#!/usr/bin/env python

# -*- coding: utf-8  -*-

################################################################################

#

#  Rattail -- Retail Software Framework

#  Copyright © 2010-2012 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 Affero 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 Affero General Public License for

#  more details.

#

#  You should have received a copy of the GNU Affero General Public License

#  along with Rattail.  If not, see <http://www.gnu.org/licenses/>.

#

################################################################################

"""

``rattail.db.cache`` -- Cache Helpers

"""

import edbob

from edbob.util import requires_impl

import rattail

class DataCacher(edbob.Object):

    def __init__(self, session=None, **kwargs):

        super(DataCacher, self).__init__(session=session, **kwargs)

    @property

    @requires_impl(is_property=True)

    def class_(self):

        pass

    @property

    def name(self):

        return self.class_.__name__

    def get_cache(self, progress):

        self.instances = {}

        query = self.session.query(self.class_)

        count = query.count()

        if not count:

            return self.instances

        prog = None

        if progress:

            prog = progress("Reading Rattail %s records into cache" % self.name, count)

        cancel = False

        for i, instance in enumerate(query, 1):

            self.cache_instance(instance)

            if prog and not prog.update(i):

                cancel = True

                break

        if prog:

            prog.destroy()

        if cancel:

            session.close()

            return None

        return self.instances

class DepartmentCacher(DataCacher):

    class_ = rattail.Department

    def cache_instance(self, dept):

        self.instances[dept.number] = dept

class SubdepartmentCacher(DataCacher):

    class_ = rattail.Subdepartment

    def cache_instance(self, subdept):

        self.instances[subdept.number] = subdept

class BrandCacher(DataCacher):

    class_ = rattail.Brand

    def cache_instance(self, brand):

        self.instances[brand.name] = brand

class VendorCacher(DataCacher):

    class_ = rattail.Vendor

    def cache_instance(self, vend):

        self.instances[vend.id] = vend

class ProductCacher(DataCacher):

    class_ = rattail.Product

    def cache_instance(self, prod):

        self.instances[prod.upc] = prod