from machine import ADC, Pin
import time 
import os

#Setup pin connections
onboard_led = Pin(25, Pin.OUT)
led_1 = Pin(14, Pin.OUT)
led_2 = Pin(5, Pin.OUT)

buzzer = Pin(17, Pin.OUT)
buzzer.value(0)

gas_sensor = ADC(Pin(26))

#safelimit for gas concentration
safe_limit = 25 #gas level baseline for danger

#create file to save the as level readings
filename = "gas_reading.csv"
if filename not in os.listdir():
    with open(filename, "w") as f:
        f.write("seconds, gas_level\n")


#setup counter and reading interval
seconds_passed = 0 #count time since the program started
reading_interval = 0.5 #time pass btn every gas reading


#warm up Gas Sensor
print("warming up the gas sensor for 60 sec")
for r in range (1, 61):
    seconds_passed  += 1
    print("warm up: {} seconds".format(seconds_passed))

    #blink onboard led  during warm up
    onboard_led.value(1)
    time.sleep(0.2)
    onboard_led(0)
    time.sleep(0.2)
    onboard_led(1)
    time.sleep(0.2)

print("Warm up successful")
onboard_led(0)

#gas sensor reading
print("Now reading gas levels every {} seconds". format(reading_interval))
while True:
    #read gas level and convert to percentages
    raw_value = gas_sensor.read_u16()#lowest level is 0 and the highest level is 65535

    #convert raw value to percentage
    gas_level = (raw_value/65535)*100
    gas_percentage = round(gas_level, 1)

    #print gas levels in percentages and the seconds_passed
    print("Gas level: {}% at {} seconds".format(gas_percentage, seconds_passed))

    #save all gas levl reading to the file (gas_reading.csv)
    with open(filename, "a") as f:
        f.write("{},{}%\n".format(seconds_passed, gas_percentage))
        #MAIN LOGIC OF THE GAS SENSOR DETECTOR
        if gas_percentage > safe_limit:
            led_1.value(1)
            time.sleep(1)
            led_1.value(0)
            time.sleep(0.5)
            led_1.value(1)
            buzzer.value(1)
            time.sleep(0.5)
            buzzer.value(0)
            time.sleep(0.5)
            buzzer.value(1)
        else:
            led_2.value(1)
            time.sleep(1)
            led_2.value(0)
            time.sleep(1)
            led_2.value(1)
            time.sleep(1)
            led_2.value(0)
            time.sleep(1)
            led_2.value(1)
            led_1.value(0)
            buzzer.value(0)
            
        seconds_passed += reading_interval
        time.sleep(reading_interval)