# -*- coding: utf-8 -*-
################################################################################
#
#  Rattail -- Retail Software Framework
#  Copyright © 2010-2017 Lance Edgar
#
#  This file is part of Rattail.
#
#  Rattail is free software: you can redistribute it and/or modify it under the
#  terms of the GNU General Public License as published by the Free Software
#  Foundation, either version 3 of the License, or (at your option) any later
#  version.
#
#  Rattail is distributed in the hope that it will be useful, but WITHOUT ANY
#  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
#  FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
#  details.
#
#  You should have received a copy of the GNU General Public License along with
#  Rattail.  If not, see <http://www.gnu.org/licenses/>.
#
################################################################################
"""
File monitor actions for creating batches
"""

from __future__ import unicode_literals, absolute_import

import logging

from rattail.db import Session, model
from rattail.config import parse_bool
from rattail.filemon import Action
from rattail.util import load_object


log = logging.getLogger(__name__)


class MakeBatch(Action):
    """
    Filemon action for making new file-based batches.  Note that this only
    handles the simple case of creating a batch with a single input data file.
    """

    def __call__(self, path, batch_type='', handler='', user='', delete_if_empty='false', **kwargs):
        """
        Make a batch from the given file path.

        :param path: Path to the source data file for the batch.

        :param type: Type of batch, specified by the batch "key" - e.g. 'labels'.

        :param handler: Spec string for the batch handler class, e.g.
           ``'rattail.batch.handheld.handler:HandheldBatchHandler'``.  Note
           that this argument is *required*.

        :param user: Username of the user which is to be credited with creating
           the batch.

        :param delete_if_empty: Set this to 'true' if you wish the batch to be
           auto-deleted in the event that it has no data rows, after being
           initially populated from the given data file.
        """
        if not handler:
            assert batch_type
            handler = self.config.require('rattail.batch', '{}.handler'.format(batch_type))
        handler = load_object(handler)(self.config)
        session = Session()
        kwargs['created_by'] = session.query(model.User).filter_by(username=user).one()
        batch = handler.make_batch(session, **kwargs)
        handler.set_input_file(batch, path)
        handler.populate(batch)
        handler.refresh_batch_status(batch)

        if parse_bool(delete_if_empty):
            session.flush()
            if not batch.data_rows:
                log.debug("auto-deleting empty '{}' batch: {}".format(handler.batch_key, batch))
                batch.delete_data(self.config)
                session.delete(batch)

        session.commit()
        session.close()