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

@@ -26,6 +26,7 @@
 
 #ifdef BROWSER_AVAILABLE
 #include "window-dock-browser.hpp"
+#include <QTimerEvent>
 #endif
 
 using namespace json11;
@@ -130,14 +131,6 @@ 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)
@@ -163,7 +156,6 @@ 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);
@@ -350,6 +342,36 @@ std::shared_ptr<Auth> YoutubeAuth::Login(QWidget *owner,
 }
 
 #ifdef BROWSER_AVAILABLE
+void YoutubeChatDock::timerEvent(QTimerEvent *event)
+{
+	if (event->timerId() != awaitLoginTimer)
+		return;
+
+	QPointer<YoutubeChatDock> this_ = this;
+	auto cb = [this_](bool found) {
+		bool previouslyLoggedIn = this_->isLoggedIn;
+		this_->isLoggedIn = found;
+		if (found ^ previouslyLoggedIn) {
+			// There was a change in login state.
+			QMetaObject::invokeMethod(this_, "EnableChatInput",
+						  Qt::QueuedConnection,
+						  Q_ARG(bool, !found));
+			this_->cefWidget->reloadPage();
+			OBSBasic *main = OBSBasic::Get();
+			if (main->GetYouTubeAppDock() != nullptr) {
+				QMetaObject::invokeMethod(
+					main->GetYouTubeAppDock(),
+					"SettingsUpdated", Qt::QueuedConnection,
+					Q_ARG(bool, !found));
+			}
+		}
+	};
+	if (panel_cookies) {
+		panel_cookies->CheckForCookie("https://www.youtube.com", "SID",
+					      cb);
+	}
+}
+
 YoutubeChatDock::YoutubeChatDock(const QString &title) : BrowserDock(title)
 {
 	lineEdit = new LineEditAutoResize();
@@ -368,6 +390,9 @@ YoutubeChatDock::YoutubeChatDock(const QString &title) : BrowserDock(title)
 			 &YoutubeChatDock::SendChatMessage);
 	QWidget::connect(sendButton, &QPushButton::pressed, this,
 			 &YoutubeChatDock::SendChatMessage);
+
+	// Check youtube.com login status periodically
+	awaitLoginTimer = startTimer(1000);
 }
 
 void YoutubeChatDock::SetWidget(QCefWidget *widget_)
@@ -425,9 +450,10 @@ 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

@@ -11,15 +11,22 @@
 #include "window-dock-browser.hpp"
 #include "lineedit-autoresize.hpp"
 #include <QHBoxLayout>
+#include <QTimerEvent>
+
 class YoutubeChatDock : public BrowserDock {
 	Q_OBJECT
 
 private:
 	std::string apiChatId;
+	int awaitLoginTimer;
+	bool isLoggedIn;
 	LineEditAutoResize *lineEdit;
 	QPushButton *sendButton;
 	QHBoxLayout *chatLayout;
 
+protected:
+	void timerEvent(QTimerEvent *event);
+
 public:
 	YoutubeChatDock(const QString &title);
 	void SetWidget(QCefWidget *widget_);
@@ -28,7 +35,7 @@ class YoutubeChatDock : public BrowserDock {
 private slots:
 	void SendChatMessage();
 	void ShowErrorMessage(const QString &error);
-	void EnableChatInput();
+	void EnableChatInput(bool visible = true);
 };
 #endif
 

UI/window-dock-youtube-app.hpp

@@ -17,7 +17,6 @@ class YouTubeAppDock : public BrowserDock {
 
 	void AccountConnected();
 	void AccountDisconnected();
-	void SettingsUpdated(bool cleanup = false);
 	void Update();
 
 	void BroadcastCreated(const char *stream_id);
@@ -29,6 +28,9 @@ 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);