# Copyright 2015 gRPC authors.
#
# 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.
"""The Python implementation of the GRPC interoperability test client."""

import argparse
import os

from google import auth as google_auth
from google.auth import jwt as google_auth_jwt
import grpc
from src.proto.grpc.testing import test_pb2_grpc

from tests.interop import methods
from tests.interop import resources


def parse_interop_client_args():
    parser = argparse.ArgumentParser()
    parser.add_argument('--server_host',
                        default="localhost",
                        type=str,
                        help='the host to which to connect')
    parser.add_argument('--server_port',
                        type=int,
                        required=True,
                        help='the port to which to connect')
    parser.add_argument('--test_case',
                        default='large_unary',
                        type=str,
                        help='the test case to execute')
    parser.add_argument('--use_tls',
                        default=False,
                        type=resources.parse_bool,
                        help='require a secure connection')
    parser.add_argument('--use_alts',
                        default=False,
                        type=resources.parse_bool,
                        help='require an ALTS secure connection')
    parser.add_argument('--use_test_ca',
                        default=False,
                        type=resources.parse_bool,
                        help='replace platform root CAs with ca.pem')
    parser.add_argument('--custom_credentials_type',
                        choices=["compute_engine_channel_creds"],
                        default=None,
                        help='use google default credentials')
    parser.add_argument('--server_host_override',
                        type=str,
                        help='the server host to which to claim to connect')
    parser.add_argument('--oauth_scope',
                        type=str,
                        help='scope for OAuth tokens')
    parser.add_argument('--default_service_account',
                        type=str,
                        help='email address of the default service account')
    parser.add_argument(
        "--grpc_test_use_grpclb_with_child_policy",
        type=str,
        help=(
            "If non-empty, set a static service config on channels created by "
            + "grpc::CreateTestChannel, that configures the grpclb LB policy " +
            "with a child policy being the value of this flag (e.g. round_robin "
            + "or pick_first)."))
    return parser.parse_args()


def _create_call_credentials(args):
    if args.test_case == 'oauth2_auth_token':
        google_credentials, unused_project_id = google_auth.default(
            scopes=[args.oauth_scope])
        google_credentials.refresh(google_auth.transport.requests.Request())
        return grpc.access_token_call_credentials(google_credentials.token)
    elif args.test_case == 'compute_engine_creds':
        google_credentials, unused_project_id = google_auth.default(
            scopes=[args.oauth_scope])
        return grpc.metadata_call_credentials(
            google_auth.transport.grpc.AuthMetadataPlugin(
                credentials=google_credentials,
                request=google_auth.transport.requests.Request()))
    elif args.test_case == 'jwt_token_creds':
        google_credentials = google_auth_jwt.OnDemandCredentials.from_service_account_file(
            os.environ[google_auth.environment_vars.CREDENTIALS])
        return grpc.metadata_call_credentials(
            google_auth.transport.grpc.AuthMetadataPlugin(
                credentials=google_credentials, request=None))
    else:
        return None


def get_secure_channel_parameters(args):
    call_credentials = _create_call_credentials(args)

    channel_opts = ()
    if args.grpc_test_use_grpclb_with_child_policy:
        channel_opts += ((
            "grpc.service_config",
            '{"loadBalancingConfig": [{"grpclb": {"childPolicy": [{"%s": {}}]}}]}'
            % args.grpc_test_use_grpclb_with_child_policy),)
    if args.custom_credentials_type is not None:
        if args.custom_credentials_type == "compute_engine_channel_creds":
            assert call_credentials is None
            google_credentials, unused_project_id = google_auth.default(
                scopes=[args.oauth_scope])
            call_creds = grpc.metadata_call_credentials(
                google_auth.transport.grpc.AuthMetadataPlugin(
                    credentials=google_credentials,
                    request=google_auth.transport.requests.Request()))
            channel_credentials = grpc.compute_engine_channel_credentials(
                call_creds)
        else:
            raise ValueError("Unknown credentials type '{}'".format(
                args.custom_credentials_type))
    elif args.use_tls:
        if args.use_test_ca:
            root_certificates = resources.test_root_certificates()
        else:
            root_certificates = None  # will load default roots.

        channel_credentials = grpc.ssl_channel_credentials(root_certificates)
        if call_credentials is not None:
            channel_credentials = grpc.composite_channel_credentials(
                channel_credentials, call_credentials)

        if args.server_host_override:
            channel_opts += ((
                'grpc.ssl_target_name_override',
                args.server_host_override,
            ),)
    elif args.use_alts:
        channel_credentials = grpc.alts_channel_credentials()

    return channel_credentials, channel_opts


def _create_channel(args):
    target = '{}:{}'.format(args.server_host, args.server_port)

    if args.use_tls or args.use_alts or args.custom_credentials_type is not None:
        channel_credentials, options = get_secure_channel_parameters(args)
        return grpc.secure_channel(target, channel_credentials, options)
    else:
        return grpc.insecure_channel(target)


def create_stub(channel, args):
    if args.test_case == "unimplemented_service":
        return test_pb2_grpc.UnimplementedServiceStub(channel)
    else:
        return test_pb2_grpc.TestServiceStub(channel)


def _test_case_from_arg(test_case_arg):
    for test_case in methods.TestCase:
        if test_case_arg == test_case.value:
            return test_case
    else:
        raise ValueError('No test case "%s"!' % test_case_arg)


def test_interoperability():
    args = parse_interop_client_args()
    channel = _create_channel(args)
    stub = create_stub(channel, args)
    test_case = _test_case_from_arg(args.test_case)
    test_case.test_interoperability(stub, args)


if __name__ == '__main__':
    test_interoperability()
