"""
An interpreted text role to link docs to Trac tickets.

To use: :ticket:`XXXXX`

Based on code from psycopg2 by Daniele Varrazzo.
"""
from docutils import nodes, utils
from docutils.parsers.rst import roles


def ticket_role(name, rawtext, text, lineno, inliner, options=None, content=None):
    if options is None:
        options = {}
    try:
        num = int(text.replace('#', ''))
    except ValueError:
        msg = inliner.reporter.error(
            "ticket number must be... a number, got '%s'" % text)
        prb = inliner.problematic(rawtext, rawtext, msg)
        return [prb], [msg]

    url_pattern = inliner.document.settings.env.app.config.ticket_url
    if url_pattern is None:
        msg = inliner.reporter.warning(
            "ticket not configured: please configure ticket_url in conf.py")
        prb = inliner.problematic(rawtext, rawtext, msg)
        return [prb], [msg]

    url = url_pattern % num
    roles.set_classes(options)
    node = nodes.reference(rawtext, '#' + utils.unescape(text), refuri=url, **options)
    return [node], []


def setup(app):
    app.add_config_value('ticket_url', None, 'env')
    app.add_role('ticket', ticket_role)