"""
    sphinx.environment.adapters.toctree
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

    Toctree adapter for sphinx.environment.

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

from typing import Any, Iterable, List
from typing import cast

from docutils import nodes
from docutils.nodes import Element, Node

from sphinx import addnodes
from sphinx.locale import __
from sphinx.util import url_re, logging
from sphinx.util.matching import Matcher
from sphinx.util.nodes import clean_astext, process_only_nodes

if False:
    # For type annotation
    from sphinx.builders import Builder
    from sphinx.environment import BuildEnvironment


logger = logging.getLogger(__name__)


class TocTree:
    def __init__(self, env: "BuildEnvironment") -> None:
        self.env = env

    def note(self, docname: str, toctreenode: addnodes.toctree) -> None:
        """Note a TOC tree directive in a document and gather information about
        file relations from it.
        """
        if toctreenode['glob']:
            self.env.glob_toctrees.add(docname)
        if toctreenode.get('numbered'):
            self.env.numbered_toctrees.add(docname)
        includefiles = toctreenode['includefiles']
        for includefile in includefiles:
            # note that if the included file is rebuilt, this one must be
            # too (since the TOC of the included file could have changed)
            self.env.files_to_rebuild.setdefault(includefile, set()).add(docname)
        self.env.toctree_includes.setdefault(docname, []).extend(includefiles)

    def resolve(self, docname: str, builder: "Builder", toctree: addnodes.toctree,
                prune: bool = True, maxdepth: int = 0, titles_only: bool = False,
                collapse: bool = False, includehidden: bool = False) -> Element:
        """Resolve a *toctree* node into individual bullet lists with titles
        as items, returning None (if no containing titles are found) or
        a new node.

        If *prune* is True, the tree is pruned to *maxdepth*, or if that is 0,
        to the value of the *maxdepth* option on the *toctree* node.
        If *titles_only* is True, only toplevel document titles will be in the
        resulting tree.
        If *collapse* is True, all branches not containing docname will
        be collapsed.
        """
        if toctree.get('hidden', False) and not includehidden:
            return None

        # For reading the following two helper function, it is useful to keep
        # in mind the node structure of a toctree (using HTML-like node names
        # for brevity):
        #
        # <ul>
        #   <li>
        #     <p><a></p>
        #     <p><a></p>
        #     ...
        #     <ul>
        #       ...
        #     </ul>
        #   </li>
        # </ul>
        #
        # The transformation is made in two passes in order to avoid
        # interactions between marking and pruning the tree (see bug #1046).

        toctree_ancestors = self.get_toctree_ancestors(docname)
        excluded = Matcher(self.env.config.exclude_patterns)

        def _toctree_add_classes(node: Element, depth: int) -> None:
            """Add 'toctree-l%d' and 'current' classes to the toctree."""
            for subnode in node.children:
                if isinstance(subnode, (addnodes.compact_paragraph,
                                        nodes.list_item)):
                    # for <p> and <li>, indicate the depth level and recurse
                    subnode['classes'].append('toctree-l%d' % (depth - 1))
                    _toctree_add_classes(subnode, depth)
                elif isinstance(subnode, nodes.bullet_list):
                    # for <ul>, just recurse
                    _toctree_add_classes(subnode, depth + 1)
                elif isinstance(subnode, nodes.reference):
                    # for <a>, identify which entries point to the current
                    # document and therefore may not be collapsed
                    if subnode['refuri'] == docname:
                        if not subnode['anchorname']:
                            # give the whole branch a 'current' class
                            # (useful for styling it differently)
                            branchnode = subnode  # type: Element
                            while branchnode:
                                branchnode['classes'].append('current')
                                branchnode = branchnode.parent
                        # mark the list_item as "on current page"
                        if subnode.parent.parent.get('iscurrent'):
                            # but only if it's not already done
                            return
                        while subnode:
                            subnode['iscurrent'] = True
                            subnode = subnode.parent

