"""Knock a flat charcoal field out of generated renders so they can be sprites."""

from __future__ import annotations

import sys
from pathlib import Path

from PIL import Image


def sample_background(image: Image.Image) -> tuple[float, float, float]:
    pixels = image.load()
    width, height = image.size
    samples: list[tuple[int, int, int]] = []
    for x, y in (
        (2, 2),
        (width - 3, 2),
        (2, height - 3),
        (width - 3, height - 3),
        (width // 2, 2),
        (width // 2, height - 3),
    ):
        pixel = pixels[x, y]
        samples.append((pixel[0], pixel[1], pixel[2]))
    count = float(len(samples))
    return (
        sum(sample[0] for sample in samples) / count,
        sum(sample[1] for sample in samples) / count,
        sum(sample[2] for sample in samples) / count,
    )


def punch(path: Path) -> None:
    image = Image.open(path).convert("RGBA")
    background = sample_background(image)
    pixels = image.load()
    width, height = image.size
    for y in range(height):
        for x in range(width):
            red, green, blue, _alpha = pixels[x, y]
            distance = (
                (red - background[0]) ** 2
                + (green - background[1]) ** 2
                + (blue - background[2]) ** 2
            ) ** 0.5
            if distance < 18:
                alpha = 0
            elif distance < 34:
                alpha = int((distance - 18) * (255.0 / 16.0))
            else:
                alpha = 255
            pixels[x, y] = (red, green, blue, alpha)
    image.save(path)


def main() -> int:
    roots = [
        Path("assets/generated/renders/machines"),
        Path("assets/generated/renders/logistics"),
        Path("assets/generated/renders/items"),
    ]
    count = 0
    for root in roots:
        for path in sorted(root.glob("*.png")):
            punch(path)
            count += 1
    print("PUNCHED %d" % count)
    return 0


if __name__ == "__main__":
    sys.exit(main())