import time
import math
import dht
from machine import Pin


# ==============================
# Pin Configuration
# ==============================

DHT_PIN = 4
LED_GREEN_PIN = 5
LED_YELLOW_PIN = 18
LED_RED_PIN = 19
BUZZER_PIN = 21


# ==============================
# Hardware Setup
# ==============================

sensor = dht.DHT22(Pin(DHT_PIN))

led_green = Pin(LED_GREEN_PIN, Pin.OUT)
led_yellow = Pin(LED_YELLOW_PIN, Pin.OUT)
led_red = Pin(LED_RED_PIN, Pin.OUT)
buzzer = Pin(BUZZER_PIN, Pin.OUT)


# ==============================
# AI Model Parameters
# Offline Logistic Regression
# ==============================

W_TEMP = 1.20
W_HUM = 0.80
BIAS = -0.50

TEMP_MEAN = 20.0
TEMP_STD = 15.0

HUM_MEAN = 50.0
HUM_STD = 30.0


# ==============================
# Sigmoid Function
# ==============================

def sigmoid(x):
    return 1 / (1 + math.exp(-x))


# ==============================
# AI Inference
# ==============================

def ai_inference(temp_c, humidity):

    # Normalize temperature
    t_norm = (temp_c - TEMP_MEAN) / TEMP_STD

    # Normalize humidity
    h_norm = (humidity - HUM_MEAN) / HUM_STD

    # Logistic regression equation
    z = (W_TEMP * t_norm) + (W_HUM * h_norm) + BIAS

    # Probability of HOT condition
    probability = sigmoid(z)

    return probability


# ==============================
# LED and Buzzer Control
# ==============================

def set_outputs(label):

    # Turn everything OFF first
    led_green.value(0)
    led_yellow.value(0)
    led_red.value(0)
    buzzer.value(0)

    # Comfortable
    if label == "COMFORTABLE":
        led_green.value(1)

    # Warm
    elif label == "WARM":
        led_yellow.value(1)

    # Hot
    elif label == "HOT":
        led_red.value(1)
        buzzer.value(1)


# ==============================
# Startup
# ==============================

print("----------------------------------------")
print("AIoT Temperature Monitoring System")
print("----------------------------------------")
print("AI decision engine ready.")
print("DHT22 connected to GPIO 4")
print("Green LED  -> GPIO 5")
print("Yellow LED -> GPIO 18")
print("Red LED    -> GPIO 19")
print("Buzzer     -> GPIO 21")
print("----------------------------------------")


# ==============================
# Main Loop
# ==============================

while True:

    try:

        # Read DHT22 sensor
        sensor.measure()

        temperature = sensor.temperature()
        humidity = sensor.humidity()

        # AI prediction
        hot_probability = ai_inference(
            temperature,
            humidity
        )

        # Classify environment
        if hot_probability < 0.33:

            label = "COMFORTABLE"

        elif hot_probability < 0.66:

            label = "WARM"

        else:

            label = "HOT"

        # Control LEDs and buzzer
        set_outputs(label)

        # Display result
        print(
            "Temperature: {:.1f} C | "
            "Humidity: {:.1f}% | "
            "HOT Probability: {:.3f} | "
            "Decision: {}".format(
                temperature,
                humidity,
                hot_probability,
                label
            )
        )

    except Exception as e:

        print("Sensor read failed:", e)

    # Wait before next reading