#ifndef FESA_ANALYSIS_THERMAL_ANALYSIS_STATE_H_
#define FESA_ANALYSIS_THERMAL_ANALYSIS_STATE_H_

#include <array>
#include <cstdint>
#include <vector>

#include "fesa/analysis/thermal_time_grid.h"
#include "fesa/core/status.h"
#include "fesa/results/thermal_result_records.h"

namespace fesa {

class AnalysisModel;
class DofManager;
class ThermalAssembly;

/// @brief Owns the immutable thermal result inventory and accepted history.
/// @note No Domain/model/assembly references survive Create; state may outlive
/// them. Numerical equilibrium and energy checks belong to the procedure before
/// Commit.
class ThermalAnalysisState final {
 public:
  /// @brief Validates the inventory/schedule and commits raw initial
  /// temperature.
  /// @note Initial frame has no recovery payload and is never projected onto
  /// BCs.
  static Result<ThermalAnalysisState> Create(const AnalysisModel& model,
                                             const DofManager& dofs,
                                             const ThermalAssembly& assembly);
  /// @brief Builds a complete typed candidate without changing accepted
  /// history.
  /// @param temperature Full node-major temperature, including prescribed
  /// values.
  /// @param reaction Constrained full residual in ReactionDofs() order, even if
  /// empty.
  /// @param flux Global element fluxes in ElementOrder(), point/trace order.
  Result<ThermalAcceptedFrame> MakeCompletedFrame(
      std::uint32_t index, Vector temperature, Vector reaction,
      std::vector<ThermalElementFlux> flux) const;
  /// @brief Atomically appends the next finite frame after exact
  /// mapping/schedule checks.
  /// @note Rejection preserves every existing frame; caller-owned candidates
  /// stay independent.
  Status CommitAcceptedFrame(const ThermalAcceptedFrame& frame);
  /// @brief Returns accepted frames, beginning with raw frame zero.
  const std::vector<ThermalAcceptedFrame>& AcceptedFrames() const noexcept;
  /// @brief Returns the most recently committed state; Create always supplies
  /// frame zero.
  const ThermalAcceptedFrame& CommittedState() const noexcept;
  /// @brief Reports whether every scheduled increment has been committed.
  bool IsComplete() const noexcept;
  /// @brief Returns the exact time-grid schedule used to validate accepted
  /// frames.
  const ThermalTimeGrid& TimeGrid() const noexcept;
  /// @brief Returns original nominal dt for metadata, independent of actual
  /// last delta.
  double NominalTimeIncrement() const noexcept;
  /// @brief Returns the exact input end time for metadata.
  double TimePeriod() const noexcept;
  /// @brief Returns active Domain node IDs in temperature row order.
  const std::vector<EntityIndex>& NodeOrder() const noexcept;
  /// @brief Returns immutable source identities corresponding to NodeOrder().
  const std::vector<SourceEntityId>& NodeSourceIds() const noexcept;
  /// @brief Returns Domain element IDs in flux/frame row order.
  const std::vector<EntityIndex>& ElementOrder() const noexcept;
  /// @brief Returns immutable source identities corresponding to
  /// ElementOrder().
  const std::vector<SourceEntityId>& ElementSourceIds() const noexcept;
  /// @brief Returns the N by 5 free=0/prescribed=1 mask.
  const std::vector<std::array<std::uint8_t, 5>>& ConstraintMask()
      const noexcept;
  /// @brief Returns prescribed node/source-DOF identities in node/station
  /// order.
  const std::vector<ThermalReactionDof>& ReactionDofs() const noexcept;
  /// @brief Returns E by 4 fixed local frames, stored once for the entire
  /// history.
  const std::vector<ThermalElementFrames>& FluxLocalFrames() const noexcept;

 private:
  /// @brief Takes an exact schedule; Create then fills the validated inventory.
  ThermalAnalysisState(ThermalTimeGrid grid, double nominal, double period);
  /// @brief Checks frame metadata, mapping, payload shape and finite values.
  Status ValidateFrame(const ThermalAcceptedFrame& frame) const;
  ThermalTimeGrid grid_;
  double nominal_;
  double period_;
  std::vector<EntityIndex> node_order_;
  std::vector<SourceEntityId> node_source_ids_;
  std::vector<EntityIndex> element_order_;
  std::vector<SourceEntityId> element_source_ids_;
  std::vector<std::array<std::uint8_t, 5>> constraint_mask_;
  std::vector<ThermalReactionDof> reaction_dofs_;
  std::vector<ThermalElementFrames> local_frames_;
  std::vector<ThermalAcceptedFrame> frames_;
};

}  // namespace fesa
#endif  // FESA_ANALYSIS_THERMAL_ANALYSIS_STATE_H_