// Copyright 2022 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
//
//     https://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.

// Code generated by protoc-gen-go_gapic. DO NOT EDIT.

package datafusion

import (
	"context"
	"fmt"
	"math"
	"net/url"
	"time"

	"cloud.google.com/go/longrunning"
	lroauto "cloud.google.com/go/longrunning/autogen"
	gax "github.com/googleapis/gax-go/v2"
	"google.golang.org/api/iterator"
	"google.golang.org/api/option"
	"google.golang.org/api/option/internaloption"
	gtransport "google.golang.org/api/transport/grpc"
	datafusionpb "google.golang.org/genproto/googleapis/cloud/datafusion/v1"
	longrunningpb "google.golang.org/genproto/googleapis/longrunning"
	"google.golang.org/grpc"
	"google.golang.org/grpc/metadata"
	"google.golang.org/protobuf/proto"
)

var newClientHook clientHook

// CallOptions contains the retry settings for each method of Client.
type CallOptions struct {
	ListAvailableVersions []gax.CallOption
	ListInstances         []gax.CallOption
	GetInstance           []gax.CallOption
	CreateInstance        []gax.CallOption
	DeleteInstance        []gax.CallOption
	UpdateInstance        []gax.CallOption
	RestartInstance       []gax.CallOption
}

func defaultGRPCClientOptions() []option.ClientOption {
	return []option.ClientOption{
		internaloption.WithDefaultEndpoint("datafusion.googleapis.com:443"),
		internaloption.WithDefaultMTLSEndpoint("datafusion.mtls.googleapis.com:443"),
		internaloption.WithDefaultAudience("https://datafusion.googleapis.com/"),
		internaloption.WithDefaultScopes(DefaultAuthScopes()...),
		internaloption.EnableJwtWithScope(),
		option.WithGRPCDialOption(grpc.WithDefaultCallOptions(
			grpc.MaxCallRecvMsgSize(math.MaxInt32))),
	}
}

func defaultCallOptions() *CallOptions {
	return &CallOptions{
		ListAvailableVersions: []gax.CallOption{},
		ListInstances:         []gax.CallOption{},
		GetInstance:           []gax.CallOption{},
		CreateInstance:        []gax.CallOption{},
		DeleteInstance:        []gax.CallOption{},
		UpdateInstance:        []gax.CallOption{},
		RestartInstance:       []gax.CallOption{},
	}
}

// internalClient is an interface that defines the methods availaible from Cloud Data Fusion API.
type internalClient interface {
	Close() error
	setGoogleClientInfo(...string)
	Connection() *grpc.ClientConn
	ListAvailableVersions(context.Context, *datafusionpb.ListAvailableVersionsRequest, ...gax.CallOption) *VersionIterator
	ListInstances(context.Context, *datafusionpb.ListInstancesRequest, ...gax.CallOption) *InstanceIterator
	GetInstance(context.Context, *datafusionpb.GetInstanceRequest, ...gax.CallOption) (*datafusionpb.Instance, error)
	CreateInstance(context.Context, *datafusionpb.CreateInstanceRequest, ...gax.CallOption) (*CreateInstanceOperation, error)
	CreateInstanceOperation(name string) *CreateInstanceOperation
	DeleteInstance(context.Context, *datafusionpb.DeleteInstanceRequest, ...gax.CallOption) (*DeleteInstanceOperation, error)
	DeleteInstanceOperation(name string) *DeleteInstanceOperation
	UpdateInstance(context.Context, *datafusionpb.UpdateInstanceRequest, ...gax.CallOption) (*UpdateInstanceOperation, error)
	UpdateInstanceOperation(name string) *UpdateInstanceOperation
	RestartInstance(context.Context, *datafusionpb.RestartInstanceRequest, ...gax.CallOption) (*RestartInstanceOperation, error)
	RestartInstanceOperation(name string) *RestartInstanceOperation
}

// Client is a client for interacting with Cloud Data Fusion API.
// Methods, except Close, may be called concurrently. However, fields must not be modified concurrently with method calls.
//
// Service for creating and managing Data Fusion instances.
// Data Fusion enables ETL developers to build code-free, data integration
// pipelines via a point-and-click UI.
type Client struct {
	// The internal transport-dependent client.
	internalClient internalClient

	// The call options for this service.
	CallOptions *CallOptions

	// LROClient is used internally to handle long-running operations.
	// It is exposed so that its CallOptions can be modified if required.
	// Users should not Close this client.
	LROClient *lroauto.OperationsClient
}

// Wrapper methods routed to the internal client.

