# Copyright 2015 Amazon.com, Inc. or its affiliates. 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. A copy of
# the License is located at
#
# http://aws.amazon.com/apache2.0/
#
# or in the "license" file accompanying this file. This file 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 sys


def import_module(name):
    """Import module given a name.

    Does not support relative imports.

    """
    __import__(name)
    return sys.modules[name]


def lazy_call(full_name):
    def _handler(**kwargs):
        module, function_name = full_name.rsplit('.', 1)
        module = import_module(module)
        return getattr(module, function_name)(**kwargs)
    return _handler


def inject_attribute(class_attributes, name, value):
    if name in class_attributes:
        raise RuntimeError(
            'Cannot inject class attribute "%s", attribute '
            'already exists in class dict.' % name)
    else:
        class_attributes[name] = value