# -*- coding: utf-8 -*-
# Author: Jon Waltman <jonathan.waltman@gmail.com>
# Copyright: This module is put into the public domain.

"""
Texinfo writer for reStructuredText.

Texinfo is the official documentation system of the GNU project and
can be used to generate multiple output formats.  This writer focuses
on producing Texinfo that is compiled to Info by the "makeinfo"
program.
"""

import docutils
from docutils import nodes, writers

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

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

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

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


## 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(s):
    """Return a string with Texinfo command characters escaped."""
    s = s.replace('@', '@@')
    s = s.replace('{', '@{')
    s = s.replace('}', '@}')
    # Prevent "--" from being converted to an "em dash"
    # s = s.replace('-', '@w{-}')
    return s

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

def escape_id(s):
    """Return an escaped string suitable for node names, menu entries,
    and xrefs anchors."""
    bad_chars = ',:.()@{}'
    for bc in bad_chars:
        s = s.replace(bc, ' ')
    s = ' '.join(s.split()).strip()
    return s


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

    settings_spec = (
        'Texinfo Specific Options',
        None,
        (
            ("Name of the resulting Info file to be created by 'makeinfo'.  "
             "Should probably end with '.info'.",
             ['--texinfo-filename'],
             {'default': '', 'metavar': '<file>'}),

            ('Specify the Info dir entry category.',
             ['--texinfo-dir-category'],
             {'default': 'Miscellaneous', 'metavar': '<name>'}),

            ('The name to use for the Info dir entry.  '
             'If not provided, no entry will be created.',
             ['--texinfo-dir-entry'],
             {'default': '', 'metavar': '<name>'}),

            ('A brief description (one or two lines) to use for the '
             'Info dir entry.',
             ['--texinfo-dir-description'],
             {'default': '', 'metavar': '<desc>'}),
            )
        )

    settings_defaults = {}
    settings_default_overrides = {'docinfo_xform': 0}

    output = None

    visitor_attributes = ('output', 'fragment')

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


class Translator(nodes.NodeVisitor):

    default_elements = {
        'filename': '',
        'title': '',
        'paragraphindent': 2,
        'exampleindent': 4,
        'direntry': '',
        'preamble': '',
        'body': '',
        }

    def __init__(self, document):
        nodes.NodeVisitor.__init__(self, document)
        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.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_node_names()
        self.collect_node_menus()
        self.collect_rellinks()

        self.short_ids = {}
        self.body = []
        self.previous_section = None
        self.section_level = 0
        self.seen_title = False
        self.next_section_targets = []
        self.escape_newlines = 0
        self.curfilestack = []

    def finish(self):
        while self.referenced_ids:
            # Handle xrefs with missing anchors
            r = self.referenced_ids.pop()
            if r not in self.written_ids:
                self.document.reporter.info(
                    "Unknown cross-reference target: `%s'" % r)
                self.add_text('@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,
                # if empty, use basename of input file
                'filename': settings.texinfo_filename,
                })
        # Title
        title = elements['title']
        if not title:
            title = self.document.next_node(nodes.title)
            title = (title and title.astext()) or '<untitled>'
        elements['title'] = 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:
            elements['direntry'] = ('@dircategory %s\n'
                                    '@direntry\n'
                                    '* %s: (%s).    %s\n'
                                    '@end direntry\n') % (
                escape_id(settings.texinfo_dir_category),
                escape_id(settings.texinfo_dir_entry),
                elements['filename'],
                escape_arg(settings.texinfo_dir_description))

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

        Assigns the attribute ``node_name`` to each section."""
        self.document['node_name'] = 'Top'
        self.node_names['Top'] = 'Top'
        self.written_ids.update(('Top', 'top'))

        for section in self.document.traverse(nodes.section):
            title = section.next_node(nodes.Titular)
            name = (title and title.astext()) or '<untitled>'
            node_id = name = escape_id(name) or '<untitled>'
            assert node_id and name
            nth, suffix = 1, ''
            while (node_id + suffix).lower() 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
            assert node_id.lower() not in self.written_ids
            section['node_name'] = node_id
            self.node_names[node_id] = name
            self.written_ids.update((node_id, node_id.lower()))

    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 = tuple(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'

    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'

    def add_text(self, text, fresh=False):
        """Add some text to the output.

