# -*- coding: utf-8 -*-

# Copyright 2020 Google LLC
#
# 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.
#

from collections import OrderedDict
import os
import re
from typing import Callable, Dict, Sequence, Tuple, Type, Union
import pkg_resources

import google.api_core.client_options as ClientOptions  # type: ignore
from google.api_core import exceptions  # type: ignore
from google.api_core import gapic_v1  # type: ignore
from google.api_core import retry as retries  # type: ignore
from google.auth import credentials  # type: ignore
from google.auth.transport import mtls  # type: ignore
from google.auth.exceptions import MutualTLSChannelError  # type: ignore
from google.oauth2 import service_account  # type: ignore

from google.cloud.servicedirectory_v1beta1.types import lookup_service
from google.cloud.servicedirectory_v1beta1.types import service

from .transports.base import LookupServiceTransport
from .transports.grpc import LookupServiceGrpcTransport


class LookupServiceClientMeta(type):
    """Metaclass for the LookupService client.

    This provides class-level methods for building and retrieving
    support objects (e.g. transport) without polluting the client instance
    objects.
    """

    _transport_registry = OrderedDict()  # type: Dict[str, Type[LookupServiceTransport]]
    _transport_registry["grpc"] = LookupServiceGrpcTransport

    def get_transport_class(cls, label: str = None) -> Type[LookupServiceTransport]:
        """Return an appropriate transport class.

        Args:
            label: The name of the desired transport. If none is
                provided, then the first transport in the registry is used.

        Returns:
            The transport class to use.
        """
        # If a specific transport is requested, return that one.
        if label:
            return cls._transport_registry[label]

        # No transport is requested; return the default (that is, the first one
        # in the dictionary).
        return next(iter(cls._transport_registry.values()))


class LookupServiceClient(metaclass=LookupServiceClientMeta):
    """Service Directory API for looking up service data at runtime."""

    @staticmethod
    def _get_default_mtls_endpoint(api_endpoint):
        """Convert api endpoint to mTLS endpoint.
        Convert "*.sandbox.googleapis.com" and "*.googleapis.com" to
        "*.mtls.sandbox.googleapis.com" and "*.mtls.googleapis.com" respectively.
        Args:
            api_endpoint (Optional[str]): the api endpoint to convert.
        Returns:
            str: converted mTLS api endpoint.
        """
        if not api_endpoint:
            return api_endpoint

        mtls_endpoint_re = re.compile(
            r"(?P<name>[^.]+)(?P<mtls>\.mtls)?(?P<sandbox>\.sandbox)?(?P<googledomain>\.googleapis\.com)?"
        )

        m = mtls_endpoint_re.match(api_endpoint)
        name, mtls, sandbox, googledomain = m.groups()
        if mtls or not googledomain:
            return api_endpoint

        if sandbox:
            return api_endpoint.replace(
                "sandbox.googleapis.com", "mtls.sandbox.googleapis.com"
            )

        return api_endpoint.replace(".googleapis.com", ".mtls.googleapis.com")

    DEFAULT_ENDPOINT = "servicedirectory.googleapis.com"
    DEFAULT_MTLS_ENDPOINT = _get_default_mtls_endpoint.__func__(  # type: ignore
        DEFAULT_ENDPOINT
    )

    @classmethod
    def from_service_account_file(cls, filename: str, *args, **kwargs):
        """Creates an instance of this client using the provided credentials
        file.

        Args:
            filename (str): The path to the service account private key json
                file.
            args: Additional arguments to pass to the constructor.
            kwargs: Additional arguments to pass to the constructor.

        Returns:
            {@api.name}: The constructed client.
        """
        credentials = service_account.Credentials.from_service_account_file(filename)
        kwargs["credentials"] = credentials
        return cls(*args, **kwargs)

    from_service_account_json = from_service_account_file

    def __init__(
        self,
        *,
        credentials: credentials.Credentials = None,
        transport: Union[str, LookupServiceTransport] = None,
        client_options: ClientOptions = None,
    ) -> None:
        """Instantiate the lookup service client.

        Args:
            credentials (Optional[google.auth.credentials.Credentials]): The
                authorization credentials to attach to requests. These
                credentials identify the application to the service; if none
                are specified, the client will attempt to ascertain the
                credentials from the environment.
            transport (Union[str, ~.LookupServiceTransport]): The
                transport to use. If set to None, a transport is chosen
                automatically.
            client_options (ClientOptions): Custom options for the client. It
                won't take effect unless ``transport`` is None.
                (1) The ``api_endpoint`` property can be used to override the
                default endpoint provided by the client. GOOGLE_API_USE_MTLS
                environment variable can also be used to override the endpoint:
                "always" (always use the default mTLS endpoint), "never" (always
                use the default regular endpoint, this is the default value for
                the environment variable) and "auto" (auto switch to the default
                mTLS endpoint if client SSL credentials is present). However,
                the ``api_endpoint`` property takes precedence if provided.
                (2) The ``client_cert_source`` property is used to provide client
                SSL credentials for mutual TLS transport. If not provided, the
                default SSL credentials will be used if present.

