import re
from typing import TYPE_CHECKING, Any, Dict, List, cast

from docutils import nodes
from docutils.nodes import Element, Node
from docutils.parsers.rst import directives
from docutils.parsers.rst.directives.admonitions import BaseAdmonition
from docutils.parsers.rst.directives.misc import Class
from docutils.parsers.rst.directives.misc import Include as BaseInclude

from sphinx import addnodes
from sphinx.domains.changeset import VersionChange  # NOQA  # for compatibility
from sphinx.locale import _, __
from sphinx.util import docname_join, logging, url_re
from sphinx.util.docutils import SphinxDirective
from sphinx.util.matching import Matcher, patfilter
from sphinx.util.nodes import explicit_title_re
from sphinx.util.typing import OptionSpec

if TYPE_CHECKING:
    from sphinx.application import Sphinx


glob_re = re.compile(r'.*[*?\[].*')
logger = logging.getLogger(__name__)


def int_or_nothing(argument: str) -> int:
    if not argument:
        return 999
    return int(argument)


class TocTree(SphinxDirective):
    """
    Directive to notify Sphinx about the hierarchical structure of the docs,
    and to include a table-of-contents like tree in the current document.
    """
    has_content = True
    required_arguments = 0
    optional_arguments = 0
    final_argument_whitespace = False
    option_spec = {
        'maxdepth': int,
        'name': directives.unchanged,
        'caption': directives.unchanged_required,
        'glob': directives.flag,
        'hidden': directives.flag,
        'includehidden': directives.flag,
        'numbered': int_or_nothing,
        'titlesonly': directives.flag,
        'reversed': directives.flag,
    }

    def run(self) -> List[Node]:
        subnode = addnodes.toctree()
        subnode['parent'] = self.env.docname

        # (title, ref) pairs, where ref may be a document, or an external link,
        # and title may be None if the document's title is to be used
        subnode['entries'] = []
        subnode['includefiles'] = []
        subnode['maxdepth'] = self.options.get('maxdepth', -1)
        subnode['caption'] = self.options.get('caption')
        subnode['glob'] = 'glob' in self.options
        subnode['hidden'] = 'hidden' in self.options
        subnode['includehidden'] = 'includehidden' in self.options
        subnode['numbered'] = self.options.get('numbered', 0)
        subnode['titlesonly'] = 'titlesonly' in self.options
        self.set_source_info(subnode)
        wrappernode = nodes.compound(classes=['toctree-wrapper'])
        wrappernode.append(subnode)
        self.add_name(wrappernode)

        ret = self.parse_content(subnode)
        ret.append(wrappernode)
        return ret

    def parse_content(self, toctree: addnodes.toctree) -> List[Node]:
        generated_docnames = frozenset(self.env.domains['std'].initial_data['labels'].keys())
        suffixes = self.config.source_suffix

        # glob target documents
        all_docnames = self.env.found_docs.copy() | generated_docnames
        all_docnames.remove(self.env.docname)  # remove current document

        ret: List[Node] = []
        excluded = Matcher(self.config.exclude_patterns)
        for entry in self.content:
            if not entry:
                continue
            # look for explicit titles ("Some Title <document>")
            explicit = explicit_title_re.match(entry)
            if (toctree['glob'] and glob_re.match(entry) and
                    not explicit and not url_re.match(entry)):
                patname = docname_join(self.env.docname, entry)
                docnames = sorted(patfilter(all_docnames, patname))
                for docname in docnames:
                    if docname in generated_docnames:
                        # don't include generated documents in globs
                        continue
                    all_docnames.remove(docname)  # don't include it again
                    toctree['entries'].append((None, docname))
                    toctree['includefiles'].append(docname)
                if not docnames:
                    logger.warning(__('toctree glob pattern %r didn\'t match any documents'),
                                   entry, location=toctree)
            else:
                if explicit:
                    ref = explicit.group(2)
                    title = explicit.group(1)
                    docname = ref
                else:
                    ref = docname = entry
                    title = None
                # remove suffixes (backwards compatibility)
                for suffix in suffixes:
                    if docname.endswith(suffix):
                        docname = docname[:-len(suffix)]
                        break
                # absolutize filenames
                docname = docname_join(self.env.docname, docname)
                if url_re.match(ref) or ref == 'self':
                    toctree['entries'].append((title, ref))
                elif docname not in self.env.found_docs | generated_docnames:
                    if excluded(self.env.doc2path(docname, False)):
                        message = __('toctree contains reference to excluded document %r')
                        subtype = 'excluded'
                    else:
                        message = __('toctree contains reference to nonexisting document %r')
                        subtype = 'not_readable'

