How to get multi-line chapter name with ClassicThesis package?

Question

I'm using the ClassicThesis by Miede for writing my thesis, the support package is Arsclassica.

It's a nice template, however I got a little problem with the Chapter name, some of them can be very long. As the result, LateX would produce very bad line breaking on chapter name.

I can use \newline command to choose when to start the new line, however the new line is not aligned. If you already use ClassicThesis, you'll see that it generate Chapter number, then a straight slash (|) to separate the number with the chapter's name. Is there any way to produce Chapter name, aligned on 2 lines?

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Minimal example provided by Vladimir:

\documentclass{scrreprt}

\usepackage{classicthesis-ldpkg}
\usepackage{classicthesis}
\usepackage{arsclassica}

\begin{document}
\chapter{This is multi line chapter title}
See how the second line of the chapter title goes under the chapter number which looks bad.
\end{document}

Answer 1

arsclassica loads titlesec, and the chapter title format is improved by replacing block with hang when using the \titleformat macro.

\documentclass{scrreprt}

\usepackage{arsclassica}

\titleformat{\chapter}[hang]% "hang" instead of "block"
    {\normalfont\Large\sffamily}%
    {{\color{halfgray}\chapterNumber\thechapter%
    \hspace{10pt}\vline}  }{10pt}%
    {\spacedallcaps}

\begin{document}
\chapter{This is multi lane chapter title}
See how the second line of the chapter title goes under the chapter number which looks bad.
\end{document}

Answer 2

it is the arsclassica which defines the chapter layout via the macro \formatchapter. Using a tabularx for the title makes sense here:

\documentclass{scrreprt}

\usepackage{classicthesis-ldpkg}
\usepackage{arsclassica,tabularx}

\renewcommand\formatchapter[1]{% 
  \begin{tabularx}{0.8\linewidth}{@{} l X @{}} 
       \chapterNumber & \spacedallcaps{#1}
  \end{tabularx}} 

\begin{document}
\chapter{This is a real multi line chapter title}
See how the second line of the chapter title goes under the chapter number which looks bad.
\end{document}