#ifndef FESA_SOLVERS_LINEAR_LINEAR_SOLVER_H_
#define FESA_SOLVERS_LINEAR_LINEAR_SOLVER_H_

#include "fesa/core/status.h"

namespace fesa {

class SparseMatrix;
class Vector;

/// @brief Separates reusable factorization from RHS substitution.
class LinearSolver {
 public:
  /// @brief Destroys a backend-neutral linear solver.
  virtual ~LinearSolver() = default;

  /// @brief Factorizes a validated free-equation matrix for reuse.
  /// @return Success or a structured solver failure.
  virtual Status Factorize(const SparseMatrix& matrix) = 0;

  /// @brief Substitutes one right-hand side using retained factorization.
  /// @param rhs Immutable right-hand side in free-equation order.
  /// @param solution Updated only after successful finite substitution.
  /// @return Success or a structured solver failure.
  virtual Status Solve(const Vector& rhs, Vector& solution) const = 0;
};

}  // namespace fesa

#endif  // FESA_SOLVERS_LINEAR_LINEAR_SOLVER_H_