# coding: utf-8
#
# Copyright 2014 The Oppia Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, softwar
# distributed under the License is distributed on an "AS-IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

"""Rules for Reals."""

__author__ = 'Sean Lip'

from extensions.rules import base


class Equals(base.RealRule):
    description = 'is equal to {{x|Real}}'

    def _evaluate(self, subject):
        return subject == self.x


class IsLessThan(base.RealRule):
    description = 'is less than {{x|Real}}'

    def _evaluate(self, subject):
        return subject < self.x


class IsGreaterThan(base.RealRule):
    description = 'is greater than {{x|Real}}'

    def _evaluate(self, subject):
        return subject > self.x


class IsLessThanOrEqualTo(base.RealRule):
    description = 'is less than or equal to {{x|Real}}'

    def _evaluate(self, subject):
        return subject <= self.x


class IsGreaterThanOrEqualTo(base.RealRule):
    description = 'is greater than or equal to {{x|Real}}'

    def _evaluate(self, subject):
        return subject >= self.x


class IsInclusivelyBetween(base.RealRule):
    description = 'is between {{a|Real}} and {{b|Real}}, inclusive'

    def _validate_params(self):
        assert self.a <= self.b

    def _evaluate(self, subject):
        return self.a <= subject <= self.b


class IsWithinTolerance(base.RealRule):
    description = 'is within {{tol|Real}} of {{x|Real}}'

    def _evaluate(self, subject):
        return IsInclusivelyBetween(
            self.x - self.tol, self.x + self.tol
        )._evaluate(subject)
