import requests
import argparse
import sys

def check_as_path(prefix, as_to_check):
    url = f'https://stat.ripe.net/data/looking-glass/data.json?resource={prefix}'
    response = requests.get(url)
    if response.ok:
        data = response.json()
        for rrc in data['data']['rrcs']:
            for peer in rrc['peers']:
                as_path = peer['as_path']
                if as_to_check in as_path:
                    print(f"CRITICAL: AS {as_to_check} found in AS path for prefix {prefix} at RRC {rrc['rrc']}")
                    return 2  # return critical
        print(f"OK: AS {as_to_check} not found in AS path for prefix {prefix}")
        return 0  # return OK
    else:
        print(f"UNKNOWN: Error fetching data from {url}")
        return 3  # return unknown

if __name__ == '__main__':
    parser = argparse.ArgumentParser(description='Check if a certain AS is in the AS path for any peers for a given prefix')
    parser.add_argument('--prefix', required=True, help='IPv4 prefix to check')
    parser.add_argument('--asn', required=True, help='AS number to check for')
    args = parser.parse_args()
    exit_code = check_as_path(args.prefix, args.asn)
    sys.exit(exit_code)