from __future__ import print_function, division, absolute_import

#
# Copyright (c) 2011 Red Hat, Inc.
#
# This software is licensed to you under the GNU General Public License,
# version 2 (GPLv2). There is NO WARRANTY for this software, express or
# implied, including the implied warranties of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE. You should have received a copy of GPLv2
# along with this software; if not, see
# http://www.gnu.org/licenses/old-licenses/gpl-2.0.txt.
#
# Red Hat trademarks are not licensed under GPLv2. No permission is
# granted to use or replicate Red Hat trademarks that are incorporated
# in this software or its documentation.
#

import logging

from rhsm.certificate import DateRange
import subscription_manager.injection as inj
from subscription_manager.isodate import parse_date

log = logging.getLogger(__name__)


class ValidProductDateRangeCalculator(object):

    def __init__(self, uep=None):
        uep = uep or inj.require(inj.CP_PROVIDER).get_consumer_auth_cp()
        self.identity = inj.require(inj.IDENTITY)
        if self.identity.is_valid():
            self.prod_status_cache = inj.require(inj.PROD_STATUS_CACHE)
            self.prod_status = self.prod_status_cache.load_status(
                    uep, self.identity.uuid)

    def calculate(self, product_hash):
        """
        Calculate the valid date range for the specified product based on
        today's date.

        Partially entitled products are considered when determining the
        valid range.

        NOTE:
        The returned date range will be in GMT, so keep this in mind when
        presenting these dates to the user.
        """
        # If we're not registered, don't return a valid range:
        if not self.identity.is_valid():
            return None

        if self.prod_status is None:
            return None

        for prod in self.prod_status:
            if product_hash != prod['productId']:
                continue

            # Found the product ID requested:
            if 'startDate' in prod and 'endDate' in prod:

                # Unentitled product:
                if prod['startDate'] is None or prod['endDate'] is None:
                    return None

                return DateRange(parse_date(prod['startDate']),
                    parse_date(prod['endDate']))
            else:
                # If startDate / endDate not supported
                log.warn("Server does not support product date ranges.")
                return None

        # At this point, we haven't found the installed product that was
        # asked for, which could indicate the server somehow doesn't know
        # about it yet. This is extremely weird and should be unlikely,
        # but we will log and handle gracefully:
        log.error("Requested status for installed product server does not "
                "know about: %s" % product_hash)
        return None