# copyright 2003-2014 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/>.

""" undoable transaction objects. """

from cubicweb import _

from cubicweb import RepositoryError

ACTION_LABELS = {

    'C': _('entity creation'),

    'U': _('entity update'),

    'D': _('entity deletion'),

    'A': _('relation add'),

    'R': _('relation removal'),

    }

class NoSuchTransaction(RepositoryError):

    # Used by CubicWebException

    msg = _("there is no transaction #%s")

    def __init__(self, txuuid):

        super(NoSuchTransaction, self).__init__(txuuid)

        self.txuuid = txuuid

class Transaction(object):

    """an undoable transaction"""

    def __init__(self, cnx, uuid, time, ueid):

        self.cnx = cnx

        self.uuid = uuid

        self.datetime = time

        self.user_eid = ueid

    def _execute(self, *args, **kwargs):

        """execute a query using either the req or the cnx"""

        return self.cnx.execute(*args, **kwargs)

    def __repr__(self):

        return '<Transaction %s by %s on %s>' % (

            self.uuid, self.user_eid, self.datetime)

    def user(self):

        """return the user entity which has done the transaction,

        none if not found.

        """

        return self.cnx.find('CWUser', eid=self.user_eid).one()

    def actions_list(self, public=True):

        """return an ordered list of action effectued during that transaction

        if public is true, return only 'public' action, eg not ones triggered

        under the cover by hooks.

        """

        return self.cnx.transaction_actions(self.uuid, public)

class AbstractAction(object):

    def __init__(self, action, public, order):

        self.action = action

        self.public = public

        self.order = order

    @property

    def label(self):

        return ACTION_LABELS[self.action]

    @property

    def ertype(self):

        """ Return the entity or relation type this action is related to"""

        raise NotImplementedError(self)

class EntityAction(AbstractAction):

    def __init__(self, action, public, order, etype, eid, changes):

        super(EntityAction, self).__init__(action, public, order)

        self.etype = etype

        self.eid = eid

        self.changes = changes

    def __repr__(self):

        return '<%s: %s %s (%s)>' % (

            self.label, self.eid, self.changes,

            self.public and 'dbapi' or 'hook')

    @property

    def ertype(self):

        """ Return the entity or relation type this action is related to"""

        return self.etype

class RelationAction(AbstractAction):

    def __init__(self, action, public, order, rtype, eidfrom, eidto):

        super(RelationAction, self).__init__(action, public, order)

        self.rtype = rtype

        self.eid_from = eidfrom

        self.eid_to = eidto

    def __repr__(self):

        return '<%s: %s %s %s (%s)>' % (

            self.label, self.eid_from, self.rtype, self.eid_to,

            self.public and 'dbapi' or 'hook')

    @property

    def ertype(self):

        """ Return the entity or relation type this action is related to"""

        return self.rtype