#ifndef FESA_ANALYSIS_EIGEN_ANALYSIS_STATE_H_
#define FESA_ANALYSIS_EIGEN_ANALYSIS_STATE_H_

#include <cstddef>
#include <cstdint>
#include <optional>
#include <utility>
#include <vector>

#include "fesa/math/matrix.h"
#include "fesa/solvers/eigen/eigen_solver.h"

namespace fesa {

/// @brief Identifies one requested mode without conflating equal eigenvalues.
struct EigenMode {
  std::size_t mode_id;
  double eigenvalue;
  std::uint8_t classification;
  std::size_t cluster_id;
  std::optional<double> frequency;
};

/// @brief Records the analytic mass split at one source-ordered node.
struct EigenNodalReductionRecord {
  std::uint8_t free_count;
  std::uint8_t null_count;
  std::uint8_t positive_count;
  bool rcond_available;
  double rcond_inf;
};

/// @brief Stores independently evaluated evidence for every computed pair.
struct EigenpairCheck {
  std::size_t sorted_rank;
  std::size_t solver_column;
  double eigenvalue;
  double modal_mass;
  double rayleigh_quotient;
  double eta_r;
  double eta_w;
  double rho_b;
  double eta_norm;
  double eta_energy;
  bool backend_res_available;
  double backend_res;
};

/// @brief Owns a validated modal candidate independently of static state.
/// @note Vectors are requested-mode by full source DOF; they are not response
/// displacements. Backend work vectors are released after all-c validation.
struct EigenAnalysisState {
  explicit EigenAnalysisState(FeastEigenResult backend_result)
      : backend{std::move(backend_result)} {}

  std::size_t full_dof_count{0U};
  std::size_t free_dof_count{0U};
  std::size_t mass_null_dimension{0U};
  std::size_t finite_dimension{0U};
  double characteristic_length{0.0};
  double eta_gram{0.0};
  double max_eta_orth{0.0};
  bool null_checks_applicable{false};
  double eta_mz{0.0};
  double eta_kz{0.0};
  double eta_pz{0.0};
  std::vector<std::uint8_t> constraint_mask;
  std::vector<double> prescribed_displacement;
  std::vector<EigenNodalReductionRecord> nodal_reduction;
  std::vector<EigenMode> modes;
  Matrix vectors{0U, 0U};
  std::vector<EigenpairCheck> eigenpair_checks;
  FeastEigenResult backend;
};

}  // namespace fesa

#endif  // FESA_ANALYSIS_EIGEN_ANALYSIS_STATE_H_