From b45ec9dfa571914148474c056d7d8bd99f91baed Mon Sep 17 00:00:00 2001
From: Dan Paulat <dpaulat@gmail.com>
Date: Sun, 15 Oct 2023 22:23:39 -0500
Subject: [PATCH] Enable/disable layer move buttons according to selection

---
 scwx-qt/source/scwx/qt/model/layer_model.cpp | 12 ++++
 scwx-qt/source/scwx/qt/model/layer_model.hpp |  2 +
 scwx-qt/source/scwx/qt/ui/layer_dialog.cpp   | 64 +++++++++++++++++++-
 3 files changed, 77 insertions(+), 1 deletion(-)

diff --git a/scwx-qt/source/scwx/qt/model/layer_model.cpp b/scwx-qt/source/scwx/qt/model/layer_model.cpp
index e9bbc0dd..8ced1199 100644
--- a/scwx-qt/source/scwx/qt/model/layer_model.cpp
+++ b/scwx-qt/source/scwx/qt/model/layer_model.cpp
@@ -164,6 +164,18 @@ Qt::DropActions LayerModel::supportedDropActions() const
    return Qt::DropAction::MoveAction;
 }
 
+bool LayerModel::IsMovable(int row) const
+{
+   bool movable = false;
+
+   if (0 <= row && static_cast<std::size_t>(row) < p->layers_.size())
+   {
+      movable = p->layers_.at(row).movable_;
+   }
+
+   return movable;
+}
+
 QVariant LayerModel::data(const QModelIndex& index, int role) const
 {
    static const QString enabledString  = QObject::tr("Enabled");
diff --git a/scwx-qt/source/scwx/qt/model/layer_model.hpp b/scwx-qt/source/scwx/qt/model/layer_model.hpp
index ef0aebde..b63a6f9c 100644
--- a/scwx-qt/source/scwx/qt/model/layer_model.hpp
+++ b/scwx-qt/source/scwx/qt/model/layer_model.hpp
@@ -43,6 +43,8 @@ public:
    Qt::ItemFlags   flags(const QModelIndex& index) const override;
    Qt::DropActions supportedDropActions() const override;
 
+   bool IsMovable(int row) const;
+
    QVariant data(const QModelIndex& index,
                  int                role = Qt::DisplayRole) const override;
    QVariant headerData(int             section,
diff --git a/scwx-qt/source/scwx/qt/ui/layer_dialog.cpp b/scwx-qt/source/scwx/qt/ui/layer_dialog.cpp
index 88d3515e..71783e36 100644
--- a/scwx-qt/source/scwx/qt/ui/layer_dialog.cpp
+++ b/scwx-qt/source/scwx/qt/ui/layer_dialog.cpp
@@ -18,11 +18,14 @@ class LayerDialogImpl
 {
 public:
    explicit LayerDialogImpl(LayerDialog* self) :
-       layerModel_ {new model::LayerModel(self)}
+       self_ {self}, layerModel_ {new model::LayerModel(self)}
    {
    }
    ~LayerDialogImpl() = default;
 
+   void ConnectSignals();
+
+   LayerDialog*       self_;
    model::LayerModel* layerModel_;
 };
 
@@ -49,6 +52,14 @@ LayerDialog::LayerDialog(QWidget* parent) :
             QHeaderView::ResizeMode::ResizeToContents);
       }
    }
+
+   // Disable move buttons
+   ui->moveTopButton->setEnabled(false);
+   ui->moveUpButton->setEnabled(false);
+   ui->moveDownButton->setEnabled(false);
+   ui->moveBottomButton->setEnabled(false);
+
+   p->ConnectSignals();
 }
 
 LayerDialog::~LayerDialog()
@@ -56,6 +67,57 @@ LayerDialog::~LayerDialog()
    delete ui;
 }
 
+void LayerDialogImpl::ConnectSignals()
+{
+   QObject::connect(
+      self_->ui->layerTreeView->selectionModel(),
+      &QItemSelectionModel::selectionChanged,
+      self_,
+      [this](const QItemSelection& /* selected */,
+             const QItemSelection& /* deselected */)
+      {
+         QModelIndexList selectedRows =
+            self_->ui->layerTreeView->selectionModel()->selectedRows();
+
+         bool itemsSelected    = selectedRows.size() > 0;
+         bool itemsMovableUp   = itemsSelected;
+         bool itemsMovableDown = itemsSelected;
+         int  rowCount         = layerModel_->rowCount();
+
+         for (auto& rowIndex : selectedRows)
+         {
+            int row = rowIndex.row();
+            if (!layerModel_->IsMovable(row))
+            {
+               // If an item in the selection is not movable, disable all moves
+               itemsMovableUp   = false;
+               itemsMovableDown = false;
+               break;
+            }
+            else
+            {
+               // If the first row is selected, items cannot be moved up
+               if (row == 0)
+               {
+                  itemsMovableUp = false;
+               }
+
+               // If the last row is selected, items cannot be moved down
+               if (row == rowCount - 1)
+               {
+                  itemsMovableDown = false;
+               }
+            }
+         }
+
+         // Enable move buttons according to selection
+         self_->ui->moveTopButton->setEnabled(itemsMovableUp);
+         self_->ui->moveUpButton->setEnabled(itemsMovableUp);
+         self_->ui->moveDownButton->setEnabled(itemsMovableDown);
+         self_->ui->moveBottomButton->setEnabled(itemsMovableDown);
+      });
+}
+
 } // namespace ui
 } // namespace qt
 } // namespace scwx