// Copyright 2023 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 compute

import (
	"bytes"
	"context"
	"fmt"
	"io/ioutil"
	"math"
	"net/http"
	"net/url"
	"sort"
	"time"

	computepb "cloud.google.com/go/compute/apiv1/computepb"
	gax "github.com/googleapis/gax-go/v2"
	"google.golang.org/api/googleapi"
	"google.golang.org/api/iterator"
	"google.golang.org/api/option"
	"google.golang.org/api/option/internaloption"
	httptransport "google.golang.org/api/transport/http"
	"google.golang.org/grpc"
	"google.golang.org/grpc/metadata"
	"google.golang.org/protobuf/encoding/protojson"
	"google.golang.org/protobuf/proto"
)

var newAutoscalersClientHook clientHook

// AutoscalersCallOptions contains the retry settings for each method of AutoscalersClient.
type AutoscalersCallOptions struct {
	AggregatedList []gax.CallOption
	Delete         []gax.CallOption
	Get            []gax.CallOption
	Insert         []gax.CallOption
	List           []gax.CallOption
	Patch          []gax.CallOption
	Update         []gax.CallOption
}

func defaultAutoscalersRESTCallOptions() *AutoscalersCallOptions {
	return &AutoscalersCallOptions{
		AggregatedList: []gax.CallOption{
			gax.WithRetry(func() gax.Retryer {
				return gax.OnHTTPCodes(gax.Backoff{
					Initial:    100 * time.Millisecond,
					Max:        60000 * time.Millisecond,
					Multiplier: 1.30,
				},
					http.StatusGatewayTimeout,
					http.StatusServiceUnavailable)
			}),
		},
		Delete: []gax.CallOption{},
		Get: []gax.CallOption{
			gax.WithRetry(func() gax.Retryer {
				return gax.OnHTTPCodes(gax.Backoff{
					Initial:    100 * time.Millisecond,
					Max:        60000 * time.Millisecond,
					Multiplier: 1.30,
				},
					http.StatusGatewayTimeout,
					http.StatusServiceUnavailable)
			}),
		},
		Insert: []gax.CallOption{},
		List: []gax.CallOption{
			gax.WithRetry(func() gax.Retryer {
				return gax.OnHTTPCodes(gax.Backoff{
					Initial:    100 * time.Millisecond,
					Max:        60000 * time.Millisecond,
					Multiplier: 1.30,
				},
					http.StatusGatewayTimeout,
					http.StatusServiceUnavailable)
			}),
		},
		Patch:  []gax.CallOption{},
		Update: []gax.CallOption{},
	}
}

// internalAutoscalersClient is an interface that defines the methods available from Google Compute Engine API.
type internalAutoscalersClient interface {
	Close() error
	setGoogleClientInfo(...string)
	Connection() *grpc.ClientConn
	AggregatedList(context.Context, *computepb.AggregatedListAutoscalersRequest, ...gax.CallOption) *AutoscalersScopedListPairIterator
	Delete(context.Context, *computepb.DeleteAutoscalerRequest, ...gax.CallOption) (*Operation, error)
	Get(context.Context, *computepb.GetAutoscalerRequest, ...gax.CallOption) (*computepb.Autoscaler, error)
	Insert(context.Context, *computepb.InsertAutoscalerRequest, ...gax.CallOption) (*Operation, error)
	List(context.Context, *computepb.ListAutoscalersRequest, ...gax.CallOption) *AutoscalerIterator
	Patch(context.Context, *computepb.PatchAutoscalerRequest, ...gax.CallOption) (*Operation, error)
	Update(context.Context, *computepb.UpdateAutoscalerRequest, ...gax.CallOption) (*Operation, error)
}

// AutoscalersClient is a client for interacting with Google Compute Engine API.
// Methods, except Close, may be called concurrently. However, fields must not be modified concurrently with method calls.
//
// The Autoscalers API.
type AutoscalersClient struct {
	// The internal transport-dependent client.
	internalClient internalAutoscalersClient

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

// 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 *AutoscalersClient) 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 *AutoscalersClient) setGoogleClientInfo(keyval ...string) {
	c.internalClient.setGoogleClientInfo(keyval...)
}

// Connection returns a connection to the API service.
//
// Deprecated: Connections are now pooled so this method does not always
// return the same resource.
func (c *AutoscalersClient) Connection() *grpc.ClientConn {
	return c.internalClient.Connection()
}

