Multiple updates

pkg/streamcontrol/twitch/auth/client_code.go

@@ -0,0 +1,181 @@
+package auth
+
+import (
+	"context"
+	"fmt"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/facebookincubator/go-belt/tool/experimental/errmon"
+	"github.com/facebookincubator/go-belt/tool/logger"
+	"github.com/hashicorp/go-multierror"
+	"github.com/nicklaw5/helix/v2"
+	"github.com/xaionaro-go/observability"
+	"github.com/xaionaro-go/streamctl/pkg/oauthhandler"
+)
+
+type OAuthHandler func(context.Context, oauthhandler.OAuthHandlerArgument) error
+
+func NewClientCode(
+	ctx context.Context,
+	clientID string,
+	oauthHandler OAuthHandler,
+	getOAuthListenPortsFn func() []uint16,
+	onNewClientCode func(string),
+) (_err error) {
+	logger.Debugf(ctx, "getNewClientCode")
+	defer func() { logger.Debugf(ctx, "/getNewClientCode: %v", _err) }()
+
+	if oauthHandler == nil {
+		oauthHandler = oauthhandler.OAuth2HandlerViaCLI
+	}
+
+	ctx, ctxCancelFunc := context.WithCancel(ctx)
+	cancelFunc := func() {
+		logger.Debugf(ctx, "cancelling the context")
+		ctxCancelFunc()
+	}
+
+	var errWg sync.WaitGroup
+	var resultErr error
+	errCh := make(chan error)
+	errWg.Add(1)
+	observability.Go(ctx, func(ctx context.Context) {
+		errWg.Done()
+		for err := range errCh {
+			errmon.ObserveErrorCtx(ctx, err)
+			resultErr = multierror.Append(resultErr, err)
+		}
+	})
+
+	alreadyListening := map[uint16]struct{}{}
+	var wg sync.WaitGroup
+	success := false
+
+	startHandlerForPort := func(listenPort uint16) {
+		if _, ok := alreadyListening[listenPort]; ok {
+			return
+		}
+		alreadyListening[listenPort] = struct{}{}
+
+		logger.Debugf(ctx, "starting the oauth handler at port %d", listenPort)
+		wg.Add(1)
+		{
+			listenPort := listenPort
+			observability.Go(ctx, func(ctx context.Context) {
+				defer func() { logger.Debugf(ctx, "ended the oauth handler at port %d", listenPort) }()
+				defer wg.Done()
+				authURL := GetAuthorizationURL(
+					&helix.AuthorizationURLParams{
+						ResponseType: "code", // or "token"
+						Scopes: []string{
+							"user:read:chat",
+							"chat:read",
+							"chat:edit",
+							"channel:manage:broadcast",
+							"moderator:manage:chat_messages",
+							"moderator:manage:banned_users",
+						},
+					},
+					clientID,
+					RedirectURI(listenPort),
+				)
+
+				arg := oauthhandler.OAuthHandlerArgument{
+					AuthURL:    authURL,
+					ListenPort: listenPort,
+					ExchangeFn: func(ctx context.Context, code string) (_err error) {
+						logger.Debugf(ctx, "ExchangeFn()")
+						defer func() { logger.Debugf(ctx, "/ExchangeFn(): %v", _err) }()
+						if code == "" {
+							return fmt.Errorf("code is empty")
+						}
+						onNewClientCode(code)
+						return nil
+					},
+				}
+
+				err := oauthHandler(ctx, arg)
+				if err != nil {
+					errCh <- fmt.Errorf("unable to get or exchange the oauth code to a token: %w", err)
+					return
+				}
+				cancelFunc()
+				success = true
+			})
+		}
+	}
+
+	// TODO: either support only one port as in New, or support multiple
+	//       ports as we do below
+	getPortsFn := getOAuthListenPortsFn
+	if getPortsFn == nil {
+		return fmt.Errorf("the function GetOAuthListenPorts is not set")
+	}
+
+	for _, listenPort := range getPortsFn() {
+		startHandlerForPort(listenPort)
+	}
+
+	wg.Add(1)
+	observability.Go(ctx, func(ctx context.Context) {
+		defer wg.Done()
+		t := time.NewTicker(time.Second)
+		defer t.Stop()
+		for {
+			select {
+			case <-ctx.Done():
+				return
+			case <-t.C:
+			}
+			ports := getPortsFn()
+			logger.Tracef(ctx, "oauth listener ports: %#+v", ports)
+
+			for _, listenPort := range ports {
+				startHandlerForPort(listenPort)
+			}
+		}
+	})
+
+	observability.Go(ctx, func(ctx context.Context) {
+		wg.Wait()
+		close(errCh)
+	})
+	<-ctx.Done()
+	logger.Debugf(ctx, "did successfully took a new client code? -- %v", success)
+	if !success {
+		errWg.Wait()
+		return resultErr
+	}
+	return nil
+}
+
+func RedirectURI(listenPort uint16) string {
+	return fmt.Sprintf("http://localhost:%d/", listenPort)
+}
+
+func GetAuthorizationURL(
+	params *helix.AuthorizationURLParams,
+	clientID string,
+	redirectURI string,
+) string {
+	url := helix.AuthBaseURL + "/authorize"
+	url += "?response_type=" + params.ResponseType
+	url += "&client_id=" + clientID
+	url += "&redirect_uri=" + redirectURI
+
+	if params.State != "" {
+		url += "&state=" + params.State
+	}
+
+	if params.ForceVerify {
+		url += "&force_verify=true"
+	}
+
+	if len(params.Scopes) != 0 {
+		url += "&scope=" + strings.Join(params.Scopes, "%20")
+	}
+
+	return url
+}