From a6512f2c67e924bf33b92a85a1848c9d3b57564a Mon Sep 17 00:00:00 2001
From: Bent Witthold <bent@working-copy.org>
Date: Mon, 12 Jan 2026 09:56:50 +0100
Subject: [PATCH] Added a QSortFilterProxyModel subclass to enable sorting by
 different columns in the views.

---
 CMakeLists.txt                   |  1 +
 genericcore.cpp                  |  9 ++++++-
 genericcore.h                    |  3 +++
 model/generalsortfiltermodel.cpp | 42 ++++++++++++++++++++++++++++++++
 model/generalsortfiltermodel.h   | 23 +++++++++++++++++
 5 files changed, 77 insertions(+), 1 deletion(-)
 create mode 100644 model/generalsortfiltermodel.cpp
 create mode 100644 model/generalsortfiltermodel.h

diff --git a/CMakeLists.txt b/CMakeLists.txt
index b47cfca..c7a2875 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -33,6 +33,7 @@ add_library(${TARGET_APP} STATIC
   formats/csvparser.h formats/csvparser.cpp
   # 3rd party libraries
   ../3rdParty/rapidcsv/src/rapidcsv.h
+  model/generalsortfiltermodel.h model/generalsortfiltermodel.cpp
 )
 
 include_directories(${CMAKE_CURRENT_BINARY_DIR})
diff --git a/genericcore.cpp b/genericcore.cpp
index 34ef9dd..9a29e04 100644
--- a/genericcore.cpp
+++ b/genericcore.cpp
@@ -12,6 +12,7 @@
 #include "CoreConfig.h"
 #include "constants.h"
 #include "data/filehandler.h"
+#include "model/generalsortfiltermodel.h"
 #include "model/metadata.h"
 #include "model/tablemodel.h"
 
@@ -89,6 +90,10 @@ QUndoStack* GenericCore::getModelUndoStack() const { return m_modelUndoStack; }
 
 std::shared_ptr<TableModel> GenericCore::getModel() const { return m_mainModel; }
 
+std::shared_ptr<GeneralSortFilterModel> GenericCore::getSortFilterModel() const {
+  return m_sortFilterModel;
+}
+
 /**
  * Save items to default file (in standard location).
  * @brief GenericCore::saveItems Saves item fo file.
@@ -127,7 +132,9 @@ bool GenericCore::exportCSVFile(const QString& filePath) {
 }
 
 void GenericCore::setupModels() {
-  m_mainModel = make_shared<TableModel>(m_modelUndoStack, this);
+  m_mainModel       = make_shared<TableModel>(m_modelUndoStack, this);
+  m_sortFilterModel = make_shared<GeneralSortFilterModel>(m_mainModel);
+
   // TODO add QAbstractItemModelTester
   initModelData();
 }
diff --git a/genericcore.h b/genericcore.h
index b25135c..f4a78b0 100644
--- a/genericcore.h
+++ b/genericcore.h
@@ -8,6 +8,7 @@ class QAbstractItemModel;
 class QString;
 
 class TableModel;
+class GeneralSortFilterModel;
 
 class GenericCore : public QObject {
   Q_OBJECT
@@ -24,6 +25,7 @@ class GenericCore : public QObject {
 
   QUndoStack* getModelUndoStack() const;
   std::shared_ptr<TableModel> getModel() const;
+  std::shared_ptr<GeneralSortFilterModel> getSortFilterModel() const;
 
   void saveItems();
   void importCSVFile(const QString& filePath);
@@ -35,6 +37,7 @@ class GenericCore : public QObject {
  private:
   QUndoStack* m_modelUndoStack;
   std::shared_ptr<TableModel> m_mainModel;
+  std::shared_ptr<GeneralSortFilterModel> m_sortFilterModel;
 
   void setupModels();
   void initModelData();
diff --git a/model/generalsortfiltermodel.cpp b/model/generalsortfiltermodel.cpp
new file mode 100644
index 0000000..da593af
--- /dev/null
+++ b/model/generalsortfiltermodel.cpp
@@ -0,0 +1,42 @@
+#include "generalsortfiltermodel.h"
+#include "metadata.h"
+
+GeneralSortFilterModel::GeneralSortFilterModel(std::shared_ptr<TableModel> sourceModel)
+    : QSortFilterProxyModel{sourceModel.get()}
+    , m_sourceModel(sourceModel) {
+  setSourceModel(sourceModel.get());
+
+  m_collator.setNumericMode(true);
+}
+
+bool GeneralSortFilterModel::lessThan(const QModelIndex& source_left,
+                                      const QModelIndex& source_right) const {
+  if (source_left.column() != source_right.column()) {
+    return false;
+  }
+
+  QAbstractItemModel* localSourceModel = sourceModel();
+  const int role                       = GET_ROLE_FOR_COLUMN(source_left.column());
+  const QVariant leftData              = localSourceModel->data(source_left);
+  const QVariant rightData             = localSourceModel->data(source_right);
+
+  const bool isText = STRING_ROLES.contains(role);
+  if (isText) {
+    const QString leftString  = leftData.toString();
+    const QString rightString = rightData.toString();
+    return m_collator.compare(leftString, rightString) > 0;
+  }
+  const bool isInt = INT_ROLES.contains(role);
+  if (isInt) {
+    const int leftInt  = leftData.toInt();
+    const int rightInt = rightData.toInt();
+    return leftInt > rightInt;
+  }
+  const bool isDouble = DOUBLE_ROLES.contains(role);
+  if (isDouble) {
+    const int leftInt  = leftData.toDouble();
+    const int rightInt = rightData.toDouble();
+    return leftInt > rightInt;
+  }
+  return false;
+}
diff --git a/model/generalsortfiltermodel.h b/model/generalsortfiltermodel.h
new file mode 100644
index 0000000..6084b3e
--- /dev/null
+++ b/model/generalsortfiltermodel.h
@@ -0,0 +1,23 @@
+#ifndef GENERALSORTFILTERMODEL_H
+#define GENERALSORTFILTERMODEL_H
+
+#include <QCollator>
+#include <QSortFilterProxyModel>
+
+#include "tablemodel.h"
+
+class GeneralSortFilterModel : public QSortFilterProxyModel {
+  Q_OBJECT
+ public:
+  explicit GeneralSortFilterModel(std::shared_ptr<TableModel> sourceModel = nullptr);
+
+  /// QSortFilterProxyModel interface
+ protected:
+  bool lessThan(const QModelIndex& sourceLeft, const QModelIndex& sourceRight) const override;
+
+ private:
+  std::shared_ptr<TableModel> m_sourceModel;
+  QCollator m_collator;  /// for sorting
+};
+
+#endif  // GENERALSORTFILTERMODEL_H