// AggregatedList retrieves an aggregated list of autoscalers.
func (c *AutoscalersClient) AggregatedList(ctx context.Context, req *computepb.AggregatedListAutoscalersRequest, opts ...gax.CallOption) *AutoscalersScopedListPairIterator {
	return c.internalClient.AggregatedList(ctx, req, opts...)
}

// Delete deletes the specified autoscaler.
func (c *AutoscalersClient) Delete(ctx context.Context, req *computepb.DeleteAutoscalerRequest, opts ...gax.CallOption) (*Operation, error) {
	return c.internalClient.Delete(ctx, req, opts...)
}

// Get returns the specified autoscaler resource.
func (c *AutoscalersClient) Get(ctx context.Context, req *computepb.GetAutoscalerRequest, opts ...gax.CallOption) (*computepb.Autoscaler, error) {
	return c.internalClient.Get(ctx, req, opts...)
}

// Insert creates an autoscaler in the specified project using the data included in the request.
func (c *AutoscalersClient) Insert(ctx context.Context, req *computepb.InsertAutoscalerRequest, opts ...gax.CallOption) (*Operation, error) {
	return c.internalClient.Insert(ctx, req, opts...)
}

// List retrieves a list of autoscalers contained within the specified zone.
func (c *AutoscalersClient) List(ctx context.Context, req *computepb.ListAutoscalersRequest, opts ...gax.CallOption) *AutoscalerIterator {
	return c.internalClient.List(ctx, req, opts...)
}

// Patch updates an autoscaler in the specified project using the data included in the request. This method supports PATCH semantics and uses the JSON merge patch format and processing rules.
func (c *AutoscalersClient) Patch(ctx context.Context, req *computepb.PatchAutoscalerRequest, opts ...gax.CallOption) (*Operation, error) {
	return c.internalClient.Patch(ctx, req, opts...)
}

// Update updates an autoscaler in the specified project using the data included in the request.
func (c *AutoscalersClient) Update(ctx context.Context, req *computepb.UpdateAutoscalerRequest, opts ...gax.CallOption) (*Operation, error) {
	return c.internalClient.Update(ctx, req, opts...)
}

// Methods, except Close, may be called concurrently. However, fields must not be modified concurrently with method calls.
type autoscalersRESTClient struct {
	// The http endpoint to connect to.
	endpoint string

	// The http client.
	httpClient *http.Client

	// operationClient is used to call the operation-specific management service.
	operationClient *ZoneOperationsClient

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

	// Points back to the CallOptions field of the containing AutoscalersClient
	CallOptions **AutoscalersCallOptions
}

// NewAutoscalersRESTClient creates a new autoscalers rest client.
//
// The Autoscalers API.
func NewAutoscalersRESTClient(ctx context.Context, opts ...option.ClientOption) (*AutoscalersClient, error) {
	clientOpts := append(defaultAutoscalersRESTClientOptions(), opts...)
	httpClient, endpoint, err := httptransport.NewClient(ctx, clientOpts...)
	if err != nil {
		return nil, err
	}

	callOpts := defaultAutoscalersRESTCallOptions()
	c := &autoscalersRESTClient{
		endpoint:    endpoint,
		httpClient:  httpClient,
		CallOptions: &callOpts,
	}
	c.setGoogleClientInfo()

	o := []option.ClientOption{
		option.WithHTTPClient(httpClient),
		option.WithEndpoint(endpoint),
	}
	opC, err := NewZoneOperationsRESTClient(ctx, o...)
	if err != nil {
		return nil, err
	}
	c.operationClient = opC

	return &AutoscalersClient{internalClient: c, CallOptions: callOpts}, nil
}

func defaultAutoscalersRESTClientOptions() []option.ClientOption {
	return []option.ClientOption{
		internaloption.WithDefaultEndpoint("https://compute.googleapis.com"),
		internaloption.WithDefaultMTLSEndpoint("https://compute.mtls.googleapis.com"),
		internaloption.WithDefaultAudience("https://compute.googleapis.com/"),
		internaloption.WithDefaultScopes(DefaultAuthScopes()...),
	}
}

// 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 *autoscalersRESTClient) setGoogleClientInfo(keyval ...string) {
	kv := append([]string{"gl-go", versionGo()}, keyval...)
	kv = append(kv, "gapic", getVersionClient(), "gax", gax.Version, "rest", "UNKNOWN")
	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 *autoscalersRESTClient) Close() error {
	// Replace httpClient with nil to force cleanup.
	c.httpClient = nil
	if err := c.operationClient.Close(); err != nil {
		return err
	}
	return nil
}