        Optional argument ``fresh`` means to insert a newline before
        the text if the last character out was not a newline."""
        if fresh:
            if self.body and not self.body[-1].endswith('\n'):
                self.body.append('\n')
        self.body.append(text)

    def rstrip(self):
        """Strip trailing whitespace from the current output."""
        while self.body and not self.body[-1].strip():
            del self.body[-1]
        if not self.body:
            return
        self.body[-1] = self.body[-1].rstrip()

    def add_menu_entries(self, entries):
        for entry in entries:
            name = self.node_names[entry]
            if name == entry:
                self.add_text('* %s::\n' % name, fresh=1)
            else:
                self.add_text('* %s: %s.\n' % (name, entry), fresh=1)

    def add_menu(self, section, master=False):
        entries = self.node_menus[section['node_name']]
        if not entries:
            return
        self.add_text('\n@menu\n')
        self.add_menu_entries(entries)
        if master:
            # Write the "detailed menu"
            started_detail = False
            for entry in entries:
                subentries = self.node_menus[entry]
                if not subentries:
                    continue
                if not started_detail:
                    started_detail = True
                    self.add_text('\n@detailmenu\n'
                                  ' --- The Detailed Node Listing ---\n')
                self.add_text('\n%s\n\n' % self.node_names[entry])
                self.add_menu_entries(subentries)
            if started_detail:
                self.rstrip()
                self.add_text('\n@end detailmenu\n')
        self.rstrip()
        self.add_text('\n@end menu\n\n')


    ## 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, msg_node=None):
        # Anchors can be referenced by their original id
        # or by the generated shortened id
        id = escape_id(id).lower()
        ids = (self.get_short_id(id), id)
        for id in ids:
            if id not in self.written_ids:
                self.add_text('@anchor{%s}' % id)
                self.written_ids.add(id)

    def add_xref(self, ref, name, node):
        ref = self.get_short_id(escape_id(ref).lower())
        name = ' '.join(name.split()).strip()
        if not name or ref == name:
            self.add_text('@pxref{%s}' % ref)
        else:
            self.add_text('@pxref{%s,%s}' % (ref, name))
        self.referenced_ids.add(ref)

    ## Visiting

    def visit_document(self, node):
        pass
    def depart_document(self, node):
        pass

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

    def visit_section(self, node):
        self.next_section_targets.extend(node.get('ids', []))
        if not self.seen_title:
            return
        if self.previous_section:
            self.add_menu(self.previous_section)
        else:
            self.add_menu(self.document, master=True)

        node_name = node['node_name']
        pointers = tuple([node_name] + self.rellinks[node_name])
        self.add_text('\n@node %s,%s,%s,%s\n' % pointers)
        if node_name != node_name.lower():
            self.add_text('@anchor{%s}' % node_name.lower())
        for id in self.next_section_targets:
            self.add_anchor(id, node)

        self.next_section_targets = []
        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):
            raise nodes.SkipNode
        elif isinstance(parent, nodes.sidebar):
            self.visit_rubric(node)
        elif isinstance(parent, nodes.topic):
            raise nodes.SkipNode
        elif not isinstance(parent, nodes.section):
            self.document.reporter.warning(
                'encountered title node not in section, topic, table, '
                'admonition or sidebar', base_node=node)
            self.visit_rubric(node)
        else:
            try:
                heading = self.headings[self.section_level]
            except IndexError:
                heading = self.headings[-1]
            self.add_text('%s ' % heading, fresh=1)

    def depart_title(self, node):
        self.add_text('', fresh=1)

    def visit_rubric(self, node):
        try:
            rubric = self.rubrics[self.section_level]
        except IndexError:
            rubric = self.rubrics[-1]
        self.add_text('%s ' % rubric, fresh=1)
    def depart_rubric(self, node):
        self.add_text('', fresh=1)

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

    ## References

    def visit_target(self, node):
        if node.get('ids'):
            self.add_anchor(node['ids'][0], node)
        elif node.get('refid'):
            # Section targets need to go after the start of the section.
            next = node.next_node(ascend=1, siblings=1)
            while isinstance(next, nodes.target):
                next = next.next_node(ascend=1, siblings=1)
            if isinstance(next, nodes.section):
                self.next_section_targets.append(node['refid'])
                return
            self.add_anchor(node['refid'], node)
        elif node.get('refuri'):
            pass
        else:
            self.document.reporter.error("Unknown target type: %r" % node)

