refactor: buttons and friends (#6102)

src/widgets/buttons/NotebookButton.hpp

@@ -0,0 +1,40 @@
+#pragma once
+
+#include "widgets/buttons/Button.hpp"
+
+#include <QWidget>
+
+namespace chatterino {
+
+class Notebook;
+
+class NotebookButton : public Button
+{
+    Q_OBJECT
+
+public:
+    enum Icon { None, Plus, User, Settings };
+
+    explicit NotebookButton(Notebook *parent);
+
+    void setIcon(Icon icon);
+    Icon getIcon() const;
+
+protected:
+    void paintContent(QPainter &painter) override;
+
+    void themeChangedEvent() override;
+    void dragEnterEvent(QDragEnterEvent *) override;
+    void dragLeaveEvent(QDragLeaveEvent *) override;
+    void dropEvent(QDropEvent *) override;
+
+    void hideEvent(QHideEvent *) override;
+    void showEvent(QShowEvent *) override;
+
+private:
+    Notebook *parent_ = nullptr;
+    QPoint mousePos_;
+    Icon icon_ = None;
+};
+
+}  // namespace chatterino