from machine import Pin, ADC, Timer, I2C
from i2c_lcd import I2cLcd
import math

# Initialize I2C and LCD
sda = Pin(0)
scl = Pin(1)
adc_pot = ADC(26)  # ADC pin for thermistor
i2c = I2C(0, sda=sda, scl=scl, freq=400000)
pin_cords = [2, 3, 4, 5, 6]
blink_timer = Timer()  # Single global timer for blinking
active_pins = []
devices = i2c.scan()
idcaddr = devices[0]
lcd = I2cLcd(i2c, idcaddr, 2, 16)

# Thermistor Constants
R1 = 10000   # Fixed resistor in voltage divider (ohms)
B = 3950     # Thermistor B coefficient
T0 = 298.15  # Reference temperature in Kelvin (25°C)
R0 = 10000   # Thermistor resistance at 25°C (ohms)

pins = [Pin(pin_cords[i], Pin.OUT) for i in range(5)]

# Variables
cnt = 0  # Counter for yellow blinking time
is_red_blinking = False  # Flag to check if red LED should blink

def update_temperature(timer):
    lcd.clear()
    adc_value = adc_pot.read_u16()  # Read ADC value (0-65535)

    # Convert ADC value to thermistor resistance
    if adc_value == 0:
        return  # Prevent division by zero

    R_thermistor = R1 * ((65535 / adc_value) - 1)

    # Calculate temperature using the Steinhart-Hart equation
    temp_kelvin = 1 / (1 / T0 + (1 / B) * math.log(R_thermistor / R0))
    temp_celsius = temp_kelvin - 273.15  # Convert to Celsius

    # Display the temperature on LCD
    lcd.putstr(f"Temp: {temp_celsius:.2f} C")
    blink_light(temp_celsius)

def toggle_leds(timer):
    """Toggle only the active LEDs for blinking effect."""
    for pin in active_pins:
        pin.toggle()

def print_led():
    lcd.clear()
    lcd.putstr("DANGER")

def blink_light(temp):
    global cnt, is_red_blinking, active_pins

    print(f"Temperature: {temp:.2f}°C")  # Debugging Output

    # Turn off all LEDs first
    for x in pins:
        x.off()

    # Determine which LEDs should be active
    if 0 <= temp <= 30:
        active_pins = [pins[0]]  # Green LED (Low temp)
    elif 30 < temp < 60:
        active_pins = [pins[1]]  # Yellow LED (Warning stage)
        cnt += 1  # Increase count each second

        if cnt >= 5:  # If Yellow LED blinks for 5 sec
            active_pins = [pins[2],pins[3],pins[4]]  # Switch to Red LED blinking
            print_led()
            is_red_blinking = True
    else:
        active_pins = [pins[2],pins[3], pins[4]]  # Other LEDs (Danger stage)
        print_led()

    # Turn on only the selected LEDs
    for pin in active_pins:
        pin.on()

    # Start blinking effect for active LEDs
    blink_timer.init(period=1000, mode=Timer.PERIODIC, callback=toggle_leds)

# Set up a timer to update the display every 1000ms (1 second)
timer = Timer()
timer.init(period=1000, mode=Timer.PERIODIC, callback=update_temperature)