UI: Enable first-party YouTube Chat features in OBS

Unlock the full feature set of the YouTube Chat dock in OBS by removing
custom scripting/CSS logic. Enable the signed-in experience for live
streaming content creators (sharing login credentials with the YouTube
Control panel dock, see
#10747).

This will allow OBS users to utilize features _already_ supported in the
YouTube Chat plugin, such as

* creating polls
* managing Q&A sessions
* a rich emoji set in the input panel
* emoji fountains
* moderation tools

and many more. These features are available to users who are logged-in
to YouTube Chat and/or the YouTube Control panel.

UI/auth-youtube.cpp

@@ -138,14 +138,6 @@ bool YoutubeAuth::LoadInternal()
 	return implicit ? !token.empty() : !refresh_token.empty();
 }
 
-#ifdef BROWSER_AVAILABLE
-static const char *ytchat_script = "\
-const obsCSS = document.createElement('style');\
-obsCSS.innerHTML = \"#panel-pages.yt-live-chat-renderer {display: none;}\
-yt-live-chat-viewer-engagement-message-renderer {display: none;}\";\
-document.querySelector('head').appendChild(obsCSS);";
-#endif
-
 void YoutubeAuth::LoadUI()
 {
 	if (uiLoaded)
@@ -171,7 +163,6 @@ void YoutubeAuth::LoadUI()
 
 	browser = cef->create_widget(chat, YOUTUBE_CHAT_PLACEHOLDER_URL,
 				     panel_cookies);
-	browser->setStartupScript(ytchat_script);
 
 	chat->SetWidget(browser);
 	main->AddDockWidget(chat, Qt::RightDockWidgetArea);
@@ -219,6 +210,7 @@ void YoutubeAuth::ResetChat()
 {
 #ifdef BROWSER_AVAILABLE
 	if (chat && chat->cefWidget) {
+		chat->SetApiChatId("");
 		chat->cefWidget->setURL(YOUTUBE_CHAT_PLACEHOLDER_URL);
 	}
 #endif
@@ -399,13 +391,44 @@ void YoutubeChatDock::SetWidget(QCefWidget *widget_)
 	setWidget(widget);
 
 	cefWidget.reset(widget_);
+
+	QWidget::connect(cefWidget.get(), &QCefWidget::urlChanged, this,
+			 &YoutubeChatDock::YoutubeCookieCheck);
 }
 
 void YoutubeChatDock::SetApiChatId(const std::string &id)
 {
 	this->apiChatId = id;
-	QMetaObject::invokeMethod(this, "EnableChatInput",
-				  Qt::QueuedConnection);
+	QMetaObject::invokeMethod(this, "EnableChatInput", Qt::QueuedConnection,
+				  Q_ARG(bool, !id.empty()));
+}
+
+void YoutubeChatDock::YoutubeCookieCheck()
+{
+	QPointer<YoutubeChatDock> this_ = this;
+	auto cb = [this_](bool currentlyLoggedIn) {
+		bool previouslyLoggedIn = this_->isLoggedIn;
+		this_->isLoggedIn = currentlyLoggedIn;
+		bool loginStateChanged =
+			(currentlyLoggedIn && !previouslyLoggedIn) ||
+			(!currentlyLoggedIn && previouslyLoggedIn);
+		if (loginStateChanged) {
+			QMetaObject::invokeMethod(
+				this_, "EnableChatInput", Qt::QueuedConnection,
+				Q_ARG(bool, !currentlyLoggedIn));
+			OBSBasic *main = OBSBasic::Get();
+			if (main->GetYouTubeAppDock() != nullptr) {
+				QMetaObject::invokeMethod(
+					main->GetYouTubeAppDock(),
+					"SettingsUpdated", Qt::QueuedConnection,
+					Q_ARG(bool, !currentlyLoggedIn));
+			}
+		}
+	};
+	if (panel_cookies) {
+		panel_cookies->CheckForCookie("https://www.youtube.com", "SID",
+					      cb);
+	}
 }
 
 void YoutubeChatDock::SendChatMessage()
@@ -442,9 +465,10 @@ void YoutubeChatDock::ShowErrorMessage(const QString &error)
 			     QTStr("YouTube.Chat.Error.Text").arg(error));
 }
 
-void YoutubeChatDock::EnableChatInput()
+void YoutubeChatDock::EnableChatInput(bool visible)
 {
-	lineEdit->setVisible(true);
-	sendButton->setVisible(true);
+	bool setVisible = visible && !isLoggedIn;
+	lineEdit->setVisible(setVisible);
+	sendButton->setVisible(setVisible);
 }
 #endif

UI/auth-youtube.hpp

@@ -16,6 +16,7 @@ class YoutubeChatDock : public BrowserDock {
 
 private:
 	std::string apiChatId;
+	bool isLoggedIn;
 	LineEditAutoResize *lineEdit;
 	QPushButton *sendButton;
 	QHBoxLayout *chatLayout;
@@ -26,9 +27,10 @@ class YoutubeChatDock : public BrowserDock {
 	void SetApiChatId(const std::string &id);
 
 private slots:
+	void YoutubeCookieCheck();
 	void SendChatMessage();
 	void ShowErrorMessage(const QString &error);
-	void EnableChatInput();
+	void EnableChatInput(bool visible);
 };
 #endif
 

UI/window-dock-youtube-app.hpp

@@ -16,7 +16,6 @@ class YouTubeAppDock : public BrowserDock {
 
 	void AccountConnected();
 	void AccountDisconnected();
-	void SettingsUpdated(bool cleanup = false);
 	void Update();
 
 	void BroadcastCreated(const char *stream_id);
@@ -28,6 +27,9 @@ class YouTubeAppDock : public BrowserDock {
 	static YoutubeApiWrappers *GetYTApi();
 	static void CleanupYouTubeUrls();
 
+public slots:
+	void SettingsUpdated(bool cleanup = false);
+
 protected:
 	void IngestionStarted(const char *stream_id, streaming_mode_t mode);
 	void IngestionStopped(const char *stream_id, streaming_mode_t mode);