        def _entries_from_toctree(toctreenode: addnodes.toctree, parents: List[str],
                                  separate: bool = False, subtree: bool = False
                                  ) -> List[Element]:
            """Return TOC entries for a toctree node."""
            refs = [(e[0], e[1]) for e in toctreenode['entries']]
            entries = []  # type: List[Element]
            for (title, ref) in refs:
                try:
                    refdoc = None
                    if url_re.match(ref):
                        if title is None:
                            title = ref
                        reference = nodes.reference('', '', internal=False,
                                                    refuri=ref, anchorname='',
                                                    *[nodes.Text(title)])
                        para = addnodes.compact_paragraph('', '', reference)
                        item = nodes.list_item('', para)
                        toc = nodes.bullet_list('', item)
                    elif ref == 'self':
                        # 'self' refers to the document from which this
                        # toctree originates
                        ref = toctreenode['parent']
                        if not title:
                            title = clean_astext(self.env.titles[ref])
                        reference = nodes.reference('', '', internal=True,
                                                    refuri=ref,
                                                    anchorname='',
                                                    *[nodes.Text(title)])
                        para = addnodes.compact_paragraph('', '', reference)
                        item = nodes.list_item('', para)
                        # don't show subitems
                        toc = nodes.bullet_list('', item)
                    else:
                        if ref in parents:
                            logger.warning(__('circular toctree references '
                                              'detected, ignoring: %s <- %s'),
                                           ref, ' <- '.join(parents),
                                           location=ref, type='toc', subtype='circular')
                            continue
                        refdoc = ref
                        toc = self.env.tocs[ref].deepcopy()
                        maxdepth = self.env.metadata[ref].get('tocdepth', 0)
                        if ref not in toctree_ancestors or (prune and maxdepth > 0):
                            self._toctree_prune(toc, 2, maxdepth, collapse)
                        process_only_nodes(toc, builder.tags)
                        if title and toc.children and len(toc.children) == 1:
                            child = toc.children[0]
                            for refnode in child.traverse(nodes.reference):
                                if refnode['refuri'] == ref and \
                                   not refnode['anchorname']:
                                    refnode.children = [nodes.Text(title)]
                    if not toc.children:
                        # empty toc means: no titles will show up in the toctree
                        logger.warning(__('toctree contains reference to document %r that '
                                          'doesn\'t have a title: no link will be generated'),
                                       ref, location=toctreenode)
                except KeyError:
                    # this is raised if the included file does not exist
                    if excluded(self.env.doc2path(ref, None)):
                        message = __('toctree contains reference to excluded document %r')
                    else:
                        message = __('toctree contains reference to nonexisting document %r')

                    logger.warning(message, ref, location=toctreenode)
                else:
                    # if titles_only is given, only keep the main title and
                    # sub-toctrees
                    if titles_only:
                        # children of toc are:
                        # - list_item + compact_paragraph + (reference and subtoc)
                        # - only + subtoc
                        # - toctree
                        children = cast(Iterable[nodes.Element], toc)

                        # delete everything but the toplevel title(s)
                        # and toctrees
                        for toplevel in children:
                            # nodes with length 1 don't have any children anyway
                            if len(toplevel) > 1:
                                subtrees = toplevel.traverse(addnodes.toctree)
                                if subtrees:
                                    toplevel[1][:] = subtrees  # type: ignore
                                else:
                                    toplevel.pop(1)
                    # resolve all sub-toctrees
                    for subtocnode in toc.traverse(addnodes.toctree):
                        if not (subtocnode.get('hidden', False) and
                                not includehidden):
                            i = subtocnode.parent.index(subtocnode) + 1
                            for entry in _entries_from_toctree(
                                    subtocnode, [refdoc] + parents,
                                    subtree=True):
                                subtocnode.parent.insert(i, entry)
                                i += 1
                            subtocnode.parent.remove(subtocnode)
                    if separate:
                        entries.append(toc)
                    else:
                        children = cast(Iterable[nodes.Element], toc)
                        entries.extend(children)
            if not subtree and not separate:
                ret = nodes.bullet_list()
                ret += entries
                return [ret]
            return entries

        maxdepth = maxdepth or toctree.get('maxdepth', -1)
        if not titles_only and toctree.get('titlesonly', False):
            titles_only = True
        if not includehidden and toctree.get('includehidden', False):
            includehidden = True

