# SPDX-FileCopyrightText: 2025 Pagong
# SPDX-License-Identifier: MIT

import time
import board
import neopixel
import math

####################### 

# for Rpi-Pico with 16x16 NeoPixel-Matrix
NUM_COLS   = 16
NUM_CELLS  = 16
NUM_PIXELS = (NUM_COLS * NUM_CELLS)  # Update this to match the number of LEDs.

SPEED = 0.1        # Increase to slow down the effect. Decrease to speed it up.
BRIGHTNESS = 0.1   # A number between 0.0 and 1.0, where 0.0 is off, and 1.0 is max.

PIN = board.GP28   # This is the default pin on my RPi-Pico with 16x16 NeoPixel matrix
pixels = neopixel.NeoPixel(PIN, NUM_PIXELS, brightness=BRIGHTNESS, auto_write=False)

#####################

def lerp(begin, end, t):
    return begin + t*(end-begin)

def hsv2rgb(h, s, v):
    g = h*6.0
    i = math.floor(g)
    f = g - i

    p = v * (1.0 - s)
    q = v * (1.0 - s*f)
    t = v * (1.0 - s*(1.0-f))

    r, g, b = [
        (v, t, p),
        (q, v, p),
        (p, v, t),
        (p, q, v),
        (t, p, v),
        (v, p, q),
    ][int(i)%6]

    return int(r*255), int(g*255), int(b*255)

#####################

hue_A = 15  # 15
sat_A = 230
val_min = 120.0

hue_B = 95  # 95
sat_B = 255
val_max = 255.0

palette = []
def breathe():
    step = 1.0   # 0.5
    delta = (val_max - val_min) / 2.35040238
    max_range = 128

    for i in range(2*max_range):
        dV = (math.exp(math.sin(step * i/max_range * math.pi)) - 0.36787944) * delta
        val = val_min + dV
        t = (val - val_min) / (val_max - val_min)
        hue = lerp(hue_A, hue_B, t)
        sat = lerp(sat_A, sat_B, t)
        
        rgb = hsv2rgb(hue/255.0, sat/255.0, val/255.0)
        #print(i, dV, val, rgb)
        palette.append(rgb)

#####################

pulse = 2.5
breathe()
      
while True:
    for i in range(256):
        color = palette[int(pulse*i)&255]
        pixels.fill(color)
        pixels.show()
        time.sleep(SPEED)