import json

import etcd3 as etcd3
from retrying import retry

CLUSTER_INFO_KEY = '/syncthing_monitor/cluster_info'


@retry
def append_device_id(device_id, host, port=2379):
    cluster_info = {'devices': []}

    etcd = etcd3.client(host=host, port=port)

    with etcd.lock('syncthing_monitor'):
        raw_value = etcd.get(CLUSTER_INFO_KEY)[0]

        if raw_value is not None:
            cluster_info = json.loads(raw_value)

        if not any(device_id in element for element in cluster_info['devices']):
            cluster_info['devices'].append(device_id)

        print("Updating etcd value for '{0}': {1}".format(CLUSTER_INFO_KEY, json.dumps(cluster_info)), flush=True)
        etcd.put(CLUSTER_INFO_KEY, json.dumps(cluster_info))