"""
    sphinx.ext.autosectionlabel
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~

    Allow reference sections by :ref: role using its title.

    :copyright: Copyright 2007-2020 by the Sphinx team, see AUTHORS.
    :license: BSD, see LICENSE for details.
"""

from typing import Any, Dict
from typing import cast

from docutils import nodes
from docutils.nodes import Node

from sphinx.application import Sphinx
from sphinx.domains.std import StandardDomain
from sphinx.locale import __
from sphinx.util import logging
from sphinx.util.nodes import clean_astext


logger = logging.getLogger(__name__)


def get_node_depth(node: Node) -> int:
    i = 0
    cur_node = node
    while cur_node.parent != node.document:
        cur_node = cur_node.parent
        i += 1
    return i


def register_sections_as_label(app: Sphinx, document: Node) -> None:
    domain = cast(StandardDomain, app.env.get_domain('std'))
    for node in document.traverse(nodes.section):
        if (app.config.autosectionlabel_maxdepth and
                get_node_depth(node) >= app.config.autosectionlabel_maxdepth):
            continue
        labelid = node['ids'][0]
        docname = app.env.docname
        title = cast(nodes.title, node[0])
        ref_name = getattr(title, 'rawsource', title.astext())
        if app.config.autosectionlabel_prefix_document:
            name = nodes.fully_normalize_name(docname + ':' + ref_name)
        else:
            name = nodes.fully_normalize_name(ref_name)
        sectname = clean_astext(title)

        if name in domain.labels:
            logger.warning(__('duplicate label %s, other instance in %s'),
                           name, app.env.doc2path(domain.labels[name][0]),
                           location=node, type='autosectionlabel', subtype=docname)

        domain.anonlabels[name] = docname, labelid
        domain.labels[name] = docname, labelid, sectname


def setup(app: Sphinx) -> Dict[str, Any]:
    app.add_config_value('autosectionlabel_prefix_document', False, 'env')
    app.add_config_value('autosectionlabel_maxdepth', None, 'env')
    app.connect('doctree-read', register_sections_as_label)

    return {
        'version': 'builtin',
        'parallel_read_safe': True,
        'parallel_write_safe': True,
    }