# demand.py

# Demand sheet and related classes.

#

# Copyright (C) 2014-2015  Red Hat, Inc.

#

# This copyrighted material is made available to anyone wishing to use,

# modify, copy, or redistribute it subject to the terms and conditions of

# the GNU General Public License v.2, or (at your option) any later version.

# This program is distributed in the hope that it will be useful, but WITHOUT

# ANY WARRANTY expressed or implied, including the implied warranties 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 this program; if not, write to the

# Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

# 02110-1301, USA.  Any Red Hat trademarks that are incorporated in the

# source code or documentation are not subject to the GNU General Public

# License and may only be used or replicated with the express permission of

# Red Hat, Inc.

#

from __future__ import unicode_literals

class _BoolDefault(object):

    def __init__(self, default):

        self.default = default

        self._storing_name = '__%s%x' % (self.__class__.__name__, id(self))

    def __get__(self, obj, objtype=None):

        objdict = obj.__dict__

        if self._storing_name in objdict:

            return objdict[self._storing_name]

        return self.default

    def __set__(self, obj, val):

        objdict = obj.__dict__

        if self._storing_name in objdict:

            current_val = objdict[self._storing_name]

            if current_val != val:

                raise AttributeError('Demand already set.')

        objdict[self._storing_name] = val

class DemandSheet(object):

    """Collection of demands that different CLI parts have on other parts. :api"""

    # :api...

    allow_erasing = _BoolDefault(False)

    available_repos = _BoolDefault(False)

    resolving = _BoolDefault(False)

    root_user = _BoolDefault(False)

    sack_activation = _BoolDefault(False)

    load_system_repo = _BoolDefault(True)

    success_exit_status = 0

    cacheonly = _BoolDefault(False)

    fresh_metadata = _BoolDefault(True)

    freshest_metadata = _BoolDefault(False)

    changelogs = _BoolDefault(False)

    transaction_display = None

    # This demand controlls applicability of the plugins that could filter

    # repositories packages (e.g. versionlock).

    # If it stays None, the demands.resolving is used as a fallback.

    plugin_filtering_enabled = _BoolDefault(None)