# copyright 2010-2012 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/>.

"""hooks for repository sources synchronization"""

_ = unicode

from socket import gethostname

from logilab.common.decorators import clear_cache

from cubicweb import validation_error

from cubicweb.predicates import is_instance

from cubicweb.server import SOURCE_TYPES, hook

class SourceHook(hook.Hook):

    __abstract__ = True

    category = 'cw.sources'

# repo sources synchronization #################################################

class SourceAddedOp(hook.Operation):

    entity = None # make pylint happy

    def postcommit_event(self):

        self.cnx.repo.add_source(self.entity)

class SourceAddedHook(SourceHook):

    __regid__ = 'cw.sources.added'

    __select__ = SourceHook.__select__ & is_instance('CWSource')

    events = ('after_add_entity',)

    def __call__(self):

        try:

            sourcecls = SOURCE_TYPES[self.entity.type]

        except KeyError:

            msg = _('Unknown source type')

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

        # ignore creation of the system source done during database

        # initialisation, as config for this source is in a file and handling

        # is done separatly (no need for the operation either)

        if self.entity.name != 'system':

            sourcecls.check_conf_dict(self.entity.eid, self.entity.host_config,

                                      fail_if_unknown=not self._cw.vreg.config.repairing)

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

class SourceRemovedOp(hook.Operation):

    uri = None # make pylint happy

    def postcommit_event(self):

        self.cnx.repo.remove_source(self.uri)

class SourceRemovedHook(SourceHook):

    __regid__ = 'cw.sources.removed'

    __select__ = SourceHook.__select__ & is_instance('CWSource')

    events = ('before_delete_entity',)

    def __call__(self):

        if self.entity.name == 'system':

            msg = _("You cannot remove the system source")

            raise validation_error(self.entity, {None: msg})

        SourceRemovedOp(self._cw, uri=self.entity.name)

class SourceConfigUpdatedOp(hook.DataOperationMixIn, hook.Operation):

    def precommit_event(self):

        self.__processed = []

        for source in self.get_data():

            if not self.cnx.deleted_in_transaction(source.eid):

                conf = source.repo_source.check_config(source)

                self.__processed.append( (source, conf) )

    def postcommit_event(self):

        for source, conf in self.__processed:

            source.repo_source.update_config(source, conf)

class SourceRenamedOp(hook.LateOperation):

    oldname = newname = None # make pylint happy

    def precommit_event(self):

        source = self.cnx.repo.sources_by_uri[self.oldname]

        sql = 'UPDATE entities SET asource=%(newname)s WHERE asource=%(oldname)s'

        self.cnx.system_sql(sql, {'oldname': self.oldname,

                                      'newname': self.newname})

    def postcommit_event(self):

        repo = self.cnx.repo

        # XXX race condition

        source = repo.sources_by_uri.pop(self.oldname)

        source.uri = self.newname

        source.public_config['uri'] = self.newname

        repo.sources_by_uri[self.newname] = source

        repo._type_source_cache.clear()

        clear_cache(repo, 'source_defs')

class SourceUpdatedHook(SourceHook):

    __regid__ = 'cw.sources.configupdate'

    __select__ = SourceHook.__select__ & is_instance('CWSource')

    events = ('before_update_entity',)

    def __call__(self):

        if 'name' in self.entity.cw_edited:

            oldname, newname = self.entity.cw_edited.oldnewvalue('name')

            if oldname == 'system':

                msg = _("You cannot rename the system source")

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

            SourceRenamedOp(self._cw, oldname=oldname, newname=newname)

        if 'config' in self.entity.cw_edited:

            if self.entity.name == 'system' and self.entity.config:

                msg = _("Configuration of the system source goes to "

                        "the 'sources' file, not in the database")

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

            SourceConfigUpdatedOp.get_instance(self._cw).add_data(self.entity)

class SourceHostConfigUpdatedHook(SourceHook):

    __regid__ = 'cw.sources.hostconfigupdate'

    __select__ = SourceHook.__select__ & is_instance('CWSourceHostConfig')

    events = ('after_add_entity', 'after_update_entity', 'before_delete_entity',)

    def __call__(self):

        if self.entity.match(gethostname()):

            if self.event == 'after_update_entity' and \

                   not 'config' in self.entity.cw_edited:

                return

            try:

                SourceConfigUpdatedOp.get_instance(self._cw).add_data(self.entity.cwsource)

            except IndexError:

                # XXX no source linked to the host config yet

                pass

# source mapping synchronization ###############################################

#

# Expect cw_for_source/cw_schema are immutable relations (i.e. can't change from

# a source or schema to another).

class SourceMappingImmutableHook(SourceHook):

    """check cw_for_source and cw_schema are immutable relations

    XXX empty delete perms would be enough?

    """

    __regid__ = 'cw.sources.mapping.immutable'

    __select__ = SourceHook.__select__ & hook.match_rtype('cw_for_source', 'cw_schema')

    events = ('before_add_relation',)

    def __call__(self):

        if not self._cw.added_in_transaction(self.eidfrom):

            msg = _("You can't change this relation")

            raise validation_error(self.eidfrom, {self.rtype: msg})

class SourceMappingChangedOp(hook.DataOperationMixIn, hook.Operation):

    def check_or_update(self, checkonly):

        cnx = self.cnx

        # take care, can't call get_data() twice

        try:

            data = self.__data

        except AttributeError:

            data = self.__data = self.get_data()

        for schemacfg, source in data:

            if source is None:

                source = schemacfg.cwsource.repo_source

            if cnx.added_in_transaction(schemacfg.eid):

                if not cnx.deleted_in_transaction(schemacfg.eid):

                    source.add_schema_config(schemacfg, checkonly=checkonly)

            elif cnx.deleted_in_transaction(schemacfg.eid):

                source.del_schema_config(schemacfg, checkonly=checkonly)

            else:

                source.update_schema_config(schemacfg, checkonly=checkonly)

    def precommit_event(self):

        self.check_or_update(True)

    def postcommit_event(self):

        self.check_or_update(False)

class SourceMappingChangedHook(SourceHook):

    __regid__ = 'cw.sources.schemaconfig'

    __select__ = SourceHook.__select__ & is_instance('CWSourceSchemaConfig')

    events = ('after_add_entity', 'after_update_entity')

    def __call__(self):

        if self.event == 'after_add_entity' or (

            self.event == 'after_update_entity' and 'options' in self.entity.cw_edited):

            SourceMappingChangedOp.get_instance(self._cw).add_data(

                (self.entity, None) )

class SourceMappingDeleteHook(SourceHook):

    __regid__ = 'cw.sources.delschemaconfig'

    __select__ = SourceHook.__select__ & hook.match_rtype('cw_for_source')

    events = ('before_delete_relation',)

    def __call__(self):

        SourceMappingChangedOp.get_instance(self._cw).add_data(

            (self._cw.entity_from_eid(self.eidfrom),

             self._cw.entity_from_eid(self.eidto).repo_source) )