#ifndef FESA_ANALYSIS_ANALYSIS_MODEL_H_
#define FESA_ANALYSIS_ANALYSIS_MODEL_H_

#include <vector>

#include "fesa/model/domain.h"

namespace fesa {

/// @brief Provides the active-step view into a non-owned Domain.
/// @note The referenced Domain must outlive this object and retains all
/// semantic ownership.
class AnalysisModel {
 public:
  /// @brief Creates the sole active-step view for a valid Domain.
  /// @param domain Domain that remains alive for the returned view's lifetime.
  /// @return A stable view or an input-cardinality failure.
  static Result<AnalysisModel> Create(const Domain& domain);

  /// @brief Returns the non-owned Domain backing this view.
  const Domain& GetDomain() const noexcept;

  /// @brief Returns the sole active static step.
  const StaticStepDefinition& Step() const noexcept;

  /// @brief Returns active beam element indices in stable internal order.
  const std::vector<EntityIndex>& ActiveElements() const noexcept;

  /// @brief Returns reachable material indices in stable internal order.
  const std::vector<EntityIndex>& ActiveMaterials() const noexcept;

  /// @brief Returns reachable beam-section indices in stable internal order.
  const std::vector<EntityIndex>& ActiveSections() const noexcept;

  /// @brief Returns boundary-condition indices in source order.
  const std::vector<EntityIndex>& ActiveBoundaryConditions() const noexcept;

  /// @brief Returns concentrated-load indices in source order.
  const std::vector<EntityIndex>& ActiveLoads() const noexcept;

 private:
  /// @brief Builds stable indices without copying the referenced Domain.
  explicit AnalysisModel(const Domain& domain);

  const Domain* domain_;
  std::vector<EntityIndex> active_elements_;
  std::vector<EntityIndex> active_materials_;
  std::vector<EntityIndex> active_sections_;
  std::vector<EntityIndex> active_boundary_conditions_;
  std::vector<EntityIndex> active_loads_;
};

}  // namespace fesa

#endif  // FESA_ANALYSIS_ANALYSIS_MODEL_H_