# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.

import functools

import requests

from requests_mock import adapter
from requests_mock import exceptions

DELETE = 'DELETE'
GET = 'GET'
HEAD = 'HEAD'
OPTIONS = 'OPTIONS'
PATCH = 'PATCH'
POST = 'POST'
PUT = 'PUT'

_original_send = requests.Session.send


class MockerCore(object):
    """A wrapper around common mocking functions.

    Automate the process of mocking the requests library. This will keep the
    same general options available and prevent repeating code.
    """

    _PROXY_FUNCS = set(['last_request',
                        'add_matcher',
                        'request_history',
                        'called',
                        'called_once',
                        'call_count'])

    case_sensitive = False
    """case_sensitive handles a backwards incompatible bug. The URL used to
    match against our matches and that is saved in request_history is always
    lowercased. This is incorrect as it reports incorrect history to the user
    and doesn't allow case sensitive path matching.

    Unfortunately fixing this change is backwards incompatible in the 1.X
    series as people may rely on this behaviour. To work around this you can
    globally set:

    requests_mock.mock.case_sensitive = True

    which will prevent the lowercase being executed and return case sensitive
    url and query information.

    This will become the default in a 2.X release. See bug: #1584008.
    """

    def __init__(self, **kwargs):
        case_sensitive = kwargs.pop('case_sensitive', self.case_sensitive)
        self._adapter = adapter.Adapter(case_sensitive=case_sensitive)

        self._real_http = kwargs.pop('real_http', False)
        self._last_send = None

        if kwargs:
            raise TypeError('Unexpected Arguments: %s' % ', '.join(kwargs))

    def start(self):
        """Start mocking requests.

        Install the adapter and the wrappers required to intercept requests.
        """
        if self._last_send:
            raise RuntimeError('Mocker has already been started')

        self._last_send = requests.Session.send

        def _fake_get_adapter(session, url):
            return self._adapter

        def _fake_send(session, request, **kwargs):
            real_get_adapter = requests.Session.get_adapter
            requests.Session.get_adapter = _fake_get_adapter

            # NOTE(jamielennox): self._last_send vs _original_send. Whilst it
            # seems like here we would use _last_send there is the possibility
            # that the user has messed up and is somehow nesting their mockers.
            # If we call last_send at this point then we end up calling this
            # function again and the outer level adapter ends up winning.
            # All we really care about here is that our adapter is in place
            # before calling send so we always jump directly to the real
            # function so that our most recently patched send call ends up
            # putting in the most recent adapter. It feels funny, but it works.

            try:
                return _original_send(session, request, **kwargs)
            except exceptions.NoMockAddress:
                if not self._real_http:
                    raise
            except adapter._RunRealHTTP:
                # this mocker wants you to run the request through the real
                # requests library rather than the mocking. Let it.
                pass
            finally:
                requests.Session.get_adapter = real_get_adapter

            return _original_send(session, request, **kwargs)

        requests.Session.send = _fake_send

    def stop(self):
        """Stop mocking requests.

        This should have no impact if mocking has not been started.
        """
        if self._last_send:
            requests.Session.send = self._last_send
            self._last_send = None

    def __getattr__(self, name):
        if name in self._PROXY_FUNCS:
            try:
                return getattr(self._adapter, name)
            except AttributeError:
                pass

        raise AttributeError(name)

    def register_uri(self, *args, **kwargs):
        # you can pass real_http here, but it's private to pass direct to the
        # adapter, because if you pass direct to the adapter you'll see the exc
        kwargs['_real_http'] = kwargs.pop('real_http', False)
        return self._adapter.register_uri(*args, **kwargs)

    def request(self, *args, **kwargs):
        return self.register_uri(*args, **kwargs)

    def get(self, *args, **kwargs):
        return self.request(GET, *args, **kwargs)

    def options(self, *args, **kwargs):
        return self.request(OPTIONS, *args, **kwargs)

    def head(self, *args, **kwargs):
        return self.request(HEAD, *args, **kwargs)

    def post(self, *args, **kwargs):
        return self.request(POST, *args, **kwargs)

    def put(self, *args, **kwargs):
        return self.request(PUT, *args, **kwargs)

    def patch(self, *args, **kwargs):
        return self.request(PATCH, *args, **kwargs)

    def delete(self, *args, **kwargs):
        return self.request(DELETE, *args, **kwargs)


class Mocker(MockerCore):
    """The standard entry point for mock Adapter loading.
    """

    #: Defines with what should method name begin to be patched
    TEST_PREFIX = 'test'

    def __init__(self, **kwargs):
        """Create a new mocker adapter.

        :param str kw: Pass the mock object through to the decorated function
            as this named keyword argument, rather than a positional argument.
        :param bool real_http: True to send the request to the real requested
            uri if there is not a mock installed for it. Defaults to False.
        """
        self._kw = kwargs.pop('kw', None)
        super(Mocker, self).__init__(**kwargs)

    def __enter__(self):
        self.start()
        return self

    def __exit__(self, type, value, traceback):
        self.stop()

    def __call__(self, obj):
        if isinstance(obj, type):
            return self.decorate_class(obj)

        return self.decorate_callable(obj)

    def copy(self):
        """Returns an exact copy of current mock
        """
        m = Mocker(
            kw=self._kw,
            real_http=self._real_http
        )
        return m

    def decorate_callable(self, func):
        """Decorates a callable

        :param callable func: callable to decorate
        """
        @functools.wraps(func)
        def inner(*args, **kwargs):
            with self as m:
                if self._kw:
                    kwargs[self._kw] = m
                else:
                    args = list(args)
                    args.append(m)

                return func(*args, **kwargs)

        return inner

    def decorate_class(self, klass):
        """Decorates methods in a class with request_mock

        Method will be decorated only if it name begins with `TEST_PREFIX`

        :param object klass: class which methods will be decorated
        """
        for attr_name in dir(klass):
            if not attr_name.startswith(self.TEST_PREFIX):
                continue

            attr = getattr(klass, attr_name)
            if not hasattr(attr, '__call__'):
                continue

            m = self.copy()
            setattr(klass, attr_name, m(attr))

        return klass


mock = Mocker
