# PassingColors
# Reference: https://wokwi.com/projects/384675870918916097
# by xfpd: https://wokwi.com/makers/xfpd

from machine import Pin
import time
import neopixel
ws_pin  =    13
NUMPIXELS =  24          # NeoPixel ring size
pixDELAY  =  100         # Delay for pixel persistence

GRN_Base = (NUMPIXELS // 4)
BLU_Base = (NUMPIXELS // 2)
YEL_Base = ((NUMPIXELS * 3) // 4)

def collide():
  global i

  # RED pixel follows the counter (at the bottom of this function)
  RED = i

  # GREEN pixel starts at 1/4 (.25) position on the ring
  GRN = GRN_Base - i
  if (GRN < 0) :
    GRN = NUMPIXELS + GRN

  # BLUE pixels starts at 1/2 (.5) position on the ring
  BLU = BLU_Base + i
  if (BLU > NUMPIXELS - 1):
    BLU = BLU - NUMPIXELS

  # YELLOW pixel starts at 3/4 (.75) position on the ring
  YEL = YEL_Base - i
  if (YEL < 0):
    YEL = abs(NUMPIXELS + YEL)

  print("RED %5d | GRN %5d | BLU %5d | YEL %5d" %(RED, GRN, BLU, YEL))
  pixels[RED] =(255, 0, 0)
  pixels[GRN] =(0, 255, 0)
  pixels[BLU] =(0, 0, 255)
  pixels[YEL] =(255, 255, 0)
  pixels.write()
  time.sleep_ms(pixDELAY)

  # BLACK-out the trailing colored pixel
  pixels.fill((0, 0, 0))
  pixels.write() # show the black-out

  if (i < (NUMPIXELS-1)):
    i = i + 1
  else:
    i = 0

# Start Function
if __name__ == '__main__':
  pixels = neopixel.NeoPixel(Pin(ws_pin), NUMPIXELS)
  i=0 # counter
  while True:
    collide()