// Close closes the connection to the API service. The user should invoke this when
// the client is no longer required.
func (c *Client) Close() error {
	return c.internalClient.Close()
}

// setGoogleClientInfo sets the name and version of the application in
// the `x-goog-api-client` header passed on each request. Intended for
// use by Google-written clients.
func (c *Client) setGoogleClientInfo(keyval ...string) {
	c.internalClient.setGoogleClientInfo(keyval...)
}

// Connection returns a connection to the API service.
//
// Deprecated.
func (c *Client) Connection() *grpc.ClientConn {
	return c.internalClient.Connection()
}

// ListAvailableVersions lists possible versions for Data Fusion instances in the specified project
// and location.
func (c *Client) ListAvailableVersions(ctx context.Context, req *datafusionpb.ListAvailableVersionsRequest, opts ...gax.CallOption) *VersionIterator {
	return c.internalClient.ListAvailableVersions(ctx, req, opts...)
}

// ListInstances lists Data Fusion instances in the specified project and location.
func (c *Client) ListInstances(ctx context.Context, req *datafusionpb.ListInstancesRequest, opts ...gax.CallOption) *InstanceIterator {
	return c.internalClient.ListInstances(ctx, req, opts...)
}

// GetInstance gets details of a single Data Fusion instance.
func (c *Client) GetInstance(ctx context.Context, req *datafusionpb.GetInstanceRequest, opts ...gax.CallOption) (*datafusionpb.Instance, error) {
	return c.internalClient.GetInstance(ctx, req, opts...)
}

// CreateInstance creates a new Data Fusion instance in the specified project and location.
func (c *Client) CreateInstance(ctx context.Context, req *datafusionpb.CreateInstanceRequest, opts ...gax.CallOption) (*CreateInstanceOperation, error) {
	return c.internalClient.CreateInstance(ctx, req, opts...)
}

// CreateInstanceOperation returns a new CreateInstanceOperation from a given name.
// The name must be that of a previously created CreateInstanceOperation, possibly from a different process.
func (c *Client) CreateInstanceOperation(name string) *CreateInstanceOperation {
	return c.internalClient.CreateInstanceOperation(name)
}

// DeleteInstance deletes a single Date Fusion instance.
func (c *Client) DeleteInstance(ctx context.Context, req *datafusionpb.DeleteInstanceRequest, opts ...gax.CallOption) (*DeleteInstanceOperation, error) {
	return c.internalClient.DeleteInstance(ctx, req, opts...)
}

// DeleteInstanceOperation returns a new DeleteInstanceOperation from a given name.
// The name must be that of a previously created DeleteInstanceOperation, possibly from a different process.
func (c *Client) DeleteInstanceOperation(name string) *DeleteInstanceOperation {
	return c.internalClient.DeleteInstanceOperation(name)
}

// UpdateInstance updates a single Data Fusion instance.
func (c *Client) UpdateInstance(ctx context.Context, req *datafusionpb.UpdateInstanceRequest, opts ...gax.CallOption) (*UpdateInstanceOperation, error) {
	return c.internalClient.UpdateInstance(ctx, req, opts...)
}

// UpdateInstanceOperation returns a new UpdateInstanceOperation from a given name.
// The name must be that of a previously created UpdateInstanceOperation, possibly from a different process.
func (c *Client) UpdateInstanceOperation(name string) *UpdateInstanceOperation {
	return c.internalClient.UpdateInstanceOperation(name)
}

// RestartInstance restart a single Data Fusion instance.
// At the end of an operation instance is fully restarted.
func (c *Client) RestartInstance(ctx context.Context, req *datafusionpb.RestartInstanceRequest, opts ...gax.CallOption) (*RestartInstanceOperation, error) {
	return c.internalClient.RestartInstance(ctx, req, opts...)
}

// RestartInstanceOperation returns a new RestartInstanceOperation from a given name.
// The name must be that of a previously created RestartInstanceOperation, possibly from a different process.
func (c *Client) RestartInstanceOperation(name string) *RestartInstanceOperation {
	return c.internalClient.RestartInstanceOperation(name)
}

// gRPCClient is a client for interacting with Cloud Data Fusion API over gRPC transport.
//
// Methods, except Close, may be called concurrently. However, fields must not be modified concurrently with method calls.
type gRPCClient struct {
	// Connection pool of gRPC connections to the service.
	connPool gtransport.ConnPool

