"""Tests for TLS/SSL support."""
# -*- coding: utf-8 -*-
# vim: set fileencoding=utf-8 :

from __future__ import absolute_import, division, print_function
__metaclass__ = type

import functools
import os
import ssl
import sys
import threading
import time

import OpenSSL.SSL
import pytest
import requests
import six
import trustme

from .._compat import bton, ntob, ntou
from .._compat import IS_ABOVE_OPENSSL10, IS_PYPY
from .._compat import IS_LINUX, IS_MACOS, IS_WINDOWS
from ..server import Gateway, HTTPServer, get_ssl_adapter_class
from ..testing import (
    ANY_INTERFACE_IPV4,
    ANY_INTERFACE_IPV6,
    EPHEMERAL_PORT,
    # get_server_client,
    _get_conn_data,
    _probe_ipv6_sock,
)


IS_GITHUB_ACTIONS_WORKFLOW = bool(os.getenv('GITHUB_WORKFLOW'))
IS_LIBRESSL_BACKEND = ssl.OPENSSL_VERSION.startswith('LibreSSL')
IS_PYOPENSSL_SSL_VERSION_1_0 = (
    OpenSSL.SSL.SSLeay_version(OpenSSL.SSL.SSLEAY_VERSION).
    startswith(b'OpenSSL 1.0.')
)
PY27 = sys.version_info[:2] == (2, 7)
PY34 = sys.version_info[:2] == (3, 4)


_stdlib_to_openssl_verify = {
    ssl.CERT_NONE: OpenSSL.SSL.VERIFY_NONE,
    ssl.CERT_OPTIONAL: OpenSSL.SSL.VERIFY_PEER,
    ssl.CERT_REQUIRED:
        OpenSSL.SSL.VERIFY_PEER + OpenSSL.SSL.VERIFY_FAIL_IF_NO_PEER_CERT,
}


fails_under_py3 = pytest.mark.xfail(
    not six.PY2,
    reason='Fails under Python 3+',
)


fails_under_py3_in_pypy = pytest.mark.xfail(
    not six.PY2 and IS_PYPY,
    reason='Fails under PyPy3',
)


missing_ipv6 = pytest.mark.skipif(
    not _probe_ipv6_sock('::1'),
    reason=''
    'IPv6 is disabled '
    '(for example, under Travis CI '
    'which runs under GCE supporting only IPv4)',
)


class HelloWorldGateway(Gateway):
    """Gateway responding with Hello World to root URI."""

    def respond(self):
        """Respond with dummy content via HTTP."""
        req = self.req
        req_uri = bton(req.uri)
        if req_uri == '/':
            req.status = b'200 OK'
            req.ensure_headers_sent()
            req.write(b'Hello world!')
            return
        return super(HelloWorldGateway, self).respond()


def make_tls_http_server(bind_addr, ssl_adapter):
    """Create and start an HTTP server bound to bind_addr."""
    httpserver = HTTPServer(
        bind_addr=bind_addr,
        gateway=HelloWorldGateway,
    )
    # httpserver.gateway = HelloWorldGateway
    httpserver.ssl_adapter = ssl_adapter

    threading.Thread(target=httpserver.safe_start).start()

    while not httpserver.ready:
        time.sleep(0.1)

    return httpserver


@pytest.fixture
def tls_http_server():
    """Provision a server creator as a fixture."""
    def start_srv():
        bind_addr, ssl_adapter = yield
        httpserver = make_tls_http_server(bind_addr, ssl_adapter)
        yield httpserver
        yield httpserver

    srv_creator = iter(start_srv())
    next(srv_creator)
    yield srv_creator
    try:
        while True:
            httpserver = next(srv_creator)
            if httpserver is not None:
                httpserver.stop()
    except StopIteration:
        pass


@pytest.fixture
def ca():
    """Provide a certificate authority via fixture."""
    return trustme.CA()


@pytest.fixture
def tls_ca_certificate_pem_path(ca):
    """Provide a certificate authority certificate file via fixture."""
    with ca.cert_pem.tempfile() as ca_cert_pem:
        yield ca_cert_pem


@pytest.fixture
def tls_certificate(ca):
    """Provide a leaf certificate via fixture."""
    interface, host, port = _get_conn_data(ANY_INTERFACE_IPV4)
    return ca.issue_server_cert(ntou(interface), )


@pytest.fixture
def tls_certificate_chain_pem_path(tls_certificate):
    """Provide a certificate chain PEM file path via fixture."""
    with tls_certificate.private_key_and_cert_chain_pem.tempfile() as cert_pem:
        yield cert_pem


@pytest.fixture
def tls_certificate_private_key_pem_path(tls_certificate):
    """Provide a certificate private key PEM file path via fixture."""
    with tls_certificate.private_key_pem.tempfile() as cert_key_pem:
        yield cert_key_pem


