#!python3


import collections
import contextlib
import inspect
import logging
import os
import subprocess
import sys
import tempfile
import time

import pytest


# append cwd to module importable paths (pytest-3 should be executed from main
# directory).
sys.path.append(os.path.realpath("."))
import acme_dns_tiny


acme_dns_tiny.log_configure = False


ACME_STAGING_DIRECTORY = \
        'https://acme-staging-v02.api.letsencrypt.org/directory'
DOMAIN  = os.getenv('TEST_DOMAIN')
CONTACT = os.getenv('TEST_CONTACT') # form: mailto:name@domain
SCRIPT  = os.getenv('TEST_SCRIPT')


# all possible key types and raise expectation (key considered too weak)
key_types = (
        ('rsa', 4096, False),
        ('rsa', 2048, False),
        ('rsa', 1024, True), # this key type is not recommended
        ('ecdsa', 384, False),
        ('ecdsa', 256, False),
)

# the first case of success expectation, try also to test the anti-replay
# nonce expiration retry mechanism by waiting for it to expire (more than
# 5min).
first_success_case_nonce_timeout_done = False
original_sreq_method = acme_dns_tiny.ACME.sreq


nonce_expiration_sreq_wrapper_counter_max = 3
nonce_expiration_sreq_wrapper_counter = nonce_expiration_sreq_wrapper_counter_max
def nonce_expiration_sreq_wrapper(*args, **kwargs):
    global nonce_expiration_sreq_wrapper_counter
    nonce_expiration_sreq_wrapper_counter -= 1
    if nonce_expiration_sreq_wrapper_counter <= 0:
        nonce_expiration_sreq_wrapper_counter = nonce_expiration_sreq_wrapper_counter_max
        wait = 30
        logging.info('waiting %dmin for nonce expiration test', wait)
        for i in range(wait, 0, -1):
            logging.info('%d min left', i)
            time.sleep(60)
        acme_dns_tiny.ACME.sreq = original_sreq_method # reset original method
    return original_sreq_method(*args, **kwargs)


@contextlib.contextmanager
def does_not_raise():
    yield


def _gen_rsa_key(path, size):
    acme_dns_tiny.openssl(['genrsa', '-out', path, str(size)])


def _gen_ecdsa_key(path, size):
    acme_dns_tiny.openssl([
        'ecparam',
        '-genkey',
        '-name', f'secp{size}r1',
        '-out', path,
    ])


#@pytest.fixture(scope='module')
def keys_generator():
    #tmpdir = tmpdir_factory.mktemp("data")

    def _gen_key(role, type_name, key_size):
        name = f'{role}_{type_name}_{key_size}.key'
        generator_map = {'rsa': _gen_rsa_key, 'ecdsa': _gen_ecdsa_key}
        #path = str(tmpdir.join(name))
        def operate(tmpdir):
            path = str(tmpdir.join(name))
            if not os.path.exists(path):
                generator_map[type_name](path, key_size)
            return path
        return operate
        #return {
        #        'name': name,
        #        'path': operate,
        #}

    def _gen_keys_normal(type_account, type_domain):
        account_key = _gen_key('account', type_account[0], type_account[1])
        domain_key = _gen_key('domain', type_domain[0], type_domain[1])

        return {
                'account_key_path': account_key,
                'domain_key_path':  domain_key,
                'raise_expected':   type_account[2] or type_domain[2],
        }

    def _normal_name(type1, type2):
        return f'{type1[0]}{type1[1]}/{type2[0]}{type2[1]}'

    def _gen_keys_same(type_accountdomain):
        keypath = _gen_key(
                'accountdomain', type_accountdomain[0], type_accountdomain[1])
        return {
                'account_key_path':   keypath,
                'domain_key_path':    keypath,
                'raise_expected':     True,
        }

    def _same_name(type1):
        return f'{type1[0]}{type1[1]}/same'

    from itertools import chain, product
    yield from chain(
            (pytest.param(_gen_keys_normal(*x), id=_normal_name(*x))
                for x in product(key_types, key_types)
                # TODO: as for now client does not support ec account keytype
                # so skip it for now.
                if 'ecdsa' not in x[0][0]),
            (pytest.param(_gen_keys_same(x), id=_same_name(x))
                for x in key_types
                # TODO: as for now client does not support ec account keytype
                # so skip it for now.
                if 'ecdsa' not in x[0]),
    )


@pytest.fixture(scope='module', params=keys_generator())
def account_domain_key(request):
    return request.param


@pytest.fixture(scope='module', params=[
    {'subj': f'/CN={DOMAIN}',   'san': None},
    {'subj': f'/CN=*.{DOMAIN}', 'san': None},
    {'subj': f'/',              'san': f'DNS:{DOMAIN},DNS:www.{DOMAIN}'},
    {'subj': f'/CN={DOMAIN}',   'san': f'DNS:www.{DOMAIN}'},
    {'subj': f'/',              'san': f'DNS:{DOMAIN},DNS:*.{DOMAIN}'},
])
def subj_fixture(request):
    return request.param