        # NOTE: previously, this was separate=True, but that leads to artificial
        # separation when two or more toctree entries form a logical unit, so
        # separating mode is no longer used -- it's kept here for history's sake
        tocentries = _entries_from_toctree(toctree, [], separate=False)
        if not tocentries:
            return None

        newnode = addnodes.compact_paragraph('', '')
        caption = toctree.attributes.get('caption')
        if caption:
            caption_node = nodes.caption(caption, '', *[nodes.Text(caption)])
            caption_node.line = toctree.line
            caption_node.source = toctree.source
            caption_node.rawsource = toctree['rawcaption']
            if hasattr(toctree, 'uid'):
                # move uid to caption_node to translate it
                caption_node.uid = toctree.uid  # type: ignore
                del toctree.uid  # type: ignore
            newnode += caption_node
        newnode.extend(tocentries)
        newnode['toctree'] = True

        # prune the tree to maxdepth, also set toc depth and current classes
        _toctree_add_classes(newnode, 1)
        self._toctree_prune(newnode, 1, maxdepth if prune else 0, collapse)

        if isinstance(newnode[-1], nodes.Element) and len(newnode[-1]) == 0:  # No titles found
            return None

        # set the target paths in the toctrees (they are not known at TOC
        # generation time)
        for refnode in newnode.traverse(nodes.reference):
            if not url_re.match(refnode['refuri']):
                refnode['refuri'] = builder.get_relative_uri(
                    docname, refnode['refuri']) + refnode['anchorname']
        return newnode

    def get_toctree_ancestors(self, docname: str) -> List[str]:
        parent = {}
        for p, children in self.env.toctree_includes.items():
            for child in children:
                parent[child] = p
        ancestors = []  # type: List[str]
        d = docname
        while d in parent and d not in ancestors:
            ancestors.append(d)
            d = parent[d]
        return ancestors

    def _toctree_prune(self, node: Element, depth: int, maxdepth: int, collapse: bool = False
                       ) -> None:
        """Utility: Cut a TOC at a specified depth."""
        for subnode in node.children[:]:
            if isinstance(subnode, (addnodes.compact_paragraph,
                                    nodes.list_item)):
                # for <p> and <li>, just recurse
                self._toctree_prune(subnode, depth, maxdepth, collapse)
            elif isinstance(subnode, nodes.bullet_list):
                # for <ul>, determine if the depth is too large or if the
                # entry is to be collapsed
                if maxdepth > 0 and depth > maxdepth:
                    subnode.parent.replace(subnode, [])
                else:
                    # cull sub-entries whose parents aren't 'current'
                    if (collapse and depth > 1 and
                            'iscurrent' not in subnode.parent):
                        subnode.parent.remove(subnode)
                    else:
                        # recurse on visible children
                        self._toctree_prune(subnode, depth + 1, maxdepth,  collapse)

    def get_toc_for(self, docname: str, builder: "Builder") -> Node:
        """Return a TOC nodetree -- for use on the same page only!"""
        tocdepth = self.env.metadata[docname].get('tocdepth', 0)
        try:
            toc = self.env.tocs[docname].deepcopy()
            self._toctree_prune(toc, 2, tocdepth)
        except KeyError:
            # the document does not exist anymore: return a dummy node that
            # renders to nothing
            return nodes.paragraph()
        process_only_nodes(toc, builder.tags)
        for node in toc.traverse(nodes.reference):
            node['refuri'] = node['anchorname'] or '#'
        return toc

    def get_toctree_for(self, docname: str, builder: "Builder", collapse: bool,
                        **kwargs: Any) -> Element:
        """Return the global TOC nodetree."""
        doctree = self.env.get_doctree(self.env.config.master_doc)
        toctrees = []  # type: List[Element]
        if 'includehidden' not in kwargs:
            kwargs['includehidden'] = True
        if 'maxdepth' not in kwargs:
            kwargs['maxdepth'] = 0
        kwargs['collapse'] = collapse
        for toctreenode in doctree.traverse(addnodes.toctree):
            toctree = self.resolve(docname, builder, toctreenode, prune=True, **kwargs)
            if toctree:
                toctrees.append(toctree)
        if not toctrees:
            return None
        result = toctrees[0]
        for toctree in toctrees[1:]:
            result.extend(toctree.children)
        return result
