# -*- coding: utf-8 -*-
"""
    sphinx.writers.texinfo
    ~~~~~~~~~~~~~~~~~~~~~~

    Custom docutils writer for Texinfo.

    :copyright: Copyright 2007-2011 by the Sphinx team, see AUTHORS.
    :license: BSD, see LICENSE for details.
"""

import re
import string
import textwrap
from os import path

from docutils import nodes, writers

from sphinx import addnodes, __version__
from sphinx.locale import versionlabels, _
from sphinx.util import ustrftime
from sphinx.writers.latex import collected_footnote


COPYING = """\
@quotation
%(project)s %(release)s, %(date)s

%(author)s

Copyright @copyright{} %(copyright)s
@end quotation
"""

TEMPLATE = """\
\\input texinfo   @c -*-texinfo-*-
@c %%**start of header
@setfilename %(filename)s
@documentencoding UTF-8
@ifinfo
@*Generated by Sphinx """ + __version__ + """.@*
@end ifinfo
@settitle %(title)s
@defindex ge
@paragraphindent %(paragraphindent)s
@exampleindent %(exampleindent)s
@afourlatex
%(direntry)s
@c %%**end of header

@copying
%(copying)s
@end copying

@titlepage
@title %(title)s
@insertcopying
@end titlepage
@contents

@c %%** start of user preamble
%(preamble)s
@c %%** end of user preamble

@ifnottex
@node Top
@top %(title)s
@insertcopying
@end ifnottex

@c %%**start of body
%(body)s
@c %%**end of body
@bye
"""


def find_subsections(section):
    """Return a list of subsections for the given ``section``."""
    result = []
    for child in section.children:
        if isinstance(child, nodes.section):
            result.append(child)
            continue
        result.extend(find_subsections(child))
    return result


class TexinfoWriter(writers.Writer):
    """Texinfo writer for generating Texinfo documents."""
    supported = ('texinfo', 'texi')

    settings_spec = (
        'Texinfo Specific Options', None, (
            ("Name of the Info file", ['--texinfo-filename'], {'default': ''}),
            ('Dir entry', ['--texinfo-dir-entry'], {'default': ''}),
            ('Description', ['--texinfo-dir-description'], {'default': ''}),
            ('Category', ['--texinfo-dir-category'], {'default':
                                                          'Miscellaneous'})))

    settings_defaults = {}

    output = None

    visitor_attributes = ('output', 'fragment')

    def __init__(self, builder):
        writers.Writer.__init__(self)
        self.builder = builder

    def translate(self):
        self.visitor = visitor = TexinfoTranslator(self.document, self.builder)
        self.document.walkabout(visitor)
        visitor.finish()
        for attr in self.visitor_attributes:
            setattr(self, attr, getattr(visitor, attr))


class TexinfoTranslator(nodes.NodeVisitor):

    ignore_missing_images = False

    default_elements = {
        'author': '',
        'body': '',
        'copying': '',
        'date': '',
        'direntry': '',
        'exampleindent': 4,
        'filename': '',
        'paragraphindent': 2,
        'preamble': '',
        'project': '',
        'release': '',
        'title': '',
        }

    def __init__(self, document, builder):
        nodes.NodeVisitor.__init__(self, document)
        self.builder = builder
        self.init_settings()

        self.written_ids = set()    # node names and anchors in output
        self.referenced_ids = set() # node names and anchors that should
                                    # be in output
        self.indices = []     # (node name, content)
        self.short_ids = {}   # anchors --> short ids
        self.node_names = {}  # node name --> node's name to display
        self.node_menus = {}  # node name --> node's menu entries
        self.rellinks = {}    # node name --> (next, previous, up)

        self.collect_indices()
        self.collect_node_names()
        self.collect_node_menus()
        self.collect_rellinks()

        self.body = []
        self.context = []
        self.previous_section = None
        self.section_level = 0
        self.seen_title = False
        self.next_section_ids = set()
        self.escape_newlines = 0
        self.curfilestack = []
        self.footnotestack = []
        self.in_footnote = 0
        self.handled_abbrs = set()

    def finish(self):
        if self.previous_section is None:
            self.add_menu('Top')
        for index in self.indices:
            name, content = index
            pointers = tuple([name] + self.rellinks[name])
            self.body.append('\n@node %s,%s,%s,%s\n' % pointers)
            self.body.append('@unnumbered %s\n\n%s\n' % (name, content))

        while self.referenced_ids:
            # handle xrefs with missing anchors
            r = self.referenced_ids.pop()
            if r not in self.written_ids:
                self.body.append('@anchor{%s}@w{%s}\n' % (r, ' ' * 30))
        self.fragment = ''.join(self.body).strip() + '\n'
        self.elements['body'] = self.fragment
        self.output = TEMPLATE % self.elements

