import logging
import uuid

from data.database import User, configure
from app import app

logger = logging.getLogger(__name__)

def backfill_user_uuids():
  logger.setLevel(logging.DEBUG)
  logger.debug('User UUID Backfill: Began execution')

  # Make sure we have a reference to the current DB.
  configure(app.config)
  logger.debug('User UUID Backfill: Database configured')

  # Check to see if any users are missing uuids.
  has_missing_uuids = bool(list(User
                                 .select()
                                 .where(User.uuid >> None)
                                 .limit(1)))
  if not has_missing_uuids:
    logger.debug('User UUID Backfill: No migration needed')
    return

  logger.debug('User UUID Backfill: Starting migration')
  while True:
    batch_users = list(User
                       .select()
                       .where(User.uuid >> None)
                       .limit(100))

    if len(batch_users) == 0:
      # There are no users left to backfill. We're done!
      logging.debug('User UUID Backfill: Backfill completed')
      return

    logging.debug('User UUID Backfill: Found %s records to update' % len(batch_users))
    for user in batch_users:
      user.uuid = str(uuid.uuid4())
      user.save()

if __name__ == "__main__":
  logging.basicConfig(level=logging.DEBUG)
  logging.getLogger('boto').setLevel(logging.CRITICAL)
  logging.getLogger('peewee').setLevel(logging.CRITICAL)

  backfill_user_uuids()