// Connection returns a connection to the API service.
//
// Deprecated: This method always returns nil.
func (c *autoscalersRESTClient) Connection() *grpc.ClientConn {
	return nil
}

// AggregatedList retrieves an aggregated list of autoscalers.
func (c *autoscalersRESTClient) AggregatedList(ctx context.Context, req *computepb.AggregatedListAutoscalersRequest, opts ...gax.CallOption) *AutoscalersScopedListPairIterator {
	it := &AutoscalersScopedListPairIterator{}
	req = proto.Clone(req).(*computepb.AggregatedListAutoscalersRequest)
	unm := protojson.UnmarshalOptions{AllowPartial: true, DiscardUnknown: true}
	it.InternalFetch = func(pageSize int, pageToken string) ([]AutoscalersScopedListPair, string, error) {
		resp := &computepb.AutoscalerAggregatedList{}
		if pageToken != "" {
			req.PageToken = proto.String(pageToken)
		}
		if pageSize > math.MaxInt32 {
			req.MaxResults = proto.Uint32(math.MaxInt32)
		} else if pageSize != 0 {
			req.MaxResults = proto.Uint32(uint32(pageSize))
		}
		baseUrl, err := url.Parse(c.endpoint)
		if err != nil {
			return nil, "", err
		}
		baseUrl.Path += fmt.Sprintf("/compute/v1/projects/%v/aggregated/autoscalers", req.GetProject())

		params := url.Values{}
		if req != nil && req.Filter != nil {
			params.Add("filter", fmt.Sprintf("%v", req.GetFilter()))
		}
		if req != nil && req.IncludeAllScopes != nil {
			params.Add("includeAllScopes", fmt.Sprintf("%v", req.GetIncludeAllScopes()))
		}
		if req != nil && req.MaxResults != nil {
			params.Add("maxResults", fmt.Sprintf("%v", req.GetMaxResults()))
		}
		if req != nil && req.OrderBy != nil {
			params.Add("orderBy", fmt.Sprintf("%v", req.GetOrderBy()))
		}
		if req != nil && req.PageToken != nil {
			params.Add("pageToken", fmt.Sprintf("%v", req.GetPageToken()))
		}
		if req != nil && req.ReturnPartialSuccess != nil {
			params.Add("returnPartialSuccess", fmt.Sprintf("%v", req.GetReturnPartialSuccess()))
		}

		baseUrl.RawQuery = params.Encode()

		// Build HTTP headers from client and context metadata.
		headers := buildHeaders(ctx, c.xGoogMetadata, metadata.Pairs("Content-Type", "application/json"))
		e := gax.Invoke(ctx, func(ctx context.Context, settings gax.CallSettings) error {
			if settings.Path != "" {
				baseUrl.Path = settings.Path
			}
			httpReq, err := http.NewRequest("GET", baseUrl.String(), nil)
			if err != nil {
				return err
			}
			httpReq.Header = headers

			httpRsp, err := c.httpClient.Do(httpReq)
			if err != nil {
				return err
			}
			defer httpRsp.Body.Close()

			if err = googleapi.CheckResponse(httpRsp); err != nil {
				return err
			}

			buf, err := ioutil.ReadAll(httpRsp.Body)
			if err != nil {
				return err
			}

			if err := unm.Unmarshal(buf, resp); err != nil {
				return maybeUnknownEnum(err)
			}

			return nil
		}, opts...)
		if e != nil {
			return nil, "", e
		}
		it.Response = resp

		elems := make([]AutoscalersScopedListPair, 0, len(resp.GetItems()))
		for k, v := range resp.GetItems() {
			elems = append(elems, AutoscalersScopedListPair{k, v})
		}
		sort.Slice(elems, func(i, j int) bool { return elems[i].Key < elems[j].Key })

		return elems, 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.GetMaxResults())
	it.pageInfo.Token = req.GetPageToken()

	return it
}

// Delete deletes the specified autoscaler.
func (c *autoscalersRESTClient) Delete(ctx context.Context, req *computepb.DeleteAutoscalerRequest, opts ...gax.CallOption) (*Operation, error) {
	baseUrl, err := url.Parse(c.endpoint)
	if err != nil {
		return nil, err
	}
	baseUrl.Path += fmt.Sprintf("/compute/v1/projects/%v/zones/%v/autoscalers/%v", req.GetProject(), req.GetZone(), req.GetAutoscaler())

	params := url.Values{}
	if req != nil && req.RequestId != nil {
		params.Add("requestId", fmt.Sprintf("%v", req.GetRequestId()))
	}

	baseUrl.RawQuery = params.Encode()

