#
#  Copyright (c) 2005 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
#

"""
Implementation of the utilities needed for the relations package.

$Id$
"""

from zope.interface import Interface, Attribute, implements
from zope.app import zapi
from zope.app.catalog.catalog import Catalog
from zope.app.catalog.field import FieldIndex
from zope.app.intid.interfaces import IIntIds

from interfaces import IRelationsRegistry


class DummyRelationsRegistry(object):
    """ Dummy implementation for demonstration and test purposes.
    """

    implements(IRelationsRegistry)

    def __init__(self):
        self.relations = []

    def register(self, relation):
        if relation not in self.relations:
            self.relations.append(relation)
    
    def unregister(self, relation):
        if relation in self.relations:
            self.relations.remove(relation)
    
    def query(self, **kw):
        result = []
        for r in self.relations:
            hit = True
            for k in kw:
                if ((k == 'relationship' and r.__class__ != kw[k])
                 or (k != 'relationship'
                        and (not hasattr(r, k) or getattr(r, k) != kw[k]))):
                    hit = False
                    break
            if hit:
                result.append(r)
        return result


class RelationsRegistry(Catalog):
    """ Local utility for registering (cataloguing) and searching relations.
    """

    implements(IRelationsRegistry)

    indexesSetUp = False

    def setupIndexes(self):
        self['relationship'] = FieldIndex('relationship', IIndexableRelation)
        self['first'] = FieldIndex('first', IIndexableRelation)
        self['second'] = FieldIndex('second', IIndexableRelation)
        self['third'] = FieldIndex('third', IIndexableRelation)
        self.indexesSetUp = True

    def register(self, relation):
        if not self.indexesSetUp:
            self.setupIndexes()
        self.index_doc(_getUid(relation), relation)
    
    def unregister(self, relation):
        self.unindex_doc(_getUid(relation))
    
    def query(self, **kw):
        for k in kw:
            if k == 'relationship':
                quString = _getClassString(kw[k])
            else:
                quString = _getUid(kw[k])
            # set min, max
            kw[k] = (quString, quString)
        return self.searchResults(**kw)


    
class IIndexableRelation(Interface):
    """ Provides the attributes needed for indexing relation objects in
        a catalog-based registry.
    """


class IndexableRelationAdapter(object):
    """ Adapter for providing the attributes needed for indexing
        relation objects.
    """

    implements(IIndexableRelation)

    def __init__(self, context):
        self.context = context

    def getRelationship(self):
        return _getRelationship(self.context)
    relationship = property(getRelationship)

    def __getattr__(self, attr):
        value = getattr(self.context, attr)
        return _getUid(value)

        
def _getUid(ob):
    return zapi.getUtility(IIntIds).getId(ob)

def _getRelationship(relation):
    return _getClassString(relation.__class__)

def _getClassString(cls):
    return cls.__module__ + '.' + cls.__name__