Add writeValueAtRange for index-range array writes

3 files changed, 118 insertions, 3 deletions

diff --git a/demo/NodePage.qml b/demo/NodePage.qml
index e677232..9b23502 100644
--- a/demo/NodePage.qml
+++ b/demo/NodePage.qml
@@ -91,6 +91,19 @@ Page {
             ]
         },
         {
+            title: "Index Range Write",
+            description: "Write to specific array elements using OPC UA index"
+                + " range syntax. Examples: \"0\" = first element,"
+                + " \"0:2\" = elements 0–2. Enter the range and the value(s)"
+                + " to write (comma-separated for multi-element ranges).",
+            indexRange: true,
+            nodes: [
+                "ns=1;s=int32_rw_array",
+                "ns=1;s=float_rw_array",
+                "ns=1;s=string_rw_array"
+            ]
+        },
+        {
             title: "Non-Existent Nodes",
             description: "These node IDs do not exist on the server."
                 + " The row should show no value and no metadata in the tooltip.",
@@ -243,19 +256,41 @@ Page {
                     }
 
                     // Column 3: Edit area (writable) or READ-ONLY label
+
+                    // Normal write controls (non-index-range pages)
                     TextField {
                         id: editField
-                        visible: node.writable
+                        visible: node.writable && !currentPage.indexRange
                         Layout.fillWidth: true
                         placeholderText: "Enter value..."
                         onAccepted: node.writeValue(text)
                     }
                     Button {
-                        id: writeButton
-                        visible: node.writable
+                        visible: node.writable && !currentPage.indexRange
                         text: "Write"
                         onClicked: node.writeValue(editField.text)
                     }
+
+                    // Index range write controls
+                    TextField {
+                        id: rangeField
+                        visible: node.writable && currentPage.indexRange === true
+                        Layout.preferredWidth: 60
+                        placeholderText: "Range"
+                    }
+                    TextField {
+                        id: rangeValueField
+                        visible: node.writable && currentPage.indexRange === true
+                        Layout.fillWidth: true
+                        placeholderText: "Value(s)..."
+                        onAccepted: node.writeValueAtRange(text, rangeField.text)
+                    }
+                    Button {
+                        visible: node.writable && currentPage.indexRange === true
+                        text: "Write Range"
+                        onClicked: node.writeValueAtRange(rangeValueField.text, rangeField.text)
+                    }
+
                     Label {
                         visible: !node.writable
                         text: "(READ-ONLY)"
diff --git a/src/OpcUaMonitoredNode.cpp b/src/OpcUaMonitoredNode.cpp
index cd93730..922ad43 100644
--- a/src/OpcUaMonitoredNode.cpp
+++ b/src/OpcUaMonitoredNode.cpp
@@ -177,6 +177,7 @@ OpcUaMonitoredNode::teardownNode ()
   emit infoChanged ();
 
   m_valueType = QOpcUa::Types::Undefined;
+  m_pendingRangeWrite = false;
 
   if (m_writable)
     {
@@ -270,6 +271,9 @@ OpcUaMonitoredNode::handleAttributeUpdated (QOpcUa::NodeAttribute attr,
 void
 OpcUaMonitoredNode::handleValueUpdated (const QVariant &value)
 {
+  if (m_pendingRangeWrite)
+    return;
+
   m_value = value;
   emit valueChanged ();
 
@@ -306,6 +310,8 @@ OpcUaMonitoredNode::handleAttributeWritten (QOpcUa::NodeAttribute attr,
   if (attr != QOpcUa::NodeAttribute::Value)
     return;
 
+  m_pendingRangeWrite = false;
+
   bool ok = (statusCode == QOpcUa::Good);
   emit writeCompleted (ok, ok ? QStringLiteral ("Write successful")
                               : QOpcUa::statusToString (statusCode));
@@ -511,3 +517,64 @@ OpcUaMonitoredNode::writeValue (const QVariant &value)
     emit writeCompleted (false,
                          QStringLiteral ("Write request failed to dispatch"));
 }
+
+void
+OpcUaMonitoredNode::writeValueAtRange (const QVariant &value,
+                                       const QString &indexRange)
+{
+  if (!m_node)
+    {
+      emit writeCompleted (false, QStringLiteral ("Node not connected"));
+      return;
+    }
+  if (!m_writable)
+    {
+      emit writeCompleted (false, QStringLiteral ("Node is read-only"));
+      return;
+    }
+  if (m_valueType == QOpcUa::Types::Undefined)
+    {
+      emit writeCompleted (false,
+                           QStringLiteral ("Data type not yet resolved"));
+      return;
+    }
+  if (indexRange.isEmpty ())
+    {
+      emit writeCompleted (false, QStringLiteral ("Index range is empty"));
+      return;
+    }
+
+  QVariant toWrite = value;
+
+  // If the input is a comma-separated string, split into a list so
+  // coerceValue can handle each element (e.g. "10, 20" for range "0:1").
+  if (value.metaType ().id () == QMetaType::QString
+      && value.toString ().contains (QLatin1Char (',')))
+    {
+      QStringList parts
+          = value.toString ().split (QLatin1Char (','), Qt::SkipEmptyParts);
+      QVariantList list;
+      list.reserve (parts.size ());
+      for (const QString &part : parts)
+        list.append (QVariant (part.trimmed ()));
+      toWrite = QVariant::fromValue (list);
+    }
+
+  QVariant coerced = coerceValue (toWrite);
+  if (!coerced.isValid ())
+    {
+      emit writeCompleted (
+          false, QStringLiteral ("Cannot convert value to node data type"));
+      return;
+    }
+
+  m_pendingRangeWrite = true;
+
+  if (!m_node->writeAttributeRange (QOpcUa::NodeAttribute::Value, coerced,
+                                    indexRange, m_valueType))
+    {
+      m_pendingRangeWrite = false;
+      emit writeCompleted (
+          false, QStringLiteral ("Write range request failed to dispatch"));
+    }
+}
diff --git a/src/OpcUaMonitoredNode.h b/src/OpcUaMonitoredNode.h
index 2e86b2c..2ecffb7 100644
--- a/src/OpcUaMonitoredNode.h
+++ b/src/OpcUaMonitoredNode.h
@@ -88,6 +88,18 @@ public:
    */
   Q_INVOKABLE void writeValue (const QVariant &value);
 
+  /**
+   * @brief Write a value to a specific index range of an array node.
+   *
+   * @a indexRange uses OPC UA syntax: "0" for first element,
+   * "0:3" for elements 0–3, "0,1" for 2D indexing.
+   * For multi-element writes, @a value can be a comma-separated
+   * string or a QVariantList.
+   * Result is reported asynchronously via writeCompleted().
+   */
+  Q_INVOKABLE void writeValueAtRange (const QVariant &value,
+                                      const QString &indexRange);
+
   void classBegin () override;
   void componentComplete () override;
 
@@ -129,6 +141,7 @@ private:
   bool m_writable = false;
   QVariant m_value;
   OpcUaNodeInfo m_info;
+  bool m_pendingRangeWrite = false;
 };
 
 #endif // OPCUAMONITOREDNODE_H