#!/usr/bin/env python3
import argparse
from pathlib import Path

import cv2
import numpy as np


def odd_positive(value: str) -> int:
    size = int(value)
    if size < 1 or size % 2 == 0:
        raise argparse.ArgumentTypeError("kernel size must be a positive odd integer")
    return size


parser = argparse.ArgumentParser(
    description="Apply an OpenCV morphology operation to a binary mask."
)
parser.add_argument("input_mask", type=Path)
parser.add_argument("output_mask", type=Path)
parser.add_argument(
    "--operation",
    choices=("erode", "dilate", "open", "close"),
    default="open",
)
parser.add_argument("--kernel-size", type=odd_positive, default=5)
args = parser.parse_args()