# 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
import codecs

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
    backend_class = DotBackend
    backend_kwargs = {'ratio': 'compress', 'size': '30,10'}

    def cell_call(self, row, col):
        if 'MSIE 8' in self._cw.useragent():
            return
        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(self.backend_class(graphname, None,
                                                      **self.backend_kwargs))
        # image file
        fd, tmpfile = tempfile.mkstemp('.svg')
        os.close(fd)
        generator.generate(visitor, prophdlr, tmpfile)
        with codecs.open(tmpfile, 'rb', encoding='utf-8') as svgfile:
            self.w(svgfile.read())

    def build_visitor(self, entity):
        raise NotImplementedError

    def build_dotpropshandler(self):
        return DotPropsHandler(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_long_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'}