#!/usr/bin/env python3
"""Verify a selected real configuration on the authorized disposable ALT VM."""
import argparse
import ipaddress
import json
import os
import socket
import subprocess


def command(*args):
    return subprocess.run(args, check=True, capture_output=True, text=True, timeout=35).stdout.strip()


def public_ipv4():
    value = command('curl', '-4', '--noproxy', '*', '--fail', '--silent', '--show-error',
                    '--connect-timeout', '5', '--max-time', '15', 'https://ifconfig.me')
    return str(ipaddress.IPv4Address(value))


def main():
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument('--expected-ip', required=True, type=ipaddress.IPv4Address)
    args = parser.parse_args()
    assert os.geteuid() == 0 and socket.gethostname() == 'altctlrs'
    binary = '/usr/local/bin/roentgen'
    status = json.loads(command(binary, 'status', '--json'))
    assert not status['requested_enabled'], 'Start with proxying disabled'
    assert status['selected_configuration'], 'Select the real configuration before running'
    direct = public_ipv4()
    try:
        command(binary, 'enable')
        status = json.loads(command(binary, 'status', '--json'))
        assert status['requested_enabled'] and status['routing'] == 'tun', status
        proxied = public_ipv4()
        assert proxied == str(args.expected_ip), (proxied, str(args.expected_ip))
        assert proxied != direct, 'Proxy IPv4 must differ from direct IPv4'
    finally:
        command(binary, 'disable')
    restored = public_ipv4()
    assert restored == direct, (restored, direct)
    print(json.dumps({'direct_ipv4': direct, 'tun_ipv4': proxied, 'restored_ipv4': restored}))


if __name__ == '__main__':
    main()