# copyright 2003-2011 LOGILAB S.A. (Paris, FRANCE), all rights reserved.

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

#

# This file is part of CubicWeb.

#

# CubicWeb is free software: you can redistribute it and/or modify it under the

# terms of the GNU Lesser General Public License as published by the Free

# Software Foundation, either version 2.1 of the License, or (at your option)

# any later version.

#

# CubicWeb is distributed in the hope that it will be useful, but WITHOUT

# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS

# FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more

# details.

#

# You should have received a copy of the GNU Lesser General Public License along

# with CubicWeb.  If not, see <http://www.gnu.org/licenses/>.

"""Some parsers to detect action to do from text

Currently only a parser to look for state change instruction is provided.

Take care to security when you're using it, think about the user that

will provide the text to analyze...

"""

__docformat__ = "restructuredtext en"

import re

from cubicweb import UnknownEid

from cubicweb.view import Component

class TextAnalyzer(Component):

    """analyze and extract information from plain text by calling registered

    text parsers

    """

    __regid__ = 'textanalyzer'

    def parse(self, caller, text):

        for parsercls in self._cw.vreg['components'].get('textparser', ()):

            parsercls(self._cw).parse(caller, text)

class TextParser(Component):

    """base class for text parser, responsible to extract some information

    from plain text. When something is done, it usually call the

      .fire_event(something, {event args})

    method on the caller.

    """

    __regid__ = 'textparser'

    __abstract__ = True

    def parse(self, caller, text):

        raise NotImplementedError

class ChangeStateTextParser(TextParser):

    """search some text for change state instruction in the form

         :<transition name>: #?<eid>

    """

    instr_rgx = re.compile(':(\w+):\s*#?(\d+)', re.U)

    def parse(self, caller, text):

        for trname, eid in self.instr_rgx.findall(text):

            try:

                entity = self._cw.entity_from_eid(int(eid))

            except UnknownEid:

                self.error("can't get entity with eid %s", eid)

                continue

            if not hasattr(entity, 'in_state'):

                self.error('bad change state instruction for eid %s', eid)

                continue

            iworkflowable = entity.cw_adapt_to('IWorkflowable')

            if iworkflowable.current_workflow:

                tr = iworkflowable.current_workflow.transition_by_name(trname)

            else:

                tr = None

            if tr and tr.may_be_fired(entity.eid):

                try:

                    trinfo = iworkflowable.fire_transition(tr)

                    caller.fire_event('state-changed', {'trinfo': trinfo,

                                                        'entity': entity})

                except Exception:

                    self.exception('while changing state of %s', entity)

            else:

                self.error("can't pass transition %s on entity %s",

                           trname, entity)