    ## Helper routines

    def init_settings(self):
        settings = self.settings = self.document.settings
        elements = self.elements = self.default_elements.copy()
        elements.update({
                # if empty, the title is set to the first section title
                'title': settings.title,
                'author': settings.author,
                # if empty, use basename of input file
                'filename': settings.texinfo_filename,
                'release': self.escape(self.builder.config.release),
                'project': self.escape(self.builder.config.project),
                'copyright': self.escape(self.builder.config.copyright),
                'date': self.escape(self.builder.config.today or
                                    ustrftime(self.builder.config.today_fmt
                                              or _('%B %d, %Y')))
                })
        # title
        title = elements['title']
        if not title:
            title = self.document.next_node(nodes.title)
            title = (title and title.astext()) or '<untitled>'
        elements['title'] = self.escape_id(title) or '<untitled>'
        # filename
        if not elements['filename']:
            elements['filename'] = self.document.get('source') or 'untitled'
            if elements['filename'][-4:] in ('.txt', '.rst'):
                elements['filename'] = elements['filename'][:-4]
            elements['filename'] += '.info'
        # direntry
        if settings.texinfo_dir_entry:
            entry = self.format_menu_entry(
                self.escape_menu(settings.texinfo_dir_entry),
                '(%s)' % elements['filename'],
                self.escape_arg(settings.texinfo_dir_description))
            elements['direntry'] = ('@dircategory %s\n'
                                    '@direntry\n'
                                    '%s'
                                    '@end direntry\n') % (
                self.escape_id(settings.texinfo_dir_category), entry)
        elements['copying'] = COPYING % elements
        # allow the user to override them all
        elements.update(settings.texinfo_elements)

    def collect_node_names(self):
        """Generates a unique id for each section.

        Assigns the attribute ``node_name`` to each section."""
        # must have a "Top" node
        self.document['node_name'] = 'Top'
        self.node_names['Top'] = 'Top'
        self.written_ids.update(('Top', 'top'))
        # each index is a node
        for name, content in self.indices:
            self.node_names[name] = name
            self.written_ids.add(name)
        # each section is also a node
        for section in self.document.traverse(nodes.section):
            title = section.next_node(nodes.Titular)
            name = (title and title.astext()) or '<untitled>'
            node_id = self.escape_id(name) or '<untitled>'
            assert node_id and name
            nth, suffix = 1, ''
            while node_id + suffix in self.written_ids:
                nth += 1
                suffix = '<%s>' % nth
            node_id += suffix
            assert node_id not in self.node_names
            assert node_id not in self.written_ids
            section['node_name'] = node_id
            self.node_names[node_id] = name
            self.written_ids.add(node_id)

    def collect_node_menus(self):
        """Collect the menu entries for each "node" section."""
        node_menus = self.node_menus
        for node in ([self.document] +
                     self.document.traverse(nodes.section)):
            assert 'node_name' in node and node['node_name']
            entries = [s['node_name'] for s in find_subsections(node)]
            node_menus[node['node_name']] = entries
        # try to find a suitable "Top" node
        title = self.document.next_node(nodes.title)
        top = (title and title.parent) or self.document
        if not isinstance(top, (nodes.document, nodes.section)):
            top = self.document
        if top is not self.document:
            entries = node_menus[top['node_name']]
            entries += node_menus['Top'][1:]
            node_menus['Top'] = entries
            del node_menus[top['node_name']]
            top['node_name'] = 'Top'
        # handle the indices
        for name, content in self.indices:
            node_menus[name] = ()
            node_menus['Top'].append(name)

    def collect_rellinks(self):
        """Collect the relative links (next, previous, up) for each "node"."""
        rellinks = self.rellinks
        node_menus = self.node_menus
        for id, entries in node_menus.items():
            rellinks[id] = ['', '', '']
        # up's
        for id, entries in node_menus.items():
            for e in entries:
                rellinks[e][2] = id
        # next's and prev's
        for id, entries in node_menus.items():
            for i, id in enumerate(entries):
                # First child's prev is empty
                if i != 0:
                    rellinks[id][1] = entries[i-1]
                # Last child's next is empty
                if i != len(entries) - 1:
                    rellinks[id][0] = entries[i+1]
        # top's next is its first child
        try:
            first = node_menus['Top'][0]
        except IndexError:
            pass
        else:
            rellinks['Top'][0] = first
            rellinks[first][1] = 'Top'

    ## Escaping
    # Which characters to escape depends on the context.  In some cases,
    # namely menus and node names, it's not possible to escape certain
    # characters.

    def escape(self, s):
        """Return a string with Texinfo command characters escaped."""
        s = s.replace('@', '@@')
        s = s.replace('{', '@{')
        s = s.replace('}', '@}')
        # prevent `` and '' quote conversion
        s = s.replace('``', "`@w{`}")
        s = s.replace("''", "'@w{'}")
        # prevent "--" from being converted to an "em dash"
        # s = s.replace('-', '@w{-}')
        return s

    def escape_arg(self, s):
        """Return an escaped string suitable for use as an argument
        to a Texinfo command."""
        s = self.escape(s)
        # commas are the argument delimeters
        s = s.replace(',', '@comma{}')
        # normalize white space
        s = ' '.join(s.split()).strip()
        return s

