#    Copyright 2014 Mirantis, Inc.
#
#    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.

import re
import six


def get_body_from_env(env):
    """Exctracts request body from wsgi environment variable"""
    content_length = env.get('CONTENT_LENGTH')
    body = ''

    if content_length:  # detects None, 0 or '' values of CONTENT_LENGTH key
        length = int(content_length)
        body = env['wsgi.input'].read(length)
        env['wsgi.input'] = six.StringIO(body)

    return body


def compile_mapping_keys(mapping):
    return dict(
        [(re.compile(k), v)
         for k, v in six.iteritems(mapping)]
    )


def get_group_from_matcher(matcher_obj, string_to_match, group_name):
    """Get value corresponding to group_name if it's present in matcher_obj"""
    matched = matcher_obj.match(string_to_match)
    if matched:
        groups_dictionary = matched.groupdict()
        return groups_dictionary.get(group_name)

    return None