rechnung.sty

\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{rechnung}

\RequirePackage{fp}
\RequirePackage{calc}
\RequirePackage{array}
\RequirePackage{booktabs}

\newcounter{invoice@cost}
\newcounter{invoice@vat}

\newcommand*{\format@float}[1]{\FPround{\invoice@t}{#1}{2}$\invoice@t$}
\newcommand*{\format@int}[1]{$#1$}
\newcommand*{\total}[1]{\FPdiv{\invoice@t}{\arabic{#1}}{1000}\format@float{\invoice@t}}
\newcommand*\textPosten{Description}
\newcommand*\textPreis{Unit Price}
\newcommand*\textAnzahl{Quantity}
\newcommand*\textBetrag{Total Price}
\newcommand*\textWaehrung{CHF}

\newenvironment*{invoice}[1]{
  \setcounter{invoice@cost}{0}
  \setcounter{invoice@vat}{0}
  \def\invoice@VATval{#1}%
  % 
  \newcommand*{\Fee}[3]{%
    \addtocounter{invoice@cost}{1000 * \real{##2} * \real{##3}}%
    \addtocounter{invoice@vat}{10 * \real{#1} * \real{##2} * \real{##3}}%
    {##1} & \format@float{##2} & \format@int{##3} & \FPmul{\invoice@cost}{##2}{##3}\format@float{\invoice@cost} \cr%
  }%
  % 
  ~\par\noindent
  \begin{tabular}{p{\dimexpr0.49\linewidth-2\tabcolsep}*{3}{>{\hfill}p{\dimexpr0.17\linewidth-2\tabcolsep}}}%
    \toprule%
    {\textPosten} & {\textPreis} & {\textAnzahl} & {\textBetrag} \cr%
    \midrule%
  }{%
    \if\invoice@VATval0\else%
    \midrule%
    {Subtotal} & & & {\total{invoice@cost}} \cr%
    {VAT (\invoice@VATval\,\%)} & & & {\total{invoice@vat}} \cr%
    \fi%
    \midrule%
    \setcounter{invoice@cost}{\theinvoice@cost + \theinvoice@vat}%
		{\bfseries Total} & & & {\bfseries\boldmath \textWaehrung~\total{invoice@cost}} \cr%
    \bottomrule%
  \end{tabular}%
  \par~%
}