                    logger.warning(message, docname, type='toc', subtype=subtype,
                                   location=toctree)
                    self.env.note_reread()
                else:
                    if docname in all_docnames:
                        all_docnames.remove(docname)
                    else:
                        logger.warning(__('duplicated entry found in toctree: %s'), docname,
                                       location=toctree)

                    toctree['entries'].append((title, docname))
                    toctree['includefiles'].append(docname)

        # entries contains all entries (self references, external links etc.)
        if 'reversed' in self.options:
            toctree['entries'] = list(reversed(toctree['entries']))
            toctree['includefiles'] = list(reversed(toctree['includefiles']))

        return ret


class Author(SphinxDirective):
    """
    Directive to give the name of the author of the current document
    or section. Shown in the output only if the show_authors option is on.
    """
    has_content = False
    required_arguments = 1
    optional_arguments = 0
    final_argument_whitespace = True
    option_spec: OptionSpec = {}

    def run(self) -> List[Node]:
        if not self.config.show_authors:
            return []
        para: Element = nodes.paragraph(translatable=False)
        emph = nodes.emphasis()
        para += emph
        if self.name == 'sectionauthor':
            text = _('Section author: ')
        elif self.name == 'moduleauthor':
            text = _('Module author: ')
        elif self.name == 'codeauthor':
            text = _('Code author: ')
        else:
            text = _('Author: ')
        emph += nodes.Text(text)
        inodes, messages = self.state.inline_text(self.arguments[0], self.lineno)
        emph.extend(inodes)

        ret: List[Node] = [para]
        ret += messages
        return ret


class SeeAlso(BaseAdmonition):
    """
    An admonition mentioning things to look at as reference.
    """
    node_class = addnodes.seealso


class TabularColumns(SphinxDirective):
    """
    Directive to give an explicit tabulary column definition to LaTeX.
    """
    has_content = False
    required_arguments = 1
    optional_arguments = 0
    final_argument_whitespace = True
    option_spec: OptionSpec = {}

    def run(self) -> List[Node]:
        node = addnodes.tabular_col_spec()
        node['spec'] = self.arguments[0]
        self.set_source_info(node)
        return [node]


class Centered(SphinxDirective):
    """
    Directive to create a centered line of bold text.
    """
    has_content = False
    required_arguments = 1
    optional_arguments = 0
    final_argument_whitespace = True
    option_spec: OptionSpec = {}

    def run(self) -> List[Node]:
        if not self.arguments:
            return []
        subnode: Element = addnodes.centered()
        inodes, messages = self.state.inline_text(self.arguments[0], self.lineno)
        subnode.extend(inodes)

        ret: List[Node] = [subnode]
        ret += messages
        return ret


class Acks(SphinxDirective):
    """
    Directive for a list of names.
    """
    has_content = True
    required_arguments = 0
    optional_arguments = 0
    final_argument_whitespace = False
    option_spec: OptionSpec = {}

    def run(self) -> List[Node]:
        node = addnodes.acks()
        node.document = self.state.document
        self.state.nested_parse(self.content, self.content_offset, node)
        if len(node.children) != 1 or not isinstance(node.children[0],
                                                     nodes.bullet_list):
            logger.warning(__('.. acks content is not a list'),
                           location=(self.env.docname, self.lineno))
            return []
        return [node]


class HList(SphinxDirective):
    """
    Directive for a list that gets compacted horizontally.
    """
    has_content = True
    required_arguments = 0
    optional_arguments = 0
    final_argument_whitespace = False
    option_spec: OptionSpec = {
        'columns': int,
    }

