from markdown.extensions import Extension
from markdown.inlinepatterns import SimpleTagPattern
from markdown.inlinepatterns import SimpleTextPattern
from markdown.util import etree

from markdone_python.common import tag_pattern


class SimpleTagPattern(Pattern):  # pragma: no cover
    """
    Return element of type `tag` with a text attribute of group(3)
    of a Pattern.

    """
    def __init__(self, pattern, tag):
        Pattern.__init__(self, pattern)
        self.tag = tag

    def handleMatch(self, m):
        el = util.etree.Element(self.tag)
        el.text = m.group(3)
        return el


class MarkdoneExtension(Extension):
    def extendMarkdown(self, md, md_globals):
        md.inlinePatterns.add(
            'markdone_tag',
            SimpleTagPattern(tag_pattern.pattern, 'em'),
            '_begin',
        )