	// flag to opt out of default deadlines via GOOGLE_API_GO_EXPERIMENTAL_DISABLE_DEFAULT_DEADLINE
	disableDeadlines bool

	// Points back to the CallOptions field of the containing Client
	CallOptions **CallOptions

	// The gRPC API client.
	client datafusionpb.DataFusionClient

	// LROClient is used internally to handle long-running operations.
	// It is exposed so that its CallOptions can be modified if required.
	// Users should not Close this client.
	LROClient **lroauto.OperationsClient

	// The x-goog-* metadata to be sent with each request.
	xGoogMetadata metadata.MD
}

// NewClient creates a new data fusion client based on gRPC.
// The returned client must be Closed when it is done being used to clean up its underlying connections.
//
// Service for creating and managing Data Fusion instances.
// Data Fusion enables ETL developers to build code-free, data integration
// pipelines via a point-and-click UI.
func NewClient(ctx context.Context, opts ...option.ClientOption) (*Client, error) {
	clientOpts := defaultGRPCClientOptions()
	if newClientHook != nil {
		hookOpts, err := newClientHook(ctx, clientHookParams{})
		if err != nil {
			return nil, err
		}
		clientOpts = append(clientOpts, hookOpts...)
	}

	disableDeadlines, err := checkDisableDeadlines()
	if err != nil {
		return nil, err
	}

	connPool, err := gtransport.DialPool(ctx, append(clientOpts, opts...)...)
	if err != nil {
		return nil, err
	}
	client := Client{CallOptions: defaultCallOptions()}

	c := &gRPCClient{
		connPool:         connPool,
		disableDeadlines: disableDeadlines,
		client:           datafusionpb.NewDataFusionClient(connPool),
		CallOptions:      &client.CallOptions,
	}
	c.setGoogleClientInfo()

	client.internalClient = c

	client.LROClient, err = lroauto.NewOperationsClient(ctx, gtransport.WithConnPool(connPool))
	if err != nil {
		// This error "should not happen", since we are just reusing old connection pool
		// and never actually need to dial.
		// If this does happen, we could leak connp. However, we cannot close conn:
		// If the user invoked the constructor with option.WithGRPCConn,
		// we would close a connection that's still in use.
		// TODO: investigate error conditions.
		return nil, err
	}
	c.LROClient = &client.LROClient
	return &client, nil
}

// Connection returns a connection to the API service.
//
// Deprecated.
func (c *gRPCClient) Connection() *grpc.ClientConn {
	return c.connPool.Conn()
}

// setGoogleClientInfo sets the name and version of the application in
// the `x-goog-api-client` header passed on each request. Intended for
// use by Google-written clients.
func (c *gRPCClient) setGoogleClientInfo(keyval ...string) {
	kv := append([]string{"gl-go", versionGo()}, keyval...)
	kv = append(kv, "gapic", getVersionClient(), "gax", gax.Version, "grpc", grpc.Version)
	c.xGoogMetadata = metadata.Pairs("x-goog-api-client", gax.XGoogHeader(kv...))
}

// Close closes the connection to the API service. The user should invoke this when
// the client is no longer required.
func (c *gRPCClient) Close() error {
	return c.connPool.Close()
}

func (c *gRPCClient) ListAvailableVersions(ctx context.Context, req *datafusionpb.ListAvailableVersionsRequest, opts ...gax.CallOption) *VersionIterator {
	md := metadata.Pairs("x-goog-request-params", fmt.Sprintf("%s=%v", "parent", url.QueryEscape(req.GetParent())))

	ctx = insertMetadata(ctx, c.xGoogMetadata, md)
	opts = append((*c.CallOptions).ListAvailableVersions[0:len((*c.CallOptions).ListAvailableVersions):len((*c.CallOptions).ListAvailableVersions)], opts...)
	it := &VersionIterator{}
	req = proto.Clone(req).(*datafusionpb.ListAvailableVersionsRequest)
	it.InternalFetch = func(pageSize int, pageToken string) ([]*datafusionpb.Version, string, error) {
		resp := &datafusionpb.ListAvailableVersionsResponse{}
		if pageToken != "" {
			req.PageToken = pageToken
		}
		if pageSize > math.MaxInt32 {
			req.PageSize = math.MaxInt32
		} else if pageSize != 0 {
			req.PageSize = int32(pageSize)
		}
		err := gax.Invoke(ctx, func(ctx context.Context, settings gax.CallSettings) error {
			var err error
			resp, err = c.client.ListAvailableVersions(ctx, req, settings.GRPC...)
			return err
		}, opts...)
		if err != nil {
			return nil, "", err
		}

