from machine import Pin, ADC, I2C
import time
import dht
import network
import ujson
from umqtt.simple import MQTTClient

time.sleep(3)

# Set up Pinout
# ADC pin (GPIO 34) -> read MQ135
# DHT sensor (GPIO 15) -> read DHT22
# Relay on GPIO 26 -> Control Relay
dht_sensor = dht.DHT22(Pin(15))  # DHT22 sensor on GPIO 15
ppm_sensor = ADC(Pin(34))        # MQ135 sensor on GPIO 34
ppm_sensor.width(ADC.WIDTH_12BIT)  # 12-bit precision for ADC
led = Pin(2, Pin.OUT)  # LED for indicating working status

# Toxic air quality level threshold (PPM)
toxic = 250
start_time = 0

# Set up the relay on GPIO 26
relay = Pin(26, Pin.OUT)  
relay.off()  # Relay is initially off

# MQTT Server Parameters
MQTT_CLIENT_ID = "micropython-iot"
MQTT_BROKER = "test.mosquitto.org"
MQTT_PORT = 1883
MQTT_USER = ""
MQTT_PASSWORD = ""
MQTT_TOPIC = "iot-air-quality"

# Workig Status
def alive(t, r):
    for i in range(r):
        led.value(not led.value())
        time.sleep(t)

# Connectivity - Connect to WiFi
def connect_wifi():
    alive(.1, 4)
    sta_if = network.WLAN(network.STA_IF)
    sta_if.active(True)
    print("Connecting to WiFi", end="")
    if not sta_if.isconnected():
        sta_if.connect('Wokwi-GUEST', '')  # Use your network credentials
    while not sta_if.isconnected():
        print(".", end="")
        time.sleep(0.5)
    print(" Connected!")
    return sta_if

# MQTT Client Connection
def connect_mqtt():
    alive(.05, 8)
    global client
    client = MQTTClient(MQTT_CLIENT_ID, MQTT_BROKER, port=MQTT_PORT, user=MQTT_USER, password=MQTT_PASSWORD, keepalive=60)
    try:
        print("Connecting to MQTT server... ", end="")
        client.connect()
        print("Connected!")
    except Exception as e:
        print("MQTT connection failed:", e)
        time.sleep(2)
        connect_mqtt()

# Sensor reading functions
def read_dht22():
    try:
        dht_sensor.measure()
        temperature = dht_sensor.temperature()
        humidity = dht_sensor.humidity()
        return temperature, humidity
    except Exception as e:
        print("DHT22 Sensor error:", e)
        return "N/A", "N/A"

def read_mq135():
    try:
        ppm_value = ppm_sensor.read()
        while ppm_value == 0:
            print("Retrying MQ135 read...")
            time.sleep(1)
            ppm_value = ppm_sensor.read()
        mapped_ppm = int(ppm_value / 4.095)  # Convert to ppm value
        if mapped_ppm > toxic:
            global start_time
            start_time = time.time()
        return mapped_ppm
    except Exception as e:
        print("MQ135 Sensor error:", e)
        return "N/A"

# Output devices (Relay control based on PPM)
def control_relay(ppm_value):
    if ppm_value != "N/A" and ppm_value > toxic:
        relay.on()
        elapsed_time = time.time() - start_time
        print(f"Elapsed time: {elapsed_time:.4f} seconds")
        print(f"PPM exceeds {toxic}, Relay activated.")
    else:
        relay.off()
        print(f"PPM below {toxic}, Relay deactivated.")

# Assemble the Payload for MQTT
def assemble_payload(temperature, humidity, mapped_ppm_value):
    if temperature != "N/A" or humidity != "N/A" or mapped_ppm_value != "N/A":
        payload = ujson.dumps({
            "temperature": temperature,
            "humidity": humidity,
            "ppm": mapped_ppm_value
        })
        print("Publishing to MQTT:", payload)
        print("PPM:", mapped_ppm_value, "Temp:", temperature, "Humidity:", humidity, "%")
        return payload

# Main Function to Run the Program
def main():
    # Connect to WiFi
    connect_wifi()

    # Set up MQTT client and connect
    connect_mqtt()

    while True:
        # Read sensors
        temperature, humidity = read_dht22()
        mapped_ppm_value = read_mq135()
        
        # Control relay based on air quality
        control_relay(mapped_ppm_value)
        
        # Prepare payload for MQTT and publish
        payload = assemble_payload(temperature, humidity, mapped_ppm_value)
        client.publish(MQTT_TOPIC, payload)
        
        # Sleep for a while before reading again
        time.sleep(1)

# Run the program
main()