from django.db.models.signals import post_save,pre_delete
from django.dispatch import receiver
from eventplanner.models import Event, EventParticipation, before_read

from eventplanner_gcal.models import createGCalEvent, updateGCalEvent
from eventplanner_gcal.models import deleteGCalEvent, syncParticipationFromGoogleToLocal


class SignalLock:
    def __init__(self):
        self.locked=False

    def __enter__(self):
        if self.locked:
            return False

        self.locked=True
        return True

    def __exit__(self, type, value, traceback):
        self.locked=False

    def isLocked(self):
        return self.locked

signalLock = SignalLock()


@receiver( post_save,sender= Event)
def event_post_save_handler( **kwargs):
    if not signalLock.isLocked():
        with signalLock:
            event = kwargs['instance']
            created = kwargs['created']
            if created:
                print("Creating Gcal event")
                createGCalEvent( event ).execute()
            else:
                print( "Updating Gcal event")
                updateGCalEvent( event ).execute()



@receiver( pre_delete,sender= Event)
def event_pre_delete_handler( **kwargs):
    if not signalLock.isLocked():
        with signalLock:
            event = kwargs['instance']
            print ("Deleting GCAL event")
            deleteGCalEvent( event ).execute()


@receiver( post_save, sender=EventParticipation )
def participation_post_save_handler( **kwargs):
    if not signalLock.isLocked():
        with signalLock:
            participation = kwargs['instance']
            print("Participation post save -> update gcal")
            updateGCalEvent( participation.event ).execute()


@receiver( before_read, sender=EventParticipation )
def participation_before_read_handler( **kwargs):
    if not signalLock.isLocked():
        with signalLock:
            print("SyncParticipation from google")
            syncParticipationFromGoogleToLocal()