#!/usr/bin/env python3.7

import socket
import time

pausee = 0.00001   # time between pings in seconds
rate = 0.2         # 1/rate gives the time for a cycle in seconds
ip_base = '2001:6a8:2880:2018::'

def hue_to_rgb_float(h):
    i = int(h * 6.0)
    f = h * 6.0 - i
    g = 1.0 - f
    i %= 6
    if i == 0:
        return 1.0, f, 0.0
    elif i == 1:
        return g, 1.0, 0.0
    elif i == 2:
        return 0.0, 1.0, f
    elif i == 3:
        return 0.0, g, 1.0
    elif i == 4:
        return f, 0.0, 1.0
    else: # i == 5
        return 1.0, 0.0, g

def send_ping(send_socket, rgb):
    addr = ip_base + '%.2x:%.2x:%.2x' % rgb
    try:
        send_socket.sendto(b'\x80\0\0\0\0\0\0\0', (addr, 0, 0, 0))
    except:
        pass

def main():
    send_socket = socket.socket(socket.AF_INET6, socket.SOCK_RAW, socket.getprotobyname('ipv6-icmp'))
    while True:

        # float that increases to 1 at speed given by rate
        hue = (time.time() * rate) % 1.0  

        # returns (r, g, b) where each is between 0 and 1
        rgb_float = hue_to_rgb_float(hue)

        # returns (r, g, b) where each is a float between 0 and 255
        rgb = tuple(int(min(x * 256, 255)) for x in rgb_float)

        send_ping(send_socket, rgb)
        time.sleep(pausee)

if __name__ == '__main__':
    main()