import logging
import features

from app import storage, image_replication_queue
from data.database import Image, ImageStorage, Repository, User
from data import model
from util.registry.replication import queue_storage_replication

def backfill_replication():
  encountered = set()
  query = (Image
           .select(Image, ImageStorage, Repository, User)
           .join(ImageStorage)
           .switch(Image)
           .join(Repository)
           .join(User))

  for image in query:
    if image.storage.uuid in encountered:
      continue

    namespace = image.repository.namespace_user.username
    locations = model.user.get_region_locations(namespace)
    locations_required = locations | set(storage.default_locations)
    locations_missing = locations_required - set(image.storage.locations)
    if locations_missing:
      print "Enqueueing image storage %s to be replicated" % (image.storage.uuid)
      encountered.add(image.storage.uuid)

      if not image_replication_queue.alive([image.storage.uuid]):
        queue_storage_replication(image.repository.namespace_user.username, image.storage)


if __name__ == '__main__':
  logging.basicConfig(level=logging.INFO)
  if not features.STORAGE_REPLICATION:
    print "Storage replication is not enabled"
  else:
    backfill_replication()