from pathlib import Path

import cv2 as cv


input_path = Path("input/scene.png")
output_path = Path("output/contours.png")

image = cv.imread(str(input_path))
if image is None:
    raise SystemExit(f"Could not read {input_path}")

gray = cv.cvtColor(image, cv.COLOR_BGR2GRAY)
_, mask = cv.threshold(gray, 240, 255, cv.THRESH_BINARY_INV)

contours, _ = cv.findContours(
    mask,
    cv.RETR_EXTERNAL,
    cv.CHAIN_APPROX_SIMPLE,
)

min_area = 1000
kept_contours = [
    contour for contour in contours if cv.contourArea(contour) >= min_area
]

annotated = image.copy()
cv.drawContours(annotated, kept_contours, -1, (0, 0, 255), 3)
output_path.parent.mkdir(parents=True, exist_ok=True)
cv.imwrite(str(output_path), annotated)

print(f"raw contours: {len(contours)}")
print(f"kept contours: {len(kept_contours)}")
print(f"minimum area: {min_area}")

for index, contour in enumerate(kept_contours, start=1):
    x, y, width, height = cv.boundingRect(contour)
    area = cv.contourArea(contour)
    print(
        f"contour {index}: area={area:.1f} "
        f"bbox=({x},{y},{width},{height})"
    )

print(f"wrote: {output_path}")