Fixed comma appended to username completion when not at the beginning of the message (#3060)

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

src/widgets/splits/Split.cpp

@@ -306,6 +306,11 @@ ChannelView &Split::getChannelView()
     return *this->view_;
 }
 
+SplitInput &Split::getInput()
+{
+    return *this->input_;
+}
+
 void Split::updateInputPlaceholder()
 {
     if (!this->getChannel()->isTwitchChannel())

src/widgets/splits/Split.hpp

@@ -47,6 +47,7 @@ public:
     pajlada::Signals::NoArgSignal focusLost;
 
     ChannelView &getChannelView();
+    SplitInput &getInput();
 
     IndirectChannel getIndirectChannel();
     ChannelPtr getChannel();

src/widgets/splits/SplitInput.cpp

@@ -8,6 +8,7 @@
 #include "singletons/Settings.hpp"
 #include "singletons/Theme.hpp"
 #include "util/Clamp.hpp"
+#include "util/Helpers.hpp"
 #include "util/LayoutCreator.hpp"
 #include "widgets/Notebook.hpp"
 #include "widgets/Scrollbar.hpp"
@@ -568,8 +569,10 @@ void SplitInput::insertCompletionText(const QString &input_)
         }
         else if (text[i] == '@')
         {
-            input = "@" + input_ +
-                    (getSettings()->mentionUsersWithComma ? ", " : " ");
+            const auto userMention =
+                formatUserMention(input_, edit.isFirstWord(),
+                                  getSettings()->mentionUsersWithComma);
+            input = "@" + userMention + " ";
             done = true;
         }
 
@@ -595,6 +598,11 @@ void SplitInput::clearSelection()
     this->ui_.textEdit->setTextCursor(c);
 }
 
+bool SplitInput::isEditFirstWord() const
+{
+    return this->ui_.textEdit->isFirstWord();
+}
+
 QString SplitInput::getInputText() const
 {
     return this->ui_.textEdit->toPlainText();

src/widgets/splits/SplitInput.hpp

@@ -28,6 +28,7 @@ public:
     SplitInput(Split *_chatWidget);
 
     void clearSelection();
+    bool isEditFirstWord() const;
     QString getInputText() const;
     void insertText(const QString &text);