import uuid


...


def get_index_from_alias(alias, indices_client):
    if indices_client.exists(alias):
        return list(indices_client.get(alias).keys())[0]
    return None


def recreate_index(model, indices_client):
    """Given a model create an index in elasticsearch,
    or recreate it if an alias to it already exists

    :param model: Model we are creating the index for
    :type model: Django Model
    """
    print('(Re)creating Index for {}'.format(model.es_index_alias))
    # Configuring the settings for the index that will be created. This can later be pushed to
    # the model incase there are more settings that we need to configure
    es_index_settings = {
        'settings': {
            'index': {
                'number_of_replicas': model.es_number_of_replicas,
                'number_of_shards': model.es_number_of_shards
            }
        }
    }

    # Get the existing index name from the alias
    existing_index = get_index_from_alias(model.es_index_alias, indices_client)

    if not existing_index:
        # If the index does not exist, then this is the first time an index is
        # created for this alias, add an alias in the settings from the beginning
        es_index_settings['aliases'] = {model.es_index_alias: {}}

    # Generate a new unique index name
    new_index = "{}_{}".format(model.es_index_alias, uuid.uuid4())
    while indices_client.exists(new_index):
        new_index = "{}_{}".format(model.es_index_alias, uuid.uuid4())

    # Create the new index with the settings defined above
    indices_client.create(index=new_index, body=es_index_settings)

    # Send the mapping defined for the new index
    indices_client.put_mapping(
        # The common consensus is to use _doc since it will be deprecated later
        doc_type='_doc',
        body=model.get_es_mapping(),
        index=new_index
    )

    return existing_index, new_index