	// Build HTTP headers from client and context metadata.
	md := metadata.Pairs("x-goog-request-params", fmt.Sprintf("%s=%v&%s=%v&%s=%v", "project", url.QueryEscape(req.GetProject()), "zone", url.QueryEscape(req.GetZone()), "autoscaler", url.QueryEscape(req.GetAutoscaler())))

	headers := buildHeaders(ctx, c.xGoogMetadata, md, metadata.Pairs("Content-Type", "application/json"))
	opts = append((*c.CallOptions).Delete[0:len((*c.CallOptions).Delete):len((*c.CallOptions).Delete)], opts...)
	unm := protojson.UnmarshalOptions{AllowPartial: true, DiscardUnknown: true}
	resp := &computepb.Operation{}
	e := gax.Invoke(ctx, func(ctx context.Context, settings gax.CallSettings) error {
		if settings.Path != "" {
			baseUrl.Path = settings.Path
		}
		httpReq, err := http.NewRequest("DELETE", baseUrl.String(), nil)
		if err != nil {
			return err
		}
		httpReq = httpReq.WithContext(ctx)
		httpReq.Header = headers

		httpRsp, err := c.httpClient.Do(httpReq)
		if err != nil {
			return err
		}
		defer httpRsp.Body.Close()

		if err = googleapi.CheckResponse(httpRsp); err != nil {
			return err
		}

		buf, err := ioutil.ReadAll(httpRsp.Body)
		if err != nil {
			return err
		}

		if err := unm.Unmarshal(buf, resp); err != nil {
			return maybeUnknownEnum(err)
		}

		return nil
	}, opts...)
	if e != nil {
		return nil, e
	}
	op := &Operation{
		&zoneOperationsHandle{
			c:       c.operationClient,
			proto:   resp,
			project: req.GetProject(),
			zone:    req.GetZone(),
		},
	}
	return op, nil
}

// Get returns the specified autoscaler resource.
func (c *autoscalersRESTClient) Get(ctx context.Context, req *computepb.GetAutoscalerRequest, opts ...gax.CallOption) (*computepb.Autoscaler, error) {
	baseUrl, err := url.Parse(c.endpoint)
	if err != nil {
		return nil, err
	}
	baseUrl.Path += fmt.Sprintf("/compute/v1/projects/%v/zones/%v/autoscalers/%v", req.GetProject(), req.GetZone(), req.GetAutoscaler())

	// Build HTTP headers from client and context metadata.
	md := metadata.Pairs("x-goog-request-params", fmt.Sprintf("%s=%v&%s=%v&%s=%v", "project", url.QueryEscape(req.GetProject()), "zone", url.QueryEscape(req.GetZone()), "autoscaler", url.QueryEscape(req.GetAutoscaler())))

	headers := buildHeaders(ctx, c.xGoogMetadata, md, metadata.Pairs("Content-Type", "application/json"))
	opts = append((*c.CallOptions).Get[0:len((*c.CallOptions).Get):len((*c.CallOptions).Get)], opts...)
	unm := protojson.UnmarshalOptions{AllowPartial: true, DiscardUnknown: true}
	resp := &computepb.Autoscaler{}
	e := gax.Invoke(ctx, func(ctx context.Context, settings gax.CallSettings) error {
		if settings.Path != "" {
			baseUrl.Path = settings.Path
		}
		httpReq, err := http.NewRequest("GET", baseUrl.String(), nil)
		if err != nil {
			return err
		}
		httpReq = httpReq.WithContext(ctx)
		httpReq.Header = headers

		httpRsp, err := c.httpClient.Do(httpReq)
		if err != nil {
			return err
		}
		defer httpRsp.Body.Close()

		if err = googleapi.CheckResponse(httpRsp); err != nil {
			return err
		}

		buf, err := ioutil.ReadAll(httpRsp.Body)
		if err != nil {
			return err
		}

		if err := unm.Unmarshal(buf, resp); err != nil {
			return maybeUnknownEnum(err)
		}

