# ==============================
# RASPERITY : IoT Security System
# Secure Temperature & Humidity Monitor with MQTT + HMAC
# ==============================

import network, time, ubinascii, machine, ujson, hashlib
from umqtt.simple import MQTTClient
from machine import Pin
import dht

# ---------- CONFIG -------------
WIFI_SSID = "your_wifi_name"
WIFI_PASS = "your_wifi_password"

MQTT_BROKER = "broker.hivemq.com"   # Public free broker
MQTT_PORT   = 1883
MQTT_TOPIC  = b"rasperity/data"
CLIENT_ID   = ubinascii.hexlify(machine.unique_id())

SECRET_KEY  = b"supersecretkey"      # Shared secret for HMAC

# DHT11 sensor on GP15 (change if needed)
sensor = dht.DHT11(Pin(15))

# ---------- WIFI CONNECTION -------------
def connect_wifi():
    wlan = network.WLAN(network.STA_IF)
    wlan.active(True)
    if not wlan.isconnected():
        print("🌐 Connecting to Wi-Fi...", end="")
        wlan.connect(WIFI_SSID, WIFI_PASS)
        while not wlan.isconnected():
            print(".", end="")
            time.sleep(1)
    print("\n✅ Wi-Fi connected:", wlan.ifconfig())

# ---------- MQTT COMMUNICATION ----------
def connect_mqtt():
    try:
        client = MQTTClient(CLIENT_ID, MQTT_BROKER, port=MQTT_PORT)
        client.connect()
        print("✅ Connected to MQTT broker:", MQTT_BROKER)
        return client
    except Exception as e:
        print("❌ MQTT connect failed:", e)
        return None

def publish_mqtt(client, temp, hum):
    try:
        payload = {"temp": temp, "hum": hum}
        msg = ujson.dumps(payload)

        # Calculate HMAC signature
        signature = hmac.new(SECRET_KEY, msg.encode(), hashlib.sha256).hexdigest()
        secure_payload = ujson.dumps({"data": payload, "hmac": signature})

        client.publish(MQTT_TOPIC, secure_payload)
        print("📤 Published:", secure_payload)
    except Exception as e:
        print("⚠️ Publish error:", e)

# ---------- MAIN LOOP -------------
connect_wifi()
client = connect_mqtt()

while True:
    try:
        sensor.measure()
        temp = sensor.temperature()
        hum = sensor.humidity()
        print(f"🌡 Temp: {temp}°C  💧 Hum: {hum}%")

        if client:
            publish_mqtt(client, temp, hum)
        else:
            print("⚠️ MQTT not connected, retrying...")
            client = connect_mqtt()

    except Exception as e:
        print("⚠️ Sensor/MQTT Error:", e)

    time.sleep(5)