from machine import Pin, ADC, PWM
import time


# =====================================================
# CONFIGURATION
# =====================================================

# Magic Numbers

led_pin = 2
gas_pin = 34
buzzer_pin = 18
button_pin = 4


gas_sensor = ADC(Pin(gas_pin))

button = Pin(button_pin, Pin.IN, Pin.PULL_UP)



# Wrong hardware connections

led = Pin(led_pin, Pin.OUT)
buzzer = PWM(Pin(buzzer_pin))
buzzer.freq(1000)



# =====================================================
# SYSTEM VARIABLES
# =====================================================

alarm = False

alarm_acknowledged = False



# =====================================================
# BUTTON INTERRUPT
# =====================================================


def button_isr(pin):

    global alarm_acknowledged

    alarm_acknowledged = True

    buzzer.duty(0)



button.irq(
    trigger=Pin.IRQ_FALLING,
    handler=button_isr
)



# =====================================================
# OUTPUT CONTROL
# =====================================================
def alarm_on():

    led.on()

    buzzer.duty(512)



def alarm_off():

    led.off()

    buzzer.duty(0)



# =====================================================
# SYSTEM LOGIC
# =====================================================


def update_system(gas_value):

    global alarm
    global alarm_acknowledged


    if gas_value > 3000:


        alarm = True


        if alarm_acknowledged == False:

            alarm_on()



    else:


        alarm = False

        alarm_acknowledged = False

        alarm_off()



# =====================================================
# MAIN PROGRAM
# =====================================================


print("Gas Leak Detection Started")


while True:
    now = time.ticks_ms()
    if time.ticks_diff(now, last_read_sensor) > DEBOUNCE_SENSOR:  

    gas_value = gas_sensor.read()


    print("Gas Level:", gas_value)



    update_system(gas_value)
    # 1: syntax error
    if button.value() == 0:

        alarm_acknowledged = True

        buzzer.duty(0)



    time.sleep(1)