    def escape_id(self, s):
        """Return an escaped string suitable for node names and anchors."""
        bad_chars = ',:.()'
        for bc in bad_chars:
            s = s.replace(bc, ' ')
        s = ' '.join(s.split()).strip()
        return self.escape(s)

    def escape_menu(self, s):
        """Return an escaped string suitable for menu entries."""
        s = self.escape_arg(s)
        s = s.replace(':', ';')
        s = ' '.join(s.split()).strip()
        return s

    def ensure_eol(self):
        """Ensure the last line in body is terminated by new line."""
        if self.body and self.body[-1][-1:] != '\n':
            self.body.append('\n')

    def format_menu_entry(self, name, node_name, desc):
        if name == node_name:
            s = '* %s:: ' % (name,)
        else:
            s = '* %s: %s. ' % (name, node_name)
        offset = max((24, (len(name) + 4) % 78))
        wdesc = '\n'.join(' ' * offset + l for l in
                          textwrap.wrap(desc, width=78-offset))
        return s + wdesc.strip() + '\n'

    def add_menu_entries(self, entries, reg=re.compile(r'\s+---?\s+')):
        for entry in entries:
            name = self.node_names[entry]
            # special formatting for entries that are divided by an em-dash
            parts = reg.split(name, 1)
            if len(parts) == 2:
                name, desc = parts
            else:
                desc = ''
            name = self.escape_menu(name)
            desc = self.escape(desc)
            self.body.append(self.format_menu_entry(name, entry, desc))

    def add_menu(self, node_name):
        entries = self.node_menus[node_name]
        if not entries:
            return
        self.body.append('\n@menu\n')
        self.add_menu_entries(entries)
        if not self.node_menus[entries[0]]:
            self.body.append('\n@end menu\n')
            return

        def _add_detailed_menu(name):
            entries = self.node_menus[name]
            if not entries:
                return
            self.body.append('\n%s\n\n' % (self.escape(self.node_names[name],)))
            self.add_menu_entries(entries)
            for subentry in entries:
                _add_detailed_menu(subentry)

        if node_name == 'Top':
            self.body.append('\n@detailmenu\n'
                             ' --- The Detailed Node Listing ---\n')
        for entry in entries:
            _add_detailed_menu(entry)
        if node_name == 'Top':
            self.body.append('\n@end detailmenu')
        self.body.append('\n@end menu\n\n')

    def tex_image_length(self, width_str):
        match = re.match('(\d*\.?\d*)\s*(\S*)', width_str)
        if not match:
            # fallback
            return width_str
        res = width_str
        amount, unit = match.groups()[:2]
        if not unit or unit == "px":
            # pixels: let TeX alone
            return ''
        elif unit == "%":
            # a4paper: textwidth=418.25368pt
            res = "%d.0pt" % (float(amount) * 4.1825368)
        return res

    def collect_indices(self):
        def generate(content, collapsed):
            ret = ['\n@menu\n']
            for letter, entries in content:
                for entry in entries:
                    if not entry[3]:
                        continue
                    name = self.escape_menu(entry[0])
                    sid = self.get_short_id('%s:%s' % (entry[2], entry[3]))
                    desc = self.escape_arg(entry[6])
                    me = self.format_menu_entry(name, sid, desc)
                    ret.append(me)
            ret.append('@end menu\n')
            return ''.join(ret)

        indices_config = self.builder.config.texinfo_domain_indices
        if indices_config:
            for domain in self.builder.env.domains.itervalues():
                for indexcls in domain.indices:
                    indexname = '%s-%s' % (domain.name, indexcls.name)
                    if isinstance(indices_config, list):
                        if indexname not in indices_config:
                            continue
                    content, collapsed = indexcls(domain).generate(
                        self.builder.docnames)
                    if not content:
                        continue
                    node_name = self.escape_id(indexcls.localname)
                    self.indices.append((node_name,
                                         generate(content, collapsed)))
        self.indices.append((_('Index'), '\n@printindex ge\n'))

    # this is copied from the latex writer
    # TODO: move this to sphinx.util

    def collect_footnotes(self, node):
        fnotes = {}
        def footnotes_under(n):
            if isinstance(n, nodes.footnote):
                yield n
            else:
                for c in n.children:
                    if isinstance(c, addnodes.start_of_file):
                        continue
                    for k in footnotes_under(c):
                        yield k
        for fn in footnotes_under(node):
            num = fn.children[0].astext().strip()
            fnotes[num] = [collected_footnote(*fn.children), False]
        return fnotes

    ## xref handling

    def get_short_id(self, id):
        """Return a shorter 'id' associated with ``id``."""
        # Shorter ids improve paragraph filling in places
        # that the id is hidden by Emacs.
        try:
            sid = self.short_ids[id]
        except KeyError:
            sid = hex(len(self.short_ids))[2:]
            self.short_ids[id] = sid
        return sid

    def add_anchor(self, id, node):
        if id.startswith('index-'):
            return
        id = self.curfilestack[-1] + ':' + id
        eid = self.escape_id(id)
        sid = self.get_short_id(id)
        for id in (eid, sid):
            if id not in self.written_ids:
                self.body.append('@anchor{%s}' % id)
                self.written_ids.add(id)

    def add_xref(self, id, name, node):
        name = self.escape_menu(name)
        sid = self.get_short_id(id)
        self.body.append('@pxref{%s,,%s}' % (sid, name))
        self.referenced_ids.add(sid)
        self.referenced_ids.add(self.escape_id(id))

