"""hooks to handle attributes mapped to a custom storage

"""

from os import unlink

from cubicweb.server.hook import Hook

from cubicweb.server.sources.storages import ETYPE_ATTR_STORAGE

class BFSSHook(Hook):

    """abstract class for bytes file-system storage hooks"""

    __abstract__ = True

    category = 'bfss'

class PreAddEntityHook(BFSSHook):

    """"""

    __regid__ = 'bfss_add_entity'

    events = ('before_add_entity', )

    #__select__ = Hook.__select__ & implements('Repository')

    def __call__(self):

        for attr in ETYPE_ATTR_STORAGE.get(self.entity.__regid__, ()):

            fpath = ETYPE_ATTR_STORAGE[self.entity.__regid__][attr].entity_added(self.entity, attr)

            if fpath is not None:

                AddFileOp(filepath=fpath)

class PreUpdateEntityHook(BFSSHook):

    """"""

    __regid__ = 'bfss_update_entity'

    events = ('before_update_entity', )

    #__select__ = Hook.__select__ & implements('Repository')

    def __call__(self):

        for attr in ETYPE_ATTR_STORAGE.get(self.entity.__regid__, ()):

            ETYPE_ATTR_STORAGE[self.entity.__regid__][attr].entity_updated(self.entity, attr)

class PreDeleteEntityHook(BFSSHook):

    """"""

    __regid__ = 'bfss_delete_entity'

    events = ('before_delete_entity', )

    #__select__ = Hook.__select__ & implements('Repository')

    def __call__(self):

        for attr in ETYPE_ATTR_STORAGE.get(self.entity.__regid__, ()):

            ETYPE_ATTR_STORAGE[self.entity.__regid__][attr].entity_deleted(self.entity, attr)