#!/usr/bin/env python3

"""Send a text notification to the Home Alert ntfy topic."""

import argparse
import os
import sys
from urllib.error import HTTPError, URLError
from urllib.request import Request, urlopen


DEFAULT_TOPIC_URL = (
    "https://ntfy.sh/VK20_Home_Alert_______4671938674123049873459"
)


def send_notification(
    message,
    topic_url=None,
    timeout=10,
):
    """Send *message* to ntfy and return the server response body."""

    if not isinstance(message, str):
        raise TypeError("message must be a string")

    if not message:
        raise ValueError("message must not be empty")

    url = topic_url or os.environ.get(
        "NTFY_TOPIC_URL",
        DEFAULT_TOPIC_URL,
    )
    request = Request(
        url,
        data=message.encode("utf-8"),
        headers={"Content-Type": "text/plain; charset=utf-8"},
        method="POST",
    )

    with urlopen(request, timeout=timeout) as response:
        return response.read().decode("utf-8")


def parse_arguments():
    """Parse command-line arguments."""

    parser = argparse.ArgumentParser(
        description="Send a text message to the Home Alert ntfy topic.",
    )
    parser.add_argument(
        "message",
        nargs="+",
        help="notification text",
    )
    parser.add_argument(
        "--topic-url",
        help="override the ntfy topic URL",
    )
    parser.add_argument(
        "--timeout",
        type=float,
        default=10,
        help="request timeout in seconds (default: 10)",
    )
    return parser.parse_args()


def main():
    args = parse_arguments()

    try:
        response = send_notification(
            " ".join(args.message),
            topic_url=args.topic_url,
            timeout=args.timeout,
        )
        print(response)
        return 0

    except HTTPError as exc:
        print(
            f"ntfy returned HTTP {exc.code}: {exc.reason}",
            file=sys.stderr,
        )
    except URLError as exc:
        print(f"Could not reach ntfy: {exc.reason}", file=sys.stderr)
    except (TypeError, ValueError) as exc:
        print(f"Invalid notification: {exc}", file=sys.stderr)

    return 1


if __name__ == "__main__":
    raise SystemExit(main())