    ## Visiting

    def visit_document(self, node):
        self.footnotestack.append(self.collect_footnotes(node))
        self.curfilestack.append(node.get('docname', ''))
        if 'docname' in node:
            self.add_anchor(':doc', node)
    def depart_document(self, node):
        self.footnotestack.pop()
        self.curfilestack.pop()

    def visit_Text(self, node):
        s = self.escape(node.astext())
        if self.escape_newlines:
            s = s.replace('\n', ' ')
        self.body.append(s)
    def depart_Text(self, node):
        pass

    def visit_section(self, node):
        self.next_section_ids.update(node.get('ids', []))
        if not self.seen_title:
            return
        if self.previous_section:
            self.add_menu(self.previous_section['node_name'])
        else:
            self.add_menu('Top')

        node_name = node['node_name']
        pointers = tuple([node_name] + self.rellinks[node_name])
        self.body.append('\n@node %s,%s,%s,%s\n' % pointers)
        for id in self.next_section_ids:
            self.add_anchor(id, node)

        self.next_section_ids.clear()
        self.previous_section = node
        self.section_level += 1

    def depart_section(self, node):
        self.section_level -= 1

    headings = (
        '@unnumbered',
        '@chapter',
        '@section',
        '@subsection',
        '@subsubsection',
        )

    rubrics = (
        '@heading',
        '@subheading',
        '@subsubheading',
        )

    def visit_title(self, node):
        if not self.seen_title:
            self.seen_title = 1
            raise nodes.SkipNode
        parent = node.parent
        if isinstance(parent, nodes.table):
            return
        if isinstance(parent, (nodes.Admonition, nodes.sidebar, nodes.topic)):
            raise nodes.SkipNode
        elif not isinstance(parent, nodes.section):
            self.builder.warn(
                'encountered title node not in section, topic, table, '
                'admonition or sidebar', (self.curfilestack[-1], node.line))
            self.visit_rubric(node)
        else:
            try:
                heading = self.headings[self.section_level]
            except IndexError:
                heading = self.headings[-1]
            self.body.append('\n%s ' % heading)

    def depart_title(self, node):
        self.body.append('\n\n')

    def visit_rubric(self, node):
        if len(node.children) == 1 and node.children[0].astext() in \
                ('Footnotes', _('Footnotes')):
            raise nodes.SkipNode
        try:
            rubric = self.rubrics[self.section_level]
        except IndexError:
            rubric = self.rubrics[-1]
        self.body.append('\n%s ' % rubric)
    def depart_rubric(self, node):
        self.body.append('\n\n')

    def visit_subtitle(self, node):
        self.body.append('\n\n@noindent\n')
    def depart_subtitle(self, node):
        self.body.append('\n\n')

    ## References

    def visit_target(self, node):
        # postpone the labels until after the sectioning command
        parindex = node.parent.index(node)
        try:
            try:
                next = node.parent[parindex+1]
            except IndexError:
                # last node in parent, look at next after parent
                # (for section of equal level)
                next = node.parent.parent[node.parent.parent.index(node.parent)]
            if isinstance(next, nodes.section):
                if node.get('refid'):
                    self.next_section_ids.add(node['refid'])
                self.next_section_ids.update(node['ids'])
                return
        except IndexError:
            pass
        if 'refuri' in node:
            return
        if node.get('refid'):
            self.add_anchor(node['refid'], node)
        for id in node['ids']:
            self.add_anchor(id, node)
    def depart_target(self, node):
        pass