		it.Response = resp
		return resp.GetAvailableVersions(), resp.GetNextPageToken(), nil
	}
	fetch := func(pageSize int, pageToken string) (string, error) {
		items, nextPageToken, err := it.InternalFetch(pageSize, pageToken)
		if err != nil {
			return "", err
		}
		it.items = append(it.items, items...)
		return nextPageToken, nil
	}

	it.pageInfo, it.nextFunc = iterator.NewPageInfo(fetch, it.bufLen, it.takeBuf)
	it.pageInfo.MaxSize = int(req.GetPageSize())
	it.pageInfo.Token = req.GetPageToken()

	return it
}

func (c *gRPCClient) ListInstances(ctx context.Context, req *datafusionpb.ListInstancesRequest, opts ...gax.CallOption) *InstanceIterator {
	md := metadata.Pairs("x-goog-request-params", fmt.Sprintf("%s=%v", "parent", url.QueryEscape(req.GetParent())))

	ctx = insertMetadata(ctx, c.xGoogMetadata, md)
	opts = append((*c.CallOptions).ListInstances[0:len((*c.CallOptions).ListInstances):len((*c.CallOptions).ListInstances)], opts...)
	it := &InstanceIterator{}
	req = proto.Clone(req).(*datafusionpb.ListInstancesRequest)
	it.InternalFetch = func(pageSize int, pageToken string) ([]*datafusionpb.Instance, string, error) {
		resp := &datafusionpb.ListInstancesResponse{}
		if pageToken != "" {
			req.PageToken = pageToken
		}
		if pageSize > math.MaxInt32 {
			req.PageSize = math.MaxInt32
		} else if pageSize != 0 {
			req.PageSize = int32(pageSize)
		}
		err := gax.Invoke(ctx, func(ctx context.Context, settings gax.CallSettings) error {
			var err error
			resp, err = c.client.ListInstances(ctx, req, settings.GRPC...)
			return err
		}, opts...)
		if err != nil {
			return nil, "", err
		}

		it.Response = resp
		return resp.GetInstances(), resp.GetNextPageToken(), nil
	}
	fetch := func(pageSize int, pageToken string) (string, error) {
		items, nextPageToken, err := it.InternalFetch(pageSize, pageToken)
		if err != nil {
			return "", err
		}
		it.items = append(it.items, items...)
		return nextPageToken, nil
	}

	it.pageInfo, it.nextFunc = iterator.NewPageInfo(fetch, it.bufLen, it.takeBuf)
	it.pageInfo.MaxSize = int(req.GetPageSize())
	it.pageInfo.Token = req.GetPageToken()

	return it
}

func (c *gRPCClient) GetInstance(ctx context.Context, req *datafusionpb.GetInstanceRequest, opts ...gax.CallOption) (*datafusionpb.Instance, error) {
	if _, ok := ctx.Deadline(); !ok && !c.disableDeadlines {
		cctx, cancel := context.WithTimeout(ctx, 60000*time.Millisecond)
		defer cancel()
		ctx = cctx
	}
	md := metadata.Pairs("x-goog-request-params", fmt.Sprintf("%s=%v", "name", url.QueryEscape(req.GetName())))

	ctx = insertMetadata(ctx, c.xGoogMetadata, md)
	opts = append((*c.CallOptions).GetInstance[0:len((*c.CallOptions).GetInstance):len((*c.CallOptions).GetInstance)], opts...)
	var resp *datafusionpb.Instance
	err := gax.Invoke(ctx, func(ctx context.Context, settings gax.CallSettings) error {
		var err error
		resp, err = c.client.GetInstance(ctx, req, settings.GRPC...)
		return err
	}, opts...)
	if err != nil {
		return nil, err
	}
	return resp, nil
}

func (c *gRPCClient) CreateInstance(ctx context.Context, req *datafusionpb.CreateInstanceRequest, opts ...gax.CallOption) (*CreateInstanceOperation, error) {
	if _, ok := ctx.Deadline(); !ok && !c.disableDeadlines {
		cctx, cancel := context.WithTimeout(ctx, 60000*time.Millisecond)
		defer cancel()
		ctx = cctx
	}
	md := metadata.Pairs("x-goog-request-params", fmt.Sprintf("%s=%v", "parent", url.QueryEscape(req.GetParent())))

