import os
import json
import logging
from typing import Optional
import paho.mqtt.client as mqtt

logger = logging.getLogger(__name__)

# MQTT Configuration from environment
MQTT_BROKER_HOST = os.getenv("MQTT_BROKER_HOST", "localhost")
MQTT_BROKER_PORT = int(os.getenv("MQTT_BROKER_PORT", "1883"))
MQTT_USERNAME = os.getenv("MQTT_USERNAME", "")
MQTT_PASSWORD = os.getenv("MQTT_PASSWORD", "")
MQTT_LABEL_TOPIC = os.getenv("MQTT_LABEL_TOPIC", "vet/labels/print")

def publish_label_print(label_data: dict) -> bool:
    """
    Publish a label print request to MQTT broker
    
    Args:
        label_data: Dictionary containing label print information
        
    Returns:
        True if successful, False otherwise
    """
    try:
        # Create MQTT client
        client = mqtt.Client()
        
        # Set username and password if provided
        if MQTT_USERNAME and MQTT_PASSWORD:
            client.username_pw_set(MQTT_USERNAME, MQTT_PASSWORD)
        
        # Connect to broker
        client.connect(MQTT_BROKER_HOST, MQTT_BROKER_PORT, 60)
        
        # Start network loop to process connection
        client.loop_start()
        
        # Publish message with QoS 0 (fire and forget)
        message = json.dumps(label_data)
        result = client.publish(MQTT_LABEL_TOPIC, message, qos=0)
        
        # Stop loop and disconnect
        client.loop_stop()
        client.disconnect()
        
        if result.rc == mqtt.MQTT_ERR_SUCCESS:
            logger.info(f"Successfully published label print request to {MQTT_LABEL_TOPIC}")
            return True
        else:
            logger.error(f"Failed to publish label print request: {result.rc}")
            return False
            
    except Exception as e:
        logger.error(f"Error publishing MQTT message: {str(e)}")
        return False