    def visit_reference(self, node):
        # an xref's target is displayed in Info so we ignore a few
        # cases for the sake of appearance
        if isinstance(node.parent, (nodes.title, addnodes.desc_type,)):
            return
        if isinstance(node[0], nodes.image):
            return
        name = node.get('name', node.astext()).strip()
        uri = node.get('refuri', '')
        if not uri and node.get('refid'):
            uri = '%' + self.curfilestack[-1] + '#' + node['refid']
        if not uri:
            return
        if uri.startswith('mailto:'):
            uri = self.escape_arg(uri[7:])
            name = self.escape_arg(name)
            if not name or name == uri:
                self.body.append('@email{%s}' % uri)
            else:
                self.body.append('@email{%s,%s}' % (uri, name))
        elif uri.startswith('#'):
            # references to labels in the same document
            id = self.curfilestack[-1] + ':' + uri[1:]
            self.add_xref(id, name, node)
        elif uri.startswith('%'):
            # references to documents or labels inside documents
            hashindex = uri.find('#')
            if hashindex == -1:
                # reference to the document
                id = uri[1:] + '::doc'
            else:
                # reference to a label
                id = uri[1:].replace('#', ':')
            self.add_xref(id, name, node)
        elif uri.startswith('info:'):
            # references to an external Info file
            uri = uri[5:].replace('_', ' ')
            uri = self.escape_arg(uri)
            id = 'Top'
            if '#' in uri:
                uri, id = uri.split('#', 1)
            id = self.escape_id(id)
            name = self.escape_menu(name)
            if name == id:
                self.body.append('@pxref{%s,,,%s}' % (id, uri))
            else:
                self.body.append('@pxref{%s,,%s,%s}' % (id, name, uri))
        else:
            uri = self.escape_arg(uri)
            name = self.escape_arg(name)
            show_urls = self.builder.config.texinfo_show_urls
            if self.in_footnote:
                show_urls = 'inline'
            if not name or uri == name:
                self.body.append('@indicateurl{%s}' % uri)
            elif show_urls == 'inline':
                self.body.append('@uref{%s,%s}' % (uri, name))
            elif show_urls == 'no':
                self.body.append('@uref{%s,,%s}' % (uri, name))
            else:
                self.body.append('%s@footnote{%s}' % (name, uri))
        raise nodes.SkipNode

    def depart_reference(self, node):
        pass

    def visit_title_reference(self, node):
        text = node.astext()
        self.body.append('@cite{%s}' % self.escape_arg(text))
        raise nodes.SkipNode

    ## Blocks

    def visit_paragraph(self, node):
        if 'continued' in node or isinstance(node.parent, nodes.compound):
            self.body.append('\n@noindent')
        self.body.append('\n')
    def depart_paragraph(self, node):
        self.body.append('\n')

    def visit_block_quote(self, node):
        self.body.append('\n@quotation\n')
    def depart_block_quote(self, node):
        self.ensure_eol()
        self.body.append('@end quotation\n')

    def visit_literal_block(self, node):
        self.body.append('\n@example\n')
    def depart_literal_block(self, node):
        self.body.append('\n@end example\n\n'
                         '@noindent\n')

    visit_doctest_block = visit_literal_block
    depart_doctest_block = depart_literal_block

    def visit_line_block(self, node):
        if not isinstance(node.parent, nodes.line_block):
            self.body.append('\n\n')
        self.body.append('@display\n')
    def depart_line_block(self, node):
        self.body.append('@end display\n')
        if not isinstance(node.parent, nodes.line_block):
            self.body.append('\n\n')

    def visit_line(self, node):
        self.escape_newlines += 1
    def depart_line(self, node):
        self.body.append('@w{ }\n')
        self.escape_newlines -= 1

    ## Inline

    def visit_strong(self, node):
        self.body.append('@strong{')
    def depart_strong(self, node):
        self.body.append('}')

    def visit_emphasis(self, node):
        self.body.append('@emph{')
    def depart_emphasis(self, node):
        self.body.append('}')

    def visit_literal(self, node):
        self.body.append('@code{')
    def depart_literal(self, node):
        self.body.append('}')

    def visit_superscript(self, node):
        self.body.append('@w{^')
    def depart_superscript(self, node):
        self.body.append('}')

    def visit_subscript(self, node):
        self.body.append('@w{[')
    def depart_subscript(self, node):
        self.body.append(']}')

    ## Footnotes

    def visit_footnote(self, node):
        raise nodes.SkipNode

    def visit_collected_footnote(self, node):
        self.in_footnote += 1
        self.body.append('@footnote{')
    def depart_collected_footnote(self, node):
        self.body.append('}')
        self.in_footnote -= 1

    def visit_footnote_reference(self, node):
        num = node.astext().strip()
        try:
            footnode, used = self.footnotestack[-1][num]
        except (KeyError, IndexError):
            raise nodes.SkipNode
        # footnotes are repeated for each reference
        footnode.walkabout(self)
        raise nodes.SkipChildren

    def visit_citation(self, node):
        for id in node.get('ids'):
            self.add_anchor(id, node)
    def depart_citation(self, node):
        pass

    def visit_citation_reference(self, node):
        self.body.append('@w{[')
    def depart_citation_reference(self, node):
        self.body.append(']}')

    ## Lists

    def visit_bullet_list(self, node):
        bullet = node.get('bullet', '*')
        self.body.append('\n\n@itemize %s\n' % bullet)
    def depart_bullet_list(self, node):
        self.ensure_eol()
        self.body.append('@end itemize\n')

    def visit_enumerated_list(self, node):
        # doesn't support Roman numerals
        enum = node.get('enumtype', 'arabic')
        starters = {'arabic': '',
                    'loweralpha': 'a',
                    'upperalpha': 'A',}
        start = node.get('start', starters.get(enum, ''))
        self.body.append('\n\n@enumerate %s\n' % start)
    def depart_enumerated_list(self, node):
        self.ensure_eol()
        self.body.append('@end enumerate\n')

    def visit_list_item(self, node):
        self.body.append('\n@item ')
    def depart_list_item(self, node):
        pass