	ctx = insertMetadata(ctx, c.xGoogMetadata, md)
	opts = append((*c.CallOptions).CreateInstance[0:len((*c.CallOptions).CreateInstance):len((*c.CallOptions).CreateInstance)], opts...)
	var resp *longrunningpb.Operation
	err := gax.Invoke(ctx, func(ctx context.Context, settings gax.CallSettings) error {
		var err error
		resp, err = c.client.CreateInstance(ctx, req, settings.GRPC...)
		return err
	}, opts...)
	if err != nil {
		return nil, err
	}
	return &CreateInstanceOperation{
		lro: longrunning.InternalNewOperation(*c.LROClient, resp),
	}, nil
}

func (c *gRPCClient) DeleteInstance(ctx context.Context, req *datafusionpb.DeleteInstanceRequest, opts ...gax.CallOption) (*DeleteInstanceOperation, error) {
	if _, ok := ctx.Deadline(); !ok && !c.disableDeadlines {
		cctx, cancel := context.WithTimeout(ctx, 60000*time.Millisecond)
		defer cancel()
		ctx = cctx
	}
	md := metadata.Pairs("x-goog-request-params", fmt.Sprintf("%s=%v", "name", url.QueryEscape(req.GetName())))

	ctx = insertMetadata(ctx, c.xGoogMetadata, md)
	opts = append((*c.CallOptions).DeleteInstance[0:len((*c.CallOptions).DeleteInstance):len((*c.CallOptions).DeleteInstance)], opts...)
	var resp *longrunningpb.Operation
	err := gax.Invoke(ctx, func(ctx context.Context, settings gax.CallSettings) error {
		var err error
		resp, err = c.client.DeleteInstance(ctx, req, settings.GRPC...)
		return err
	}, opts...)
	if err != nil {
		return nil, err
	}
	return &DeleteInstanceOperation{
		lro: longrunning.InternalNewOperation(*c.LROClient, resp),
	}, nil
}

func (c *gRPCClient) UpdateInstance(ctx context.Context, req *datafusionpb.UpdateInstanceRequest, opts ...gax.CallOption) (*UpdateInstanceOperation, error) {
	if _, ok := ctx.Deadline(); !ok && !c.disableDeadlines {
		cctx, cancel := context.WithTimeout(ctx, 60000*time.Millisecond)
		defer cancel()
		ctx = cctx
	}
	md := metadata.Pairs("x-goog-request-params", fmt.Sprintf("%s=%v", "instance.name", url.QueryEscape(req.GetInstance().GetName())))

	ctx = insertMetadata(ctx, c.xGoogMetadata, md)
	opts = append((*c.CallOptions).UpdateInstance[0:len((*c.CallOptions).UpdateInstance):len((*c.CallOptions).UpdateInstance)], opts...)
	var resp *longrunningpb.Operation
	err := gax.Invoke(ctx, func(ctx context.Context, settings gax.CallSettings) error {
		var err error
		resp, err = c.client.UpdateInstance(ctx, req, settings.GRPC...)
		return err
	}, opts...)
	if err != nil {
		return nil, err
	}
	return &UpdateInstanceOperation{
		lro: longrunning.InternalNewOperation(*c.LROClient, resp),
	}, nil
}

func (c *gRPCClient) RestartInstance(ctx context.Context, req *datafusionpb.RestartInstanceRequest, opts ...gax.CallOption) (*RestartInstanceOperation, error) {
	if _, ok := ctx.Deadline(); !ok && !c.disableDeadlines {
		cctx, cancel := context.WithTimeout(ctx, 60000*time.Millisecond)
		defer cancel()
		ctx = cctx
	}
	md := metadata.Pairs("x-goog-request-params", fmt.Sprintf("%s=%v", "name", url.QueryEscape(req.GetName())))

	ctx = insertMetadata(ctx, c.xGoogMetadata, md)
	opts = append((*c.CallOptions).RestartInstance[0:len((*c.CallOptions).RestartInstance):len((*c.CallOptions).RestartInstance)], opts...)
	var resp *longrunningpb.Operation
	err := gax.Invoke(ctx, func(ctx context.Context, settings gax.CallSettings) error {
		var err error
		resp, err = c.client.RestartInstance(ctx, req, settings.GRPC...)
		return err
	}, opts...)
	if err != nil {
		return nil, err
	}
	return &RestartInstanceOperation{
		lro: longrunning.InternalNewOperation(*c.LROClient, resp),
	}, nil
}

// CreateInstanceOperation manages a long-running operation from CreateInstance.
type CreateInstanceOperation struct {
	lro *longrunning.Operation
}

