#!/usr/bin/env python3

import hashlib
import json
import paho.mqtt.client as mqtt
import socket
import ssl
import syslog
import time

notify = {}


def on_message(client, userdata, msg):
    if not msg.topic in notify:
        syslog.syslog(syslog.LOG_INFO, f"Publish config for {msg.topic}")
    elif notify[msg.topic] < time.monotonic() - 600:
        syslog.syslog(syslog.LOG_INFO, f"Refresh config for {msg.topic}")
    else:
        return
    topic = msg.topic.split("/")
    uniqueid = hashlib.md5(msg.topic.encode()).hexdigest()
    config = {
        "dev": {
            "name": topic[2].capitalize(),
            "suggested_area": topic[1].capitalize().replace("_", " "),
            "identifiers": [
                uniqueid,
            ],
        },
        "icon": "mdi:lightning-bolt",
        "name": "Power Usage",
        "state_topic": msg.topic,
        "unit_of_measurement": "W",
        "unique_id": uniqueid,
    }
    client.publish(
        topic=f"homeassistant/sensor/{uniqueid}/config", payload=json.dumps(config)
    )
    notify[msg.topic] = time.monotonic()


def connect(hostname):
    client = mqtt.Client(protocol=mqtt.MQTTv5)
    client.tls_set(
        certfile=f"/etc/ssl/{socket.gethostname()}.crt",
        keyfile=f"/etc/ssl/private/{socket.gethostname()}.key",
        ca_certs="/etc/ssl/ca.crt",
        cert_reqs=ssl.CERT_REQUIRED,
    )
    client.on_message = on_message
    client.connect(hostname, 8883)
    syslog.syslog(syslog.LOG_INFO, f"Connected to MQTT broker {hostname}")
    return client


def main():
    syslog.openlog(
        "ha_mqtt_configd", logoption=syslog.LOG_PID, facility=syslog.LOG_DAEMON
    )
    client = connect(socket.gethostname())
    try:
        client.subscribe("home/+/+/power")
        client.loop_forever()
    except KeyboardInterrupt:
        client.disconnect()
        syslog.closelog()


if __name__ == "__main__":
    main()