    ## Option List

    def visit_option_list(self, node):
        self.body.append('\n\n@table @option\n')
    def depart_option_list(self, node):
        self.ensure_eol()
        self.body.append('@end table\n')

    def visit_option_list_item(self, node):
        pass
    def depart_option_list_item(self, node):
        pass

    def visit_option_group(self, node):
        self.at_item_x = '@item'
    def depart_option_group(self, node):
        pass

    def visit_option(self, node):
        self.body.append('\n%s ' % self.at_item_x)
        self.at_item_x = '@itemx'
    def depart_option(self, node):
        pass

    def visit_option_string(self, node):
        pass
    def depart_option_string(self, node):
        pass

    def visit_option_argument(self, node):
        self.body.append(node.get('delimiter', ' '))
    def depart_option_argument(self, node):
        pass

    def visit_description(self, node):
        self.body.append('\n')
    def depart_description(self, node):
        pass

    ## Definitions

    def visit_definition_list(self, node):
        self.body.append('\n\n@table @asis\n')
    def depart_definition_list(self, node):
        self.ensure_eol()
        self.body.append('@end table\n')

    def visit_definition_list_item(self, node):
        self.at_item_x = '@item'
    def depart_definition_list_item(self, node):
        pass

    def visit_term(self, node):
        for id in node.get('ids'):
            self.add_anchor(id, node)
        # anchors and indexes need to go in front
        for n in node[::]:
            if isinstance(n, (addnodes.index, nodes.target)):
                n.walkabout(self)
                node.remove(n)
        self.body.append('\n%s ' % self.at_item_x)
        self.at_item_x = '@itemx'
    def depart_term(self, node):
        pass

    def visit_termsep(self, node):
        self.body.append('\n%s ' % self.at_item_x)
    def depart_termsep(self, node):
        pass

    def visit_classifier(self, node):
        self.body.append(' : ')
    def depart_classifier(self, node):
        pass

    def visit_definition(self, node):
        self.body.append('\n')
    def depart_definition(self, node):
        pass

    ## Tables

    def visit_table(self, node):
        self.entry_sep = '@item'
    def depart_table(self, node):
        self.body.append('\n@end multitable\n\n')

    def visit_tabular_col_spec(self, node):
        pass
    def depart_tabular_col_spec(self, node):
        pass

    def visit_colspec(self, node):
        self.colwidths.append(node['colwidth'])
        if len(self.colwidths) != self.n_cols:
            return
        self.body.append('\n\n@multitable ')
        for i, n in enumerate(self.colwidths):
            self.body.append('{%s} ' %('x' * (n+2)))
    def depart_colspec(self, node):
        pass

    def visit_tgroup(self, node):
        self.colwidths = []
        self.n_cols = node['cols']
    def depart_tgroup(self, node):
        pass

    def visit_thead(self, node):
        self.entry_sep = '@headitem'
    def depart_thead(self, node):
        pass

    def visit_tbody(self, node):
        pass
    def depart_tbody(self, node):
        pass

    def visit_row(self, node):
        pass
    def depart_row(self, node):
        self.entry_sep = '@item'

    def visit_entry(self, node):
        self.body.append('\n%s\n' % self.entry_sep)
        self.entry_sep = '@tab'
    def depart_entry(self, node):
        for i in xrange(node.get('morecols', 0)):
            self.body.append('\n@tab\n')

    ## Field Lists

    def visit_field_list(self, node):
        self.body.append('\n\n@itemize @w\n')
    def depart_field_list(self, node):
        self.ensure_eol()
        self.body.append('@end itemize\n')

    def visit_field(self, node):
        if not isinstance(node.parent, nodes.field_list):
            self.visit_field_list(node)
    def depart_field(self, node):
        if not isinstance(node.parent, nodes.field_list):
            self.depart_field_list(node)

    def visit_field_name(self, node):
        self.body.append('\n@item ')
    def depart_field_name(self, node):
        self.body.append(': ')

    def visit_field_body(self, node):
        pass
    def depart_field_body(self, node):
        pass

    ## Admonitions

    def visit_admonition(self, node, name=''):
        if not name:
            name = self.escape(node[0].astext())
        self.body.append('\n@cartouche\n'
                         '@quotation %s ' % name)
    def depart_admonition(self, node):
        self.ensure_eol()
        self.body.append('@end quotation\n'
                         '@end cartouche\n')

    def _make_visit_admonition(typ):
        def visit(self, node):
            self.visit_admonition(node, self.escape(_(typ)))
        return visit

    visit_attention = _make_visit_admonition('Attention')
    depart_attention = depart_admonition
    visit_caution = _make_visit_admonition('Caution')
    depart_caution = depart_admonition
    visit_danger = _make_visit_admonition('Danger')
    depart_danger = depart_admonition
    visit_error = _make_visit_admonition('Error')
    depart_error = depart_admonition
    visit_important = _make_visit_admonition('Important')
    depart_important = depart_admonition
    visit_note = _make_visit_admonition('Note')
    depart_note = depart_admonition
    visit_tip = _make_visit_admonition('Tip')
    depart_tip = depart_admonition
    visit_hint = _make_visit_admonition('Hint')
    depart_hint = depart_admonition
    visit_warning = _make_visit_admonition('Warning')
    depart_warning = depart_admonition

