// NewClient returns a new log client, logging to the named log in the
// provided project.
//
// The exported fields on the returned client may be modified before
// the client is used for logging. Once log entries are in flight,
// the fields must not be modified.
func NewClient(ctx context.Context, projectID, logName string, opts ...cloud.ClientOption) (*Client, error) {
	httpClient, endpoint, err := transport.NewHTTPClient(ctx, append([]cloud.ClientOption{
		cloud.WithEndpoint(prodAddr),
		cloud.WithScopes(Scope),
		cloud.WithUserAgent(userAgent),
	}, opts...)...)
	if err != nil {
		return nil, err
	}
	svc, err := api.New(httpClient)
	if err != nil {
		return nil, err
	}
	svc.BasePath = endpoint
	c := &Client{
		svc:     svc,
		logs:    api.NewProjectsLogsEntriesService(svc),
		logName: logName,
		projID:  projectID,
	}
	for i := range c.writer {
		level := Level(i)
		c.writer[level] = levelWriter{level, c}
		c.logger[level] = log.New(c.writer[level], "", 0)
	}
	return c, nil
}

// NewClient creates a new PubSub client.
func NewClient(ctx context.Context, projectID string, opts ...cloud.ClientOption) (*Client, error) {
	var o []cloud.ClientOption
	// Environment variables for gcloud emulator:
	// https://cloud.google.com/sdk/gcloud/reference/beta/emulators/pubsub/
	if addr := os.Getenv("PUBSUB_EMULATOR_HOST"); addr != "" {
		o = []cloud.ClientOption{
			cloud.WithEndpoint("http://" + addr + "/"),
			cloud.WithBaseHTTP(http.DefaultClient),
		}
	} else {
		o = []cloud.ClientOption{
			cloud.WithEndpoint(prodAddr),
			cloud.WithScopes(raw.PubsubScope, raw.CloudPlatformScope),
			cloud.WithUserAgent(userAgent),
		}
	}
	o = append(o, opts...)
	httpClient, endpoint, err := transport.NewHTTPClient(ctx, o...)
	if err != nil {
		return nil, fmt.Errorf("dialing: %v", err)
	}

	s, err := newPubSubService(httpClient, endpoint)
	if err != nil {
		return nil, fmt.Errorf("constructing pubsub client: %v", err)
	}

	c := &Client{
		projectID: projectID,
		s:         s,
	}

	return c, nil
}

// NewClient creates a new Google Cloud Storage client.
func NewClient(ctx context.Context, opts ...cloud.ClientOption) (*Client, error) {
	hc, _, err := transport.NewHTTPClient(ctx, opts...)
	if err != nil {
		return nil, fmt.Errorf("dialing: %v", err)
	}
	rawService, err := raw.New(hc)
	if err != nil {
		return nil, fmt.Errorf("storage client: %v", err)
	}
	return &Client{
		hc:  hc,
		raw: rawService,
	}, nil
}

// NewClient creates a new Google Cloud Storage client.
// The default scope is ScopeFullControl. To use a different scope, like ScopeReadOnly, use cloud.WithScopes.
func NewClient(ctx context.Context, opts ...cloud.ClientOption) (*Client, error) {
	o := []cloud.ClientOption{
		cloud.WithScopes(ScopeFullControl),
		cloud.WithUserAgent(userAgent),
	}
	opts = append(o, opts...)
	hc, _, err := transport.NewHTTPClient(ctx, opts...)
	if err != nil {
		return nil, fmt.Errorf("dialing: %v", err)
	}
	rawService, err := raw.New(hc)
	if err != nil {
		return nil, fmt.Errorf("storage client: %v", err)
	}
	return &Client{
		hc:  hc,
		raw: rawService,
	}, nil
}

// NewClient create a new PubSub client.
func NewClient(ctx context.Context, projectID string, opts ...cloud.ClientOption) (*Client, error) {
	o := []cloud.ClientOption{
		cloud.WithEndpoint(prodAddr),
		cloud.WithScopes(raw.PubsubScope, raw.CloudPlatformScope),
		cloud.WithUserAgent(userAgent),
	}
	o = append(o, opts...)
	httpClient, endpoint, err := transport.NewHTTPClient(ctx, o...)
	if err != nil {
		return nil, fmt.Errorf("dialing: %v", err)
	}

	s, err := newPubSubService(httpClient, endpoint)

	c := &Client{
		projectID: projectID,
		s:         s,
	}

	return c, nil
}

// NewClient constructs a new Client which can perform BigQuery operations.
// Operations performed via the client are billed to the specified GCP project.
func NewClient(ctx context.Context, projectID string, opts ...cloud.ClientOption) (*Client, error) {
	o := []cloud.ClientOption{
		cloud.WithEndpoint(prodAddr),
		cloud.WithScopes(Scope),
		cloud.WithUserAgent(userAgent),
	}
	o = append(o, opts...)
	httpClient, endpoint, err := transport.NewHTTPClient(ctx, o...)
	if err != nil {
		return nil, fmt.Errorf("dialing: %v", err)
	}

	s, err := newBigqueryService(httpClient, endpoint)
	if err != nil {
		return nil, fmt.Errorf("constructing bigquery client: %v", err)
	}

	c := &Client{
		service:   s,
		projectID: projectID,
	}
	return c, nil
}

// NewClient creates a new Google Stackdriver Trace client.
func NewClient(ctx context.Context, projectID string, opts ...cloud.ClientOption) (*Client, error) {
	o := []cloud.ClientOption{
		cloud.WithScopes(cloudPlatformScope),
		cloud.WithUserAgent(userAgent),
	}
	o = append(o, opts...)
	hc, basePath, err := transport.NewHTTPClient(ctx, o...)
	if err != nil {
		return nil, fmt.Errorf("creating HTTP client for Google Stackdriver Trace API: %v", err)
	}
	apiService, err := api.New(hc)
	if err != nil {
		return nil, fmt.Errorf("creating Google Stackdriver Trace API client: %v", err)
	}
	if basePath != "" {
		// An option set a basepath, so override api.New's default.
		apiService.BasePath = basePath
	}
	return &Client{
		service:   apiService,
		projectID: projectID,
	}, nil
}