Consolidate input completion code in preparation for advanced completion strategies (#4639)

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

src/widgets/helper/ResizingTextEdit.cpp

@@ -1,8 +1,8 @@
 #include "widgets/helper/ResizingTextEdit.hpp"
 
 #include "common/Common.hpp"
-#include "common/CompletionModel.hpp"
 #include "common/QLogging.hpp"
+#include "controllers/completion/TabCompletionModel.hpp"
 #include "singletons/Settings.hpp"
 
 #include <QMimeData>
@@ -160,16 +160,18 @@ void ResizingTextEdit::keyPressEvent(QKeyEvent *event)
             return;
         }
 
+        // always expected to be TabCompletionModel
         auto *completionModel =
-            static_cast<CompletionModel *>(this->completer_->model());
+            dynamic_cast<TabCompletionModel *>(this->completer_->model());
+        assert(completionModel != nullptr);
 
         if (!this->completionInProgress_)
         {
             // First type pressing tab after modifying a message, we refresh our
             // completion model
             this->completer_->setModel(completionModel);
-            completionModel->refresh(currentCompletionPrefix,
-                                     this->isFirstWord());
+            completionModel->updateResults(currentCompletionPrefix,
+                                           this->isFirstWord());
             this->completionInProgress_ = true;
             {
                 // this blocks cursor movement events from resetting tab completion
@@ -346,9 +348,4 @@ void ResizingTextEdit::insertFromMimeData(const QMimeData *source)
     insertPlainText(source->text());
 }
 
-QCompleter *ResizingTextEdit::getCompleter() const
-{
-    return this->completer_;
-}
-
 }  // namespace chatterino