// CreateInstanceOperation returns a new CreateInstanceOperation from a given name.
// The name must be that of a previously created CreateInstanceOperation, possibly from a different process.
func (c *gRPCClient) CreateInstanceOperation(name string) *CreateInstanceOperation {
	return &CreateInstanceOperation{
		lro: longrunning.InternalNewOperation(*c.LROClient, &longrunningpb.Operation{Name: name}),
	}
}

// Wait blocks until the long-running operation is completed, returning the response and any errors encountered.
//
// See documentation of Poll for error-handling information.
func (op *CreateInstanceOperation) Wait(ctx context.Context, opts ...gax.CallOption) (*datafusionpb.Instance, error) {
	var resp datafusionpb.Instance
	if err := op.lro.WaitWithInterval(ctx, &resp, time.Minute, opts...); err != nil {
		return nil, err
	}
	return &resp, nil
}

// Poll fetches the latest state of the long-running operation.
//
// Poll also fetches the latest metadata, which can be retrieved by Metadata.
//
// If Poll fails, the error is returned and op is unmodified. If Poll succeeds and
// the operation has completed with failure, the error is returned and op.Done will return true.
// If Poll succeeds and the operation has completed successfully,
// op.Done will return true, and the response of the operation is returned.
// If Poll succeeds and the operation has not completed, the returned response and error are both nil.
func (op *CreateInstanceOperation) Poll(ctx context.Context, opts ...gax.CallOption) (*datafusionpb.Instance, error) {
	var resp datafusionpb.Instance
	if err := op.lro.Poll(ctx, &resp, opts...); err != nil {
		return nil, err
	}
	if !op.Done() {
		return nil, nil
	}
	return &resp, nil
}

// Metadata returns metadata associated with the long-running operation.
// Metadata itself does not contact the server, but Poll does.
// To get the latest metadata, call this method after a successful call to Poll.
// If the metadata is not available, the returned metadata and error are both nil.
func (op *CreateInstanceOperation) Metadata() (*datafusionpb.OperationMetadata, error) {
	var meta datafusionpb.OperationMetadata
	if err := op.lro.Metadata(&meta); err == longrunning.ErrNoMetadata {
		return nil, nil
	} else if err != nil {
		return nil, err
	}
	return &meta, nil
}

// Done reports whether the long-running operation has completed.
func (op *CreateInstanceOperation) Done() bool {
	return op.lro.Done()
}

// Name returns the name of the long-running operation.
// The name is assigned by the server and is unique within the service from which the operation is created.
func (op *CreateInstanceOperation) Name() string {
	return op.lro.Name()
}

// DeleteInstanceOperation manages a long-running operation from DeleteInstance.
type DeleteInstanceOperation struct {
	lro *longrunning.Operation
}

// DeleteInstanceOperation returns a new DeleteInstanceOperation from a given name.
// The name must be that of a previously created DeleteInstanceOperation, possibly from a different process.
func (c *gRPCClient) DeleteInstanceOperation(name string) *DeleteInstanceOperation {
	return &DeleteInstanceOperation{
		lro: longrunning.InternalNewOperation(*c.LROClient, &longrunningpb.Operation{Name: name}),
	}
}

// Wait blocks until the long-running operation is completed, returning the response and any errors encountered.
//
// See documentation of Poll for error-handling information.
func (op *DeleteInstanceOperation) Wait(ctx context.Context, opts ...gax.CallOption) error {
	return op.lro.WaitWithInterval(ctx, nil, time.Minute, opts...)
}

// Poll fetches the latest state of the long-running operation.
//
// Poll also fetches the latest metadata, which can be retrieved by Metadata.
//
// If Poll fails, the error is returned and op is unmodified. If Poll succeeds and
// the operation has completed with failure, the error is returned and op.Done will return true.
// If Poll succeeds and the operation has completed successfully,
// op.Done will return true, and the response of the operation is returned.
// If Poll succeeds and the operation has not completed, the returned response and error are both nil.
func (op *DeleteInstanceOperation) Poll(ctx context.Context, opts ...gax.CallOption) error {
	return op.lro.Poll(ctx, nil, opts...)
}

// Metadata returns metadata associated with the long-running operation.
// Metadata itself does not contact the server, but Poll does.
// To get the latest metadata, call this method after a successful call to Poll.
// If the metadata is not available, the returned metadata and error are both nil.
func (op *DeleteInstanceOperation) Metadata() (*datafusionpb.OperationMetadata, error) {
	var meta datafusionpb.OperationMetadata
	if err := op.lro.Metadata(&meta); err == longrunning.ErrNoMetadata {
		return nil, nil
	} else if err != nil {
		return nil, err
	}
	return &meta, nil
}

