from machine import Pin, ADC, PWM
import time


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

on = 1000
off = 0
INTERVAL = 500
DEBUG = True

gas_sensor = ADC(Pin(34))

button = Pin(4, Pin.IN, Pin.PULL_UP)



# Wrong hardware connections

led = Pin(2, Pin.OUT)

buzzer = PWM(Pin(18, Pin.OUT), freq=50)


def log(state, msg):
    if DEBUG:
        print("[{}] [{} ms] [{}]".format(state, time.ticks_ms(), msg))

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

alarm = False

alarm_acknowledged = False

log("START", "Initalizing system")



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


def button_isr(pin):

    global alarm_acknowledged

    alarm_acknowledged = True

    buzzer.duty(off)
    log("Disabling Alarm", "Attempt to disable alarm")



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



# =====================================================
# OUTPUT CONTROL
# =====================================================


def alarm_on():

    led.on()

    buzzer.duty(on)

    log("DANGER!", "Gas Leak")



def alarm_off():

    led.off()

    buzzer.duty(off)

    log("Safe", ":)")



# =====================================================
# 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")

last = 0
while True:
    now = time.ticks_ms()
    if time.ticks_diff(now, last) > INTERVAL:
        gas_value = gas_sensor.read()


        print("Gas Level:", gas_value)



        update_system(gas_value)



        if button.value() == 0:

            alarm_acknowledged = True

            buzzer.duty(off)

        print("-" * 35)
        log("Time check", f"ΔT = {now - last}")
        print("-" * 35)

        last = now