#!/usr/bin/env python3
"""Check real NIC identities on a bridge isolated in user/net/mount namespaces."""
import argparse
import json
from pathlib import Path
import subprocess
import sys
import tempfile

sys.path.insert(0, str(Path(__file__).resolve().parents[1]))
from hydra.profiles import Profile
from hydra.runtime import Runtime


def main():
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument('--namespace-root', type=Path, help=argparse.SUPPRESS)
    args = parser.parse_args()
    if args.namespace_root is None:
        root = Path(tempfile.mkdtemp(prefix='hydra-network-', dir='/tmp'))
        print('Evidence: ' + str(root), flush=True)
        (root / 'parent-namespaces.json').write_text(json.dumps({name: str(Path('/proc/self/ns', name).readlink())
                                                               for name in ('user', 'net', 'mnt')}))
        # All bridge and /etc changes below occur after this explicit namespace
        # boundary. The inherited host bridge configuration is never modified.
        subprocess.run(['unshare', '-Urnm', '--', str(Path(sys.executable).resolve()),
                        str(Path(__file__).resolve()), '--namespace-root', str(root)], check=True)
        return
    root = args.namespace_root
    parent_namespaces = json.loads((root / 'parent-namespaces.json').read_text())
    namespaces = {name: str(Path('/proc/self/ns', name).readlink()) for name in ('user', 'net', 'mnt')}
    assert all(namespaces[name] != parent_namespaces[name] for name in namespaces), 'private namespaces required'
    private_etc = root / 'etc'
    (private_etc / 'qemu').mkdir(parents=True)
    (private_etc / 'qemu/bridge.conf').write_text('allow hydrabr0\n')
    subprocess.run(['mount', '--bind', str(private_etc), '/etc'], check=True)
    subprocess.run(['ip', 'link', 'add', 'hydrabr0', 'type', 'bridge'], check=True)
    subprocess.run(['ip', 'link', 'set', 'hydrabr0', 'up'], check=True)
    manager = Runtime(root / 'config', root / 'state', root / 'run')
    result = {'evidence': str(root), 'namespace': 'private user/net/mount',
              'parent_namespaces': parent_namespaces, 'probe_namespaces': namespaces, 'names': {}}
    try:
        for name in ('alpha', 'beta'):
            manager.add(Profile(name, memory=128, cpus=1, disk_size='8M',
                                graphics='software', network='bridge'))
            manager.start(name)

        def actual_mac(name):
            with manager._connect(manager.paths(name)) as qmp:
                network = qmp.command('human-monitor-command', {'command-line': 'info network'})
            mac = manager.profile(name).mac
            assert 'macaddr=' + mac in network, network
            assert int(mac.split(':')[0], 16) & 3 == 2
            return mac, network

        for name in ('alpha', 'beta'):
            mac, network = actual_mac(name)
            result['names'][name] = {'mac': mac, 'network': network}
        assert result['names']['alpha']['mac'] != result['names']['beta']['mac']
        links = json.loads(subprocess.check_output(['ip', '-j', 'link', 'show', 'master', 'hydrabr0'], text=True))
        assert len(links) == 2, links
        result['bridge_ports'] = [link['ifname'] for link in links]
        manager.stop('alpha', force=True)
        manager.start('alpha')
        assert actual_mac('alpha')[0] == result['names']['alpha']['mac']
        result['restart_preserved_mac'] = True
        result['dhcp_and_guest_network_drivers_pending'] = True
        result['passed'] = True
        (root / 'result.json').write_text(json.dumps(result, indent=2) + '\n')
        print(json.dumps(result, indent=2))
    finally:
        for profile in manager.profiles():
            if manager.status(profile.name)['status'] == 'running':
                manager.stop(profile.name, force=True)


if __name__ == '__main__':
    main()