"""Build a binary mask of the censored regions from detections."""

from __future__ import annotations

import cv2
import numpy as np

from ..detection.types import Detection


def detections_to_mask(
    shape: tuple[int, int], detections: list[Detection], dilate: int = 0
) -> np.ndarray:
    """White (255) over every detected region (polygon if present, else bbox)."""
    h, w = shape[:2]
    mask = np.zeros((h, w), np.uint8)
    for d in detections:
        if len(d.polygon) >= 3:
            cv2.fillPoly(mask, [np.array(d.polygon, np.int32)], 255)
        else:
            x, y, bw, bh = d.bbox
            cv2.rectangle(mask, (x, y), (x + bw, y + bh), 255, -1)
    if dilate > 0:
        k = np.ones((dilate * 2 + 1, dilate * 2 + 1), np.uint8)
        mask = cv2.dilate(mask, k)
    return mask