% \iffalse meta-comment
%
% TUDa-CI -- Corporate Design for TU Darmstadt
% ----------------------------------------------------------------------------
%
%  Copyright (C) 2018--2026 by Marei Peischl <marei@peitex.de>
%
% ============================================================================
% This work may be distributed and/or modified under the
% conditions of the LaTeX Project Public License, either version 1.3c
% of this license or (at your option) any later version.
% The latest version of this license is in
% http://www.latex-project.org/lppl.txt
% and version 1.3c or later is part of all distributions of LaTeX
% version 2008/05/04 or later.
%
% This work has the LPPL maintenance status `maintained'.
%
% The Current Maintainer of this work is
%   Marei Peischl <tuda-ci@peitex.de>
%
% The development repository can be found at
% https://github.com/tudace/tuda_latex_templates
% Please use the issue tracker for feedback!
%
% ============================================================================
%
% \fi
%
% \iffalse% no documentation on this
% \iffalse^^A Preparation for real docstrip documentation
%<*driver>
\ProvidesFile{tudaletter.dtx}[2026-06-08 v4.06 Letters for TUDa-CI, Corporate Design of TU Darmstadt]
\typeout{***********************************************************}
\typeout{No documentation included in this file! Please see tuda-ci.pdf for more information and DEMO-TUDaLetter.tex/.pdf for an example of use.}
\typeout{***********************************************************}
\stop
%</driver>
%<*class&initialization>
%<@@=ptxcd>
\NeedsTeXFormat{LaTeX2e}[2020/10/01]
\ProvidesExplClass{tudaletter}{2026-06-08}{4.06}{Letters for TUDa-CI, Corporate Design of TU Darmstadt}
%</class&initialization>
%<*driver>^^A Preparation for real docstrip documentation
\providecommand*{\TUDaDocDTXfiles}{tudaletter.dtx}
\input{tuda-ci.dtx}
%</driver>
% \fi
%
% \changes{v4.00}{2025-01-26}{Converted to DTX file}
%
% \DoNotIndex{\newcommand,\newenvironment}
%
% \GetFileInfo{tudaletter.dtx}
% \title{The \textsf{tudaletter} package}
% \author{<+author+>\thanks{Email: \href{mailto:<+email+>}{<+email+>}}}
% \date{\fileversion~from \filedate}
%
% \maketitle
%
%
% \DescribeMacro{\fileversion}
%
%
% \DescribeMacro{\filedate}
%
%
% \DescribeMacro{\opening}
%
%
% \DescribeMacro{\letterpagestyle}
%
%
% \MaybeStop{}
%
% \section{Implementation}
%
% \iffalse
%<*class>
%<*initialization>
% \fi
%
%
%    \begin{macrocode}
\str_const:Nn \c_@@_base_str {letter}
\str_new:N  \g_ptxcd_department_str
\bool_new:N \g_@@_adjust_textwidth_bool
\keys_define:nn {ptxcd/letter} {
  logo .bool_gset:N = \g_@@_letter_logo_bool,
  logo .default:n = true,
  logo .initial:n = true,
  premium .bool_gset:N = \g_@@_letter_premium_bool,
  premium .default:n = true,
  firstpagenumber .bool_gset:N = \g_@@_firstpagenumber_bool,
  firstpagenumber .initial:n = true,
  raggedright .bool_gset:N = \g_@@_letter_raggedright_bool,
  headrule .bool_gset:N = \g_@@_letter_headrule_bool,
  headrule .initial:n = true,
  headrule .default:n = true,
