"""Directory HTML builders."""

from os import path
from typing import Any, Dict, Optional

from sphinx.application import Sphinx
from sphinx.builders.html import StandaloneHTMLBuilder
from sphinx.util import logging
from sphinx.util.osutil import SEP, os_path

logger = logging.getLogger(__name__)


class DirectoryHTMLBuilder(StandaloneHTMLBuilder):
    """
    A StandaloneHTMLBuilder that creates all HTML pages as "index.html" in
    a directory given by their pagename, so that generated URLs don't have
    ``.html`` in them.
    """
    name = 'dirhtml'

    def get_target_uri(self, docname: str, typ: Optional[str] = None) -> str:
        if docname == 'index':
            return ''
        if docname.endswith(SEP + 'index'):
            return docname[:-5]  # up to sep
        return docname + SEP

    def get_outfilename(self, pagename: str) -> str:
        if pagename == 'index' or pagename.endswith(SEP + 'index'):
            outfilename = path.join(self.outdir, os_path(pagename) +
                                    self.out_suffix)
        else:
            outfilename = path.join(self.outdir, os_path(pagename),
                                    'index' + self.out_suffix)

        return outfilename


def setup(app: Sphinx) -> Dict[str, Any]:
    app.setup_extension('sphinx.builders.html')

    app.add_builder(DirectoryHTMLBuilder)

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