'''
Mission 12 - Night Light
With a function and constant
'''
from codex import *
ROOM = 15000
MAX_PERCENT = 20

def nightlight(value):
    scaled = (1 - value/ROOM) * MAX_PERCENT
    level = int(scaled)
    pixels.fill(WHITE, brightness = level)

while True:
    value = light.read()

    if value < ROOM:
        nightlight(value)
    else:
        pixels.fill(BLACK)