refactor: Muon Mockup Detector Builder: refactoring and adding endcaps (#4922)

I refactored `GeoModelMuonMockupBuilder` so that converted boxes are processed per station to produce a station-level `StaticBluePrintNode`. Then these nodes are attached to the appropriate container. 

Due to the stacking policy, three containers are attached to the root `Blueprint` and stacked along Z: one for the detector body and two for the big wheels. While the` StaticBluePrintNode`s for EM and EO are directly attached to the big-wheels containers, the body container is further composed of two containers stacked along R: the barrel container, which holds the BI, BM, BO station nodes stacked along R, and a second cylindrical container that contains the small wheels, stacked along Z.

Author: lmonaco99

Examples/Detectors/GeoModelDetector/include/ActsExamples/GeoModelDetector/GeoModelMuonMockupBuilder.hpp

@@ -53,12 +53,78 @@ class GeoModelMuonMockupBuilder : public Acts::ITrackingGeometryBuilder {
       const Acts::GeometryContext& gctx) const override;
 
  private:
+  // Enum class for the station indices
+  enum class StationIdx : std::uint8_t {
+    BI,   // Inner Barrel
+    BM,   // Middle Barrel
+    BO,   // Outer Barrel
+    EAI,  // Endcap Inner A-side
+    EAM,  // Endcap Middle A-side
+    EAO,  // Endcap Outer A-side
+    ECI,  // Endcap Inner C-side
+    ECM,  // Endcap Middle C-side
+    ECO,  // Endcap Outer C-side
+    nStations
+  };
+  // Enum class for the first level of container indices
+  enum class FirstContainerIdx : std::uint8_t {
+    Central,  // Central container for barrel & NSWs
+    BW_A,     // Big Wheel A-side
+    BW_C,     // Big Wheel C-side
+    nFirstContainers
+  };
+  // Enum class for the second level of container indices when the first is
+  // Central
+  enum class SecondContainerIdx : std::uint8_t {
+    Barrel,  // Barrel container
+    NSWs,    // NSW container
+    nSecondContainers
+  };
+
   Config m_cfg;
 
-  std::shared_ptr<Acts::Experimental::StaticBlueprintNode> buildBarrelNode(
-      const ConvertedVolList_t& boundingBoxes, const std::string& name,
-      Acts::VolumeBoundFactory& boundFactory,
-      const Acts::GeometryIdentifier& geoId) const;
+  using Box_t = ConvertedVolList_t::value_type;
+  using Node_t = Acts::Experimental::StaticBlueprintNode;
+  using NodePtr_t = std::shared_ptr<Node_t>;
+
+  /// @brief Produce a station node from the provided converted volume boxes
+  NodePtr_t processStation(const std::span<Box_t> boundingBoxes,
+                           const std::string& station, const bool isBarrel,
+                           Acts::VolumeBoundFactory& boundFactory,
+                           const Acts::GeometryIdentifier& geoId) const;
+
+  /// @brief Build a child chamber volume from the provided converted volume box
+  std::unique_ptr<Acts::TrackingVolume> buildChildChamber(
+      const Box_t& box, Acts::VolumeBoundFactory& boundFactory) const;
+
+  /// @brief Helper struct to store cylinder bounds, used to compute the overall bounds
+  ///        of a station tracking volume from its component volumes
+  struct cylBounds {
+    /// @brief Lowest radius
+    double rMin{std::numeric_limits<double>::max()};
+    /// @brief Highest radius
+    double rMax{std::numeric_limits<double>::lowest()};
+    /// @brief Lowest longitudinal coordinate
+    double zMin{std::numeric_limits<double>::max()};
+    /// @brief Highest longitudinal coordinate
+    double zMax{std::numeric_limits<double>::lowest()};
+  };
+  /// @brief Helper function to update the cylinder bounds of each station across its component volumes (chambers)
+  /// @tparam VolBounds_t: The bounds type of the chamber volume
+  /// @param volume: The chamber volume to extract the bounds from
+  /// @param bounds: The cylBounds object to be updated
+  template <Acts::VolumeBounds::BoundsType VolBounds_t>
+  void updateBounds(const Acts::TrackingVolume& volume,
+                    cylBounds& bounds) const;
+
+  // Helper function returning the station idx from a box volume
+  StationIdx getStationIdx(const Box_t& box) const;
+  // Helper function returning the first-level container idx from a station idx
+  FirstContainerIdx getFirstContainerIdx(const StationIdx& stationIdx) const;
+  // Helper function converting the station idx to string
+  static std::string stationIdxToString(const StationIdx idx);
+  // Helper function converting the first-level container idx to string
+  static std::string firstContainerIdxToString(const FirstContainerIdx idx);
 
   /// Private access method to the logger
   const Acts::Logger& logger() const { return *m_logger; }