import functools
from .ftrack_base_handler import BaseHandler


class BaseEvent(BaseHandler):
    '''Custom Event base class

    BaseEvent is based on ftrack.update event
    - get entities from event

    If want to use different event base
    - override register and *optional _translate_event method

    '''

    type = 'Event'

    def __init__(self, session):
        '''Expects a ftrack_api.Session instance'''
        super().__init__(session)

    # Decorator
    def launch_log(self, func):
        @functools.wraps(func)
        def wrapper_launch(*args, **kwargs):
            try:
                func(*args, **kwargs)
            except Exception as e:
                self.log.info('{} Failed ({})'.format(
                    self.__class__.__name__, str(e))
                )
        return wrapper_launch

    def register(self):
        '''Registers the event, subscribing the discover and launch topics.'''
        self.session.event_hub.subscribe(
            'topic=ftrack.update',
            self._launch,
            priority=self.priority
        )

    def _launch(self, event):
        self.session.rollback()
        self.session._local_cache.clear()

        self.launch(
            self.session, event
        )

        return

    def _translate_event(self, session, event):
        '''Return *event* translated structure to be used with the API.'''
        return [
            self._get_entities(session, event),
            event
        ]

    def _get_entities(
        self, session, event, ignore=['socialfeed', 'socialnotification']
    ):
        _selection = event['data'].get('entities', [])
        _entities = list()
        if isinstance(ignore, str):
            ignore = list(ignore)
        for entity in _selection:
            if entity['entityType'] in ignore:
                continue
            _entities.append(
                (
                    session.get(
                        self._get_entity_type(entity),
                        entity.get('entityId')
                    )
                )
            )
        return _entities