package option

import (
	"crypto/tls"
	"net/http"

	"golang.org/x/oauth2"
	"google.golang.org/api/internal"
	"google.golang.org/api/internal/impersonate"
	"google.golang.org/grpc"
)

type ClientOption interface {
	Apply(*internal.DialSettings)
}

func WithTokenSource(s oauth2.TokenSource) ClientOption {
	return withTokenSource{s}
}

type withTokenSource struct{ ts oauth2.TokenSource }

func (w withTokenSource) Apply(o *internal.DialSettings) {
	o.TokenSource = w.ts
}

type withCredFile string

func (w withCredFile) Apply(o *internal.DialSettings) {
	o.CredentialsFile = string(w)
}

func WithCredentialsFile(filename string) ClientOption {
	return withCredFile(filename)
}

func WithServiceAccountFile(filename string) ClientOption {
	return WithCredentialsFile(filename)
}

func WithCredentialsJSON(p []byte) ClientOption {
	return withCredentialsJSON(p)
}

type withCredentialsJSON []byte

func (w withCredentialsJSON) Apply(o *internal.DialSettings) {
	o.CredentialsJSON = make([]byte, len(w))
	copy(o.CredentialsJSON, w)
}

func WithEndpoint(url string) ClientOption {
	return withEndpoint(url)
}

type withEndpoint string

func (w withEndpoint) Apply(o *internal.DialSettings) {
	o.Endpoint = string(w)
}

func WithScopes(scope ...string) ClientOption {
	return withScopes(scope)
}

type withScopes []string

func (w withScopes) Apply(o *internal.DialSettings) {
	o.Scopes = make([]string, len(w))
	copy(o.Scopes, w)
}

func WithUserAgent(ua string) ClientOption {
	return withUA(ua)
}

type withUA string

func (w withUA) Apply(o *internal.DialSettings) { o.UserAgent = string(w) }

func WithHTTPClient(client *http.Client) ClientOption {
	return withHTTPClient{client}
}

type withHTTPClient struct{ client *http.Client }

func (w withHTTPClient) Apply(o *internal.DialSettings) {
	o.HTTPClient = w.client
}

func WithGRPCConn(conn *grpc.ClientConn) ClientOption {
	return withGRPCConn{conn}
}

type withGRPCConn struct{ conn *grpc.ClientConn }

func (w withGRPCConn) Apply(o *internal.DialSettings) {
	o.GRPCConn = w.conn
}

func WithGRPCDialOption(opt grpc.DialOption) ClientOption {
	return withGRPCDialOption{opt}
}

type withGRPCDialOption struct{ opt grpc.DialOption }

func (w withGRPCDialOption) Apply(o *internal.DialSettings) {
	o.GRPCDialOpts = append(o.GRPCDialOpts, w.opt)
}

func WithGRPCConnectionPool(size int) ClientOption {
	return withGRPCConnectionPool(size)
}

type withGRPCConnectionPool int

func (w withGRPCConnectionPool) Apply(o *internal.DialSettings) {
	o.GRPCConnPoolSize = int(w)
}

func WithAPIKey(apiKey string) ClientOption {
	return withAPIKey(apiKey)
}

type withAPIKey string

func (w withAPIKey) Apply(o *internal.DialSettings) { o.APIKey = string(w) }

func WithAudiences(audience ...string) ClientOption {
	return withAudiences(audience)
}

type withAudiences []string

func (w withAudiences) Apply(o *internal.DialSettings) {
	o.Audiences = make([]string, len(w))
	copy(o.Audiences, w)
}

func WithoutAuthentication() ClientOption {
	return withoutAuthentication{}
}

type withoutAuthentication struct{}

func (w withoutAuthentication) Apply(o *internal.DialSettings) { o.NoAuth = true }

func WithQuotaProject(quotaProject string) ClientOption {
	return withQuotaProject(quotaProject)
}

type withQuotaProject string

func (w withQuotaProject) Apply(o *internal.DialSettings) {
	o.QuotaProject = string(w)
}

func WithRequestReason(requestReason string) ClientOption {
	return withRequestReason(requestReason)
}

type withRequestReason string

func (w withRequestReason) Apply(o *internal.DialSettings) {
	o.RequestReason = string(w)
}

func WithTelemetryDisabled() ClientOption {
	return withTelemetryDisabled{}
}

type withTelemetryDisabled struct{}

func (w withTelemetryDisabled) Apply(o *internal.DialSettings) {
	o.TelemetryDisabled = true
}

type ClientCertSource = func(*tls.CertificateRequestInfo) (*tls.Certificate, error)

func WithClientCertSource(s ClientCertSource) ClientOption {
	return withClientCertSource{s}
}

type withClientCertSource struct{ s ClientCertSource }

func (w withClientCertSource) Apply(o *internal.DialSettings) {
	o.ClientCertSource = w.s
}

func ImpersonateCredentials(target string, delegates ...string) ClientOption {
	return impersonateServiceAccount{
		target:    target,
		delegates: delegates,
	}
}

type impersonateServiceAccount struct {
	target    string
	delegates []string
}

func (i impersonateServiceAccount) Apply(o *internal.DialSettings) {
	o.ImpersonationConfig = &impersonate.Config{
		Target: i.target,
	}
	o.ImpersonationConfig.Delegates = make([]string, len(i.delegates))
	copy(o.ImpersonationConfig.Delegates, i.delegates)