# Copyright (c) 2015 Uber Technologies, Inc.
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.

from __future__ import absolute_import

from functools import wraps

import mock
import contextlib2
from tornado import gen

from tchannel.errors import ProtocolError
from tchannel.tornado import TChannel
from tchannel.tornado.response import Response
from tchannel.tornado.stream import maybe_stream
from tchannel.tornado.stream import read_full
from tchannel.transport_header import ArgSchemeType

from .proxy import VCRProxy


_TChannel_request = TChannel.request


@contextlib2.contextmanager
def force_reset():
    with contextlib2.ExitStack() as exit_stack:
        exit_stack.enter_context(
            mock.patch.object(TChannel, 'request', _TChannel_request)
        )
        yield


class PatchedClientOperation(object):

    def __init__(
        self,
        vcr_client,
        hostport=None,
        service=None,
        arg_scheme=None,
        retry=None,
        parent_tracing=None,
        score_threshold=None,
    ):
        self.vcr_client = vcr_client
        self.hostport = hostport
        self.service = service or ''
        self.arg_scheme = arg_scheme or ArgSchemeType.DEFAULT

        # TODO what to do with retry, parent_tracing and score_threshold

    @gen.coroutine
    def send(self, arg1, arg2, arg3,
             headers=None,
             traceflag=None,
             attempt_times=None,
             ttl=None,
             retry_delay=None):
        arg1, arg2, arg3 = map(maybe_stream, [arg1, arg2, arg3])

        endpoint = yield read_full(arg1)

        headers = headers or {}
        headers.setdefault('as', self.arg_scheme)

        vcr_request = VCRProxy.Request(
            serviceName=self.service.encode('utf-8'),
            hostPort=self.hostport,
            endpoint=endpoint,
            headers=(yield read_full(arg2)),
            body=(yield read_full(arg3)),
            argScheme=getattr(VCRProxy.ArgScheme, self.arg_scheme.upper()),
            transportHeaders=[
                VCRProxy.TransportHeader(k, v) for k, v in headers.items()
            ],
        )

        # TODO what to do with traceflag, attempt-times, ttl, and retry_delay
        # TODO catch protocol errors

        with force_reset():
            vcr_response_future = self.vcr_client.send(vcr_request)
        try:
            vcr_response = yield vcr_response_future
        except VCRProxy.RemoteServiceError as e:
            raise ProtocolError(
                code=e.code,
                description=(
                    "The remote service threw a protocol error: %s" %
                    e.message
                )
            )
        response = Response(
            code=vcr_response.code,
            argstreams=[
                maybe_stream(endpoint),
                maybe_stream(vcr_response.headers),
                maybe_stream(vcr_response.body),
            ],
            # TODO headers=vcr_response.transportHeaders,
        )

        raise gen.Return(response)


class Patcher(object):
    """Monkey patches classes to use a VCRProxyClient to send requests."""

    def __init__(self, vcr_client):
        """
        :param vcr_client:
            The VCRProxyClient through which requests will be made.
        """
        self.vcr_client = vcr_client
        self._exit_stack = contextlib2.ExitStack()

    def _patch_request(self):

        @wraps(_TChannel_request)
        def request(channel, *args, **kwargs):
            return PatchedClientOperation(self.vcr_client, *args, **kwargs)

        return mock.patch.object(TChannel, 'request', request)

    def __enter__(self):
        self._exit_stack.enter_context(self._patch_request())

    def __exit__(self, *args):
        self._exit_stack.close()

    def __call__(self, function):
        # being used as a decorator

        @wraps(function)
        def new_function(*args, **kwargs):
            with self:
                return function(*args, **kwargs)

        return new_function
