1 files changed, 105 insertions, 0 deletions
diff --git a/src/BobinkNode.h b/src/BobinkNode.h
new file mode 100644
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--- /dev/null
+++ b/src/BobinkNode.h
@@ -0,0 +1,105 @@
+/**
+ * @file   BobinkNode.h
+ * @brief  QML component representing a single OPC UA node.
+ *
+ * Inherits QQuickItem so that monitoring is automatically tied to
+ * visibility: when the item (or any ancestor) becomes invisible
+ * (e.g. StackView navigates away, Loader unloads), the monitored
+ * item is removed from the subscription.  When visible again,
+ * monitoring resumes.
+ */
+#ifndef BOBINKNODE_H
+#define BOBINKNODE_H
+
+#include <QDateTime>
+#include <QHash>
+#include <QOpcUaNode>
+#include <QQuickItem>
+
+class BobinkNode : public QQuickItem
+{
+  Q_OBJECT
+  QML_ELEMENT
+
+  Q_PROPERTY (QString nodeId READ nodeId WRITE setNodeId NOTIFY nodeIdChanged)
+  Q_PROPERTY (QVariant value READ value WRITE setValue NOTIFY valueChanged)
+  Q_PROPERTY (NodeStatus status READ status NOTIFY statusChanged)
+  Q_PROPERTY (QDateTime sourceTimestamp READ sourceTimestamp NOTIFY
+                  sourceTimestampChanged)
+  Q_PROPERTY (QDateTime serverTimestamp READ serverTimestamp NOTIFY
+                  serverTimestampChanged)
+
+public:
+  explicit BobinkNode (QQuickItem *parent = nullptr);
+  ~BobinkNode () override;
+
+  /// Simplified OPC UA status severity.
+  enum NodeStatus
+  {
+    Good,
+    Uncertain,
+    Bad
+  };
+  Q_ENUM (NodeStatus)
+
+  QString nodeId () const;
+  void setNodeId (const QString &id);
+
+  QVariant value () const;
+  /** Setting value writes to the server; the property updates when
+   *  the server confirms via the monitored data change. */
+  void setValue (const QVariant &value);
+
+  NodeStatus status () const;
+  QDateTime sourceTimestamp () const;
+  QDateTime serverTimestamp () const;
+
+  /** Read an attribute on demand (DisplayName, Description, DataType, …).
+   *  Result arrives asynchronously via attributeRead(). */
+  Q_INVOKABLE void readAttribute (const QString &attributeName);
+
+signals:
+  void nodeIdChanged ();
+  void valueChanged ();
+  void statusChanged ();
+  void sourceTimestampChanged ();
+  void serverTimestampChanged ();
+
+  /** Emitted when a readAttribute() call completes. */
+  void attributeRead (const QString &attributeName, const QVariant &value);
+
+  /** Emitted when a write to the server fails. */
+  void writeError (const QString &message);
+
+protected:
+  void componentComplete () override;
+  void itemChange (ItemChange change, const ItemChangeData &data) override;
+
+private:
+  void startMonitoring ();
+  void stopMonitoring ();
+
+  void handleDataChange (QOpcUa::NodeAttribute attr, const QVariant &val);
+  void handleAttributeUpdated (QOpcUa::NodeAttribute attr,
+                               const QVariant &val);
+  void handleAttributeWritten (QOpcUa::NodeAttribute attr,
+                               QOpcUa::UaStatusCode statusCode);
+  void handleClientConnectedChanged ();
+
+  static NodeStatus statusFromCode (QOpcUa::UaStatusCode code);
+  static QOpcUa::NodeAttribute attributeFromName (const QString &name);
+
+  QString m_nodeId;
+  QVariant m_value;
+  NodeStatus m_status = Bad;
+  QDateTime m_sourceTimestamp;
+  QDateTime m_serverTimestamp;
+
+  QOpcUaNode *m_opcuaNode = nullptr;
+  bool m_componentComplete = false;
+
+  /** Tracks in-flight readAttribute() requests (enum → original name). */
+  QHash<QOpcUa::NodeAttribute, QString> m_pendingReads;
+};
+
+#endif // BOBINKNODE_H