client: handle channel updates

Signed-off-by: Sumner Evans <sumner.evans@automattic.com>

pkg/connector/api.go

@@ -11,9 +11,38 @@ type hasUserUpdates interface {
 	GetUsers() []tg.UserClass
 }
 
+type hasChatUpdates interface {
+	GetChats() []tg.ChatClass
+}
+
 type hasUpdates interface {
 	hasUserUpdates
-	GetChats() []tg.ChatClass
+	hasChatUpdates
+}
+
+func handleUserUpdates[U hasUserUpdates](ctx context.Context, t *TelegramClient, resp hasUserUpdates) error {
+	for _, user := range resp.GetUsers() {
+		user, ok := user.(*tg.User)
+		if !ok {
+			return fmt.Errorf("user is %T not *tg.User", user)
+		}
+		_, err := t.updateGhost(ctx, user.ID, user)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func handleChatUpdates[U hasChatUpdates](ctx context.Context, t *TelegramClient, resp hasChatUpdates) error {
+	for _, c := range resp.GetChats() {
+		if channel, ok := c.(*tg.Channel); ok {
+			if err := t.updateChannel(ctx, channel); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
 }
 
 func APICallWithOnlyUserUpdates[U hasUserUpdates](ctx context.Context, t *TelegramClient, fn func() (U, error)) (U, error) {
@@ -21,35 +50,25 @@ func APICallWithOnlyUserUpdates[U hasUserUpdates](ctx context.Context, t *Telegr
 	if err != nil {
 		return *new(U), err
 	}
+	return resp, handleUserUpdates[U](ctx, t, resp)
+}
 
-	for _, user := range resp.GetUsers() {
-		user, ok := user.(*tg.User)
-		if !ok {
-			return *new(U), fmt.Errorf("user is %T not *tg.User", user)
-		}
-		_, err := t.updateGhost(ctx, user.ID, user)
-		if err != nil {
-			return *new(U), err
-		}
+func APICallWithOnlyChatUpdates[U hasChatUpdates](ctx context.Context, t *TelegramClient, fn func() (U, error)) (U, error) {
+	resp, err := fn()
+	if err != nil {
+		return *new(U), err
 	}
-
-	return resp, nil
+	return resp, handleChatUpdates[U](ctx, t, resp)
 }
 
 // Wrapper for API calls that return a response with updates.
 func APICallWithUpdates[U hasUpdates](ctx context.Context, t *TelegramClient, fn func() (U, error)) (U, error) {
-	resp, err := APICallWithOnlyUserUpdates(ctx, t, fn)
+	resp, err := fn()
 	if err != nil {
 		return *new(U), err
 	}
-
-	for _, c := range resp.GetChats() {
-		if channel, ok := c.(*tg.Channel); ok {
-			if err := t.updateChannel(ctx, channel); err != nil {
-				return *new(U), err
-			}
-		}
+	if err = handleUserUpdates[U](ctx, t, resp); err != nil {
+		return *new(U), err
 	}
-
-	return resp, nil
+	return resp, handleChatUpdates[U](ctx, t, resp)
 }