"""Docstring."""

import os

import boto3
from botocore.exceptions import ClientError
import neo4j

client = boto3.client('sns')

neo4j_url = os.getenv('NEO4J_URL')
neo4j_username = os.getenv('NEO4J_USERNAME')
neo4j_password = os.getenv('NEO4J_PASSWORD')
neo4j_driver = neo4j.GraphDatabase.driver(
    neo4j_url,
    auth=(
        neo4j_username,
        neo4j_password
    ),
    max_retry_time=30
)


def main():
    try:
        identity_ids = get_identity_ids()
    except Exception as e:
        raise e
    finally:
        neo4j_driver.close()  # or else neo4j spews unseless errors out

    for identity_id in identity_ids:
        sns_topic_arn = f'arn:aws:sns:us-east-1:437795906767:prod-push-notifications-{identity_id}'  # noqa:E501
        missing = [
            x
            for x in get_subscriptions(sns_topic_arn)
            if not subscription_exists(x)
        ]
        if missing:
            print(f'ERROR: {sns_topic_arn}')
            for m in missing:
                print(m['SubscriptionArn'])


def subscription_exists(sns_subscription):
    try:
        client.get_endpoint_attributes(
            EndpointArn=sns_subscription['Endpoint']
        )
    except ClientError as e:
        if e.response['Error']['Code'] == 'NotFound':
            return False
        raise e
    return True


def get_subscriptions(sns_topic_arn, next_token=None, previous_subs=[]):
    result = None
    try:
        if not next_token:
            result = client.list_subscriptions_by_topic(
                TopicArn=sns_topic_arn
            )
        else:
            result = client.list_subscriptions_by_topic(
                TopicArn=sns_topic_arn,
                NextToken=next_token
            )
    except ClientError as e:
        if e.response['Error']['Code'] == 'NotFound' and\
                e.response['Error']['Message'] == 'Topic does not exist':
            print(f'ERROR: topic {sns_topic_arn} not found!')
        return []
    next_token = result.get('NextToken', None)
    total_subs = previous_subs + result['Subscriptions']
    if not next_token:
        return total_subs
    return get_subscriptions(sns_topic_arn, next_token, total_subs)


def get_identity_ids():
    session = neo4j_driver.session(access_mode='READ')
    query = '''
        MATCH(i:Identity)-[]-(d:Device)
        RETURN DISTINCT(i.id) AS id ORDER BY i.id ASC
    '''
    query_results = session.run(query)
    return [x['id'] for x in query_results]


if __name__ == '__main__':
    main()