# copyright 2003-2012 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/>.

"""Core hooks: synchronize living session on persistent data changes"""

__docformat__ = "restructuredtext en"

from cubicweb import _

from cubicweb import UnknownProperty, BadConnectionId, validation_error

from cubicweb.predicates import is_instance

from cubicweb.server import hook

def get_user_sessions(repo, ueid):

    for session in repo._sessions.values():

        if ueid == session.user.eid:

            yield session

class SyncSessionHook(hook.Hook):

    __abstract__ = True

    category = 'syncsession'

# user/groups synchronisation #################################################

class _GroupOperation(hook.Operation):

    """base class for group operation"""

    cnxuser = None # make pylint happy

    def __init__(self, cnx, *args, **kwargs):

        """override to get the group name before actual groups manipulation:

        we may temporarily loose right access during a commit event, so

        no query should be emitted while comitting

        """

        rql = 'Any N WHERE G eid %(x)s, G name N'

        result = cnx.execute(rql, {'x': kwargs['geid']}, build_descr=False)

        hook.Operation.__init__(self, cnx, *args, **kwargs)

        self.group = result[0][0]

class _DeleteGroupOp(_GroupOperation):

    """synchronize user when a in_group relation has been deleted"""

    def postcommit_event(self):

        """the observed connections set has been commited"""

        groups = self.cnxuser.groups

        try:

            groups.remove(self.group)

        except KeyError:

            self.error('user %s not in group %s',  self.cnxuser, self.group)

class _AddGroupOp(_GroupOperation):

    """synchronize user when a in_group relation has been added"""

    def postcommit_event(self):

        """the observed connections set has been commited"""

        groups = self.cnxuser.groups

        if self.group in groups:

            self.warning('user %s already in group %s', self.cnxuser,

                         self.group)

        else:

            groups.add(self.group)

class SyncInGroupHook(SyncSessionHook):

    __regid__ = 'syncingroup'

    __select__ = SyncSessionHook.__select__ & hook.match_rtype('in_group')

    events = ('after_delete_relation', 'after_add_relation')

    def __call__(self):

        if self.event == 'after_delete_relation':

            opcls = _DeleteGroupOp

        else:

            opcls = _AddGroupOp

        for session in get_user_sessions(self._cw.repo, self.eidfrom):

            opcls(self._cw, cnxuser=session.user, geid=self.eidto)

class _DelUserOp(hook.Operation):

    """close associated user's session when it is deleted"""

    def __init__(self, cnx, sessionid):

        self.sessionid = sessionid

        hook.Operation.__init__(self, cnx)

    def postcommit_event(self):

        """the observed connections set has been commited"""

        try:

            self.cnx.repo.close(self.sessionid)

        except BadConnectionId:

            pass # already closed

class CloseDeletedUserSessionsHook(SyncSessionHook):

    __regid__ = 'closession'

    __select__ = SyncSessionHook.__select__ & is_instance('CWUser')

    events = ('after_delete_entity',)

    def __call__(self):

        """modify user permission, need to update users"""

        for session in get_user_sessions(self._cw.repo, self.entity.eid):

            _DelUserOp(self._cw, session.sessionid)

# CWProperty hooks #############################################################

class _DelCWPropertyOp(hook.Operation):

    """a user's custom properties has been deleted"""

    cwpropdict = key = None # make pylint happy

    def postcommit_event(self):

        """the observed connections set has been commited"""

        try:

            del self.cwpropdict[self.key]

        except KeyError:

            self.error('%s has no associated value', self.key)

class _ChangeCWPropertyOp(hook.Operation):

    """a user's custom properties has been added/changed"""

    cwpropdict = key = value = None # make pylint happy

    def postcommit_event(self):

        """the observed connections set has been commited"""

        self.cwpropdict[self.key] = self.value

class _AddCWPropertyOp(hook.Operation):

    """a user's custom properties has been added/changed"""

    cwprop = None # make pylint happy

    def postcommit_event(self):

