scripts/example_app_with_response.py

"""https://chatgpt.com/share/19aa181c-051e-4387-9991-578603dd4590"""

import json
import queue
import threading

import paho.mqtt.client as mqtt
import streamlit as st

# Initialize Streamlit app
st.title("Actuator Control Panel")

# MQTT Configuration
HIVEMQ_HOST = st.text_input("Enter your HiveMQ host:", "", type="password")
HIVEMQ_USERNAME = st.text_input("Enter your HiveMQ username:", "")
HIVEMQ_PASSWORD = st.text_input("Enter your HiveMQ password:", "", type="password")
PORT = st.number_input(
    "Enter the port number:", min_value=1, max_value=65535, value=8883
)

# User input for the Pico ID
pico_id = st.text_input("Enter your Pico ID:", "", type="password")

# Slider for position value
position = st.slider(
    "Select the position value:", min_value=1.1, max_value=1.9, value=1.5
)

# Initialize session state for messages
if "messages" not in st.session_state:
    st.session_state.messages = []

# Queue to hold messages
message_queue = queue.Queue()


# Singleton: https://docs.streamlit.io/develop/api-reference/caching-and-state/st.cache_resource
@st.cache_resource
def get_paho_client(hostname, username, password=None, port=8883, tls=True):

    client = mqtt.Client(mqtt.CallbackAPIVersion.VERSION2, protocol=mqtt.MQTTv5)

    # The callback for when the client receives a CONNACK response from the server.
    def on_connect(client, userdata, flags, rc, properties=None):
        if rc != 0:
            print("Connected with result code " + str(rc))
        else:
            print("Connected successfully")

    client.on_connect = on_connect

    # The callback for when a PUBLISH message is received from the server.
    def on_message(client, userdata, msg):
        message_queue.put(msg.payload.decode())

    client.on_message = on_message

    # Enable TLS for secure connection
    if tls:
        client.tls_set()
    # Set username and password
    client.username_pw_set(username, password)
    # Connect to HiveMQ Cloud on port 8883 (default for MQTT)
    client.connect(hostname, port)
    client.loop_start()  # Use a non-blocking loop

    return client


def send_command(client, pico_id, position):
    # Topic
    command_topic = f"digital-pipette/picow/{pico_id}/L16-R"

    # Create and send command
    command = {"position": position}

    try:
        result = client.publish(command_topic, json.dumps(command), qos=1)
        result.wait_for_publish()  # Ensure the message is sent
        if result.rc == mqtt.MQTT_ERR_SUCCESS:
            return f"Command sent: {command} to topic {command_topic}"
        else:
            return f"Failed to send command: {result.rc}"
    except Exception as e:
        return f"An error occurred: {e}"


# Subscribe to the response topic
def subscribe_to_response(client, pico_id):
    response_topic = f"digital-pipette/picow/{pico_id}/response"
    client.subscribe(response_topic, qos=1)


# Publish button
if st.button("Send Command"):
    if not pico_id or not HIVEMQ_HOST or not HIVEMQ_USERNAME or not HIVEMQ_PASSWORD:
        st.error("Please enter all required fields.")
    else:
        client = get_paho_client(
            HIVEMQ_HOST,
            HIVEMQ_USERNAME,
            password=HIVEMQ_PASSWORD,
            port=int(PORT),
            tls=True,
        )
        subscribe_to_response(client, pico_id)
        success_msg = send_command(client, pico_id, position)
        st.success(success_msg)

        # Start a thread to listen for messages
        def listen_for_messages():
            while True:
                msg = message_queue.get()
                if msg:
                    st.session_state.messages.append(msg)
                    st.experimental_rerun()

        threading.Thread(target=listen_for_messages, daemon=True).start()

# Display received messages
for message in st.session_state.messages:
    st.write(f"Received message: {message}")