# off_button.py
#

import time
import RPi.GPIO as GPIO

# Pin definition
shutdown_pin = 17

GPIO.setwarnings(False)

#Use BCM pin numbering (i.e. the GPIO number, not pin number)
GPIO.setmode(GPIO.BCM)

# Use built-in internal pullup resistor so the pin is not floating
# if using a momentary push button without a resistor.
GPIO.setup(shutdown_pin, GPIO.IN, pull_up_down=GPIO.PUD_UP)

# modular function to shutdown Pi
def shut_down():
    print("shutting down")
    command = "/usr/bin/sudo /sbin/shutdown -h now"
    import subprocess
    process = subprocess.Popen(command.split(), stdout=subprocess.PIPE)
    output = process.communicate()[0]
    print(output)

# Check button if we want to shutdown the Pi safely
while True:
    #short delay, otherwise this code will take up a lot of the Pi's processing power
    time.sleep(0.5)

    # For troubleshooting, uncomment this line to output buton status on command line
    #print('GPIO state is = ', GPIO.input(shutdown_pin))
    if GPIO.input(shutdown_pin)== False:
        shut_down()