@pytest.mark.parametrize(
    'adapter_type',
    (
        'builtin',
        'pyopenssl',
    ),
)
def test_ssl_adapters(
    tls_http_server, adapter_type,
    tls_certificate,
    tls_certificate_chain_pem_path,
    tls_certificate_private_key_pem_path,
    tls_ca_certificate_pem_path,
):
    """Test ability to connect to server via HTTPS using adapters."""
    interface, _host, port = _get_conn_data(ANY_INTERFACE_IPV4)
    tls_adapter_cls = get_ssl_adapter_class(name=adapter_type)
    tls_adapter = tls_adapter_cls(
        tls_certificate_chain_pem_path, tls_certificate_private_key_pem_path,
    )
    if adapter_type == 'pyopenssl':
        tls_adapter.context = tls_adapter.get_context()

    tls_certificate.configure_cert(tls_adapter.context)

    tlshttpserver = tls_http_server.send(
        (
            (interface, port),
            tls_adapter,
        ),
    )

    # testclient = get_server_client(tlshttpserver)
    # testclient.get('/')

    interface, _host, port = _get_conn_data(
        tlshttpserver.bind_addr,
    )

    resp = requests.get(
        'https://' + interface + ':' + str(port) + '/',
        verify=tls_ca_certificate_pem_path,
    )

    assert resp.status_code == 200
    assert resp.text == 'Hello world!'


@pytest.mark.parametrize(
    'adapter_type',
    (
        'pyopenssl',
    ),
)
@pytest.mark.parametrize(
    'is_trusted_cert,tls_client_identity',
    (
        (True, 'localhost'), (True, '127.0.0.1'),
        (True, '*.localhost'), (True, 'not_localhost'),
        (False, 'localhost'),
    ),
)
@pytest.mark.parametrize(
    'tls_verify_mode',
    (
        ssl.CERT_NONE,  # server shouldn't validate client cert
        ssl.CERT_OPTIONAL,  # same as CERT_REQUIRED in client mode, don't use
        ssl.CERT_REQUIRED,  # server should validate if client cert CA is OK
    ),
)
def test_tls_client_auth(
    # FIXME: remove twisted logic, separate tests
    mocker,
    tls_http_server, adapter_type,
    ca,
    tls_certificate,
    tls_certificate_chain_pem_path,
    tls_certificate_private_key_pem_path,
    tls_ca_certificate_pem_path,
    is_trusted_cert, tls_client_identity,
    tls_verify_mode,
):
    """Verify that client TLS certificate auth works correctly."""
    test_cert_rejection = (
        tls_verify_mode != ssl.CERT_NONE
        and not is_trusted_cert
    )
    interface, _host, port = _get_conn_data(ANY_INTERFACE_IPV4)

    client_cert_root_ca = ca if is_trusted_cert else trustme.CA()
    with mocker.mock_module.patch(
        'idna.core.ulabel',
        return_value=ntob(tls_client_identity),
    ):
        client_cert = client_cert_root_ca.issue_server_cert(
            # FIXME: change to issue_cert once new trustme is out
            ntou(tls_client_identity),
        )
        del client_cert_root_ca

    with client_cert.private_key_and_cert_chain_pem.tempfile() as cl_pem:
        tls_adapter_cls = get_ssl_adapter_class(name=adapter_type)
        tls_adapter = tls_adapter_cls(
            tls_certificate_chain_pem_path,
            tls_certificate_private_key_pem_path,
        )
        if adapter_type == 'pyopenssl':
            tls_adapter.context = tls_adapter.get_context()
            tls_adapter.context.set_verify(
                _stdlib_to_openssl_verify[tls_verify_mode],
                lambda conn, cert, errno, depth, preverify_ok: preverify_ok,
            )
        else:
            tls_adapter.context.verify_mode = tls_verify_mode

        ca.configure_trust(tls_adapter.context)
        tls_certificate.configure_cert(tls_adapter.context)

        tlshttpserver = tls_http_server.send(
            (
                (interface, port),
                tls_adapter,
            ),
        )

        interface, _host, port = _get_conn_data(tlshttpserver.bind_addr)

        make_https_request = functools.partial(
            requests.get,
            'https://' + interface + ':' + str(port) + '/',

            # Server TLS certificate verification:
            verify=tls_ca_certificate_pem_path,

            # Client TLS certificate verification:
            cert=cl_pem,
        )

        if not test_cert_rejection:
            resp = make_https_request()
            is_req_successful = resp.status_code == 200
            if (
                    not is_req_successful
                    and IS_PYOPENSSL_SSL_VERSION_1_0
                    and adapter_type == 'builtin'
                    and tls_verify_mode == ssl.CERT_REQUIRED
                    and tls_client_identity == 'localhost'
                    and is_trusted_cert
            ) or PY34:
                pytest.xfail(
                    'OpenSSL 1.0 has problems with verifying client certs',
                )
            assert is_req_successful
            assert resp.text == 'Hello world!'
            return

        expected_ssl_errors = (
            requests.exceptions.SSLError,
            OpenSSL.SSL.Error,
        ) if PY34 else (
            requests.exceptions.SSLError,
        )
        if IS_WINDOWS or IS_GITHUB_ACTIONS_WORKFLOW:
            expected_ssl_errors += requests.exceptions.ConnectionError,
        with pytest.raises(expected_ssl_errors) as ssl_err:
            make_https_request()