		return nil
	}, opts...)
	if e != nil {
		return nil, e
	}
	return resp, nil
}

// Insert creates an autoscaler in the specified project using the data included in the request.
func (c *autoscalersRESTClient) Insert(ctx context.Context, req *computepb.InsertAutoscalerRequest, opts ...gax.CallOption) (*Operation, error) {
	m := protojson.MarshalOptions{AllowPartial: true}
	body := req.GetAutoscalerResource()
	jsonReq, err := m.Marshal(body)
	if err != nil {
		return nil, err
	}

	baseUrl, err := url.Parse(c.endpoint)
	if err != nil {
		return nil, err
	}
	baseUrl.Path += fmt.Sprintf("/compute/v1/projects/%v/zones/%v/autoscalers", req.GetProject(), req.GetZone())

	params := url.Values{}
	if req != nil && req.RequestId != nil {
		params.Add("requestId", fmt.Sprintf("%v", req.GetRequestId()))
	}

	baseUrl.RawQuery = params.Encode()

	// Build HTTP headers from client and context metadata.
	md := metadata.Pairs("x-goog-request-params", fmt.Sprintf("%s=%v&%s=%v", "project", url.QueryEscape(req.GetProject()), "zone", url.QueryEscape(req.GetZone())))

	headers := buildHeaders(ctx, c.xGoogMetadata, md, metadata.Pairs("Content-Type", "application/json"))
	opts = append((*c.CallOptions).Insert[0:len((*c.CallOptions).Insert):len((*c.CallOptions).Insert)], opts...)
	unm := protojson.UnmarshalOptions{AllowPartial: true, DiscardUnknown: true}
	resp := &computepb.Operation{}
	e := gax.Invoke(ctx, func(ctx context.Context, settings gax.CallSettings) error {
		if settings.Path != "" {
			baseUrl.Path = settings.Path
		}
		httpReq, err := http.NewRequest("POST", baseUrl.String(), bytes.NewReader(jsonReq))
		if err != nil {
			return err
		}
		httpReq = httpReq.WithContext(ctx)
		httpReq.Header = headers

		httpRsp, err := c.httpClient.Do(httpReq)
		if err != nil {
			return err
		}
		defer httpRsp.Body.Close()

		if err = googleapi.CheckResponse(httpRsp); err != nil {
			return err
		}

		buf, err := ioutil.ReadAll(httpRsp.Body)
		if err != nil {
			return err
		}

		if err := unm.Unmarshal(buf, resp); err != nil {
			return maybeUnknownEnum(err)
		}

		return nil
	}, opts...)
	if e != nil {
		return nil, e
	}
	op := &Operation{
		&zoneOperationsHandle{
			c:       c.operationClient,
			proto:   resp,
			project: req.GetProject(),
			zone:    req.GetZone(),
		},
	}
	return op, nil
}

// List retrieves a list of autoscalers contained within the specified zone.
func (c *autoscalersRESTClient) List(ctx context.Context, req *computepb.ListAutoscalersRequest, opts ...gax.CallOption) *AutoscalerIterator {
	it := &AutoscalerIterator{}
	req = proto.Clone(req).(*computepb.ListAutoscalersRequest)
	unm := protojson.UnmarshalOptions{AllowPartial: true, DiscardUnknown: true}
	it.InternalFetch = func(pageSize int, pageToken string) ([]*computepb.Autoscaler, string, error) {
		resp := &computepb.AutoscalerList{}
		if pageToken != "" {
			req.PageToken = proto.String(pageToken)
		}
		if pageSize > math.MaxInt32 {
			req.MaxResults = proto.Uint32(math.MaxInt32)
		} else if pageSize != 0 {
			req.MaxResults = proto.Uint32(uint32(pageSize))
		}
		baseUrl, err := url.Parse(c.endpoint)
		if err != nil {
			return nil, "", err
		}
		baseUrl.Path += fmt.Sprintf("/compute/v1/projects/%v/zones/%v/autoscalers", req.GetProject(), req.GetZone())

		params := url.Values{}
		if req != nil && req.Filter != nil {
			params.Add("filter", fmt.Sprintf("%v", req.GetFilter()))
		}
		if req != nil && req.MaxResults != nil {
			params.Add("maxResults", fmt.Sprintf("%v", req.GetMaxResults()))
		}
		if req != nil && req.OrderBy != nil {
			params.Add("orderBy", fmt.Sprintf("%v", req.GetOrderBy()))
		}
		if req != nil && req.PageToken != nil {
			params.Add("pageToken", fmt.Sprintf("%v", req.GetPageToken()))
		}
		if req != nil && req.ReturnPartialSuccess != nil {
			params.Add("returnPartialSuccess", fmt.Sprintf("%v", req.GetReturnPartialSuccess()))
		}

		baseUrl.RawQuery = params.Encode()

