#
#  Copyright (c) 2008 Helmut Merz helmutm@cy55.de
#
#  This program is free software; you can redistribute it and/or modify
#  it under the terms of the GNU General Public License as published by
#  the Free Software Foundation; either version 2 of the License, or
#  (at your option) any later version.
#
#  This program 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 General Public License for more details.
#
#  You should have received a copy of the GNU General Public License
#  along with this program; if not, write to the Free Software
#  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#

"""
Definition and management of special predicates and corresponding relations.

$Id$
"""

from zope import component, schema
from zope.component import adapts
from zope.interface import implements
from zope.cachedescriptors.property import Lazy
from zope.dottedname.resolve import resolve
from zope.security.proxy import removeSecurityProxy
from zope.traversing.api import getName

from loops.interfaces import ILoopsObject, IConcept, IResource, IConceptRelation
from loops.interfaces import IPredicate, IRelationAdapter #, IMappingAttributeRelation
from loops.concept import Concept
from loops.common import adapted, AdapterBase
from loops.type import TypeInterfaceSourceList


TypeInterfaceSourceList.typeInterfaces += (IPredicate,)


class Predicate(AdapterBase):
    """ typeInterface adapter for concepts of type 'predicate'.
    """

    implements(IPredicate)

    _contextAttributes = list(IPredicate) # + list(IConcept)

    def getOptions(self):
        return getattr(self.context, '_options', [])
    def setOptions(self, value):
        self.context._options = value
    options = property(getOptions, setOptions)


class PredicateInterfaceSourceList(TypeInterfaceSourceList):
    """ Collects type interfaces for predicates, i.e. interfaces that
        may be used for specifying additional attributes of relations.
    """

    predicateInterfaces = ()

    @property
    def typeInterfaces(self):
        return self.predicateInterfaces


class RelationAdapter(AdapterBase):
    """ Base class for adapters to relations that may be used for
        specifying additional attributes for relations.
    """

    implements(IRelationAdapter)
    adapts(IConceptRelation)


def adaptedRelation(relation):
    if isinstance(relation, RelationAdapter):
        return obj
    ifc = adapted(relation.predicate).predicateInterface
    if ifc is not None:
        adRelation = component.queryAdapter(relation, ifc)
        if adRelation is not None:
            return adRelation
    return relation


# standard relation adapters

#PredicateInterfaceSourceList.predicateInterfaces += (IMappingAttributeRelation,)


#class MappingAttributeRelation(AdapterBase):

    #implements(IMappingAttributeRelation)

    #_contextAttributes = list(IMappingAttributeRelation)