import json
import os
import time
from datetime import datetime

import paho.mqtt.client as mqtt

BROKER_HOST = os.getenv("MQTT_HOST", "127.0.0.1")
BROKER_PORT = int(os.getenv("MQTT_PORT", "1883"))
USERNAME = os.getenv("MQTT_USERNAME", "testuser")
PASSWORD = os.getenv("MQTT_PASSWORD", "testpass")
TOPIC = os.getenv("MQTT_TOPIC", "devices/demo")
INTERVAL = float(os.getenv("MQTT_INTERVAL", "2"))

client = mqtt.Client()
if USERNAME:
    client.username_pw_set(USERNAME, PASSWORD)

client.connect(BROKER_HOST, BROKER_PORT, 60)

try:
    counter = 0
    while True:
        payload = {
            "message": f"hello from host {counter}",
            "timestamp": datetime.utcnow().isoformat() + "Z",
        }
        client.publish(TOPIC, json.dumps(payload), qos=0)
        print(f"published to {TOPIC}: {payload}")
        counter += 1
        time.sleep(INTERVAL)
except KeyboardInterrupt:
    print("stopped")
finally:
    client.disconnect()