        if PY34 and isinstance(ssl_err, OpenSSL.SSL.Error):
            pytest.xfail(
                'OpenSSL behaves wierdly under Python 3.4 '
                'because of an outdated urllib3',
            )

        try:
            err_text = ssl_err.value.args[0].reason.args[0].args[0]
        except AttributeError:
            if PY34:
                pytest.xfail('OpenSSL behaves wierdly under Python 3.4')
            elif not six.PY2 and IS_WINDOWS:
                err_text = str(ssl_err.value)
            else:
                raise

        expected_substrings = (
            'sslv3 alert bad certificate' if IS_LIBRESSL_BACKEND
            else 'tlsv1 alert unknown ca',
        )
        if not six.PY2:
            if IS_MACOS and IS_PYPY and adapter_type == 'pyopenssl':
                expected_substrings = ('tlsv1 alert unknown ca', )
            if (
                    IS_WINDOWS
                    and tls_verify_mode in (
                        ssl.CERT_REQUIRED,
                        ssl.CERT_OPTIONAL,
                    )
                    and not is_trusted_cert
                    and tls_client_identity == 'localhost'
            ):
                expected_substrings += (
                    'bad handshake: '
                    "SysCallError(10054, 'WSAECONNRESET')",
                    "('Connection aborted.', "
                    'OSError("(10054, \'WSAECONNRESET\')"))',
                )
        assert any(e in err_text for e in expected_substrings)


@pytest.mark.parametrize(
    'ip_addr',
    (
        ANY_INTERFACE_IPV4,
        ANY_INTERFACE_IPV6,
    ),
)
def test_https_over_http_error(http_server, ip_addr):
    """Ensure that connecting over HTTPS to HTTP port is handled."""
    httpserver = http_server.send((ip_addr, EPHEMERAL_PORT))
    interface, _host, port = _get_conn_data(httpserver.bind_addr)
    with pytest.raises(ssl.SSLError) as ssl_err:
        six.moves.http_client.HTTPSConnection(
            '{interface}:{port}'.format(
                interface=interface,
                port=port,
            ),
        ).request('GET', '/')
    expected_substring = (
        'wrong version number' if IS_ABOVE_OPENSSL10
        else 'unknown protocol'
    )
    assert expected_substring in ssl_err.value.args[-1]


@pytest.mark.parametrize(
    'adapter_type',
    (
        'builtin',
        'pyopenssl',
    ),
)
@pytest.mark.parametrize(
    'ip_addr',
    (
        ANY_INTERFACE_IPV4,
        pytest.param(ANY_INTERFACE_IPV6, marks=missing_ipv6),
    ),
)
def test_http_over_https_error(
    tls_http_server, adapter_type,
    ca, ip_addr,
    tls_certificate,
    tls_certificate_chain_pem_path,
    tls_certificate_private_key_pem_path,
):
    """Ensure that connecting over HTTP to HTTPS port is handled."""
    tls_adapter_cls = get_ssl_adapter_class(name=adapter_type)
    tls_adapter = tls_adapter_cls(
        tls_certificate_chain_pem_path, tls_certificate_private_key_pem_path,
    )
    if adapter_type == 'pyopenssl':
        tls_adapter.context = tls_adapter.get_context()

    tls_certificate.configure_cert(tls_adapter.context)

    interface, _host, port = _get_conn_data(ip_addr)
    tlshttpserver = tls_http_server.send(
        (
            (interface, port),
            tls_adapter,
        ),
    )

    interface, host, port = _get_conn_data(
        tlshttpserver.bind_addr,
    )

    fqdn = interface
    if ip_addr is ANY_INTERFACE_IPV6:
        fqdn = '[{}]'.format(fqdn)

    expect_fallback_response_over_plain_http = (
        (adapter_type == 'pyopenssl'
         and (IS_ABOVE_OPENSSL10 or not six.PY2))
        or PY27
    )
    if expect_fallback_response_over_plain_http:
        resp = requests.get(
            'http://' + fqdn + ':' + str(port) + '/',
        )
        assert resp.status_code == 400
        assert resp.text == (
            'The client sent a plain HTTP request, '
            'but this server only speaks HTTPS on this port.'
        )
        return

    with pytest.raises(requests.exceptions.ConnectionError) as ssl_err:
        requests.get(  # FIXME: make stdlib ssl behave like PyOpenSSL
            'http://' + fqdn + ':' + str(port) + '/',
        )

    if IS_LINUX:
        expected_error_code, expected_error_text = (
            104, 'Connection reset by peer',
        )
    if IS_MACOS:
        expected_error_code, expected_error_text = (
            54, 'Connection reset by peer',
        )
    if IS_WINDOWS:
        expected_error_code, expected_error_text = (
            10054,
            'An existing connection was forcibly closed by the remote host',
        )

    underlying_error = ssl_err.value.args[0].args[-1]
    err_text = str(underlying_error)
    assert underlying_error.errno == expected_error_code
    assert expected_error_text in err_text