		// Build HTTP headers from client and context metadata.
		headers := buildHeaders(ctx, c.xGoogMetadata, metadata.Pairs("Content-Type", "application/json"))
		e := gax.Invoke(ctx, func(ctx context.Context, settings gax.CallSettings) error {
			if settings.Path != "" {
				baseUrl.Path = settings.Path
			}
			httpReq, err := http.NewRequest("GET", baseUrl.String(), nil)
			if err != nil {
				return err
			}
			httpReq.Header = headers

			httpRsp, err := c.httpClient.Do(httpReq)
			if err != nil {
				return err
			}
			defer httpRsp.Body.Close()

			if err = googleapi.CheckResponse(httpRsp); err != nil {
				return err
			}

			buf, err := ioutil.ReadAll(httpRsp.Body)
			if err != nil {
				return err
			}

			if err := unm.Unmarshal(buf, resp); err != nil {
				return maybeUnknownEnum(err)
			}

			return nil
		}, opts...)
		if e != nil {
			return nil, "", e
		}
		it.Response = resp
		return resp.GetItems(), 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.GetMaxResults())
	it.pageInfo.Token = req.GetPageToken()

	return it
}

// Patch updates an autoscaler in the specified project using the data included in the request. This method supports PATCH semantics and uses the JSON merge patch format and processing rules.
func (c *autoscalersRESTClient) Patch(ctx context.Context, req *computepb.PatchAutoscalerRequest, opts ...gax.CallOption) (*Operation, error) {
	m := protojson.MarshalOptions{AllowPartial: true}
	body := req.GetAutoscalerResource()
	jsonReq, err := m.Marshal(body)
	if err != nil {
		return nil, err
	}

	baseUrl, err := url.Parse(c.endpoint)
	if err != nil {
		return nil, err
	}
	baseUrl.Path += fmt.Sprintf("/compute/v1/projects/%v/zones/%v/autoscalers", req.GetProject(), req.GetZone())

	params := url.Values{}
	if req != nil && req.Autoscaler != nil {
		params.Add("autoscaler", fmt.Sprintf("%v", req.GetAutoscaler()))
	}
	if req != nil && req.RequestId != nil {
		params.Add("requestId", fmt.Sprintf("%v", req.GetRequestId()))
	}

	baseUrl.RawQuery = params.Encode()

	// Build HTTP headers from client and context metadata.
	md := metadata.Pairs("x-goog-request-params", fmt.Sprintf("%s=%v&%s=%v", "project", url.QueryEscape(req.GetProject()), "zone", url.QueryEscape(req.GetZone())))

	headers := buildHeaders(ctx, c.xGoogMetadata, md, metadata.Pairs("Content-Type", "application/json"))
	opts = append((*c.CallOptions).Patch[0:len((*c.CallOptions).Patch):len((*c.CallOptions).Patch)], opts...)
	unm := protojson.UnmarshalOptions{AllowPartial: true, DiscardUnknown: true}
	resp := &computepb.Operation{}
	e := gax.Invoke(ctx, func(ctx context.Context, settings gax.CallSettings) error {
		if settings.Path != "" {
			baseUrl.Path = settings.Path
		}
		httpReq, err := http.NewRequest("PATCH", baseUrl.String(), bytes.NewReader(jsonReq))
		if err != nil {
			return err
		}
		httpReq = httpReq.WithContext(ctx)
		httpReq.Header = headers

		httpRsp, err := c.httpClient.Do(httpReq)
		if err != nil {
			return err
		}
		defer httpRsp.Body.Close()

		if err = googleapi.CheckResponse(httpRsp); err != nil {
			return err
		}

		buf, err := ioutil.ReadAll(httpRsp.Body)
		if err != nil {
			return err
		}

		if err := unm.Unmarshal(buf, resp); err != nil {
			return maybeUnknownEnum(err)
		}

		return nil
	}, opts...)
	if e != nil {
		return nil, e
	}
	op := &Operation{
		&zoneOperationsHandle{
			c:       c.operationClient,
			proto:   resp,
			project: req.GetProject(),
			zone:    req.GetZone(),
		},
	}
	return op, nil
}

