import json

import etcd3 as etcd3
from retrying import retry

CLUSTER_INFO_KEY = '/syncthing_monitor/cluster_info'


class EtcdClient:
    def __init__(self, host):
        self.host = host

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

        etcd = etcd3.client(host=self.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))

    @retry
    def get_device_list(self, port=2379):
        cluster_info = {'devices': []}

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

        raw_value = etcd.get(CLUSTER_INFO_KEY)[0]

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

        print("Obtained cluster_info devices from etcd: {0}".format(json.dumps(cluster_info['devices'])))
        return cluster_info['devices']