#!/usr/bin/env python3
"""Simple deployment health check utility."""

from __future__ import annotations

import argparse
import json
import sys
import time
from urllib.error import HTTPError, URLError
from urllib.request import urlopen


def parse_args() -> argparse.Namespace:
    parser = argparse.ArgumentParser(description="Poll an HTTP health endpoint until it is ready.")
    parser.add_argument("url", help="Health endpoint URL, e.g. https://vault.example.com/health")
    parser.add_argument("--timeout", type=int, default=120, help="Maximum wait time in seconds")
    parser.add_argument("--interval", type=int, default=5, help="Poll interval in seconds")
    parser.add_argument("--expect-status", default="ok", help="Expected JSON status field")
    parser.add_argument(
        "--expect-environment",
        default=None,
        help="Optional expected JSON environment field",
    )
    return parser.parse_args()


def fetch_json(url: str) -> dict:
    with urlopen(url, timeout=10) as response:
        body = response.read().decode("utf-8")
        return json.loads(body)


def main() -> int:
    args = parse_args()
    deadline = time.time() + args.timeout
    last_error = "unknown error"

    while time.time() < deadline:
        try:
            payload = fetch_json(args.url)
            if payload.get("status") != args.expect_status:
                raise RuntimeError(f"unexpected status: {payload!r}")
            if args.expect_environment and payload.get("environment") != args.expect_environment:
                raise RuntimeError(f"unexpected environment: {payload!r}")
            print(f"healthcheck passed: {payload}")
            return 0
        except (HTTPError, URLError, TimeoutError, ValueError, RuntimeError) as exc:
            last_error = str(exc)
            time.sleep(args.interval)

    print(f"healthcheck failed after {args.timeout}s: {last_error}", file=sys.stderr)
    return 1


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