    ## Misc

    def visit_docinfo(self, node):
        raise nodes.SkipNode

    def visit_generated(self, node):
        raise nodes.SkipNode

    def visit_header(self, node):
        raise nodes.SkipNode

    def visit_footer(self, node):
        raise nodes.SkipNode

    def visit_container(self, node):
        pass
    def depart_container(self, node):
        pass

    def visit_decoration(self, node):
        pass
    def depart_decoration(self, node):
        pass

    def visit_topic(self, node):
        # ignore TOC's since we have to have a "menu" anyway
        if 'contents' in node.get('classes', []):
            raise nodes.SkipNode
        title = node[0]
        self.visit_rubric(title)
        self.body.append('%s\n' % self.escape(title.astext()))
    def depart_topic(self, node):
        pass

    def visit_transition(self, node):
        self.body.append('\n\n@exdent @w{    %s}\n\n' % ('* ' * 30))
    def depart_transition(self, node):
        pass

    def visit_attribution(self, node):
        self.body.append('\n\n@center --- ')
    def depart_attribution(self, node):
        self.body.append('\n\n')

    def visit_raw(self, node):
        format = node.get('format', '').split()
        if 'texinfo' in format or 'texi' in format:
            self.body.append(node.astext())
        raise nodes.SkipNode

    def visit_figure(self, node):
        self.body.append('\n\n@float Figure\n')
    def depart_figure(self, node):
        self.body.append('\n@end float\n\n')

    def visit_caption(self, node):
        if not isinstance(node.parent, nodes.figure):
            self.builder.warn('caption not inside a figure.',
                              (self.curfilestack[-1], node.line))
            return
        self.body.append('\n@caption{')
    def depart_caption(self, node):
        if isinstance(node.parent, nodes.figure):
            self.body.append('}\n')

    def visit_image(self, node):
        if node['uri'] in self.builder.images:
            uri = self.builder.images[node['uri']]
        else:
            # missing image!
            if self.ignore_missing_images:
                return
            uri = node['uri']
        if uri.find('://') != -1:
            # ignore remote images
            return
        name, ext = path.splitext(uri)
        attrs = node.attributes
        # width and height ignored in non-tex output
        width = self.tex_image_length(attrs.get('width', ''))
        height = self.tex_image_length(attrs.get('height', ''))
        alt = self.escape_arg(attrs.get('alt', ''))
        self.body.append('\n@image{%s,%s,%s,%s,%s}\n' %
                         (name, width, height, alt, ext[1:]))
    def depart_image(self, node):
        pass

    def visit_compound(self, node):
        pass
    def depart_compound(self, node):
        pass

    def visit_sidebar(self, node):
        self.visit_topic(node)
    def depart_sidebar(self, node):
        self.depart_topic(node)

    def visit_label(self, node):
        self.body.append('@w{(')
    def depart_label(self, node):
        self.body.append(')} ')

    def visit_legend(self, node):
        pass
    def depart_legend(self, node):
        pass

    def visit_substitution_reference(self, node):
        pass
    def depart_substitution_reference(self, node):
        pass

    def visit_substitution_definition(self, node):
        raise nodes.SkipNode

    def visit_system_message(self, node):
        self.body.append('\n@w{----------- System Message: %s/%s -----------} '
                         '(%s, line %s)\n' % (
                node.get('type', '?'),
                node.get('level', '?'),
                self.escape(node.get('source', '?')),
                node.get('line', '?')))
    def depart_system_message(self, node):
        pass

    def visit_comment(self, node):
        self.body.append('\n')
        for line in node.astext().splitlines():
            self.body.append('@c %s\n' % line)
        raise nodes.SkipNode

    def visit_problematic(self, node):
        self.body.append('>')
    def depart_problematic(self, node):
        self.body.append('<')

    def unimplemented_visit(self, node):
        self.builder.warn("unimplemented node type: %r" % node,
                          (self.curfilestack[-1], node.line))

    def unknown_visit(self, node):
        self.builder.warn("unknown node type: %r" % node,
                          (self.curfilestack[-1], node.line))
    def unknown_departure(self, node):
        pass

