#!/usr/bin/env python3
"""Create a TOR hidden service

  $ ./hidden_service.py [port]

When no argument is provided, port defaults to 22.  The script creates a hidden
service where 127.0.0.1:[port] is served over Tor.  The onion address and
authentication cookie are printed on standard output.  The private key and the
authentication cookie are saved in a pickle file (keys.pkl) to be reused on
subsequent runs.

@author Suvayu Ali
@date   2018-07-19

"""

import os
import pickle

from stem.control import Controller


def hs_options(overrides):
    """Default ephemeral hidden service options

    Options can be overridden by passing an override dictionary.

    """
    opts = {
        'key_type': 'NEW',
        'key_content': 'BEST',
        'discard_key': False,
        'await_publication': True,
        'basic_auth': {'bob': None},
    }
    opts.update(overrides)
    return opts.copy()


def hs_restore(store):
    """Restore the private key and authentication credentials from disk.

    On first run, the private key and authentication credentials are stored in
    a pickle file on disk.  `store` is the path to the pickle file.

    """
    if os.path.exists(store):
        with open(store, mode='br') as store:
            key = pickle.load(store)
            return dict(key_type=key.private_key_type,
                        key_content=key.private_key,
                        basic_auth=key.client_auth)
    else:
        return {}


def hs_store(key, store):
    """Save the private key and authentication credentials"""
    if not os.path.exists(store):
        with open(store, mode='bw') as store:
            pickle.dump(key, store)


if len(sys.argv) < 2:
    port = 22                   # default to SSH
else:
    port = sys.argv[1]


with Controller.from_port(port=9051) as ctrlr:
    ctrlr.authenticate()

    opts = hs_options(hs_restore('keys.pkl'))
    res = ctrlr.create_ephemeral_hidden_service(port, **opts)

    print('onion: {}.onion'.format(res.service_id))
    print('auth: {}'.format(res.client_auth.get(
        'bob', opts['basic_auth'].get('bob'))))

    hs_store(res, 'keys.pkl')

    try:
        while True:
            pass
    except KeyboardInterrupt:
        pass
    finally:
        print('Stopping hidden service')
        code = ctrlr.remove_ephemeral_hidden_service(res.service_id)
        print('success: {}'.format(code))