import logging

from data.database import Image, ImageStorage, db, db_for_update
from app import app
from util.migrate import yield_random_entries


logger = logging.getLogger(__name__)


def backfill_parent_id():
  logger.setLevel(logging.DEBUG)

  logger.debug('backfill_parent_id: Starting')
  logger.debug('backfill_parent_id: This can be a LONG RUNNING OPERATION. Please wait!')

  def fetch_batch():
    return (Image
            .select(Image.id, Image.ancestors)
            .join(ImageStorage)
            .where(Image.parent_id >> None, Image.ancestors != '/',
                   ImageStorage.uploading == False))

  for to_backfill in yield_random_entries(fetch_batch, 10000, 0.3):
    with app.config['DB_TRANSACTION_FACTORY'](db):
      try:
        image = db_for_update(Image
                              .select()
                              .where(Image.id == to_backfill.id)).get()
        image.parent_id = int(to_backfill.ancestors.split('/')[-2])
        image.save()
      except Image.DoesNotExist:
        pass

  logger.debug('backfill_parent_id: Completed')

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

  backfill_parent_id()