#!/usr/bin/env python3

import argparse
import base64
import json
import logging
import ssl
import urllib.parse
import urllib.request

logging.basicConfig(level=logging.INFO, format="%(asctime)s %(levelname)s: %(message)s")
logger = logging.getLogger(__name__)

ROUTER_HOST = "192.168.1.1"
ROUTER_USERNAME = "abdus"
ROUTER_PASSWORD = "xAsametk50"


def parse_args() -> argparse.Namespace:
    parser = argparse.ArgumentParser(
        description="Log in to the Zyxel router over HTTPS and reboot it",
        formatter_class=argparse.ArgumentDefaultsHelpFormatter,
    )
    parser.add_argument("--host", default=ROUTER_HOST)
    parser.add_argument("--username", default=ROUTER_USERNAME)
    parser.add_argument("--timeout", type=float, default=15.0, help="Request timeout in seconds")
    parser.add_argument("--dry-run", action="store_true", help="Log in but do not reboot")
    return parser.parse_args()


def build_opener() -> urllib.request.OpenerDirector:
    # The router uses a self-signed certificate. Over HTTPS the UI skips its RSA/AES login layer.
    context = ssl.create_default_context()
    context.check_hostname = False
    context.verify_mode = ssl.CERT_NONE
    return urllib.request.build_opener(
        urllib.request.HTTPSHandler(context=context),
        urllib.request.HTTPCookieProcessor(),
    )


def post(opener: urllib.request.OpenerDirector, url: str, body: dict, timeout: float) -> dict:
    request = urllib.request.Request(
        url=url,
        data=json.dumps(body).encode(),
        headers={"Content-Type": "application/json"},
        method="POST",
    )
    with opener.open(request, timeout=timeout) as response:
        raw = response.read().decode()
    return json.loads(raw) if raw.strip() else {}


def login(opener: urllib.request.OpenerDirector, base_url: str, username: str, timeout: float) -> str:
    body = post(
        opener=opener,
        url=f"{base_url}/UserLogin",
        body={
            "Input_Account": username,
            "Input_Passwd": base64.b64encode(ROUTER_PASSWORD.encode()).decode(),
            "currLang": "en",
            "RememberPassword": 0,
            "SHA512_password": False,
        },
        timeout=timeout,
    )
    if body.get("result") != "ZCFG_SUCCESS":
        raise RuntimeError(f"Login rejected: {body}")
    return body.get("sessionkey", "")


def reboot(opener: urllib.request.OpenerDirector, base_url: str, session_key: str, timeout: float) -> None:
    query = f"?{urllib.parse.urlencode({'sessionkey': session_key})}" if session_key else ""
    body = post(opener=opener, url=f"{base_url}/cgi-bin/Reboot{query}", body={}, timeout=timeout)
    logger.info("Reboot response: %s", body)


def main() -> None:
    args = parse_args()
    base_url = f"https://{args.host}"
    opener = build_opener()

    session_key = login(opener=opener, base_url=base_url, username=args.username, timeout=args.timeout)
    logger.info("Logged in as %s", args.username)
    if args.dry_run:
        logger.info("Dry run, not rebooting")
        return
    reboot(opener=opener, base_url=base_url, session_key=session_key, timeout=args.timeout)
    logger.info("Reboot request sent, router is back in about a minute")


if __name__ == "__main__":
    main()