from machine import Pin, I2C, ADC
import utime
import ssd1306
from dht import DHT22

# ---------------------- Setup ----------------------
# Ultrasonic sensor
trigger = Pin(27, Pin.OUT)
echo = Pin(26, Pin.IN)

# DHT22
dht = DHT22(Pin(15))

# Potentiometer (Battery level)
battery = ADC(28)

# OLED display
i2c = I2C(0, scl=Pin(1), sda=Pin(0))
oled = ssd1306.SSD1306_I2C(128, 64, i2c)

# ---------------------- Functions ----------------------
def get_distance():
    trigger.low()
    utime.sleep_us(2)
    trigger.high()
    utime.sleep_us(10)
    trigger.low()
    
    # Wait for echo
    while echo.value() == 0:
        signal_off = utime.ticks_us()
    while echo.value() == 1:
        signal_on = utime.ticks_us()
        
    time_passed = signal_on - signal_off
    distance = (time_passed * 0.0343) / 2
    return round(distance, 2)

def get_battery_level():
    adc_val = battery.read_u16()  # 0–65535
    voltage = (adc_val / 65535) * 3.3
    percent = (voltage / 3.3) * 100
    return round(percent, 1)

def display_data(temp, hum, dist, batt):
    oled.fill(0)
    oled.text("SMART MONITOR", 10, 0)
    oled.text("Temp: {:.1f}C".format(temp), 0, 16)
    oled.text("Hum: {:.1f}%".format(hum), 0, 26)
    oled.text("Dist: {:.1f}cm".format(dist), 0, 36)
    oled.text("Batt: {:.1f}%".format(batt), 0, 46)
    
    if temp > 70:
        oled.text("!! DANGER !!", 20, 56)
        
    oled.show()

# ---------------------- Main Loop ----------------------
while True:
    try:
        # Read DHT22
        dht.measure()
        temp = dht.temperature()
        hum = dht.humidity()
        
        # Read Ultrasonic
        dist = get_distance()
        
        # Read Potentiometer
        batt = get_battery_level()
        
        # Print to console
        print(f"Temp: {temp}C  Hum: {hum}%  Dist: {dist}cm  Batt: {batt}%")
        
        # Update OLED
        display_data(temp, hum, dist, batt)
        
        utime.sleep(2)
        
    except Exception as e:
        print("Error:", e)
        utime.sleep(2)