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

import cv2 as cv
import numpy as np


def clamp_alpha(value: str) -> float:
    alpha = float(value)
    if not 0.0 <= alpha <= 1.0:
        raise argparse.ArgumentTypeError("alpha must be between 0.0 and 1.0")
    return alpha


parser = argparse.ArgumentParser(description="Draw text and shape overlays with OpenCV.")
parser.add_argument("input_image", type=Path)
parser.add_argument("output_image", type=Path)
parser.add_argument("--alpha", type=clamp_alpha, default=0.35)
args = parser.parse_args()

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

annotated = image.copy()
height, width = annotated.shape[:2]

box_start = (int(width * 0.12), int(height * 0.18))
box_end = (int(width * 0.62), int(height * 0.58))
label_origin = (box_start[0] + 18, box_start[1] - 14)
center = (int(width * 0.75), int(height * 0.34))
radius = max(18, min(width, height) // 16)
polyline = np.array(
    [
        (int(width * 0.18), int(height * 0.76)),
        (int(width * 0.36), int(height * 0.66)),
        (int(width * 0.55), int(height * 0.82)),
    ],
    dtype=np.int32,
).reshape((-1, 1, 2))

overlay = annotated.copy()
cv.rectangle(overlay, box_start, box_end, (0, 180, 255), cv.FILLED)
cv.addWeighted(overlay, args.alpha, annotated, 1.0 - args.alpha, 0, annotated)

cv.rectangle(annotated, box_start, box_end, (0, 140, 255), 3, cv.LINE_AA)
cv.putText(
    annotated,
    "inspection zone",
    label_origin,
    cv.FONT_HERSHEY_SIMPLEX,
    0.8,
    (0, 0, 0),
    4,
    cv.LINE_AA,
)
cv.putText(
    annotated,
    "inspection zone",
    label_origin,
    cv.FONT_HERSHEY_SIMPLEX,
    0.8,
    (255, 255, 255),
    2,
    cv.LINE_AA,
)
cv.circle(annotated, center, radius, (255, 80, 80), 3, cv.LINE_AA)
cv.drawMarker(annotated, center, (255, 255, 255), cv.MARKER_CROSS, radius * 2, 2, cv.LINE_AA)
cv.polylines(annotated, [polyline], False, (80, 255, 80), 4, 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}")

changed = cv.absdiff(image, annotated)
changed_pixels = int(np.count_nonzero(cv.cvtColor(changed, cv.COLOR_BGR2GRAY)))
x1, y1 = box_start
x2, y2 = box_end
roi_changed = cv.absdiff(image[y1:y2, x1:x2], annotated[y1:y2, x1:x2])
roi_pixels = int(np.count_nonzero(cv.cvtColor(roi_changed, cv.COLOR_BGR2GRAY)))

print(f"input: {args.input_image}")
print(f"alpha: {args.alpha:.2f}")
print(f"changed pixels: {changed_pixels}")
print(f"inspection zone changed pixels: {roi_pixels}")
print(f"output: {args.output_image}")