    def run(self) -> List[Node]:
        ncolumns = self.options.get('columns', 2)
        node = nodes.paragraph()
        node.document = self.state.document
        self.state.nested_parse(self.content, self.content_offset, node)
        if len(node.children) != 1 or not isinstance(node.children[0],
                                                     nodes.bullet_list):
            logger.warning(__('.. hlist content is not a list'),
                           location=(self.env.docname, self.lineno))
            return []
        fulllist = node.children[0]
        # create a hlist node where the items are distributed
        npercol, nmore = divmod(len(fulllist), ncolumns)
        index = 0
        newnode = addnodes.hlist()
        newnode['ncolumns'] = str(ncolumns)
        for column in range(ncolumns):
            endindex = index + ((npercol + 1) if column < nmore else npercol)
            bullet_list = nodes.bullet_list()
            bullet_list += fulllist.children[index:endindex]
            newnode += addnodes.hlistcol('', bullet_list)
            index = endindex
        return [newnode]


class Only(SphinxDirective):
    """
    Directive to only include text if the given tag(s) are enabled.
    """
    has_content = True
    required_arguments = 1
    optional_arguments = 0
    final_argument_whitespace = True
    option_spec: OptionSpec = {}

    def run(self) -> List[Node]:
        node = addnodes.only()
        node.document = self.state.document
        self.set_source_info(node)
        node['expr'] = self.arguments[0]

        # Same as util.nested_parse_with_titles but try to handle nested
        # sections which should be raised higher up the doctree.
        memo: Any = self.state.memo
        surrounding_title_styles = memo.title_styles
        surrounding_section_level = memo.section_level
        memo.title_styles = []
        memo.section_level = 0
        try:
            self.state.nested_parse(self.content, self.content_offset,
                                    node, match_titles=True)
            title_styles = memo.title_styles
            if (not surrounding_title_styles or
                    not title_styles or
                    title_styles[0] not in surrounding_title_styles or
                    not self.state.parent):
                # No nested sections so no special handling needed.
                return [node]
            # Calculate the depths of the current and nested sections.
            current_depth = 0
            parent = self.state.parent
            while parent:
                current_depth += 1
                parent = parent.parent
            current_depth -= 2
            title_style = title_styles[0]
            nested_depth = len(surrounding_title_styles)
            if title_style in surrounding_title_styles:
                nested_depth = surrounding_title_styles.index(title_style)
            # Use these depths to determine where the nested sections should
            # be placed in the doctree.
            n_sects_to_raise = current_depth - nested_depth + 1
            parent = cast(nodes.Element, self.state.parent)
            for _i in range(n_sects_to_raise):
                if parent.parent:
                    parent = parent.parent
            parent.append(node)
            return []
        finally:
            memo.title_styles = surrounding_title_styles
            memo.section_level = surrounding_section_level


class Include(BaseInclude, SphinxDirective):
    """
    Like the standard "Include" directive, but interprets absolute paths
    "correctly", i.e. relative to source directory.
    """

    def run(self) -> List[Node]:
        if self.arguments[0].startswith('<') and \
           self.arguments[0].endswith('>'):
            # docutils "standard" includes, do not do path processing
            return super().run()
        rel_filename, filename = self.env.relfn2path(self.arguments[0])
        self.arguments[0] = filename
        self.env.note_included(filename)
        return super().run()


def setup(app: "Sphinx") -> Dict[str, Any]:
    directives.register_directive('toctree', TocTree)
    directives.register_directive('sectionauthor', Author)
    directives.register_directive('moduleauthor', Author)
    directives.register_directive('codeauthor', Author)
    directives.register_directive('seealso', SeeAlso)
    directives.register_directive('tabularcolumns', TabularColumns)
    directives.register_directive('centered', Centered)
    directives.register_directive('acks', Acks)
    directives.register_directive('hlist', HList)
    directives.register_directive('only', Only)
    directives.register_directive('include', Include)

    # register the standard rst class directive under a different name
    # only for backwards compatibility now
    directives.register_directive('cssclass', Class)
    # new standard name when default-domain with "class" is in effect
    directives.register_directive('rst-class', Class)

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