import picounicorn

picounicorn.init()


# From CPython Lib/colorsys.py
def hsv_to_rgb(h, s, v):
    if s == 0.0:
        return v, v, v
    i = int(h * 6.0)
    f = (h * 6.0) - i
    p = v * (1.0 - s)
    q = v * (1.0 - s * f)
    t = v * (1.0 - s * (1.0 - f))
    i = i % 6
    if i == 0:
        return v, t, p
    if i == 1:
        return q, v, p
    if i == 2:
        return p, v, t
    if i == 3:
        return p, q, v
    if i == 4:
        return t, p, v
    if i == 5:
        return v, p, q


w = picounicorn.get_width()
h = picounicorn.get_height()

# Display a rainbow across Pico Unicorn
for x in range(w):
    for y in range(h):
        r, g, b = [int(c * 255) for c in hsv_to_rgb(x / w, y / h, 1.0)]
        picounicorn.set_pixel(x, y, r, g, b)

print("Press Button A")

while not picounicorn.is_pressed(picounicorn.BUTTON_A):  # Wait for Button A to be pressed
    pass

# Clear the display
for x in range(w):
    for y in range(h):
        picounicorn.set_pixel(x, y, 0, 0, 0)

print("Button A pressed!")