docs: add doxygen comments for NetworkManager.h

src/Engine/Network/NetworkManager.h

@@ -7,30 +7,95 @@
 #include <QObject>
 
 namespace enzo::nt {
+/**
+* @brief The central coordinator of the engine's node system.
+*
+* The network manager is the central coordinator of the engine’s node system.
+* It manages the lifecycle of operators, including their creation, storage,
+* and validation, while also tracking dependencies between them. Acting
+* as a singleton, it ensures that all parts of the engine work with a single
+* consistent view of the network, providing global access. Beyond just storing
+* operators, it also controls cooking and traversing dependency graphs,
+* ensuring that updates flow correctly through the network when nodes change.
+*
+* @todo remove Qobject inheritance, this is no longer needed since switching to boost signals.
+*
+*/
 class NetworkManager
 : public QObject
 {
     Q_OBJECT
 public:
-    // delete copy constructor
+    /// @brief Deleted the copy constructor for singleton.
     NetworkManager(const NetworkManager& obj) = delete;
 
+    /// @brief Returns a reference to the singleton instance.
     static NetworkManager& getInstance();
 
-    // functions
+    /**
+    * @brief Creates a new node in the network
+    *
+    * @param OpInfo Data designating the properties of the node.
+    *
+    * @returns The operator ID of the newly created onode
+    */
     OpId addOperator(op::OpInfo opInfo);
+
+    /** @brief Returns the operator ID for the node with its display flag set.
+    * There can only be only be one operator displayed at a time.
+    * Return value is nullop if no node is set to display
+    */
     std::optional<OpId> getDisplayOp();
+
+
+    /**
+    * @brief Returns whether the node exists in the network and is valid.
+    * @param opId Operator ID of the node to check the validity of.
+    */
     bool isValidOp(nt::OpId opId);
+
+    /**
+    * @brief Returns a reference to the GeometryOperator with the given OpId
+    */
     GeometryOperator& getGeoOperator(nt::OpId opId);
+
+    /**
+    * @brief Sets given OpId to be dislayed, releasing previous display Node
+    */
     void setDisplayOp(OpId opId);
+
+    /**
+    * @brief Set the selection state for the given node.
+    *
+    * @param opId The node to set the state on.
+    * @param selected The selection state, true selects the node, false unselects it.
+    * @param add By default all other nodes are unselected, this parameter
+    * allows adding a selected node without deslecting any others.
+    */
     void setSelectedNode(OpId opId, bool selected, bool add=false);
+
+    /**
+    * @brief Returns the OpIds for all selected nodes.
+    */
     const std::vector<enzo::nt::OpId>& getSelectedNodes();
 
+    /** @name Signals
+    * @{
+    */
+    // @brief A signal emitted when the display node is changed
     boost::signals2::signal<void (nt::OpId)> displayNodeChanged;
-    boost::signals2::signal<void (std::vector<nt::OpId> selectedNodeIds)> selectedNodesChanged;
+
+    // @brief A signal emitted when the geometry to be displayed is changed
+    // This is different to #displayNodeChanged because the state of geometry
+    // in a node can change based on parameters or other factors.
     boost::signals2::signal<void (enzo::geo::Geometry& geometry)> displayGeoChanged;
 
+    // @brief A signal emitted when the selection of nodes changes
+    boost::signals2::signal<void (std::vector<nt::OpId> selectedNodeIds)> selectedNodesChanged;
+    /** @} */
+
     #ifdef UNIT_TEST
+    /// @brief For use in unit tests, resets the state of the operator.
         void _reset();
     #endif