#!usr/bin/python

"""

Meta Data Extension for Python-Markdown

=======================================

This extension adds Meta Data handling to markdown.

Basic Usage:

    >>> import markdown

    >>> text = '''Title: A Test Doc.

    ... Author: Waylan Limberg

    ...         John Doe

    ... Blank_Data:

    ...

    ... The body. This is paragraph one.

    ... '''

    >>> md = markdown.Markdown(['meta'])

    >>> md.convert(text)

    u'<p>The body. This is paragraph one.</p>'

    >>> md.Meta

    {u'blank_data': [u''], u'author': [u'Waylan Limberg', u'John Doe'], u'title': [u'A Test Doc.']}

Make sure text without Meta Data still works (markdown < 1.6b returns a <p>).

    >>> text = '    Some Code - not extra lines of meta data.'

    >>> md = markdown.Markdown(['meta'])

    >>> md.convert(text)

    u'<pre><code>Some Code - not extra lines of meta data.\\n</code></pre>'

    >>> md.Meta

    {}

Copyright 2007-2008 [Waylan Limberg](http://achinghead.com).

Project website: <http://www.freewisdom.org/project/python-markdown/Meta-Data>

Contact: markdown@freewisdom.org

License: BSD (see ../docs/LICENSE for details)

"""

import re

import markdown

# Global Vars

META_RE = re.compile(r'^[ ]{0,3}(?P<key>[A-Za-z0-9_-]+):\s*(?P<value>.*)')

META_MORE_RE = re.compile(r'^[ ]{4,}(?P<value>.*)')

class MetaExtension (markdown.Extension):

    """ Meta-Data extension for Python-Markdown. """

    def extendMarkdown(self, md, md_globals):

        """ Add MetaPreprocessor to Markdown instance. """

        md.preprocessors.add("meta", MetaPreprocessor(md), "_begin")

class MetaPreprocessor(markdown.preprocessors.Preprocessor):

    """ Get Meta-Data. """

    def run(self, lines):

        """ Parse Meta-Data and store in Markdown.Meta. """

        meta = {}

        key = None

        while 1:

            line = lines.pop(0)

            if line.strip() == '':

                break # blank line - done

            m1 = META_RE.match(line)

            if m1:

                key = m1.group('key').lower().strip()

                value = m1.group('value').strip()

                try:

                    meta[key].append(value)

                except KeyError:

                    meta[key] = [value]

            else:

                m2 = META_MORE_RE.match(line)

                if m2 and key:

                    # Add another line to existing key

                    meta[key].append(m2.group('value').strip())

                else:

                    lines.insert(0, line)

                    break # no meta data - done

        self.markdown.Meta = meta

        return lines

def makeExtension(configs={}):

    return MetaExtension(configs=configs)

if __name__ == "__main__":

    import doctest

    doctest.testmod()