# copyright 2003-2010 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 basic stuff to build dot generated graph images"""

__docformat__ = "restructuredtext en"

_ = unicode

import tempfile

import os

from logilab.mtconverter import xml_escape

from logilab.common.graph import GraphGenerator, DotBackend

from cubicweb.view import EntityView

from cubicweb.utils import make_uid

class DotGraphView(EntityView):

    __abstract__ = True

    def cell_call(self, row, col):

        entity = self.cw_rset.get_entity(row, col)

        visitor = self.build_visitor(entity)

        prophdlr = self.build_dotpropshandler()

        graphname = 'dotgraph%s' % str(entity.eid)

        generator = GraphGenerator(DotBackend(graphname, None,

                                              ratio='compress', size='30,10'))

        # map file

        pmap, mapfile = tempfile.mkstemp(".map", graphname)

        os.close(pmap)

        # image file

        fd, tmpfile = tempfile.mkstemp('.png')

        os.close(fd)

        generator.generate(visitor, prophdlr, tmpfile, mapfile)

        filekeyid = make_uid()

        self._cw.session.data[filekeyid] = tmpfile

        self.w(u'<img src="%s" alt="%s" usemap="#%s" />' % (

            xml_escape(entity.absolute_url(vid='tmppng', tmpfile=filekeyid)),

            xml_escape(self._cw._('Data connection graph for %s') % entity.name),

            graphname))

        stream = open(mapfile, 'r').read()

        stream = stream.decode(self._cw.encoding)

        self.w(stream)

        os.unlink(mapfile)

    def build_visitor(self, entity):

        raise NotImplementedError

    def build_dotpropshandler(self):

        return DotGraphPropsHandler(self._cw)

class DotPropsHandler(object):

    def __init__(self, req):

        self._ = req._

    def node_properties(self, entity):

        """return default DOT drawing options for a state or transition"""

        return {'label': entity.dc_title(),

                'href': entity.absolute_url(),

                'fontname': 'Courier', 'fontsize': 10, 'shape':'box',

                 }

    def edge_properties(self, transition, fromstate, tostate):

        return {'label': '', 'dir': 'forward',

                'color': 'black', 'style': 'filled'}