chapter style latex horizontal line

chapter style latex horizontal line

I want a chapter style like this:
1
------chapter name-------------
text text text text tex
t text text text text t
I have come this far:
\documentclass{book}
\usepackage{titlesec}
\newcommand*{\xdash}[1][3em]{\rule[0.5ex]{#1}{0.55pt}}
\titleformat{\chapter}[display]
{\Large}{\filleft\Huge\thechapter}{1ex}{\xdash[2em]}[]
\begin{document}
\chapter
{Introduction}
Text text text text
\end{document}
but I can not get it right. I want the horizontal line to be longer then
the "normal" text and I want the line to be before and after the chapter
name. Thanks in advance