Make /delete errors a bit more verbose (#3350)

Co-authored-by: Rasmus Karlsson <rasmus.karlsson@pajlada.com>

src/controllers/commands/CommandController.cpp

@@ -866,6 +866,43 @@ void CommandController::initialize(Settings &, Paths &paths)
 
         return "";
     });
+    this->registerCommand(
+        "/delete", [](const QStringList &words, ChannelPtr channel) -> QString {
+            // This is a wrapper over the standard Twitch /delete command
+            // We use this to ensure the user gets better error messages for missing or malformed arguments
+            if (words.size() < 2)
+            {
+                channel->addMessage(
+                    makeSystemMessage("Usage: /delete <msg-id> - Deletes the "
+                                      "specified message."));
+                return "";
+            }
+
+            auto messageID = words.at(1);
+            auto uuid = QUuid(messageID);
+            if (uuid.isNull())
+            {
+                // The message id must be a valid UUID
+                channel->addMessage(makeSystemMessage(
+                    QString("Invalid msg-id: \"%1\"").arg(messageID)));
+                return "";
+            }
+
+            auto msg = channel->findMessage(messageID);
+            if (msg != nullptr)
+            {
+                if (msg->loginName == channel->getName() &&
+                    !channel->isBroadcaster())
+                {
+                    channel->addMessage(makeSystemMessage(
+                        "You cannot delete the broadcaster's messages unless "
+                        "you are the broadcaster."));
+                    return "";
+                }
+            }
+
+            return QString("/delete ") + messageID;
+        });
 
     this->registerCommand("/raw", [](const QStringList &words, ChannelPtr) {
         getApp()->twitch2->sendRawMessage(words.mid(1).join(" "));

src/providers/twitch/IrcMessageHandler.cpp

@@ -807,10 +807,17 @@ void IrcMessageHandler::handleNoticeMessage(Communi::IrcNoticeMessage *message)
         }
 
         QString tags = message->tags().value("msg-id").toString();
-        if (tags == "bad_delete_message_error" || tags == "usage_delete")
+        if (tags == "usage_delete")
         {
             channel->addMessage(makeSystemMessage(
-                "Usage: /delete <msg-id>. Can't take more than one argument"));
+                "Usage: /delete <msg-id> - Deletes the specified message. "
+                "Can't take more than one argument."));
+        }
+        else if (tags == "bad_delete_message_error")
+        {
+            channel->addMessage(makeSystemMessage(
+                "There was a problem deleting the message. "
+                "It might be from another channel or too old to delete."));
         }
         else if (tags == "host_on" || tags == "host_target_went_offline")
         {