"""Service controls using the same deployment lock and verified runtime layout."""
import json
import subprocess

READ_ACTIONS = {'status', 'log', 'info'}
WRITE_ACTIONS = {'start', 'stop', 'restart', 'enable', 'disable', 'setup'}


def setup_unit(deployment):
    home = deployment.home
    if not deployment.site.is_dir() or not (home / 'opt/jdk25/bin/java').is_file():
        raise RuntimeError('Expected Hostsharing site and installed JDK must exist')
    unit = home / '.config/systemd/user/werkjournal-backend.service'
    if any(path.is_symlink() for path in (home / '.config', home / '.config/systemd', unit.parent,
                                         unit, unit.with_name(unit.name + '.next'),
                                         unit.with_name(unit.name + '.previous'), unit.with_name(unit.name + '.previous.next'))):
        raise RuntimeError('Unit paths must not be symlinks')
    if deployment.command('systemctl', '--user', 'show', deployment.service, '--property=DropInPaths', '--value'):
        raise RuntimeError('Existing service overrides require operator review')
    unit.parent.mkdir(parents=True, exist_ok=True)
    previous = unit.read_text() if unit.exists() else None
    rendered = SERVICE_UNIT_TEMPLATE.format(home=str(home))
    # Keep one previous unit without reading or touching the secret EnvironmentFile.
    if previous is not None and previous != rendered:
        atomic(unit.with_name(unit.name + '.previous'), previous)
    atomic(unit, rendered)
    try:
        deployment.command('systemctl', '--user', 'daemon-reload')
    except Exception:
        if previous is None:
            unit.unlink()
            sync_directory(unit.parent)
        else:
            atomic(unit, previous)
        try:
            deployment.command('systemctl', '--user', 'daemon-reload')
        except Exception:
            pass
        raise


def service_info(deployment):
    deployed = deployment.app / 'deployed.json'
    before = deployed.read_bytes()
    expected = json.loads(before)
    selected = (deployment.app / 'current').resolve()
    try:
        verified = manifest(deployment.app / 'current') == expected
    except (OSError, ValueError):
        verified = False
    def responds(url):
        try:
            with urllib.request.urlopen(url + '/api/v1/info', timeout=5) as response:
                value = json.load(response)
            return isinstance(value, dict) and value.get('application') == 'werkjournal' and value.get('version') == expected.get('version')
        except (OSError, ValueError):
            return False
    backend = responds('http://127.0.0.1:18090')
    maintenance = deployment.flag.exists()
    public = None if maintenance else responds(deployment.url)
    transition = (deployment.pending.exists() or (deployment.app / 'pending-restore.json').exists()
                  or deployed.read_bytes() != before or (deployment.app / 'current').resolve() != selected
                  or deployment.flag.exists() != maintenance)
    result = {'version': expected.get('version'), 'commit': expected.get('commit'),
              'service': deployment.command('systemctl', '--user', 'show', deployment.service, '--property=ActiveState', '--value'),
              'maintenance': maintenance, 'transition': transition, 'releaseVerified': verified,
              'backendReady': backend, 'publicReady': public}
    print(json.dumps(result))
    return 0 if verified and backend and result['service'] == 'active' and not transition and public is not False else 1


def control(deployment, action, arguments=()):
    if action not in READ_ACTIONS | WRITE_ACTIONS:
        raise ValueError('Unknown service action')
    if arguments and action != 'log':
        raise ValueError('Only log accepts additional arguments')
    if action == 'status':
        return subprocess.call(['systemctl', '--user', 'status', deployment.service, '--no-pager'])
    if action == 'log':
        return subprocess.call(['journalctl', '--user', '-u', deployment.service, '-n', '100',
                                *arguments, '--no-pager'])
    if action == 'info':
        return service_info(deployment)

    with (deployment.app / '.deploy.lock').open('a') as lock:
        fcntl.flock(lock, fcntl.LOCK_EX | fcntl.LOCK_NB)
        if deployment.pending.exists():
            raise RuntimeError('Resolve the pending deployment with remote backend recover first')
        if (deployment.app / 'pending-restore.json').exists():
            raise RuntimeError('Resolve the pending operator restore first')
        if action == 'setup':
            setup_unit(deployment)
            print('Service unit installed and reloaded; running process unchanged.')
            return 0
        deployment.preflight(check_data=action in {'start', 'restart'})
        # Do not expose an upload or an incompletely promoted release through restart.
        if action in {'start', 'restart'}:
            expected = manifest(deployment.app / 'current')
            deployed = json.loads((deployment.app / 'deployed.json').read_text())
            if expected != deployed:
                raise RuntimeError('Current release differs from the verified deployment manifest')
        if action in {'stop', 'restart'}:
            deployment.stop()
        if action in {'start', 'restart'}:
            deployment.start()
            deployment.ready(expected)
        if action in {'enable', 'disable'}:
            deployment.command('systemctl', '--user', action, deployment.service)
        print('Service action completed: ' + action)
        if deployment.flag.exists():
            print('Existing maintenance remains active; this command does not remove it.')
    return 0


if __name__ == '__main__':
    os.umask(0o077)
    try:
        raise SystemExit(control(Deployment(Path.home()), sys.argv[1], sys.argv[2:]))
    except (OSError, RuntimeError, ValueError, subprocess.SubprocessError) as error:
        print('Service action failed: ' + str(error), file=sys.stderr)
        raise SystemExit(1)