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

# MQTT Server Parameters
MQTT_CLIENT_ID = "esp32-parking-system"
MQTT_BROKER = "test.mosquitto.org"  # Using a reliable public broker
MQTT_PORT = 1883  # Standard MQTT port
MQTT_TOPIC = "parking/status"

# Define IR sensors on GPIO pins
ir_sensor_1 = Pin(15, Pin.IN)
ir_sensor_2 = Pin(23, Pin.IN)
ir_sensor_3 = Pin(16, Pin.IN)

# Threshold for detecting obstacle (1 = detected, 0 = vacant)
THRESHOLD = 1

def connect_to_wifi():
    """Connect to WiFi network."""
    print("Connecting to WiFi...", end="")
    sta_if = network.WLAN(network.STA_IF)
    sta_if.active(True)
    sta_if.connect('Wokwi-GUEST', '')  # Open WiFi in Wokwi
    while not sta_if.isconnected():
        print(".", end="")
        time.sleep(0.5)
    print(" Connected! IP:", sta_if.ifconfig()[0])

def connect_to_mqtt():
    """Connect to the MQTT broker."""
    while True:
        try:
            print("Connecting to MQTT broker...")
            client = MQTTClient(MQTT_CLIENT_ID, MQTT_BROKER, port=MQTT_PORT)
            client.connect()
            print("Connected to MQTT!")
            return client
        except Exception as e:
            print("Failed to connect to MQTT:", e)
            time.sleep(5)  # Retry every 5 seconds

def get_parking_status(sensor):
    """Check if parking space is occupied or vacant."""
    return "Occupied" if sensor.value() >= THRESHOLD else "Vacant"

# Connect to WiFi and MQTT
connect_to_wifi()
client = connect_to_mqtt()

# Store previous states to detect changes
prev_status = {"parking_space_1": "", "parking_space_2": "", "parking_space_3": ""}

while True:
    print("Checking parking status...")

    # Read sensor values and determine statuses
    current_status = {
        "parking_space_1": get_parking_status(ir_sensor_1),
        "parking_space_2": get_parking_status(ir_sensor_2),
        "parking_space_3": get_parking_status(ir_sensor_3),
    }

    # Publish if there is a change in status
    if current_status != prev_status:
        message = ujson.dumps(current_status)
        print(f"Status changed! Publishing: {message}")
        client.publish(MQTT_TOPIC, message)
        prev_status = current_status  # Update previous status
    else:
        print("No change in status.")

    time.sleep(2)  # Check every 2 seconds