  textwidth .choice:,
  textwidth / wide .code:n = \bool_gset_true:N \g_@@_adjust_textwidth_bool,
  textwidth / narrow .code:n = \bool_gset_false:N  \g_@@_adjust_textwidth_bool,
  textwidth .initial:n = wide,
%</initialization>
%<gobble>}
%    \end{macrocode}
% \iffalse
%<*packages>
% \fi
%    \begin{macrocode}
% \begin{documentation}
% \DescribeMacro{\@fontsizefilebase}
%
% \end{documentation}
% \begin{implementation}
% \begin{macro}{\@fontsizefilebase}
%    \begin{macrocode}
\newcommand*{\@fontsizefilebase}{tudalettersize}
%    \end{macrocode}
% \end{macro}
% \end{implementation}
%
%    \begin{macrocode}
\PassOptionsToClass{fontsize=10pt,parskip=full-}{scrletter}
\PassOptionsToPackage{refline=nodate,addrfield=topaligned,firstfoot=false,pagenumber=botright}{scrletter}
\LoadClass{scrletter}
%    \end{macrocode}
% Load the TUDa-colorscheme
%    \begin{macrocode}
\RequirePackage{tudacolors}
\RequirePackage{tudafonts}
\RequirePackage{graphicx}
\RequirePackage{afterpage}
\RequirePackage{ragged2e}
\bool_if:NTF \g_@@_letter_premium_bool {
  \cs_new:Nn \ptxcd_premiumcolor: {accentcolor}
  \cs_new:Nn \ptxcd_use_premiumcolor: {\color{accentcolor}}
  \cs_set:Nn \ptxcd_use_premiumcolor_text: {\color{textaccentcolor}}
}{
  \cs_new:Nn \ptxcd_premiumcolor: {black}
  \let\ptxcd_use_premiumcolor:\relax
  \let\ptxcd_use_premiumcolor_text:\relax
}
%    \end{macrocode}
% %%%%Briefbogen
% % Spacing:
%    \begin{macrocode}
\dim_const:Nn \c_ptxcd_HeadMargin_dim {12.5mm}
\dim_const:Nn \c_ptxcd_LeftMargin_dim {24.0mm}
\dim_const:Nn \c_@@_firstpage_extraindent_dim {-\paperwidth+120mm +\c_ptxcd_LeftMargin_dim  +\c_ptxcd_HeadMargin_dim}
\bool_if:NTF \g_@@_adjust_textwidth_bool
  {
    \dim_const:Nn \c_ptxcd_RightMargin_dim  {\c_ptxcd_HeadMargin_dim}
  }{
    \dim_const:Nn \c_ptxcd_RightMargin_dim  {\c_ptxcd_HeadMargin_dim-\c_@@_firstpage_extraindent_dim}
  }
\dim_const:Nn \c_ptxcd_BottomMargin_dim {20mm}
\dim_const:Nn \c_ptxcd_Linewidth_dim {\paperwidth-\c_ptxcd_LeftMargin_dim-\c_ptxcd_RightMargin_dim}
\RequirePackage{geometry}
\geometry{
  twoside=false,
  left=\c_ptxcd_LeftMargin_dim,
  right=\c_ptxcd_RightMargin_dim,
  bottom=\c_ptxcd_BottomMargin_dim,
  footskip=7mm,
}
\dim_const:Nn \c_ptxcd_textwidth_dim {\textwidth}
\bool_if:NTF \g_@@_letter_logo_bool {
  \geometry{top=64mm}
} {
  \geometry{top=30mm}
}
%    \end{macrocode}
% \iffalse
%</packages>
%<*pdfx>
% \fi
% \changes{v4.00}{2025-01-26}{Unify pdfx/pdfa mechanism structure over all document types}
%    \begin{macrocode}
\if_bool:N \g_ptxcd_pdfx_bool
  \PassOptionsToPackage{a-2b}{pdfx}
%    \end{macrocode}
% Workaround posted by David Carlisle on tex.stackexchange
% Thanks to Ulrike Fischer for mentioning it in #472
%    \begin{macrocode}
  \let \_@@_grouplevel_before_pdfx: \currentgrouplevel
  \chardef\currentgrouplevel0
  \ExplSyntaxOff
  \RequirePackage{pdfx}
  \ExplSyntaxOn
  \let \currentgrouplevel \_@@_grouplevel_before_pdfx:
  \cs_undefine:N \_@@_grouplevel_before_pdfx:
%    \end{macrocode}
% end of the workaround
%    \begin{macrocode}
