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

from typing import Any, Dict, cast

from docutils import nodes
from docutils.nodes import Node

import sphinx
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.findall(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)

        logger.debug(__('section "%s" gets labeled as "%s"'),
                     ref_name, name,
                     location=node, type='autosectionlabel', subtype=docname)
        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': sphinx.__display_version__,
        'parallel_read_safe': True,
        'parallel_write_safe': True,
    }