    def visit_reference(self, node):
        if isinstance(node.parent, nodes.title):
            return
        if isinstance(node[0], nodes.image):
            return
        name = node.get('name', node.astext()).strip()
        if node.get('refid'):
            self.add_xref(escape_id(node['refid']),
                          escape_id(name), node)
            raise nodes.SkipNode
        if not node.get('refuri'):
            self.document.reporter.error("Unknown reference type: %s" % node)
            return
        uri = node['refuri']
        if uri.startswith('#'):
            self.add_xref(escape_id(uri[1:]), escape_id(name), node)
        elif uri.startswith('%'):
            id = uri[1:]
            if '#' in id:
                src, id = uri[1:].split('#', 1)
            assert '#' not in id
            self.add_xref(escape_id(id), escape_id(name), node)
        elif uri.startswith('mailto:'):
            uri = escape_arg(uri[7:])
            name = escape_arg(name)
            if not name or name == uri:
                self.add_text('@email{%s}' % uri)
            else:
                self.add_text('@email{%s,%s}' % (uri, name))
        elif uri.startswith('info:'):
            uri = uri[5:].replace('_', ' ')
            uri = escape_arg(uri)
            id = 'Top'
            if '#' in uri:
                uri, id = uri.split('#', 1)
            id = escape_id(id)
            name = escape_id(name)
            if name == id:
                self.add_text('@pxref{%s,,,%s}' % (id, uri))
            else:
                self.add_text('@pxref{%s,,%s,%s}' % (id, name, uri))
        else:
            uri = escape_arg(uri)
            name = escape_arg(name)
            if not name or uri == name:
                self.add_text('@indicateurl{%s}' % uri)
            else:
                self.add_text('@uref{%s,%s}' % (uri, name))
        raise nodes.SkipNode

    def depart_reference(self, node):
        pass

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

    ## Blocks

    def visit_paragraph(self, node):
        if 'continued' in node or isinstance(node.parent, nodes.compound):
            self.add_text('@noindent\n', fresh=1)
    def depart_paragraph(self, node):
        self.add_text('\n\n')

    def visit_block_quote(self, node):
        self.rstrip()
        self.add_text('\n\n@quotation\n')
    def depart_block_quote(self, node):
        self.rstrip()
        self.add_text('\n@end quotation\n\n')

    def visit_literal_block(self, node):
        self.rstrip()
        self.add_text('\n\n@example\n')
    def depart_literal_block(self, node):
        self.rstrip()
        self.add_text('\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):
        self.add_text('@display\n', fresh=1)
    def depart_line_block(self, node):
        self.add_text('@end display\n', fresh=1)

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

    ## Inline

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

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

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

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

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

    ## Footnotes

    def visit_footnote(self, node):
        self.visit_block_quote(node)
    def depart_footnote(self, node):
        self.depart_block_quote(node)

    def visit_footnote_reference(self, node):
        self.add_text('@w{(')
    def depart_footnote_reference(self, node):
        self.add_text(')}')

    visit_citation = visit_footnote
    depart_citation = depart_footnote

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

    ## Lists

    def visit_bullet_list(self, node):
        bullet = node.get('bullet', '*')
        self.rstrip()
        self.add_text('\n\n@itemize %s\n' % bullet)
    def depart_bullet_list(self, node):
        self.rstrip()
        self.add_text('\n@end itemize\n\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.rstrip()
        self.add_text('\n\n@enumerate %s\n' % start)
    def depart_enumerated_list(self, node):
        self.rstrip()
        self.add_text('\n@end enumerate\n\n')

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

    ## Option List

    def visit_option_list(self, node):
        self.add_text('\n@table @option\n')
    def depart_option_list(self, node):
        self.rstrip()
        self.add_text('\n@end table\n\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.add_text(self.at_item_x + ' ', fresh=1)
        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.add_text(node.get('delimiter', ' '))
    def depart_option_argument(self, node):
        pass

    def visit_description(self, node):
        self.add_text('', fresh=1)
    def depart_description(self, node):
        pass

    ## Definitions

    def visit_definition_list(self, node):
        self.add_text('\n@table @asis\n')
    def depart_definition_list(self, node):
        self.rstrip()
        self.add_text('\n@end table\n\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):
        if node.get('ids') and node['ids'][0]:
            self.add_anchor(node['ids'][0], node)
        self.add_text(self.at_item_x + ' ', fresh=1)
        self.at_item_x = '@itemx'
    def depart_term(self, node):
        pass

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

    def visit_definition(self, node):
        self.add_text('', fresh=1)
    def depart_definition(self, node):
        pass

