"""Core hooks: workflow related hooks

:organization: Logilab

:copyright: 2001-2009 LOGILAB S.A. (Paris, FRANCE), license is LGPL v2.

:contact: http://www.logilab.fr/ -- mailto:contact@logilab.fr

:license: GNU Lesser General Public License, v2.1 - http://www.gnu.org/licenses

"""

__docformat__ = "restructuredtext en"

from datetime import datetime

from cubicweb import RepositoryError, ValidationError

from cubicweb.interfaces import IWorkflowable

from cubicweb.selectors import entity_implements

from cubicweb.server import hook

def _change_state(session, x, oldstate, newstate):

    nocheck = session.transaction_data.setdefault('skip-security', set())

    nocheck.add((x, 'in_state', oldstate))

    nocheck.add((x, 'in_state', newstate))

    # delete previous state first in case we're using a super session

    session.delete_relation(x, 'in_state', oldstate)

    session.add_relation(x, 'in_state', newstate)

class _SetInitialStateOp(hook.Operation):

    """make initial state be a default state"""

    def precommit_event(self):

        session = self.session

        entity = self.entity

        # if there is an initial state and the entity's state is not set,

        # use the initial state as a default state

        if not (session.deleted_in_transaction(entity.eid) or entity.in_state) \

               and entity.current_workflow:

            state = entity.current_workflow.initial

            if state:

                # use super session to by-pass security checks

                session.super_session.add_relation(entity.eid, 'in_state',

                                                   state.eid)

class _WorkflowChangedOp(hook.Operation):

    """fix entity current state when changing its workflow"""

    def precommit_event(self):

        session = self.session

            return

        entity = session.entity_from_eid(self.eid)

            if not deststate:

                msg = session._('workflow has no initial state')

                raise ValidationError(entity.eid, {'custom_workflow': msg})

                # nothing to do

                return

            # if there are no history, simply go to new workflow's initial state

            if not entity.workflow_history:

                if entity.current_state.eid != deststate.eid:

                    _change_state(session, entity.eid,

                                  entity.current_state.eid, deststate.eid)

                return

            msg = session._('workflow changed to "%s"')

class WorkflowHook(hook.Hook):

    __abstract__ = True

    category = 'worfklow'

class SetInitialStateHook(WorkflowHook):

    __id__ = 'wfsetinitial'

    __select__ = WorkflowHook.__select__ & entity_implements(IWorkflowable)

    events = ('after_add_entity',)

    def __call__(self):

        _SetInitialStateOp(self._cw, entity=self.entity)

class PrepareStateChangeHook(WorkflowHook):

    """record previous state information"""

    __id__ = 'cwdelstate'

    __select__ = WorkflowHook.__select__ & hook.match_rtype('in_state')

    events = ('before_delete_relation',)

    def __call__(self):

        self._cw.transaction_data.setdefault('pendingrelations', []).append(

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

class FireTransitionHook(WorkflowHook):

    """check the transition is allowed, add missing information. Expect that:

    * wf_info_for inlined relation is set

    * by_transition or to_state (managers only) inlined relation is set

    """

    __id__ = 'wffiretransition'

    __select__ = WorkflowHook.__select__ & entity_implements('TrInfo')

    events = ('before_add_entity',)

    def __call__(self):

        session = self._cw

        entity = self.entity

        # first retreive entity to which the state change apply

        try:

            foreid = entity['wf_info_for']

        except KeyError:

            msg = session._('mandatory relation')

            raise ValidationError(entity.eid, {'wf_info_for': msg})

        forentity = session.entity_from_eid(foreid)

        if wf is None:

            msg = session._('related entity has no workflow set')

            raise ValidationError(entity.eid, {None: msg})

        # then check it has a state set

        fromstate = forentity.current_state

        if fromstate is None:

            msg = session._('related entity has no state')

            raise ValidationError(entity.eid, {None: msg})

        # no investigate the requested state change...

        try:

            treid = entity['by_transition']

        except KeyError:

            # no transition set, check user is a manager and destination state is

            # specified (and valid)

                msg = session._('mandatory relation')

                raise ValidationError(entity.eid, {'by_transition': msg})

            deststateeid = entity.get('to_state')

            if not deststateeid:

                msg = session._('mandatory relation')

                raise ValidationError(entity.eid, {'by_transition': msg})

            deststate = wf.state_by_eid(deststateeid)

                raise ValidationError(entity.eid, {'to_state': msg})

        else:

        # everything is ok, add missing information on the trinfo entity

        entity['from_state'] = fromstate.eid

        entity['to_state'] = deststateeid

        nocheck = session.transaction_data.setdefault('skip-security', set())

        nocheck.add((entity.eid, 'from_state', fromstate.eid))

        nocheck.add((entity.eid, 'to_state', deststateeid))

class FiredTransitionHook(WorkflowHook):

    """change related entity state"""

    __id__ = 'wffiretransition'

    __select__ = WorkflowHook.__select__ & entity_implements('TrInfo')

    events = ('after_add_entity',)

    def __call__(self):

class SetModificationDateOnStateChange(WorkflowHook):

    """update entity's modification date after changing its state"""

    __id__ = 'wfsyncmdate'

    __select__ = WorkflowHook.__select__ & hook.match_rtype('in_state')

    events = ('after_add_relation',)

    def __call__(self):

        if self._cw.added_in_transaction(self.eidfrom):

            # new entity, not needed

            return

        entity = self._cw.entity_from_eid(self.eidfrom)

        try:

            entity.set_attributes(modification_date=datetime.now(),

                                  _cw_unsafe=True)

        except RepositoryError, ex:

            # usually occurs if entity is coming from a read-only source

            # (eg ldap user)

            self.warning('cant change modification date for %s: %s', entity, ex)

class SetCustomWorkflow(WorkflowHook):

    __id__ = 'wfsetcustom'

    __select__ = WorkflowHook.__select__ & hook.match_rtype('custom_workflow')

    events = ('after_add_relation',)

    def __call__(self):

        _WorkflowChangedOp(self._cw, eid=self.eidfrom, wfeid=self.eidto)

class DelCustomWorkflow(SetCustomWorkflow):

    __id__ = 'wfdelcustom'

    events = ('after_delete_relation',)

    def __call__(self):

        entity = self._cw.entity_from_eid(self.eidfrom)

        typewf = entity.cwetype_workflow()

        if typewf is not None:

            _WorkflowChangedOp(self._cw, eid=self.eidfrom, wfeid=typewf.eid)

class DelWorkflowHook(WorkflowHook):

    __id__ = 'wfdel'

    __select__ = WorkflowHook.__select__ & entity_implements('Workflow')

    events = ('after_delete_entity',)

    def __call__(self):

        # cleanup unused state and transition

        self._cw.execute('DELETE State X WHERE NOT X state_of Y')

        self._cw.execute('DELETE Transition X WHERE NOT X transition_of Y')