// Done reports whether the long-running operation has completed.
func (op *DeleteInstanceOperation) Done() bool {
	return op.lro.Done()
}

// Name returns the name of the long-running operation.
// The name is assigned by the server and is unique within the service from which the operation is created.
func (op *DeleteInstanceOperation) Name() string {
	return op.lro.Name()
}

// RestartInstanceOperation manages a long-running operation from RestartInstance.
type RestartInstanceOperation struct {
	lro *longrunning.Operation
}

// RestartInstanceOperation returns a new RestartInstanceOperation from a given name.
// The name must be that of a previously created RestartInstanceOperation, possibly from a different process.
func (c *gRPCClient) RestartInstanceOperation(name string) *RestartInstanceOperation {
	return &RestartInstanceOperation{
		lro: longrunning.InternalNewOperation(*c.LROClient, &longrunningpb.Operation{Name: name}),
	}
}

// Wait blocks until the long-running operation is completed, returning the response and any errors encountered.
//
// See documentation of Poll for error-handling information.
func (op *RestartInstanceOperation) Wait(ctx context.Context, opts ...gax.CallOption) (*datafusionpb.Instance, error) {
	var resp datafusionpb.Instance
	if err := op.lro.WaitWithInterval(ctx, &resp, time.Minute, opts...); err != nil {
		return nil, err
	}
	return &resp, nil
}

// Poll fetches the latest state of the long-running operation.
//
// Poll also fetches the latest metadata, which can be retrieved by Metadata.
//
// If Poll fails, the error is returned and op is unmodified. If Poll succeeds and
// the operation has completed with failure, the error is returned and op.Done will return true.
// If Poll succeeds and the operation has completed successfully,
// op.Done will return true, and the response of the operation is returned.
// If Poll succeeds and the operation has not completed, the returned response and error are both nil.
func (op *RestartInstanceOperation) Poll(ctx context.Context, opts ...gax.CallOption) (*datafusionpb.Instance, error) {
	var resp datafusionpb.Instance
	if err := op.lro.Poll(ctx, &resp, opts...); err != nil {
		return nil, err
	}
	if !op.Done() {
		return nil, nil
	}
	return &resp, nil
}

// Metadata returns metadata associated with the long-running operation.
// Metadata itself does not contact the server, but Poll does.
// To get the latest metadata, call this method after a successful call to Poll.
// If the metadata is not available, the returned metadata and error are both nil.
func (op *RestartInstanceOperation) Metadata() (*datafusionpb.OperationMetadata, error) {
	var meta datafusionpb.OperationMetadata
	if err := op.lro.Metadata(&meta); err == longrunning.ErrNoMetadata {
		return nil, nil
	} else if err != nil {
		return nil, err
	}
	return &meta, nil
}

// Done reports whether the long-running operation has completed.
func (op *RestartInstanceOperation) Done() bool {
	return op.lro.Done()
}

// Name returns the name of the long-running operation.
// The name is assigned by the server and is unique within the service from which the operation is created.
func (op *RestartInstanceOperation) Name() string {
	return op.lro.Name()
}

// UpdateInstanceOperation manages a long-running operation from UpdateInstance.
type UpdateInstanceOperation struct {
	lro *longrunning.Operation
}

// UpdateInstanceOperation returns a new UpdateInstanceOperation from a given name.
// The name must be that of a previously created UpdateInstanceOperation, possibly from a different process.
func (c *gRPCClient) UpdateInstanceOperation(name string) *UpdateInstanceOperation {
	return &UpdateInstanceOperation{
		lro: longrunning.InternalNewOperation(*c.LROClient, &longrunningpb.Operation{Name: name}),
	}
}

// Wait blocks until the long-running operation is completed, returning the response and any errors encountered.
//
// See documentation of Poll for error-handling information.
func (op *UpdateInstanceOperation) Wait(ctx context.Context, opts ...gax.CallOption) (*datafusionpb.Instance, error) {
	var resp datafusionpb.Instance
	if err := op.lro.WaitWithInterval(ctx, &resp, time.Minute, opts...); err != nil {
		return nil, err
	}
	return &resp, nil
}

