from argparse import ArgumentParser
from pathlib import Path

import cv2 as cv


parser = ArgumentParser()
parser.add_argument("--input", default="input/scene.png", help="Source image")
parser.add_argument("--output", default="output/scene-copy.png", help="Output image")
args = parser.parse_args()

input_path = Path(args.input)
output_path = Path(args.output)
output_path.parent.mkdir(parents=True, exist_ok=True)

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

if not cv.imwrite(str(output_path), image):
    raise SystemExit(f"could not write output image: {output_path}")

written = cv.imread(str(output_path), cv.IMREAD_COLOR)
if written is None:
    raise SystemExit(f"could not read written image: {output_path}")

if written.shape != image.shape:
    raise SystemExit(f"shape changed: source={image.shape} written={written.shape}")

source_height, source_width = image.shape[:2]
written_height, written_width = written.shape[:2]
source_channels = 1 if image.ndim == 2 else image.shape[2]
written_channels = 1 if written.ndim == 2 else written.shape[2]

print(f"read: {input_path}")
print(f"source: {source_width}x{source_height} channels={source_channels} dtype={image.dtype}")
print(f"wrote: {output_path}")
print(f"verified: {written_width}x{written_height} channels={written_channels} dtype={written.dtype}")