From 6c2527b7f4e87d82813180f20461e8e9c98e1087 Mon Sep 17 00:00:00 2001
From: Nav <nav@navnav.me>
Date: Thu, 23 Mar 2023 19:20:50 +0000
Subject: [PATCH] Implemented support for multi-select and selection limit in
 ListScene widget

---
 .../Widgets/ListView/ListScene.cpp            | 33 +++++++++++++++----
 .../Widgets/ListView/ListScene.hpp            |  7 ++--
 2 files changed, 31 insertions(+), 9 deletions(-)

diff --git a/src/Insight/UserInterfaces/InsightWindow/Widgets/ListView/ListScene.cpp b/src/Insight/UserInterfaces/InsightWindow/Widgets/ListView/ListScene.cpp
index 6b46ab09..64d1cd55 100644
--- a/src/Insight/UserInterfaces/InsightWindow/Widgets/ListView/ListScene.cpp
+++ b/src/Insight/UserInterfaces/InsightWindow/Widgets/ListView/ListScene.cpp
@@ -19,6 +19,10 @@ namespace Bloom::Widgets
         this->setItems(std::move(items));
     }
 
+    void ListScene::setSelectionLimit(std::uint8_t selectionLimit) {
+        this->selectionLimit = selectionLimit;
+    }
+
     void ListScene::refreshGeometry() {
         const auto* viewport = this->viewport();
         const auto viewportWidth = viewport != nullptr ? viewport->width() : 0;
@@ -90,10 +94,26 @@ namespace Bloom::Widgets
     void ListScene::mousePressEvent(QGraphicsSceneMouseEvent* mouseEvent) {
         const auto button = mouseEvent->button();
 
-        if (this->selectedItem != nullptr) {
-            this->selectedItem->selected = false;
-            this->selectedItem->update();
-            this->selectedItem = nullptr;
+        const auto selectedItemCount = this->selectedItems.size();
+        if (selectedItemCount > 0) {
+            const auto ctrlModifierEnabled = (mouseEvent->modifiers() & Qt::ControlModifier) != 0;
+            if (!ctrlModifierEnabled || selectedItemCount >= this->selectionLimit) {
+                const auto itemsToRemove = ctrlModifierEnabled
+                    ? selectedItemCount - this->selectionLimit + 1
+                    : selectedItemCount;
+
+                auto itemIt = this->selectedItems.begin();
+                while (
+                    itemIt != this->selectedItems.end()
+                    && (selectedItemCount - this->selectedItems.size()) < itemsToRemove
+                ) {
+                    auto& item = *itemIt;
+                    item->selected = false;
+                    item->update();
+
+                    this->selectedItems.erase(itemIt++);
+                }
+            }
         }
 
         const auto mousePosition = mouseEvent->buttonDownScenePos(button);
@@ -108,12 +128,11 @@ namespace Bloom::Widgets
             return;
         }
 
-        this->selectedItem = clickedListItem;
-
+        this->selectedItems.push_back(clickedListItem);
         clickedListItem->selected = true;
         clickedListItem->update();
 
-        emit this->selectionChanged(this->selectedItem);
+        emit this->selectionChanged(this->selectedItems);
         emit this->itemClicked(clickedListItem);
     }
 
diff --git a/src/Insight/UserInterfaces/InsightWindow/Widgets/ListView/ListScene.hpp b/src/Insight/UserInterfaces/InsightWindow/Widgets/ListView/ListScene.hpp
index f96cfab0..37e967ab 100644
--- a/src/Insight/UserInterfaces/InsightWindow/Widgets/ListView/ListScene.hpp
+++ b/src/Insight/UserInterfaces/InsightWindow/Widgets/ListView/ListScene.hpp
@@ -4,6 +4,7 @@
 #include <QGraphicsView>
 #include <QMargins>
 #include <vector>
+#include <list>
 #include <QGraphicsSceneMouseEvent>
 #include <QGraphicsSceneWheelEvent>
 #include <QGraphicsSceneContextMenuEvent>
@@ -28,13 +29,14 @@ namespace Bloom::Widgets
         );
 
         void refreshGeometry();
+        void setSelectionLimit(std::uint8_t selectionLimit);
         void setItems(const std::vector<ListItem*>& items);
         void addListItem(ListItem* item);
         void sortItems();
         void setEnabled(bool enabled);
 
     signals:
-        void selectionChanged(ListItem* selectedItem);
+        void selectionChanged(const std::list<ListItem*>& selectedItems);
         void itemClicked(ListItem* item);
         void itemDoubleClicked(ListItem* item);
         void itemContextMenu(ListItem* item, QPoint sourcePosition);
@@ -48,7 +50,8 @@ namespace Bloom::Widgets
         std::vector<ListItem*> listItems;
         QGraphicsView* const parent;
         bool enabled = false;
-        ListItem* selectedItem = nullptr;
+        std::list<ListItem*> selectedItems;
+        std::uint8_t selectionLimit = 1;
 
         QWidget* viewport() const {
             const auto views = this->views();