        """the observed connections set has been commited"""

        cwprop = self.cwprop

        if not cwprop.for_user:

            self.cnx.vreg['propertyvalues'][cwprop.pkey] = cwprop.value

        # if for_user is set, update is handled by a ChangeCWPropertyOp operation

class AddCWPropertyHook(SyncSessionHook):

    __regid__ = 'addcwprop'

    __select__ = SyncSessionHook.__select__ & is_instance('CWProperty')

    events = ('after_add_entity',)

    def __call__(self):

        key, value = self.entity.pkey, self.entity.value

        if key.startswith('sources.'):

            return

        cnx = self._cw

        try:

            value = cnx.vreg.typed_value(key, value)

        except UnknownProperty:

            msg = _('unknown property key %s')

            raise validation_error(self.entity, {('pkey', 'subject'): msg}, (key,))

        except ValueError as ex:

            raise validation_error(self.entity,

                                  {('value', 'subject'): str(ex)})

        if not cnx.user.matching_groups('managers'):

            cnx.add_relation(self.entity.eid, 'for_user', cnx.user.eid)

        else:

            _AddCWPropertyOp(cnx, cwprop=self.entity)

class UpdateCWPropertyHook(AddCWPropertyHook):

    __regid__ = 'updatecwprop'

    events = ('after_update_entity',)

    def __call__(self):

        entity = self.entity

        if not ('pkey' in entity.cw_edited or

                'value' in entity.cw_edited):

            return

        key, value = entity.pkey, entity.value

        if key.startswith('sources.'):

            return

        cnx = self._cw

        try:

            value = cnx.vreg.typed_value(key, value)

        except UnknownProperty:

            return

        except ValueError as ex:

            raise validation_error(entity, {('value', 'subject'): str(ex)})

        if entity.for_user:

            for session in get_user_sessions(cnx.repo, entity.for_user[0].eid):

                _ChangeCWPropertyOp(cnx, cwpropdict=session.user.properties,

                                    key=key, value=value)

        else:

            # site wide properties

            _ChangeCWPropertyOp(cnx, cwpropdict=cnx.vreg['propertyvalues'],

                              key=key, value=value)

class DeleteCWPropertyHook(AddCWPropertyHook):

    __regid__ = 'delcwprop'

    events = ('before_delete_entity',)

    def __call__(self):

        eid = self.entity.eid

        cnx = self._cw

        for eidfrom, rtype, eidto in cnx.transaction_data.get('pendingrelations', ()):

            if rtype == 'for_user' and eidfrom == self.entity.eid:

                # if for_user was set, delete has already been handled

                break

        else:

            _DelCWPropertyOp(cnx, cwpropdict=cnx.vreg['propertyvalues'],

                             key=self.entity.pkey)

class AddForUserRelationHook(SyncSessionHook):

    __regid__ = 'addcwpropforuser'

    __select__ = SyncSessionHook.__select__ & hook.match_rtype('for_user')

    events = ('after_add_relation',)

    def __call__(self):

        cnx = self._cw

        eidfrom = self.eidfrom

        if not cnx.entity_metas(eidfrom)['type'] == 'CWProperty':

            return

        key, value = cnx.execute('Any K,V WHERE P eid %(x)s,P pkey K,P value V',

                                     {'x': eidfrom})[0]

        if cnx.vreg.property_info(key)['sitewide']:

            msg = _("site-wide property can't be set for user")

            raise validation_error(eidfrom, {('for_user', 'subject'): msg})

        for session in get_user_sessions(cnx.repo, self.eidto):

            _ChangeCWPropertyOp(cnx, cwpropdict=session.user.properties,

                              key=key, value=value)

class DelForUserRelationHook(AddForUserRelationHook):

    __regid__ = 'delcwpropforuser'

    events = ('after_delete_relation',)

    def __call__(self):

        cnx = self._cw

        key = cnx.execute('Any K WHERE P eid %(x)s, P pkey K',

                              {'x': self.eidfrom})[0][0]

        cnx.transaction_data.setdefault('pendingrelations', []).append(

            (self.eidfrom, self.rtype, self.eidto))

        for session in get_user_sessions(cnx.repo, self.eidto):

            _DelCWPropertyOp(cnx, cwpropdict=session.user.properties, key=key)