// Update updates an autoscaler in the specified project using the data included in the request.
func (c *autoscalersRESTClient) Update(ctx context.Context, req *computepb.UpdateAutoscalerRequest, opts ...gax.CallOption) (*Operation, error) {
	m := protojson.MarshalOptions{AllowPartial: true}
	body := req.GetAutoscalerResource()
	jsonReq, err := m.Marshal(body)
	if err != nil {
		return nil, err
	}

	baseUrl, err := url.Parse(c.endpoint)
	if err != nil {
		return nil, err
	}
	baseUrl.Path += fmt.Sprintf("/compute/v1/projects/%v/zones/%v/autoscalers", req.GetProject(), req.GetZone())

	params := url.Values{}
	if req != nil && req.Autoscaler != nil {
		params.Add("autoscaler", fmt.Sprintf("%v", req.GetAutoscaler()))
	}
	if req != nil && req.RequestId != nil {
		params.Add("requestId", fmt.Sprintf("%v", req.GetRequestId()))
	}

	baseUrl.RawQuery = params.Encode()

	// Build HTTP headers from client and context metadata.
	md := metadata.Pairs("x-goog-request-params", fmt.Sprintf("%s=%v&%s=%v", "project", url.QueryEscape(req.GetProject()), "zone", url.QueryEscape(req.GetZone())))

	headers := buildHeaders(ctx, c.xGoogMetadata, md, metadata.Pairs("Content-Type", "application/json"))
	opts = append((*c.CallOptions).Update[0:len((*c.CallOptions).Update):len((*c.CallOptions).Update)], opts...)
	unm := protojson.UnmarshalOptions{AllowPartial: true, DiscardUnknown: true}
	resp := &computepb.Operation{}
	e := gax.Invoke(ctx, func(ctx context.Context, settings gax.CallSettings) error {
		if settings.Path != "" {
			baseUrl.Path = settings.Path
		}
		httpReq, err := http.NewRequest("PUT", baseUrl.String(), bytes.NewReader(jsonReq))
		if err != nil {
			return err
		}
		httpReq = httpReq.WithContext(ctx)
		httpReq.Header = headers

		httpRsp, err := c.httpClient.Do(httpReq)
		if err != nil {
			return err
		}
		defer httpRsp.Body.Close()

		if err = googleapi.CheckResponse(httpRsp); err != nil {
			return err
		}

		buf, err := ioutil.ReadAll(httpRsp.Body)
		if err != nil {
			return err
		}

		if err := unm.Unmarshal(buf, resp); err != nil {
			return maybeUnknownEnum(err)
		}

		return nil
	}, opts...)
	if e != nil {
		return nil, e
	}
	op := &Operation{
		&zoneOperationsHandle{
			c:       c.operationClient,
			proto:   resp,
			project: req.GetProject(),
			zone:    req.GetZone(),
		},
	}
	return op, nil
}

// AutoscalerIterator manages a stream of *computepb.Autoscaler.
type AutoscalerIterator struct {
	items    []*computepb.Autoscaler
	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 []*computepb.Autoscaler, nextPageToken string, err error)
}

// PageInfo supports pagination. See the google.golang.org/api/iterator package for details.
func (it *AutoscalerIterator) 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 *AutoscalerIterator) Next() (*computepb.Autoscaler, error) {
	var item *computepb.Autoscaler
	if err := it.nextFunc(); err != nil {
		return item, err
	}
	item = it.items[0]
	it.items = it.items[1:]
	return item, nil
}

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

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

// AutoscalersScopedListPair is a holder type for string/*computepb.AutoscalersScopedList map entries
type AutoscalersScopedListPair struct {
	Key   string
	Value *computepb.AutoscalersScopedList
}

// AutoscalersScopedListPairIterator manages a stream of AutoscalersScopedListPair.
type AutoscalersScopedListPairIterator struct {
	items    []AutoscalersScopedListPair
	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 []AutoscalersScopedListPair, nextPageToken string, err error)
}

// PageInfo supports pagination. See the google.golang.org/api/iterator package for details.
func (it *AutoscalersScopedListPairIterator) 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 *AutoscalersScopedListPairIterator) Next() (AutoscalersScopedListPair, error) {
	var item AutoscalersScopedListPair
	if err := it.nextFunc(); err != nil {
		return item, err
	}
	item = it.items[0]
	it.items = it.items[1:]
	return item, nil
}

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

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