import random
from stellar import StellarUnicorn

graphics = None
palette = None

# setup heat value buffer and fire parameters
width = StellarUnicorn.WIDTH + 2
height = StellarUnicorn.HEIGHT + 4
heat = [[0.0 for y in range(height)] for x in range(width)]
fire_spawns = 5
damping_factor = 0.97


def init():
    # a palette of five fiery colours (white, yellow, orange, red, smoke)
    global palette
    palette = [
        graphics.create_pen(0, 0, 0),
        graphics.create_pen(20, 20, 20),
        graphics.create_pen(180, 30, 0),
        graphics.create_pen(220, 160, 0),
        graphics.create_pen(255, 255, 180)
    ]


# returns the palette entry for a given heat value
@micropython.native  # noqa: F821
def pen_from_value(value):
    if value < 0.15:
        return palette[0]
    elif value < 0.25:
        return palette[1]
    elif value < 0.35:
        return palette[2]
    elif value < 0.45:
        return palette[3]
    return palette[4]


@micropython.native  # noqa: F821
def draw():
    # clear the the rows off the bottom of the display
    for x in range(width):
        heat[x][height - 1] = 0.0
        heat[x][height - 2] = 0.0

    # add new fire spawns
    for c in range(fire_spawns):
        x = random.randint(0, width - 4) + 2
        heat[x + 0][height - 1] = 1.0
        heat[x + 1][height - 1] = 1.0
        heat[x - 1][height - 1] = 1.0
        heat[x + 0][height - 2] = 1.0
        heat[x + 1][height - 2] = 1.0
        heat[x - 1][height - 2] = 1.0

    # average and damp out each value to create rising flame effect
    for y in range(0, height - 2):
        for x in range(1, width - 1):
            # update this pixel by averaging the below pixels
            average = (
                heat[x][y] + heat[x][y + 1] + heat[x][y + 2] + heat[x - 1][y + 1] + heat[x + 1][y + 1]
            ) / 5.0

            # damping factor to ensure flame tapers out towards the top of the displays
            average *= damping_factor

            # update the heat map with our newly averaged value
            heat[x][y] = average

    # render the heat values to the graphics buffer
    for y in range(StellarUnicorn.HEIGHT):
        for x in range(StellarUnicorn.WIDTH):
            graphics.set_pen(pen_from_value(heat[x + 1][y]))
            graphics.pixel(x, y)


def test():
    print("A")