CSR_ARGS_COUNTER = 0

@pytest.fixture(scope='module', params=[
    pytest.param(None, id='no_separator/no_contact'),
    pytest.param({'args': {'--separator': '\\0'}}, id='separator'),
    pytest.param({'args': {'--contact': [CONTACT]}}, id='contact'),
    pytest.param({'args': {
        '--contact': [CONTACT],
        '--separator': '\\0',
        }}, id='separator+contact'),
])
def main_args(tmpdir_factory, account_domain_key, request, subj_fixture):

    global CSR_ARGS_COUNTER
    CSR_ARGS_COUNTER += 1

    tmpdir = tmpdir_factory.mktemp("data")
    #keysdef = account_domain_key.values[0]
    keysdef = account_domain_key
    #print('debug', keysdef)

    default_args = {
            '--acme-directory': ACME_STAGING_DIRECTORY,
            '--script': SCRIPT,
            '--account-key': keysdef['account_key_path'](tmpdir),
            #'--ttl': 60, # already the default
            '--ttl': None,
            '--separator': None,
            '--contact': None,
            '--verbose': None,
            '--quiet': None,
    }

    if request.param:
        default_args.update(request.param.get('args', {}))

    if default_args['--separator'] is not None:
        assert default_args['--separator'] == '\\0'
        assert default_args['--separator'].encode(
                'utf8').decode('unicode_escape') == '\0'

    name = f'{CSR_ARGS_COUNTER:02X}'
    domain_key = keysdef['domain_key_path'](tmpdir)
    path = str(tmpdir.join(name))
    with tempfile.NamedTemporaryFile('w', encoding='utf8') as conf, \
            open('/etc/ssl/openssl.cnf', 'r', encoding='utf8') as orig:
        conf.write(orig.read())
        conf.write(f'\n[SAN]\nsubjectAltName={subj_fixture["san"]}\n')
        conf.flush()
        openssl_san_args = []
        if subj_fixture['san']:
            openssl_san_args = ['-reqexts', 'SAN', '-config', conf.name]
        acme_dns_tiny.openssl([
            'req', '-new', '-key', domain_key,
            '-subj', subj_fixture['subj'], *openssl_san_args,
            '-out', path
        ])

    return {**default_args, '--csr': path}, keysdef['raise_expected']


def test_sanity_env():
    'check environment is correctly set before running other tests'
    assert bool(DOMAIN)
    assert bool(CONTACT)
    assert bool(SCRIPT)


def test_sanity_command():
    'check ssh access is correctly working before getting further'
    subprocess.run([SCRIPT, 'add', f'_acme-challenge.{DOMAIN}.', 'dummy'])


def assert_cert(capsys, args):
    captured = capsys.readouterr()
    #assert not captured.err
    #certlist = captured.out.split()

    logging.debug('captured stdout %s', captured.out)
    logging.debug('captured stderr %s', captured.err)

    if args['--separator'] is None:
        assert '\0' not in captured.out
    else:
        assert '\0' in captured.out

    for chain in captured.out.split('\0'):
        assert chain.count('-----BEGIN CERTIFICATE-----') >= 2
        assert chain.count('-----END CERTIFICATE-----') >= 2

        textchain = acme_dns_tiny.openssl(['x509', '-text', '-noout'],
                stdin=chain)
        assert 'Issuer' in textchain

        certtool_out = subprocess.check_output([
            'certtool', '-e', '--verify-profile', 'low'], input=chain,
            encoding='utf8')
        assert ' Verified.' in certtool_out
        assert certtool_out.count('Subject:') >= 3


def module_main_caller(*, capsys, args, expectation, do_expire_nonce):
    logging.info(f'module_main_caller({args}, {expectation})')

    logging.debug('before call to acme_dns_tiny.main()')
    with expectation:
        acme_dns_tiny.ACME.sreq = original_sreq_method
        if do_expire_nonce:
            logging.info('doing expire nonce test')
            first_success_case_nonce_timeout_done = True
            acme_dns_tiny.ACME.sreq = nonce_expiration_sreq_wrapper
        acme_dns_tiny.main(args)
        # check_cert is under the expectation context manager since if
        # acme_dns_tiny.main() raises, following statement must not be run.
        assert_cert(capsys, args)
    logging.debug('after call to acme_dns_tiny.main()')


def test_main(main_args, capsys):
    t_start = time.time()
    args = main_args[0]
    raise_expected = main_args[1]
    do_expire_nonce = False
    #print('subj', subj, 'args', args)
    expectation = does_not_raise()
    if raise_expected:
        expectation = pytest.raises(ValueError)
    elif not first_success_case_nonce_timeout_done:
        do_expire_nonce = True
    module_main_caller(capsys=capsys, args=args, expectation=expectation,
                       do_expire_nonce=do_expire_nonce)
    t_stop = time.time()

    # calculate for letsencrypt rate limit (50account per hour)
    t_diff = 216 - (t_stop - t_start)
    if t_diff > 0:
        time.sleep(t_diff)