#!/usr/bin/env python3
"""MJPEG-Stream auslesen.

Beispiele:
  python3 webcam.py                      # Verbindung testen, Frame-Infos ausgeben
  python3 webcam.py --snapshot bild.jpg  # ein Einzelbild speichern
  python3 webcam.py --save frames/ -n 50 # 50 Frames als JPEG speichern
  python3 webcam.py --show               # Live-Fenster (benötigt opencv-python + numpy)
"""
import argparse
import os
import sys
import time

import requests

URL = "http://192.168.10.82:8080/stream.mjpg"
SOI, EOI = b"\xff\xd8", b"\xff\xd9"


def frames(url, timeout=10):
    """Generator: liefert jedes JPEG-Frame des MJPEG-Streams als bytes."""
    with requests.get(url, stream=True, timeout=timeout) as r:
        r.raise_for_status()
        buf = b""
        for chunk in r.iter_content(chunk_size=4096):
            buf += chunk
            while True:
                start = buf.find(SOI)
                if start < 0:
                    buf = b""
                    break
                end = buf.find(EOI, start + 2)
                if end < 0:
                    buf = buf[start:]
                    break
                yield buf[start:end + 2]
                buf = buf[end + 2:]


def main():
    p = argparse.ArgumentParser(description=__doc__, formatter_class=argparse.RawDescriptionHelpFormatter)
    p.add_argument("--url", default=URL)
    p.add_argument("--snapshot", metavar="DATEI", help="ein Frame speichern und beenden")
    p.add_argument("--save", metavar="ORDNER", help="Frames in Ordner speichern")
    p.add_argument("-n", type=int, default=0, help="nach N Frames beenden (0 = endlos)")
    p.add_argument("--show", action="store_true", help="Live-Fenster anzeigen (OpenCV)")
    a = p.parse_args()

    if a.show:
        import cv2
        import numpy as np
    if a.save:
        os.makedirs(a.save, exist_ok=True)

    count, t0 = 0, time.time()
    try:
        for jpg in frames(a.url):
            count += 1
            if a.snapshot:
                with open(a.snapshot, "wb") as f:
                    f.write(jpg)
                print(f"Gespeichert: {a.snapshot} ({len(jpg)} Bytes)")
                return
            if a.save:
                with open(os.path.join(a.save, f"frame_{count:06d}.jpg"), "wb") as f:
                    f.write(jpg)
            if a.show:
                img = cv2.imdecode(np.frombuffer(jpg, np.uint8), cv2.IMREAD_COLOR)
                cv2.imshow("Webcam", img)
                if cv2.waitKey(1) & 0xFF in (ord("q"), 27):
                    break
            fps = count / (time.time() - t0)
            print(f"\rFrame {count}  {len(jpg)} Bytes  {fps:.1f} fps", end="", flush=True)
            if a.n and count >= a.n:
                break
    except KeyboardInterrupt:
        pass
    except requests.RequestException as e:
        sys.exit(f"Verbindungsfehler: {e}")
    print()


if __name__ == "__main__":
    main()