\else:
  \PassOptionsToPackage{hidelinks, unicode}{hyperref}
  \RequirePackage{hyperref}
\fi:
%    \end{macrocode}
% \iffalse
%</pdfx>
%<*body>
% \fi
% \changes{v4.00}{2025-01-26}{Unify pdfx/pdfa mechanism structure over all document types}
%    \begin{macrocode}
\RequirePackage[paper=a4]{tudarules}% might load pgfcore, so it has to be loaded after pdfx
\setplength{firstheadhpos}{\c_ptxcd_HeadMargin_dim}
\setplength{firstheadvpos}{\c_ptxcd_HeadMargin_dim}
\setplength{firstheadwidth}{\dim_eval:n {\paperwidth - 2\c_ptxcd_HeadMargin_dim}}
\setplength{firstfootvpos}{\dim_eval:n {\paperheight -17mm}}
\setplength{firstfoothpos}{\useplength{firstheadhpos}}
\setplength{firstfootwidth}{\useplength{firstheadwidth}}
\setplength{toaddrhpos}{\c_ptxcd_LeftMargin_dim}
\setplength{toaddrvpos}{50mm}
\setplength{backaddrheight}{4mm}
\setplength{toaddrindent}{0mm}
\setplength{refhpos}{\c_ptxcd_LeftMargin_dim}
\setplength{refvpos}{106mm}
\setplength{subjectaftervskip}{2\baselineskip}
\setplength{lochpos}{\c_ptxcd_HeadMargin_dim}
\setplength{locvpos}{\dimexpr\useplength{refvpos}+\useplength{subjectaftervskip}+1.4\baselineskip\relax}
\setplength{refaftervskip}{0pt}
\setplength{subjectbeforevskip}{0pt}
\setplength{locwidth}{\dimexpr\paperwidth-154,5mm -\c_ptxcd_HeadMargin_dim\relax}
\setplength{locheight}{\dimexpr\paperheight-\useplength{locvpos}-\c_ptxcd_BottomMargin_dim\relax}
\bool_if:NTF \g_@@_letter_headrule_bool {
  \ptxcd_makeheadrule[width=\useplength{firstheadwidth},color=identbarcolor]{ptxcd_LetterheadRule}
} {
  \box_new:N \ptxcd_LetterheadRule_box
  \def\ptxcd_LetterheadRule{}
}
\ptxcd_makefootrule[width=\useplength{firstheadwidth}]{ptxcd_LetterfootRule}
\box_new:N \g_TUDaLetter_firsthead_box
\hbox_gset:Nn \g_TUDaLetter_firsthead_box {
  \parbox[t]{\useplength{firstheadwidth}}{
    \raggedleft
    \smash{\ptxcd_LetterheadRule}
    \par
    \vspace{.5\c_ptxcd_logoheight_dim}
    \makebox[\_@@_logowidth:][l]{\_@@_insert_logo:}
  }
}
\box_gset_dp:Nn \g_TUDaLetter_firsthead_box {\c_zero_dim}
\setkomavar{firsthead}{
  \box_use:N \g_TUDaLetter_firsthead_box
}
\KOMAoptions{backaddress=plain}
\setkomavar{backaddressseparator}{\,$\vert$\,}
%    \end{macrocode}
% \begin{documentation}
% \subsection{Additional KOMA Variables defined for TUDa-CI}
% The letter template requires some additional variables:
% \begin{description}
% \item[frominstitution] institute/department/… in German
% \item[frominstitution-en] institute/department/… in English
% \item[fromfunction] position or job title of the sender
% \end{description}
% \end{documentation}
% \begin{implementation}
%    \begin{macrocode}
\newkomavar{frominstitution}
\newkomavar{frominstitution-en}
\newkomavar{fromfunction}
%    \end{macrocode}
%    \begin{macrocode}
\newkomafont{ptxcd_location}{\accentfont\normalcolor}
\setkomafont{fromname}{\small}
\newkomafont{ptxcd_frominst}{\small\ptxcd_use_premiumcolor_text: }
\setkomafont{fromaddress}{\footnotesize}
\setkomafont{refname}{}
\setkomafont{refvalue}{}
\setkomafont{pageheadfoot}{\footnotesize}
