#
# Copyright (c) 2014-2017 AT&T Intellectual Property
#
# 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, software
# 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.

"""Valet Resource Constraints"""

import string

from heat.engine import constraints


class GroupNameConstraint(constraints.BaseCustomConstraint):
    """Validator for Valet Group name."""

    def validate(self, value, context):
        """Validation callback."""
        valid_characters = string.letters + string.digits + "-._~"
        if not value:
            self._error_message = "Group name must not be empty"
            return False
        elif not set(value) <= set(valid_characters):
            self._error_message = ("Group name must contain only uppercase "
                                   "and lowercase letters, decimal digits, "
                                   "hyphens, periods, underscores, and tildes "
                                   "[RFC 3986, Section 2.3]")
            return False
        return True