckboxOther[width]{label} - a checkbox for a write-in option
\NewDocumentCommand{\CheckboxOther}{O{0.5} m}{%
	\par%
	\full@CheckBox\quad#2\quad\full@TextField{#1}%
	\par\vspace{\formskip}%
}

% high-level structure

% Section{title} - a form section
\NewDocumentCommand{\Section}{m}{%
	\vspace{1.5cm}%
	{\Large\bfseries #1}%
	\par\vspace{2\formskip}%
}

% Subsection{title} - slightly smaller than section
\NewDocumentCommand{\Subsection}{m}{%
	\vspace{1.0cm}%
	{\large\bfseries #1}%
	\par\vspace{\formskip}%
}

% Rule - a horizontal rule, with correct spacing
\NewDocumentCommand{\Rule}{}{%
	\vspace{\formskip}%
	\rule{\linewidth}{\borderwidth}%
	\vspace{2\formskip}%
}

% RuleSection - rule followed by a small note *immediately* below, before the spacing
%               (e.g. to separate public / internal sections of a form)
\NewDocumentCommand{\RuleSection}{m}{%
	\vspace{\formskip}%
	\leavevmode\rule{\linewidth}{\borderwidth}\\%
	{\details{#1}}%
	\par\vspace{2\formskip}
}

% \begin{Indented}[factor] ... \end{Indented} - indent a section
\NewDocumentEnvironment{Indented}{O{}}{%
	\begin{adjustwidth}{#1\indentstep}{0pt}%
}{%
	\end{adjustwidth}%
}

% TwoColumns{left}{right} - put two sections side-by-side
\NewDocumentCommand{\TwoColumns}{m m}{%
	\begin{minipage}[t]{0.48\linewidth}%
		#1%
	\end{minipage}%
	\hfill
	\begin{minipage}[t]{0.48\linewidth}%
		#2%
	\end{minipage}%
	\par
}

% details{text} - (use instead of font sizes, small text)
\NewDocumentCommand{\details}{m}{%
	{\scriptsize #1}%
}

% % % common title patterns

% LogoTitle{title} - logo on the right, title on the left
\NewDocumentCommand{\LogoTitle}{m}{
	\begin{tikzpicture}[remember picture, overlay]
		\node[anchor=north east] at (current page.north east) [xshift=-1.5cm, yshift=-1.5cm] {%
			\includegraphics[width=3cm]{logo.pdf}%
		};
	\end{tikzpicture}%
	\\[1cm]{\huge\bfseries #1}\\[1.5cm]
}

% AddressTitle{title} - title at the top, address, then the form below
\NewDocumentCommand{\AddressTitle}{m}{
	\@dinaddress
	\\[1cm]\smash{{\huge\bfseries #1}}\\[4cm]
}

% need to emit \Form ; hyperref generates incomplete CheckBox appearance data,
% which causes problems with some viewers - so it's currently better not to
% generate any at all
\AtBeginDocument{
\Form[NeedAppearances=false]
}