import ipaddress
import json
import os
import sys
from urllib.error import HTTPError, URLError
from urllib.parse import urlencode
from urllib.request import Request, HTTPRedirectHandler, build_opener


class NoRedirect(HTTPRedirectHandler):
    def redirect_request(self, request, fp, code, message, headers, new_url):
        return None


def check_ip(ip, api_key):
    ipaddress.ip_address(ip)
    if not api_key:
        raise ValueError("Set PROXYRADAR_API_KEY on your server.")
    query = urlencode({"ip": ip, "format": "json"})
    request = Request(
        "https://proxyradar.io/v1/check?" + query,
        headers={"Authorization": "Bearer " + api_key, "Accept": "application/json"},
    )
    try:
        with build_opener(NoRedirect()).open(request, timeout=15) as response:
            raw = response.read(65537)
        if len(raw) > 65536:
            raise ValueError("Response too large")
        data = json.loads(raw)
        if not isinstance(data, dict) or data.get("status") != "success":
            raise ValueError("Unexpected response")
        if type(data.get("proxy")) is not int or data["proxy"] not in (0, 1):
            raise ValueError("Unexpected verdict")
        return {"ip": data["ip"], "proxy": data["proxy"], "flags": data.get("flags")}
    except HTTPError as error:
        raise RuntimeError(f"Lookup unavailable (HTTP {error.code}); result is unknown.") from None
    except (URLError, TimeoutError, ValueError, KeyError):
        raise RuntimeError("Lookup unavailable; result is unknown.") from None


if __name__ == "__main__":
    if len(sys.argv) != 2:
        sys.exit("Usage: python proxy-check.py PUBLIC_IP")
    try:
        result = check_ip(sys.argv[1], os.environ.get("PROXYRADAR_API_KEY", ""))
        print(json.dumps(result, indent=2))
    except (ValueError, RuntimeError) as error:
        sys.exit(str(error))