#!/usr/bin/env python3
# /// script
# requires-python = ">=3.10"
# dependencies = [
#     "paho-mqtt>=2.0",
# ]
# ///
"""Fake Zigbee device for doorbell E2E validation.

Subscribes to a "set" topic and echoes a TOGGLE back to a "state" topic
(retained), emulating a Zigbee smart plug at the MQTT layer. This lets the
doorbell E2E probe confirm the full chain (ntfy.sh -> listener -> MQTT -> device)
without toggling a real lamp.

Env vars:
    MQTT_HOST     default "mosquitto"
    MQTT_PORT     default 1883
    SET_TOPIC     default "zigbee2mqtt/DoorbellProbe/set"
    STATE_TOPIC   default "zigbee2mqtt/DoorbellProbe"
"""
import json
import os

import paho.mqtt.client as mqtt

MQTT_HOST = os.environ.get("MQTT_HOST", "mosquitto")
MQTT_PORT = int(os.environ.get("MQTT_PORT", "1883"))
SET_TOPIC = os.environ.get("SET_TOPIC", "zigbee2mqtt/DoorbellProbe/set")
STATE_TOPIC = os.environ.get("STATE_TOPIC", "zigbee2mqtt/DoorbellProbe")


def log(msg: str) -> None:
    print(msg, flush=True)


def on_connect(client, userdata, flags, reason_code, properties=None):
    log(f"connected to {MQTT_HOST}:{MQTT_PORT} (rc={reason_code})")
    client.subscribe(SET_TOPIC)


def on_message(client, userdata, msg):
    log(f"echo -> {STATE_TOPIC} (from {msg.topic})")
    client.publish(STATE_TOPIC, json.dumps({"state": "TOGGLE", "echo": True}), retain=True)


def main() -> None:
    log(f"fake-device: {SET_TOPIC} -> {STATE_TOPIC}")
    client = mqtt.Client(mqtt.CallbackAPIVersion.VERSION2)
    client.on_connect = on_connect
    client.on_message = on_message
    while True:
        try:
            client.connect(MQTT_HOST, MQTT_PORT, 60)
            break
        except Exception as e:
            log(f"connect failed: {e}; retry in 5s")
            import time
            time.sleep(5)
    client.loop_forever()


if __name__ == "__main__":
    main()