%    \end{macrocode}
% \end{implementation}
% \begin{documentation}
% \DescribeMacro{\TUD@locfield}
%
% \end{documentation}
% \begin{implementation}
% \begin{macro}{\TUD@locfield}
%    \begin{macrocode}
\newcommand{\TUD@locfield}{%
  \usekomafont{ptxcd_location}\usekomafont{fromaddress}
  \setparsizes{\z@}{\z@}{\z@ plus 1fil}
  \par@updaterelative
  \begingroup
  \int_compare:nT {0 < \@pageat <3} {
    \ptxcd_letterpagemark:\\[\baselineskip]
  }
  \usekomafont{ptxcd_frominst}
  \Ifkomavarempty{frominstitution}{}{%
    {\usekomavar[\raggedright]{frominstitution}}
    \\[\baselineskip]}%
  \Ifkomavarempty{frominstitution-en}{}{%
    \usekomavar[\raggedright]{frominstitution-en}
    \\[\baselineskip]}%
  \endgroup
  \Ifkomavarempty{fromlogo}{}{\usekomavar{fromlogo}\\[\baselineskip]}%
  \Ifkomavarempty{fromname}{}
  {{\usekomafont{fromname}\usekomavar{fromname}}
    \Ifkomavarempty{fromfunction}{}{\\\usekomavar{fromfunction}}
    \\[\baselineskip]}%
  \Ifkomavarempty{fromaddress}{}{\usekomavar{fromaddress}\\[\baselineskip]}%
  \@tempswafalse
  \clist_map_inline:nn {fromphone, fromfax, fromemail, fromurl}{
    \@tempswatrue
    \Ifkomavarempty{##1}{}{
      \Ifkomavarempty*{##1}{}{\makebox[1cm][l]{\usekomavar*{##1}}}\usekomavar{##1}\par
    }
  }
  \if@tempswa
    \vspace{2\baselineskip}
  \fi
  \Ifkomavarempty*{date}{}{\usekomavar*{date}\\\usekomavar{date}}
  \seq_use:Nn  \g_@@_reffields_seq {}
  \Ifkomavarempty{frombank}{}{\vfill%
    \Ifkomavarempty*{frombank}{Bankverbindung}{\usekomavar*{frombank}}\\\usekomavar{frombank}
  }
}
%    \end{macrocode}
% \end{macro}
% \end{implementation}
%
%    \begin{macrocode}
\setkomavar{location}{\parbox[t][.45\paperheight][t]{\useplength{locwidth}}{\TUD@locfield}}
\tl_const:Nn \ptxcd_reffield_separator_tl {\\}
\cs_new:Nn \ptxcd_set_reffield:n {
  \Ifkomavarempty{#1}{}{%
    \if@tempswa\\[\baselineskip]\fi
    \parbox[t]{\linewidth}{\noindent\raggedright
      \usekomafont{refname}
      \usekomavar*{#1}\ptxcd_reffield_separator_tl
      \usekomafont{refvalue}
      \usekomavar{#1}
    }%
    \@tempswatrue
  }%
}
\seq_new:N  \g_@@_reffields_seq
\newlength{\TUD@page@free}
\newcounter{TUD@page@free@lines}
\dim_new:N \g_@@_page_free_dim
\int_new:N \g_@@_free_lines_int
%    \end{macrocode}
% \begin{documentation}
% \DescribeMacro{\opening}
%
% \end{documentation}
% \begin{implementation}
% \begin{macro}{\opening}
%    \begin{macrocode}
\renewcommand{\opening}[1]{%
  \widowpenalty=100
  \@PapersizeWarning
  \seq_gclear:N \g_@@_reffields_seq
  \renewcommand*{\@set@reffield}[1]{
    \typeout{Field: ##1}%
    \str_if_eq:nnT {##1}{datemarkerfield}{%
      \let\scr@datemarkerfield@var=\scr@date@var
      \let\scr@datemarkerfield@name=\scr@date@name
      \setkomavar{date}{}%
    }
    \Ifkomavarempty{##1}{}{%
      \seq_gput_right:Nn \g_@@_reffields_seq {%
        \ptxcd_set_reffield:n {##1}
      }%
    }%
  }
  \let\do@set@reffield\@set@reffield
  \@set@reffields
  \removereffields
  \@gen@firsthead
  \@mkboth{\scr@fromname@var}{\scr@subject@var}%
  \thispagestyle{letter.first}\noindent