    ## Tables

    def visit_table(self, node):
        self.entry_sep = '@item'
    def depart_table(self, node):
        self.rstrip()
        self.add_text('\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.add_text('@multitable ', fresh=1)
        for i, n in enumerate(self.colwidths):
            self.add_text('{%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.rstrip()
        self.add_text('\n%s ' % self.entry_sep)
        self.entry_sep = '@tab'
    def depart_entry(self, node):
        for i in xrange(node.get('morecols', 0)):
            self.add_text('@tab\n', fresh=1)
        self.add_text('', fresh=1)

    ## Field Lists

    def visit_field_list(self, node):
        self.add_text('\n@itemize @w\n')
    def depart_field_list(self, node):
        self.rstrip()
        self.add_text('\n@end itemize\n\n')

    def visit_field(self, node):
        if not isinstance(node.parent, nodes.field_list):
            self.visit_field_list(None)
    def depart_field(self, node):
        if not isinstance(node.parent, nodes.field_list):
            self.depart_field_list(None)

    def visit_field_name(self, node):
        self.add_text('@item ', fresh=1)
    def depart_field_name(self, node):
        self.add_text(':')

    def visit_field_body(self, node):
        self.add_text('', fresh=1)
    def depart_field_body(self, node):
        pass

    ## Admonitions

    def visit_admonition(self, node):
        title = escape(node[0].astext())
        self.add_text('\n@cartouche\n'
                       '@quotation %s\n' % title)
    def depart_admonition(self, node):
        self.rstrip()
        self.add_text('\n@end quotation\n'
                       '@end cartouche\n\n')

    def _make_visit_admonition(typ):
        def visit(self, node):
            title = escape(typ)
            self.add_text('\n@cartouche\n'
                          '@quotation %s\n' % title)
        return visit

    visit_attention = _make_visit_admonition('Attention')
    visit_caution   = _make_visit_admonition('Caution')
    visit_danger    = _make_visit_admonition('Danger')
    visit_error     = _make_visit_admonition('Error')
    visit_important = _make_visit_admonition('Important')
    visit_note      = _make_visit_admonition('Note')
    visit_tip       = _make_visit_admonition('Tip')
    visit_hint      = _make_visit_admonition('Hint')
    visit_warning   = _make_visit_admonition('Warning')

    depart_attention = depart_admonition
    depart_caution   = depart_admonition
    depart_danger    = depart_admonition
    depart_error     = depart_admonition
    depart_important = depart_admonition
    depart_note      = depart_admonition
    depart_tip       = depart_admonition
    depart_hint      = depart_admonition
    depart_warning   = depart_admonition

    ## Misc

    def visit_docinfo(self, node):
        # No 'docinfo_xform'
        raise nodes.SkipNode

    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.add_text('%s\n' % escape(title.astext()))
        self.visit_block_quote(node)
    def depart_topic(self, node):
        self.depart_block_quote(node)

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

    def visit_transition(self, node):
        self.add_text('\n\n@noindent\n'
                      '@exdent @w{%s}\n\n'
                      '@noindent\n' % ('_' * 70))
    def depart_transition(self, node):
        pass

    def visit_attribution(self, node):
        self.add_text('@flushright\n', fresh=1)
    def depart_attribution(self, node):
        self.add_text('@end flushright\n', fresh=1)

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

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

    def visit_caption(self, node):
        if not isinstance(node.parent, nodes.figure):
            self.document.reporter.warning('Caption not inside a figure.',
                                           base_node=node)
            return
        self.add_text('@caption{', fresh=1)
    def depart_caption(self, node):
        if isinstance(node.parent, nodes.figure):
            self.rstrip()
            self.add_text('}\n')

    def visit_image(self, node):
        self.add_text('@w{[image]}')
        raise nodes.SkipNode
    def depart_image(self, node):
        pass

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

    def visit_sidebar(self, node):
        pass
    def depart_sidebar(self, node):
        pass

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

    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 depart_substitution_definition(self, node):
        pass

    def visit_system_message(self, node):
        self.add_text('\n@format\n'
                       '---------- SYSTEM MESSAGE -----------\n')
    def depart_system_message(self, node):
        self.rstrip()
        self.add_text('\n------------------------------------\n'
                      '@end format\n')

    def visit_comment(self, node):
        for line in node.astext().splitlines():
            self.add_text('@c %s\n' % line, fresh=1)
        raise nodes.SkipNode
    def depart_comment(self, node):
        pass

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

    def unimplemented_visit(self, node):
        self.document.reporter.error("Unimplemented node type: `%s'"
                                     % node.__class__.__name__, base_node=node)

    def unknown_visit(self, node):
        self.document.reporter.error("Unknown node type: `%s'"
                                     % node.__class__.__name__, base_node=node)
    def unknown_departure(self, node):
        pass