"""rest publishing functions

contains some functions and setup of docutils for cubicweb. Provides the

following ReST directives:

* `eid`, create link to entity in the repository by their eid

* `card`, create link to card entity in the repository by their wikiid

  (proposing to create it when the refered card doesn't exist yet)

* `winclude`, reference to a web documentation file (in wdoc/ directories)

* `sourcecode` (if pygments is installed), source code colorization

:organization: Logilab

:copyright: 2001-2010 LOGILAB S.A. (Paris, FRANCE), license is LGPL v2.

:contact: http://www.logilab.fr/ -- mailto:contact@logilab.fr

:license: GNU Lesser General Public License, v2.1 - http://www.gnu.org/licenses

"""

__docformat__ = "restructuredtext en"

from cStringIO import StringIO

from itertools import chain

from logging import getLogger

from os.path import join

from docutils import statemachine, nodes, utils, io

from docutils.core import publish_string

from docutils.parsers.rst import Parser, states, directives

from docutils.parsers.rst.roles import register_canonical_role, set_classes

from logilab.mtconverter import ESC_UCAR_TABLE, ESC_CAR_TABLE, xml_escape

from cubicweb import UnknownEid

from cubicweb.ext.html4zope import Writer

# We provide our own parser as an attempt to get rid of

# state machine reinstanciation

import re

# compile states.Body patterns

for k, v in states.Body.patterns.items():

    if isinstance(v, str):

        states.Body.patterns[k] = re.compile(v)

# register ReStructured Text mimetype / extensions

import mimetypes

mimetypes.add_type('text/rest', '.rest')

mimetypes.add_type('text/rest', '.rst')

LOGGER = getLogger('cubicweb.rest')

def eid_reference_role(role, rawtext, text, lineno, inliner,

                       options={}, content=[]):

    try:

        try:

            eid_num, rest = text.split(u':', 1)

        except:

            eid_num, rest = text, '#'+text

        eid_num = int(eid_num)

        if eid_num < 0:

            raise ValueError

    except ValueError:

        msg = inliner.reporter.error(

            'EID number must be a positive number; "%s" is invalid.'

            % text, line=lineno)

        prb = inliner.problematic(rawtext, rawtext, msg)

        return [prb], [msg]

    # Base URL mainly used by inliner.pep_reference; so this is correct:

    context = inliner.document.settings.context

    try:

        refedentity = context._cw.entity_from_eid(eid_num)

    except UnknownEid:

        ref = '#'

        rest += u' ' + context._cw._('(UNEXISTANT EID)')

    else:

        ref = refedentity.absolute_url()

    set_classes(options)

    return [nodes.reference(rawtext, utils.unescape(rest), refuri=ref,

                            **options)], []

def winclude_directive(name, arguments, options, content, lineno,

                       content_offset, block_text, state, state_machine):

    """Include a reST file as part of the content of this reST file.

    same as standard include directive but using config.locate_doc_resource to

    get actual file to include.

    Most part of this implementation is copied from `include` directive defined

    in `docutils.parsers.rst.directives.misc`

    """

    context = state.document.settings.context

    source = state_machine.input_lines.source(

        lineno - state_machine.input_offset - 1)

    #source_dir = os.path.dirname(os.path.abspath(source))

    fid = arguments[0]

    for lang in chain((context._cw.lang, context.vreg.property_value('ui.language')),

                      context.config.available_languages()):

        rid = '%s_%s.rst' % (fid, lang)

        resourcedir = context.config.locate_doc_file(rid)

        if resourcedir:

            break

    else:

        severe = state_machine.reporter.severe(

              'Problems with "%s" directive path:\nno resource matching %s.'

              % (name, fid),

              nodes.literal_block(block_text, block_text), line=lineno)

        return [severe]

    path = join(resourcedir, rid)

    encoding = options.get('encoding', state.document.settings.input_encoding)

    try:

        state.document.settings.record_dependencies.add(path)

        include_file = io.FileInput(

            source_path=path, encoding=encoding,

            error_handler=state.document.settings.input_encoding_error_handler,

            handle_io_errors=None)

    except IOError, error:

        severe = state_machine.reporter.severe(

              'Problems with "%s" directive path:\n%s: %s.'

