"""Rainbow NeoPixel sweep — self-contained (stdlib + simulated hardware only)."""

import time

from machine import Pin
import neopixel

# --- helpers (same logic as bundled led_patterns.py, inlined here)


def _clamp(channel: int) -> int:
    return max(0, min(255, int(channel)))


def wheel(pos: int):
    """Return rainbow RGB at position 0–255."""
    pos = 255 - (pos & 255)
    if pos < 85:
        return (_clamp(255 - pos * 3), 0, _clamp(pos * 3))
    if pos < 170:
        pos -= 85
        return (0, _clamp(pos * 3), _clamp(255 - pos * 3))
    pos -= 170
    return (_clamp(pos * 3), _clamp(255 - pos * 3), 0)


def rainbow_frame(led_count: int, frame: int, step: int = 4):
    if led_count <= 0:
        return []
    return [wheel((i * 256 // led_count + frame * step) & 255) for i in range(led_count)]


# --- demo

NUM_LEDS = 16

np = neopixel.NeoPixel(Pin(4), NUM_LEDS)

for frame in range(120):
    frame_colors = rainbow_frame(len(np), frame, step=5)
    for i, color in enumerate(frame_colors):
        np[i] = color
    np.write()
    time.sleep(0.05)

np.fill((0, 0, 0))
np.write()