"""The app icons: the asterisk, white with square ends, on the ground colour. Same geometry as icons/icon.svg.

    python3 tools/icons.py            -> icons/icon-512.png, icons/icon-192.png, icons/apple-touch-icon.png

Needs Pillow (pip install pillow). Drawn at 4x and downsampled so the edges are clean.
"""
import math
import sys
from pathlib import Path

try:
    from PIL import Image, ImageDraw
except ImportError:  # pragma: no cover
    sys.exit("pip install pillow")

ROOT = Path(__file__).resolve().parent.parent
GROUND, INK = (11, 11, 14, 255), (237, 240, 240, 255)


def asterisk(size: int) -> Image.Image:
    ss = 4
    W = size * ss
    im = Image.new("RGBA", (W, W), GROUND)
    d = ImageDraw.Draw(im)
    c = W / 2
    half, width = 150 / 512 * W, 58 / 512 * W     # arm half-length and stroke width, as in icon.svg
    for k in range(3):
        a = math.radians(90 + 60 * k)
        dx, dy = math.cos(a), math.sin(a)
        nx, ny = -dy * width / 2, dx * width / 2
        p1 = (c - dx * half, c - dy * half)
        p2 = (c + dx * half, c + dy * half)
        d.polygon([(p1[0] + nx, p1[1] + ny), (p2[0] + nx, p2[1] + ny), (p2[0] - nx, p2[1] - ny), (p1[0] - nx, p1[1] - ny)], fill=INK)
    return im.resize((size, size), Image.LANCZOS)


if __name__ == "__main__":
    out = ROOT / "icons"
    out.mkdir(exist_ok=True)
    for name, size in (("icon-512.png", 512), ("icon-192.png", 192), ("apple-touch-icon.png", 180)):
        asterisk(size).convert("RGB").save(out / name, optimize=True)
        print("built: icons/" + name)