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

import cv2 as cv


parser = argparse.ArgumentParser(description="Detect and decode one QR code with OpenCV.")
parser.add_argument("input_image", type=Path)
parser.add_argument("output_image", type=Path)
args = parser.parse_args()

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

detector = cv.QRCodeDetector()
payload, points, straight_qrcode = detector.detectAndDecode(image)

if points is None or not payload:
    raise SystemExit("QR code not detected or decoded")

corners = points.reshape(-1, 2)
annotated = image.copy()
cv.polylines(annotated, [corners.astype(int)], isClosed=True, color=(0, 255, 0), thickness=3)

for index, (x_coord, y_coord) in enumerate(corners, start=1):
    point = (int(round(x_coord)), int(round(y_coord)))
    cv.circle(annotated, point, 6, (0, 0, 255), -1)
    cv.putText(
        annotated,
        str(index),
        (point[0] + 8, point[1] - 8),
        cv.FONT_HERSHEY_SIMPLEX,
        0.6,
        (0, 0, 255),
        2,
        cv.LINE_AA,
    )

args.output_image.parent.mkdir(parents=True, exist_ok=True)
if not cv.imwrite(str(args.output_image), annotated):
    raise SystemExit(f"could not write image: {args.output_image}")

print(f"payload: {payload}")
print("corners:")
for index, (x_coord, y_coord) in enumerate(corners, start=1):
    print(f"  {index}: ({x_coord:.1f}, {y_coord:.1f})")

if straight_qrcode is not None and straight_qrcode.size:
    height, width = straight_qrcode.shape[:2]
    print(f"straight QR size: {width}x{height}")

print(f"output: {args.output_image}")