import network
import time
from umqtt.simple import MQTTClient
from machine import Pin, time_pulse_us

print(" Starting ESP32 Smart Parking...")

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

# MQTT Broker
MQTT_BROKER = "broker.hivemq.com"
MQTT_PORT = 1883
MQTT_TOPIC = b"smart_parking/status"

# Slot configuration
slots = [
    {"name": "A1", "trig": 5, "echo": 18, "red": 15, "green": 14},
    {"name": "A2", "trig": 19, "echo": 21, "red": 22, "green": 23},
    {"name": "A3", "trig": 13, "echo": 12, "red": 27, "green": 26},
    {"name": "A4", "trig": 25, "echo": 33, "red": 32, "green": 4},
    {"name": "A5", "trig": 16, "echo": 17, "red": 2, "green": 1}
]

# GPIO setup
print("🔧 Setting up GPIO pins...")
for slot in slots:
    slot["trig"] = Pin(slot["trig"], Pin.OUT)
    slot["echo"] = Pin(slot["echo"], Pin.IN)
    slot["red"] = Pin(slot["red"], Pin.OUT)
    slot["green"] = Pin(slot["green"], Pin.OUT)
print("GPIO Setup Complete")

# Connect to WiFi
def connect_wifi():
    print(" Attempting WiFi connection...")
    wlan = network.WLAN(network.STA_IF)
    wlan.active(True)
    print(" WLAN Active")
    wlan.connect(SSID, PASSWORD)
    print("Connecting to WiFi...")
    while not wlan.isconnected():
        time.sleep(1)
        print("⏳ Waiting for connection...")
    print("WiFi Connected:", wlan.ifconfig())

# Connect to MQTT
def connect_mqtt():
    print("📡 Attempting MQTT connection...")
    client = MQTTClient("esp32-client", MQTT_BROKER, port=MQTT_PORT)
    client.connect()
    print("MQTT Connected")
    return client

# Distance logic
def get_distance(trig, echo):
    print("📏 Measuring distance...")
    trig.value(0)
    time.sleep_us(2)
    trig.value(1)
    time.sleep_us(10)
    trig.value(0)
    duration = time_pulse_us(echo, 1, 30000)
    print(f"Duration: {duration}")
    return (duration * 0.0343) / 2

# Publish status
def publish(client, slot_name, status):
    message = '{"slot": "' + slot_name + '", "status": "' + status + '"}'
    client.publish(MQTT_TOPIC, message)
    print("Published:", message)

# Main Logic
try:
    connect_wifi()
    mqtt_client = connect_mqtt()
    while True:
        for slot in slots:
            dist = get_distance(slot["trig"], slot["echo"])
            print(f"{slot['name']} Distance: {dist:.2f} cm")
            if dist < 10:
                slot["red"].on()
                slot["green"].off()
                publish(mqtt_client, slot["name"], "Occupied")
            else:
                slot["red"].off()
                slot["green"].on()
                publish(mqtt_client, slot["name"], "Available")
        time.sleep(5)
except Exception as e:
    print(" Error:", str(e))
    while True:
        time.sleep(1)