              % (name, error.__class__.__name__, error),

              nodes.literal_block(block_text, block_text), line=lineno)

        return [severe]

    try:

        include_text = include_file.read()

    except UnicodeError, error:

        severe = state_machine.reporter.severe(

              'Problem with "%s" directive:\n%s: %s'

              % (name, error.__class__.__name__, error),

              nodes.literal_block(block_text, block_text), line=lineno)

        return [severe]

    if options.has_key('literal'):

        literal_block = nodes.literal_block(include_text, include_text,

                                            source=path)

        literal_block.line = 1

        return literal_block

    else:

        include_lines = statemachine.string2lines(include_text,

                                                  convert_whitespace=1)

        state_machine.insert_input(include_lines, path)

        return []

winclude_directive.arguments = (1, 0, 1)

winclude_directive.options = {'literal': directives.flag,

                              'encoding': directives.encoding}

try:

    from pygments import highlight

    from pygments.lexers import get_lexer_by_name, LEXERS

    from pygments.formatters import HtmlFormatter

except ImportError:

    pygments_directive = None

else:

    _PYGMENTS_FORMATTER = HtmlFormatter()

    def pygments_directive(name, arguments, options, content, lineno,

                           content_offset, block_text, state, state_machine):

        try:

            lexer = get_lexer_by_name(arguments[0])

        except ValueError:

            # no lexer found

            lexer = get_lexer_by_name('text')

        parsed = highlight(u'\n'.join(content), lexer, _PYGMENTS_FORMATTER)

        # don't fail if no context set on the sourcecode directive

        try:

            context = state.document.settings.context

            context._cw.add_css('pygments.css')

        except AttributeError:

            # used outside cubicweb

            pass

        return [nodes.raw('', parsed, format='html')]

    pygments_directive.arguments = (1, 0, 1)

    pygments_directive.content = 1

class CubicWebReSTParser(Parser):

    """The (customized) reStructuredText parser."""

    def __init__(self):

        self.initial_state = 'Body'

        self.state_classes = states.state_classes

        self.inliner = states.Inliner()

        self.statemachine = states.RSTStateMachine(

              state_classes=self.state_classes,

              initial_state=self.initial_state,

              debug=0)

    def parse(self, inputstring, document):

        """Parse `inputstring` and populate `document`, a document tree."""

        self.setup_parse(inputstring, document)

        inputlines = statemachine.string2lines(inputstring,

                                               convert_whitespace=1)

        self.statemachine.run(inputlines, document, inliner=self.inliner)

        self.finish_parse()

def rest_publish(context, data):

    """publish a string formatted as ReStructured Text to HTML

    :type context: a cubicweb application object

    :type data: str

    :param data: some ReST text

    :rtype: unicode

    :return:

      the data formatted as HTML or the original data if an error occured

    """

    req = context._cw

    if isinstance(data, unicode):

        encoding = 'unicode'

        # remove unprintable characters unauthorized in xml

        data = data.translate(ESC_UCAR_TABLE)

    else:

        encoding = req.encoding

        # remove unprintable characters unauthorized in xml

        data = data.translate(ESC_CAR_TABLE)

    settings = {'input_encoding': encoding, 'output_encoding': 'unicode',

                'warning_stream': StringIO(), 'context': context,

                # dunno what's the max, severe is 4, and we never want a crash

                # (though try/except may be a better option...)

                'halt_level': 10,

                }

    if context:

        if hasattr(req, 'url'):

            base_url = req.url()

        elif hasattr(context, 'absolute_url'):

            base_url = context.absolute_url()

        else:

            base_url = req.base_url()

    else:

        base_url = None

    try:

        return publish_string(writer=Writer(base_url=base_url),

                              parser=CubicWebReSTParser(), source=data,

                              settings_overrides=settings)

    except Exception:

        LOGGER.exception('error while publishing ReST text')

        if not isinstance(data, unicode):

            data = unicode(data, encoding, 'replace')

        return xml_escape(req._('error while publishing ReST text')

                           + '\n\n' + data)

_INITIALIZED = False

def cw_rest_init():

    global _INITIALIZED

    if _INITIALIZED:

        return

    _INITIALIZED = True

    register_canonical_role('eid', eid_reference_role)

    directives.register_directive('winclude', winclude_directive)

    if pygments_directive is not None:

        directives.register_directive('sourcecode', pygments_directive)