#!/usr/bin/env python3
import cv2
import hashlib
import secrets
import time
import argparse

def fetch_frame_opencv(url):
    cap = cv2.VideoCapture(url)
    ret, frame = cap.read()
    cap.release()
    if not ret:
        raise ValueError("Failed to fetch frame.")
    return frame

def generate_random_numbers(frame, bit_lengths):
    _, img_encoded = cv2.imencode('.jpg', frame)
    img_bytes = img_encoded.tobytes()
    entropy = hashlib.sha256(img_bytes).digest()
    return {length: secrets.randbits(length) for length in bit_lengths}

def main():
    parser = argparse.ArgumentParser(description="Generate random numbers from camera entropy.")
    parser.add_argument("--url", default="http://192.168.0.200/mjpg/video.mjpg", help="Camera MJPEG stream URL")
    parser.add_argument("--single", type=int, default=1, help="Generate N random numbers and exit (default: 1)")
    parser.add_argument("--bit", type=int, default=256, help="Bit length of each random number (default: 256)")
    args = parser.parse_args()

    for i in range(args.single):
        try:
            frame = fetch_frame_opencv(args.url)
            random_numbers = generate_random_numbers(frame, [args.bit])
            for number in random_numbers.values():
                print(f"{number:x}")  # Print as hex without '0x' prefix
        except Exception as e:
            print(f"Error: {e}", file=sys.stderr)
            return 1
        if args.single > 1 and i < args.single - 1:
            time.sleep(1)  # Small delay between frames in single mode

if __name__ == "__main__":
    import sys
    main()