#!/usr/bin/env python

'''

WikiLinks Extension for Python-Markdown

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

Converts [[WikiLinks]] to relative links.  Requires Python-Markdown 2.0+

Basic usage:

    >>> import markdown

    >>> text = "Some text with a [[WikiLink]]."

    >>> html = markdown.markdown(text, ['wikilinks'])

    >>> html

    u'<p>Some text with a <a class="wikilink" href="/WikiLink/">WikiLink</a>.</p>'

Whitespace behavior:

    >>> markdown.markdown('[[ foo bar_baz ]]', ['wikilinks'])

    u'<p><a class="wikilink" href="/foo_bar_baz/">foo bar_baz</a></p>'

    >>> markdown.markdown('foo [[ ]] bar', ['wikilinks'])

    u'<p>foo  bar</p>'

To define custom settings the simple way:

    >>> markdown.markdown(text, 

    ...     ['wikilinks(base_url=/wiki/,end_url=.html,html_class=foo)']

    ... )

    u'<p>Some text with a <a class="foo" href="/wiki/WikiLink.html">WikiLink</a>.</p>'

Custom settings the complex way:

    >>> md = markdown.Markdown(

    ...     extensions = ['wikilinks'], 

    ...     extension_configs = {'wikilinks': [

    ...                                 ('base_url', 'http://example.com/'), 

    ...                                 ('end_url', '.html'),

    ...                                 ('html_class', '') ]},

    ...     safe_mode = True)

    >>> md.convert(text)

    u'<p>Some text with a <a href="http://example.com/WikiLink.html">WikiLink</a>.</p>'

Use MetaData with mdx_meta.py (Note the blank html_class in MetaData):

    >>> text = """wiki_base_url: http://example.com/

    ... wiki_end_url:   .html

    ... wiki_html_class:

    ...

    ... Some text with a [[WikiLink]]."""

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

    >>> md.convert(text)

    u'<p>Some text with a <a href="http://example.com/WikiLink.html">WikiLink</a>.</p>'

MetaData should not carry over to next document:

    >>> md.convert("No [[MetaData]] here.")

    u'<p>No <a class="wikilink" href="/MetaData/">MetaData</a> here.</p>'

Define a custom URL builder:

    >>> def my_url_builder(label, base, end):

    ...     return '/bar/'

    >>> md = markdown.Markdown(extensions=['wikilinks'], 

    ...         extension_configs={'wikilinks' : [('build_url', my_url_builder)]})

    >>> md.convert('[[foo]]')

    u'<p><a class="wikilink" href="/bar/">foo</a></p>'

From the command line:

    python markdown.py -x wikilinks(base_url=http://example.com/,end_url=.html,html_class=foo) src.txt

By [Waylan Limberg](http://achinghead.com/).

License: [BSD](http://www.opensource.org/licenses/bsd-license.php) 

Dependencies:

* [Python 2.3+](http://python.org)

* [Markdown 2.0+](http://www.freewisdom.org/projects/python-markdown/)

'''

import markdown

import re

def build_url(label, base, end):

    """ Build a url from the label, a base, and an end. """

    clean_label = re.sub(r'([ ]+_)|(_[ ]+)|([ ]+)', '_', label)

    return '%s%s%s'% (base, clean_label, end)

class WikiLinkExtension(markdown.Extension):

    def __init__(self, configs):

        # set extension defaults

        self.config = {

                        'base_url' : ['/', 'String to append to beginning or URL.'],

                        'end_url' : ['/', 'String to append to end of URL.'],

                        'html_class' : ['wikilink', 'CSS hook. Leave blank for none.'],

                        'build_url' : [build_url, 'Callable formats URL from label.'],

        }

        # Override defaults with user settings

        for key, value in configs :

            self.setConfig(key, value)

    def extendMarkdown(self, md, md_globals):

        self.md = md

        # append to end of inline patterns

        WIKILINK_RE = r'\[\[([\w0-9_ -]+)\]\]'

        wikilinkPattern = WikiLinks(WIKILINK_RE, self.config)

        wikilinkPattern.md = md

        md.inlinePatterns.add('wikilink', wikilinkPattern, "<not_strong")

class WikiLinks(markdown.inlinepatterns.Pattern):

    def __init__(self, pattern, config):

        markdown.inlinepatterns.Pattern.__init__(self, pattern)

        self.config = config

    def handleMatch(self, m):

        if m.group(2).strip():

            base_url, end_url, html_class = self._getMeta()

            label = m.group(2).strip()

            url = self.config['build_url'][0](label, base_url, end_url)

            a = markdown.util.etree.Element('a')

            a.text = label 

            a.set('href', url)

            if html_class:

                a.set('class', html_class)

        else:

            a = ''

        return a

    def _getMeta(self):

        """ Return meta data or config data. """

        base_url = self.config['base_url'][0]

        end_url = self.config['end_url'][0]

        html_class = self.config['html_class'][0]

        if hasattr(self.md, 'Meta'):

            if self.md.Meta.has_key('wiki_base_url'):

                base_url = self.md.Meta['wiki_base_url'][0]

            if self.md.Meta.has_key('wiki_end_url'):

                end_url = self.md.Meta['wiki_end_url'][0]

            if self.md.Meta.has_key('wiki_html_class'):

                html_class = self.md.Meta['wiki_html_class'][0]

        return base_url, end_url, html_class

def makeExtension(configs=None) :

    return WikiLinkExtension(configs=configs)

if __name__ == "__main__":

    import doctest

    doctest.testmod()