# -*- coding: utf-8 -*-
"""Make near-black logo background transparent."""
from pathlib import Path

from PIL import Image

ROOT = Path(__file__).resolve().parents[1]
FILES = [
    ROOT / "apps/web/public/brand/logo.png",
    ROOT / "apps/web/public/brand/montactLogo.png",
]


def knockout(src: Path) -> None:
    im = Image.open(src).convert("RGBA")
    pixels = im.load()
    w, h = im.size
    for y in range(h):
        for x in range(w):
            r, g, b, a = pixels[x, y]
            luma = 0.2126 * r + 0.7152 * g + 0.0722 * b
            chroma = max(r, g, b) - min(r, g, b)
            # Keep teal M (has chroma). Knock out near-black / gray canvas.
            if luma < 28 and chroma < 18:
                pixels[x, y] = (r, g, b, 0)
            elif luma < 48 and chroma < 22:
                pixels[x, y] = (r, g, b, int(a * (luma - 28) / 20))
    im.save(src)
    print(f"updated {src}")


if __name__ == "__main__":
    for path in FILES:
        if path.exists():
            knockout(path)
        else:
            print(f"missing {path}")