  \Ifkomavarempty{toname}{\setkomavar{toname}{\mbox{}}}{}
  \@foldmarks\@firstheadfootfield\@addrfield\@locfield
  \ifdim\useplength{subjectvpos}=\z@\else\@subjfield\fi
  \@datefield
  \@makelettertitle
  \ifdim\useplength{subjectvpos}=\z@\if@subjafter\else\@subjfield\fi\fi
  {\setparsizes{\z@}{\z@}{\z@ plus 1fil}\par@updaterelative#1\par}%
  {\setlength{\@tempdima}{\baselineskip}%
    \addtolength{\@tempdima}{-\parskip}%
    \ifdim \@tempdima>\z@\vskip\@tempdima\fi}%
  \ifdim\useplength{subjectvpos}=\z@\if@subjafter\@subjfield\fi\fi
  \setcounter{equation}{0}%
  \@afterheading%
  \@nobreaktrue
  \@afterindentfalse
  \bool_if:NT \g_@@_adjust_textwidth_bool {
    \everypar{%
      \if@nobreak
        \@nobreakfalse\clubpenalty\@M
        \if@afterindent
          \else{\setbox\z@\lastbox}
        \fi
      \else
        \clubpenalty\@clubpenalty
      \fi
      \ifnum\thepage=1%
        \dim_gset:Nn \g_@@_page_free_dim {-\pagegoal + \pagetotal}
        \dim_compare:nTF {-\g_@@_page_free_dim>2\baselineskip}
        {
          \int_gset:Nn \g_@@_free_lines_int {\fp_eval:n {ceil(\g_@@_page_free_dim/\baselineskip)}}
          \int_compare:nT {\g_@@_free_lines_int<0} {
            \hangafter=\g_@@_free_lines_int\hangindent=\c_@@_firstpage_extraindent_dim%
          }
        } {
          \dim_compare:nT {-\TUD@page@free>\baselineskip} {
            \hangafter=-2\hangindent=\c_@@_firstpage_extraindent_dim%
          }
        }
      \fi%
    }%
    \global\setlength{\linewidth}{\dim_eval:n {\c_ptxcd_Linewidth_dim + \c_@@_firstpage_extraindent_dim}}
    \afterpage{
      \global\setlength{\linewidth}{\c_ptxcd_Linewidth_dim}
      \widowpenalty=10000
    }
  }
}
%    \end{macrocode}
% \end{macro}
% \end{implementation}
%
%    \begin{macrocode}
\AtBeginDocument{%
  \raggedbottom%
}
\setkomafont{backaddress}{\accentfont\tiny\ptxcd_use_premiumcolor_text:\raisebox{\dimexpr-\totalheight+\ht\strutbox\relax}{\rule{\z@}{4mm}}}
\raggedbottom
\int_new:N \l_ptxcd_letter_lastpage_int
\cs_new:Nn \ptxcd_letterpagemark: {
  %get lastpage for this letter if not already done
  \int_compare:nNnTF {\value{page}} = {1} {
      \bool_if:NTF \g_@@_firstpagenumber_bool
      {\bool_set_true:N \l_tmpa_bool}
      {\bool_set_false:N \l_tmpa_bool}
    }
    {\bool_set_true:N \l_tmpa_bool}
  \bool_if:NT \l_tmpa_bool {
    \int_if_exist:cF {c_ptxcd_letter\thisletter _lastpage_int} {
      \cs_if_exist:cTF {r@\thisletter.lastpage} {
        \int_const:cn {c_ptxcd_letter\thisletter _lastpage_int} {
          \exp_args:NNc \expandafter \@secondoffive { r@\thisletter.lastpage}
        }
      } {
        %warning -> rerun latex
        \int_const:cn {c_ptxcd_letter\thisletter _lastpage_int} {0}
      }
    }
    \usekomafont{pagenumber}\pagename\nobreakspace\thepage
    \int_compare:nT {
      \int_use:c {c_ptxcd_letter\thisletter _lastpage_int}
      > 1
    } {/\int_to_arabic:n{\int_use:c {c_ptxcd_letter\thisletter _lastpage_int}}}
  }
}
\setkomavar{firstfoot}{\usekomavar{nextfoot}}
\setkomavar{nextfoot}{%
