fix(helix-chat): show better error messages (#5276)

CHANGELOG.md

@@ -186,7 +186,7 @@
 - Dev: Added signal to invalidate paint buffers of channel views without forcing a relayout. (#5123)
 - Dev: Specialize `Atomic<std::shared_ptr<T>>` if underlying standard library supports it. (#5133)
 - Dev: Added the `developer_name` field to the Linux AppData specification. (#5138)
-- Dev: Twitch messages can be sent using Twitch's Helix API instead of IRC (disabled by default). (#5200)
+- Dev: Twitch messages can be sent using Twitch's Helix API instead of IRC (disabled by default). (#5200, #5276)
 - Dev: Added estimation for image sizes to avoid layout shifts. (#5192)
 - Dev: Added the `launachable` entry to Linux AppData. (#5210)
 - Dev: Cleaned up and optimized resources. (#5222)

src/providers/twitch/TwitchIrcServer.cpp

@@ -39,9 +39,17 @@ const QString SEVENTV_EVENTAPI_URL = "wss://events.7tv.io/v3";
 void sendHelixMessage(const std::shared_ptr<TwitchChannel> &channel,
                       const QString &message, const QString &replyParentId = {})
 {
+    auto broadcasterID = channel->roomId();
+    if (broadcasterID.isEmpty())
+    {
+        channel->addMessage(makeSystemMessage(
+            "Sending messages in this channel isn't possible."));
+        return;
+    }
+
     getHelix()->sendChatMessage(
         {
-            .broadcasterID = channel->roomId(),
+            .broadcasterID = broadcasterID,
             .senderID =
                 getIApp()->getAccounts()->twitch.getCurrent()->getUserId(),
             .message = message,
@@ -68,13 +76,18 @@ void sendHelixMessage(const std::shared_ptr<TwitchChannel> &channel,
             }();
             chan->addMessage(errorMessage);
         },
-        [weak = std::weak_ptr(channel)](auto error, const auto &message) {
+        [weak = std::weak_ptr(channel)](auto error, auto message) {
             auto chan = weak.lock();
             if (!chan)
             {
                 return;
             }
 
+            if (message.isEmpty())
+            {
+                message = "(empty message)";
+            }
+
             using Error = decltype(error);
 
             auto errorMessage = [&]() -> QString {