// Poll fetches the latest state of the long-running operation.
//
// Poll also fetches the latest metadata, which can be retrieved by Metadata.
//
// If Poll fails, the error is returned and op is unmodified. If Poll succeeds and
// the operation has completed with failure, the error is returned and op.Done will return true.
// If Poll succeeds and the operation has completed successfully,
// op.Done will return true, and the response of the operation is returned.
// If Poll succeeds and the operation has not completed, the returned response and error are both nil.
func (op *UpdateInstanceOperation) Poll(ctx context.Context, opts ...gax.CallOption) (*datafusionpb.Instance, error) {
	var resp datafusionpb.Instance
	if err := op.lro.Poll(ctx, &resp, opts...); err != nil {
		return nil, err
	}
	if !op.Done() {
		return nil, nil
	}
	return &resp, nil
}

// Metadata returns metadata associated with the long-running operation.
// Metadata itself does not contact the server, but Poll does.
// To get the latest metadata, call this method after a successful call to Poll.
// If the metadata is not available, the returned metadata and error are both nil.
func (op *UpdateInstanceOperation) Metadata() (*datafusionpb.OperationMetadata, error) {
	var meta datafusionpb.OperationMetadata
	if err := op.lro.Metadata(&meta); err == longrunning.ErrNoMetadata {
		return nil, nil
	} else if err != nil {
		return nil, err
	}
	return &meta, nil
}

// Done reports whether the long-running operation has completed.
func (op *UpdateInstanceOperation) Done() bool {
	return op.lro.Done()
}

// Name returns the name of the long-running operation.
// The name is assigned by the server and is unique within the service from which the operation is created.
func (op *UpdateInstanceOperation) Name() string {
	return op.lro.Name()
}

// InstanceIterator manages a stream of *datafusionpb.Instance.
type InstanceIterator struct {
	items    []*datafusionpb.Instance
	pageInfo *iterator.PageInfo
	nextFunc func() error

	// Response is the raw response for the current page.
	// It must be cast to the RPC response type.
	// Calling Next() or InternalFetch() updates this value.
	Response interface{}

	// InternalFetch is for use by the Google Cloud Libraries only.
	// It is not part of the stable interface of this package.
	//
	// InternalFetch returns results from a single call to the underlying RPC.
	// The number of results is no greater than pageSize.
	// If there are no more results, nextPageToken is empty and err is nil.
	InternalFetch func(pageSize int, pageToken string) (results []*datafusionpb.Instance, nextPageToken string, err error)
}

// PageInfo supports pagination. See the google.golang.org/api/iterator package for details.
func (it *InstanceIterator) PageInfo() *iterator.PageInfo {
	return it.pageInfo
}

// Next returns the next result. Its second return value is iterator.Done if there are no more
// results. Once Next returns Done, all subsequent calls will return Done.
func (it *InstanceIterator) Next() (*datafusionpb.Instance, error) {
	var item *datafusionpb.Instance
	if err := it.nextFunc(); err != nil {
		return item, err
	}
	item = it.items[0]
	it.items = it.items[1:]
	return item, nil
}

func (it *InstanceIterator) bufLen() int {
	return len(it.items)
}

func (it *InstanceIterator) takeBuf() interface{} {
	b := it.items
	it.items = nil
	return b
}

// VersionIterator manages a stream of *datafusionpb.Version.
type VersionIterator struct {
	items    []*datafusionpb.Version
	pageInfo *iterator.PageInfo
	nextFunc func() error

	// Response is the raw response for the current page.
	// It must be cast to the RPC response type.
	// Calling Next() or InternalFetch() updates this value.
	Response interface{}

	// InternalFetch is for use by the Google Cloud Libraries only.
	// It is not part of the stable interface of this package.
	//
	// InternalFetch returns results from a single call to the underlying RPC.
	// The number of results is no greater than pageSize.
	// If there are no more results, nextPageToken is empty and err is nil.
	InternalFetch func(pageSize int, pageToken string) (results []*datafusionpb.Version, nextPageToken string, err error)
}

// PageInfo supports pagination. See the google.golang.org/api/iterator package for details.
func (it *VersionIterator) PageInfo() *iterator.PageInfo {
	return it.pageInfo
}

// Next returns the next result. Its second return value is iterator.Done if there are no more
// results. Once Next returns Done, all subsequent calls will return Done.
func (it *VersionIterator) Next() (*datafusionpb.Version, error) {
	var item *datafusionpb.Version
	if err := it.nextFunc(); err != nil {
		return item, err
	}
	item = it.items[0]
	it.items = it.items[1:]
	return item, nil
}

func (it *VersionIterator) bufLen() int {
	return len(it.items)
}

func (it *VersionIterator) takeBuf() interface{} {
	b := it.items
	it.items = nil
	return b
}