  \ifnum\@pageat>2
    \parbox[c]{\layerwidth}{%
      \ifcase\@pageat\or\or\or\raggedright\or\centering\or\raggedleft\fi
      \strut\pagemark%
    }%
  \fi
}
\cs_set_eq:NN \letterpagemark \ptxcd_letterpagemark:
\bool_if:NT \g_@@_letter_headrule_bool {
  \bool_if:NTF \g_@@_letter_logo_bool {
    \setkomavar{nexthead}{\raisebox{\topskip}{\box_use:N \g_TUDaLetter_firsthead_box}}
  }{
    \setkomavar{nexthead}{\raisebox{\depth}{\ptxcd_LetterheadRule}}
  }
}
\newpairofpagestyles[letter]{TUDaLetter}{
  \exp_args:Nx \KOMAoptions{
    footwidth=\dimexpr\paperwidth-2\c_ptxcd_HeadMargin_dim \c_colon_str-\dim_eval:n {\c_ptxcd_HeadMargin_dim -1mm},
    headwidth=\dimexpr\paperwidth-2\c_ptxcd_HeadMargin_dim \c_colon_str-\dim_eval:n {\c_ptxcd_HeadMargin_dim -1mm},
    footsepline=.5\c_ptxcd_smallrule_dim,plainfootsepline
  }
  \ModifyLayer[voffset=\c_ptxcd_HeadMargin_dim,align=tl]{TUDaLetter.head.even}
  \ModifyLayer[voffset=\c_ptxcd_HeadMargin_dim,align=tl]{TUDaLetter.head.odd}
  \ModifyLayer[voffset=\c_ptxcd_HeadMargin_dim,align=tl]{TUDaLetter.head.oneside}
  \ModifyLayer[voffset=\c_ptxcd_HeadMargin_dim,align=tl]{plain.TUDaLetter.head.even}
  \ModifyLayer[voffset=\c_ptxcd_HeadMargin_dim,align=tl]{plain.TUDaLetter.head.odd}
  \ModifyLayer[voffset=\c_ptxcd_HeadMargin_dim,align=tl]{plain.TUDaLetter.head.oneside}
  \lehead{\usekomavar{nexthead}}%
  \lohead{\usekomavar{nexthead}}%
  \lefoot{\usekomavar{nextfoot}}%
  \lofoot{\usekomavar{nextfoot}}%
}
\DeclarePageStyleByLayers{TUDaLetter.first}{TUDaLetter.foot.even,TUDaLetter.foot.odd,TUDaLetter.foot.oneside,TUDaLetter.foot.above.line}
\pagestyle{TUDaLetter}
\DeclarePageStyleAlias{letter.first}{TUDaLetter.first}
%    \end{macrocode}
% \begin{documentation}
% \DescribeMacro{\letterpagestyle}
%
% \end{documentation}
% \begin{implementation}
% \begin{macro}{\letterpagestyle}
%    \begin{macrocode}
\def\letterpagestyle{TUDaLetter}
%    \end{macrocode}
% \end{macro}
% \end{implementation}
%
% Widows and clubs
%    \begin{macrocode}
\widowpenalty=10000
\clubpenalty=10000
%    \end{macrocode}
% default values
%    \begin{macrocode}
\setkomavar*{fromemail}{}
\setkomavar*{fromurl}{}
\setkomavar{backaddress}{Technische~ Universität~ Darmstadt\\Karolinenplatz~ 5\\64289~ Darmstadt}
%    \end{macrocode}
% renewcaptions
%    \begin{macrocode}
\defcaptionname{german,ngerman,austrian,naustrian,%
  swissgerman,nswissgerman}\yourmailname{Ihre~ Nachricht}%
\defcaptionname{german, ngerman,austrian,naustrian,%
  swissgerman,nswissgerman}\phonename{Tel.}%
%    \end{macrocode}
% signature raggedright
%    \begin{macrocode}
\let\raggedsignature\raggedright
\bool_if:NT \g_@@_letter_raggedright_bool {\AtBeginLetter{\RaggedRight}}
%    \end{macrocode}
% backwards compatibility for KOMA-Script
%    \begin{macrocode}
\cs_if_exist:NF \Ifkomavarempty{
  \let\Ifkomavarempty\ifkomavarempty
}
\file_if_exist_input:n {\g_@@_config_prefix_tl\g_ptxcd_department_str.cfg}
%    \end{macrocode}

%
% \iffalse
%</body>
%</class>
% \fi
% \Finale
% \fi^^A No documentation on this
\endinput