    ### Sphinx specific

    def visit_productionlist(self, node):
        self.visit_literal_block(None)
        names = []
        for production in node:
            names.append(production['tokenname'])
        maxlen = max(len(name) for name in names)
        for production in node:
            if production['tokenname']:
                for id in production.get('ids'):
                    self.add_anchor(id, production)
                s = production['tokenname'].ljust(maxlen) + ' ::='
                lastname = production['tokenname']
            else:
                s = '%s    ' % (' '*maxlen)
            self.body.append(self.escape(s))
            self.body.append(self.escape(production.astext() + '\n'))
        self.depart_literal_block(None)
        raise nodes.SkipNode

    def visit_production(self, node):
        pass
    def depart_production(self, node):
        pass

    def visit_literal_emphasis(self, node):
        self.body.append('@code{')
    def depart_literal_emphasis(self, node):
        self.body.append('}')

    def visit_index(self, node):
        # terminate the line but don't prevent paragraph breaks
        if isinstance(node.parent, nodes.paragraph):
            self.ensure_eol()
        else:
            self.body.append('\n')
        for entry in node['entries']:
            typ, text, tid, text2 = entry
            text = self.escape_menu(text)
            self.body.append('@geindex %s\n' % text)

    def visit_refcount(self, node):
        self.body.append('\n')
    def depart_refcount(self, node):
        self.body.append('\n')

    def visit_versionmodified(self, node):
        intro = versionlabels[node['type']] % node['version']
        if node.children:
            intro += ': '
        else:
            intro += '.'
        self.body.append('\n%s' % self.escape(intro))
    def depart_versionmodified(self, node):
        self.body.append('\n')

    def visit_start_of_file(self, node):
        # add a document target
        self.next_section_ids.add(':doc')
        self.curfilestack.append(node['docname'])
        self.footnotestack.append(self.collect_footnotes(node))
    def depart_start_of_file(self, node):
        self.curfilestack.pop()
        self.footnotestack.pop()

    def visit_centered(self, node):
        txt = self.escape_arg(node.astext())
        self.body.append('\n\n@center %s\n\n' % txt)
        raise nodes.SkipNode

    def visit_seealso(self, node):
        self.visit_topic(node)
    def depart_seealso(self, node):
        self.depart_topic(node)

    def visit_meta(self, node):
        raise nodes.SkipNode

    def visit_glossary(self, node):
        pass
    def depart_glossary(self, node):
        pass

    def visit_acks(self, node):
        self.body.append('\n\n')
        self.body.append(', '.join(n.astext()
                                for n in node.children[0].children) + '.')
        self.body.append('\n\n')
        raise nodes.SkipNode

    def visit_highlightlang(self, node):
        pass
    def depart_highlightlang(self, node):
        pass

    ## Desc

    def visit_desc(self, node):
        self.at_deffnx = '@deffn'
    def depart_desc(self, node):
        self.ensure_eol()
        self.body.append('@end deffn\n')

    def visit_desc_signature(self, node):
        objtype = node.parent['objtype']
        if objtype != 'describe':
            for id in node.get('ids'):
                self.add_anchor(id, node)
        # use the full name of the objtype for the category
        try:
            domain = self.builder.env.domains[node.parent['domain']]
            primary = self.builder.config.primary_domain
            name = domain.get_type_name(domain.object_types[objtype],
                                        primary == domain.name)
        except KeyError:
            name = objtype
        category = self.escape_arg(string.capwords(name))
        self.body.append('\n%s {%s} ' % (self.at_deffnx, category))
        self.at_deffnx = '@deffnx'
    def depart_desc_signature(self, node):
        self.body.append("\n")

    def visit_desc_name(self, node):
        pass
    def depart_desc_name(self, node):
        pass

    def visit_desc_addname(self, node):
        pass
    def depart_desc_addname(self, node):
        pass

    def visit_desc_type(self, node):
        pass
    def depart_desc_type(self, node):
        pass

    def visit_desc_returns(self, node):
        self.body.append(' -> ')
    def depart_desc_returns(self, node):
        pass

    def visit_desc_parameterlist(self, node):
        self.body.append(' (')
        self.first_param = 1
    def depart_desc_parameterlist(self, node):
        self.body.append(')')

    def visit_desc_parameter(self, node):
        if not self.first_param:
            self.body.append(', ')
        else:
            self.first_param = 0
        text = self.escape(node.astext())
        # replace no-break spaces with normal ones
        text = text.replace(u' ', '@w{ }')
        self.body.append(text)
        raise nodes.SkipNode

    def visit_desc_optional(self, node):
        self.body.append('[')
    def depart_desc_optional(self, node):
        self.body.append(']')

    def visit_desc_annotation(self, node):
        raise nodes.SkipNode

    def visit_desc_content(self, node):
        pass
    def depart_desc_content(self, node):
        pass

    def visit_inline(self, node):
        pass
    def depart_inline(self, node):
        pass

    def visit_abbreviation(self, node):
        abbr = node.astext()
        self.body.append('@abbr{')
        if node.hasattr('explanation') and abbr not in self.handled_abbrs:
            self.context.append(',%s}' % self.escape_arg(node['explanation']))
            self.handled_abbrs.add(abbr)
        else:
            self.context.append('}')
    def depart_abbreviation(self, node):
        self.body.append(self.context.pop())

    def visit_download_reference(self, node):
        pass
    def depart_download_reference(self, node):
        pass

    def visit_hlist(self, node):
        self.visit_bullet_list(node)
    def depart_hlist(self, node):
        self.depart_bullet_list(node)

    def visit_hlistcol(self, node):
        pass
    def depart_hlistcol(self, node):
        pass

    def visit_pending_xref(self, node):
        pass
    def depart_pending_xref(self, node):
        pass
