# Copyright 2014-2015, Tresys Technology, LLC
#
# This file is part of SETools.
#
# SETools is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as
# published by the Free Software Foundation, either version 2.1 of
# the License, or (at your option) any later version.
#
# SETools 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 Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with SETools.  If not, see
# <http://www.gnu.org/licenses/>.
#
import logging
import re
from typing import cast, Iterable

from .query import PolicyQuery
from .descriptors import CriteriaDescriptor, CriteriaSetDescriptor
from .mixins import MatchObjClass
from .policyrep import AnyDefault, DefaultRange, DefaultRuletype, DefaultValue, DefaultRangeValue


class DefaultQuery(MatchObjClass, PolicyQuery):

    """
    Query default_* statements.

    Parameter:
    policy          The policy to query.

    Keyword Parameters/Class attributes:
    ruletype        The rule type(s) to match.
    tclass          The object class(es) to match.
    tclass_regex    If true, use a regular expression for
                    matching the rule's object class.
    default         The default to base new contexts (e.g. "source" or "target")
    default_range   The range to use on new context, default_range only
                    ("low", "high", "low_high")
    """

    ruletype = CriteriaSetDescriptor(enum_class=DefaultRuletype)
    default = CriteriaDescriptor(enum_class=DefaultValue)
    default_range = CriteriaDescriptor(enum_class=DefaultRangeValue)

    def __init__(self, policy, **kwargs) -> None:
        super(DefaultQuery, self).__init__(policy, **kwargs)
        self.log = logging.getLogger(__name__)

    def results(self) -> Iterable[AnyDefault]:
        """Generator which yields all matching default_* statements."""
        self.log.info("Generating default_* results from {0.policy}".format(self))
        self.log.debug("Ruletypes: {0.ruletype!r}".format(self))
        self._match_object_class_debug(self.log)
        self.log.debug("Default: {0.default!r}".format(self))
        self.log.debug("Range: {0.default_range!r}".format(self))

        for d in self.policy.defaults():
            if self.ruletype and d.ruletype not in self.ruletype:
                continue

            if not self._match_object_class(d):
                continue

            if self.default and d.default != self.default:
                continue

            if self.default_range:
                try:
                    if cast(DefaultRange, d).default_range != self.default_range:
                        continue
                except AttributeError:
                    continue

            yield d