# Taken from https://github.com/django/django/blob/master/docs/_ext/djangodocs.py

import re
from sphinx import addnodes


# RE for option descriptions without a '--' prefix
simple_option_desc_re = re.compile(
        r'([-_a-zA-Z0-9]+)(\s*.*?)(?=,\s+(?:/|-|--)|$)')


def setup(app):
    app.add_crossref_type(
        directivename="setting",
        rolename="setting",
        indextemplate="pair: %s; setting",
    )
    app.add_crossref_type(
        directivename="templatetag",
        rolename="ttag",
        indextemplate="pair: %s; template tag"
    )
    app.add_crossref_type(
        directivename="templatefilter",
        rolename="tfilter",
        indextemplate="pair: %s; template filter"
    )
    app.add_crossref_type(
        directivename="fieldlookup",
        rolename="lookup",
        indextemplate="pair: %s; field lookup type",
    )
    app.add_description_unit(
        directivename="django-admin",
        rolename="djadmin",
        indextemplate="pair: %s; django-admin command",
        parse_node=parse_django_admin_node,
    )
    app.add_description_unit(
        directivename="django-admin-option",
        rolename="djadminopt",
        indextemplate="pair: %s; django-admin command-line option",
        parse_node=parse_django_adminopt_node,
    )


def parse_django_admin_node(env, sig, signode):
    command = sig.split(' ')[0]
    env._django_curr_admin_command = command
    title = "django-admin.py %s" % sig
    signode += addnodes.desc_name(title, title)
    return sig


def parse_django_adminopt_node(env, sig, signode):
    """A copy of sphinx.directives.CmdoptionDesc.parse_signature()"""
    from sphinx.domains.std import option_desc_re
    count = 0
    firstname = ''
    for m in option_desc_re.finditer(sig):
        optname, args = m.groups()
        if count:
            signode += addnodes.desc_addname(', ', ', ')
        signode += addnodes.desc_name(optname, optname)
        signode += addnodes.desc_addname(args, args)
        if not count:
            firstname = optname
        count += 1
    if not count:
        for m in simple_option_desc_re.finditer(sig):
            optname, args = m.groups()
            if count:
                signode += addnodes.desc_addname(', ', ', ')
            signode += addnodes.desc_name(optname, optname)
            signode += addnodes.desc_addname(args, args)
            if not count:
                firstname = optname
            count += 1
    if not firstname:
        raise ValueError
    return firstname