import markdown
import cgi

class MathJaxPattern(markdown.inlinepatterns.Pattern):

    def __init__(self, md):
        markdown.inlinepatterns.Pattern.__init__(self, r'(?<!\\)(\$\$?)(.+?)\2', md)

    def handleMatch(self, m):
        # Pass the math code through, unmodified except for basic entity substitutions.
        # Stored in htmlStash so it doesn't get further processed by Markdown.
        text = cgi.escape(m.group(2) + m.group(3) + m.group(2))
        return self.markdown.htmlStash.store(text)

class MathJaxExtension(markdown.Extension):
    def extendMarkdown(self, md, md_globals):
        # Needs to come before escape matching because \ is pretty important in LaTeX
        md.inlinePatterns.add('mathjax', MathJaxPattern(md), '<escape')

def makeExtension(configs=[]):
    return MathJaxExtension(configs)