from __future__ import annotations

import sys
from pathlib import Path

from PIL import Image


def build_square_ico(src: Path, dst: Path) -> None:
    im = Image.open(src).convert("RGBA")
    w, h = im.size
    s = max(w, h)
    square = Image.new("RGBA", (s, s), (0, 0, 0, 0))
    square.paste(im, ((s - w) // 2, (s - h) // 2))
    square = square.resize((256, 256), Image.LANCZOS)

    # A single 256x256 icon is sufficient for modern Windows; smaller sizes
    # will be auto-derived by the shell if needed.
    square.save(dst, format="ICO")


def main(argv: list[str]) -> int:
    if len(argv) != 3:
        print("Usage: python make_icon.py <src.ico> <dst.ico>", file=sys.stderr)
        return 2

    src = Path(argv[1]).resolve()
    dst = Path(argv[2]).resolve()

    if not src.exists():
        print(f"Icon source not found: {src}", file=sys.stderr)
        return 2

    build_square_ico(src, dst)
    print(f"Wrote: {dst}")
    return 0


if __name__ == "__main__":
    raise SystemExit(main(sys.argv))