        Raises:
            google.auth.exceptions.MutualTLSChannelError: If mutual TLS transport
                creation failed for any reason.
        """
        if isinstance(client_options, dict):
            client_options = ClientOptions.from_dict(client_options)
        if client_options is None:
            client_options = ClientOptions.ClientOptions()

        if transport is None and client_options.api_endpoint is None:
            use_mtls_env = os.getenv("GOOGLE_API_USE_MTLS", "never")
            if use_mtls_env == "never":
                client_options.api_endpoint = self.DEFAULT_ENDPOINT
            elif use_mtls_env == "always":
                client_options.api_endpoint = self.DEFAULT_MTLS_ENDPOINT
            elif use_mtls_env == "auto":
                has_client_cert_source = (
                    client_options.client_cert_source is not None
                    or mtls.has_default_client_cert_source()
                )
                client_options.api_endpoint = (
                    self.DEFAULT_MTLS_ENDPOINT
                    if has_client_cert_source
                    else self.DEFAULT_ENDPOINT
                )
            else:
                raise MutualTLSChannelError(
                    "Unsupported GOOGLE_API_USE_MTLS value. Accepted values: Never, Auto, Always"
                )

        # Save or instantiate the transport.
        # Ordinarily, we provide the transport, but allowing a custom transport
        # instance provides an extensibility point for unusual situations.
        if isinstance(transport, LookupServiceTransport):
            # transport is a LookupServiceTransport instance.
            if credentials:
                raise ValueError(
                    "When providing a transport instance, "
                    "provide its credentials directly."
                )
            self._transport = transport
        elif isinstance(transport, str):
            Transport = type(self).get_transport_class(transport)
            self._transport = Transport(
                credentials=credentials, host=self.DEFAULT_ENDPOINT
            )
        else:
            self._transport = LookupServiceGrpcTransport(
                credentials=credentials,
                host=client_options.api_endpoint,
                api_mtls_endpoint=client_options.api_endpoint,
                client_cert_source=client_options.client_cert_source,
            )

    def resolve_service(
        self,
        request: lookup_service.ResolveServiceRequest = None,
        *,
        retry: retries.Retry = gapic_v1.method.DEFAULT,
        timeout: float = None,
        metadata: Sequence[Tuple[str, str]] = (),
    ) -> lookup_service.ResolveServiceResponse:
        r"""Returns a
        [service][google.cloud.servicedirectory.v1beta1.Service] and its
        associated endpoints. Resolving a service is not considered an
        active developer method.

        Args:
            request (:class:`~.lookup_service.ResolveServiceRequest`):
                The request object. The request message for
                [LookupService.ResolveService][google.cloud.servicedirectory.v1beta1.LookupService.ResolveService].
                Looks up a service by its name, returns the service and
                its endpoints.

            retry (google.api_core.retry.Retry): Designation of what errors, if any,
                should be retried.
            timeout (float): The timeout for this request.
            metadata (Sequence[Tuple[str, str]]): Strings which should be
                sent along with the request as metadata.

        Returns:
            ~.lookup_service.ResolveServiceResponse:
                The response message for
                [LookupService.ResolveService][google.cloud.servicedirectory.v1beta1.LookupService.ResolveService].

        """
        # Create or coerce a protobuf request object.

        request = lookup_service.ResolveServiceRequest(request)

        # Wrap the RPC method; this adds retry and timeout information,
        # and friendly error handling.
        rpc = gapic_v1.method.wrap_method(
            self._transport.resolve_service,
            default_timeout=None,
            client_info=_client_info,
        )

        # Certain fields should be provided within the metadata header;
        # add these here.
        metadata = tuple(metadata) + (
            gapic_v1.routing_header.to_grpc_metadata((("name", request.name),)),
        )

        # Send the request.
        response = rpc(request, retry=retry, timeout=timeout, metadata=metadata)

        # Done; return the response.
        return response


try:
    _client_info = gapic_v1.client_info.ClientInfo(
        gapic_version=pkg_resources.get_distribution(
            "google-cloud-service-directory"
        ).version
    )
except pkg_resources.DistributionNotFound:
    _client_info = gapic_v1.client_info.ClientInfo()


__all__ = ("LookupServiceClient",)
