from machine import Pin
from time import sleep
from umqtt.simple import MQTTClient
import network

# WiFi credentials
SSID = "Wokwi-GUEST"
PASSWORD = ""

# MQTT Broker details
MQTT_BROKER = "rail.kls.ac.th"
MQTT_TOPIC = "railtest007"
CLIENT_ID = "esp32_wokwi_client" # Unique client ID

# LED Pin (GPIO26)
LED_PIN = 26
led = Pin(LED_PIN, Pin.OUT)

# --- WiFi Connection ---
def connect_wifi():
    print("Connecting to WiFi...", end="")
    sta_if = network.WLAN(network.STA_IF)
    sta_if.active(True)
    sta_if.connect(SSID, PASSWORD)
    while not sta_if.isconnected():
        print(".", end="")
        sleep(0.5)
    print("\nWiFi Connected!")
    print("IP Address:", sta_if.ifconfig()[0])

# --- MQTT Callback Function ---
def mqtt_callback(topic, msg):
    print(f"Received MQTT message: Topic='{topic.decode()}', Message='{msg.decode()}'")
    if msg.decode() == "true":
        led.value(1)  # Turn LED ON
        print("LED ON")
    elif msg.decode() == "false":
        led.value(0)  # Turn LED OFF
        print("LED OFF")

# --- Main Program ---
def main():
    connect_wifi()

    # Initialize MQTT Client
    client = MQTTClient(CLIENT_ID, MQTT_BROKER)
    client.set_callback(mqtt_callback)
    client.connect()
    print(f"Connected to MQTT Broker: {MQTT_BROKER}")

    # Subscribe to the topic
    client.subscribe(MQTT_TOPIC)
    print(f"Subscribed to topic: {MQTT_TOPIC}")

    try:
        while True:
            client.check_msg() # Check for new MQTT messages
            sleep(1)
    except Exception as e:
        print(f"An error occurred: {e}")
    finally:
        client.disconnect()
        print("Disconnected from MQTT Broker.")

if __name__ == "__main__":
    main()