from machine import Pin, ADC, I2C, time_pulse_us
from time import sleep
import dht
import network
from umqtt.simple import MQTTClient
from i2c_lcd import I2cLcd

# ================= WIFI + MQTT =================

WIFI_SSID = "Wokwi-GUEST"
WIFI_PASS = ""

MQTT_BROKER = "test.mosquitto.org"
CLIENT_ID = "esp32-iot-demo"
TOPIC_SOIL = b"iot/demo/soil"
TOPIC_TEMP = b"iot/demo/temp"
TOPIC_WATER = b"iot/demo/water"

wlan = network.WLAN(network.STA_IF)
wlan.active(True)
wlan.connect(WIFI_SSID, WIFI_PASS)
while not wlan.isconnected():
    sleep(0.5)

mqtt = MQTTClient(CLIENT_ID, MQTT_BROKER)
mqtt.connect()

# ================= HARDWARE =================

# DHT22
dht_sensor = dht.DHT22(Pin(23))

# Soil sensor (potentiometer)
soil_adc = ADC(Pin(36))
soil_adc.atten(ADC.ATTN_11DB)
soil_adc.width(ADC.WIDTH_12BIT)

# Ultrasonic
trig = Pin(33, Pin.OUT)
echo = Pin(32, Pin.IN)

# Relay
relay = Pin(13, Pin.OUT)
relay.value(0)

# Water alarm LED
led_water = Pin(22, Pin.OUT)
led_water.value(0)

# LCD1602 I2C
i2c = I2C(0, scl=Pin(18), sda=Pin(19), freq=400000)
lcd = I2cLcd(i2c, 0x27, 2, 16)

# ================= PARAMETERS =================

SOIL_THRESHOLD = 30
WATER_LEVEL_MAX_CM = 25
READ_INTERVAL = 5

# ================= FUNCTIONS =================

def read_soil():
    return round((soil_adc.read() / 4095) * 100, 1)

def read_ultrasonic():
    trig.value(0)
    sleep(0.000002)
    trig.value(1)
    sleep(0.00001)
    trig.value(0)
    try:
        t = time_pulse_us(echo, 1, 30000)
        return (t * 0.0343) / 2
    except OSError:
        return None

# ================= MAIN LOOP =================

while True:
    try:
        dht_sensor.measure()
        temp = dht_sensor.temperature()
        hum = dht_sensor.humidity()
    except OSError:
        temp = hum = None

    soil = read_soil()
    dist = read_ultrasonic()
    water_low = True if dist is None else dist > WATER_LEVEL_MAX_CM

    # Control logic
    if water_low:
        relay.value(0)
        led_water.value(1)
        mqtt.publish(TOPIC_WATER, b"LOW")
    else:
        led_water.value(0)
        mqtt.publish(TOPIC_WATER, b"OK")
        relay.value(1 if soil < SOIL_THRESHOLD else 0)

    # LCD update
    lcd.clear()
    lcd.move_to(0, 0)
    lcd.putstr("Soil:{:>4.1f}%".format(soil))
    lcd.move_to(0, 1)
    if temp is not None:
        lcd.putstr("T:{:>4.1f}C".format(temp))
        mqtt.publish(TOPIC_TEMP, str(temp))
    else:
        lcd.putstr("DHT Error")

    mqtt.publish(TOPIC_SOIL, str(soil))

    print("Soil:", soil, "Temp:", temp, "Water low:", water_low)

    sleep(READ_INTERVAL)