"""Factory function for creating an es client."""

import boto3
from elasticsearch import Elasticsearch
from elasticsearch import RequestsHttpConnection
from requests_aws4auth import AWS4Auth


def create_es_client(hosts: list):
    """Create a new ElasticSearch client."""
    username = password = creds = None
    if hosts[0]:
        username = hosts[0].get("username")
        password = hosts[0].get("password")
    if username and password:
        # If we have user creds, prefer these over v4 signature.
        creds = (username, password)

    return Elasticsearch(
        hosts=hosts,
        http_auth=creds or get_signature(),
        use_ssl=True,
        verify_certs=True,
        connection_class=RequestsHttpConnection)


def get_signature():
    """Get a aws auth v4 signature."""
    session = boto3.session.Session()
    credentials = session.get_credentials()
    return AWS4Auth(
        credentials.access_key,
        credentials.secret_key,
        session.region_name,
        "es",
        session_token=credentials.token)