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#ifndef DART_OPTIMIZER_IPOPT_IPOPTSOLVER_HPP_
#define DART_OPTIMIZER_IPOPT_IPOPTSOLVER_HPP_

#include <coin/IpIpoptApplication.hpp>
#include <coin/IpTNLP.hpp>

#include <memory>

#include "dart/optimizer/Solver.hpp"

namespace dart {
namespace optimizer {

class Problem;
class DartTNLP;

/// \brief class IpoptSolver
class IpoptSolver : public Solver
{
public:
  /// Default constructor
  IpoptSolver(const Solver::Properties& _properties = Solver::Properties());

  /// Alternative Constructor
  explicit IpoptSolver(std::shared_ptr<Problem> _problem);

  /// Destructor
  virtual ~IpoptSolver();

  // Documentation inherited
  bool solve() override;

  // Documentation inherited
  std::string getType() const override;

  // Documentation inherited
  std::shared_ptr<Solver> clone() const override;

  /// Get the application interface for this IpoptSolver
  const Ipopt::SmartPtr<Ipopt::IpoptApplication>& getApplication();

  /// Get a const application interface for this IpoptSolver
  Ipopt::SmartPtr<const Ipopt::IpoptApplication> getApplication() const;

private:
  /// Constructor used during cloning
  IpoptSolver(
      const Properties& _properties,
      const Ipopt::SmartPtr<Ipopt::IpoptApplication>& _app);

  /// IPOPT nonlinear programming problem
  Ipopt::SmartPtr<Ipopt::TNLP> mNlp;

  /// Main application class for making calls to Ipopt
  Ipopt::SmartPtr<Ipopt::IpoptApplication> mIpoptApp;
};

/// class DartTNLP
class DartTNLP : public Ipopt::TNLP
{
public:
  friend class IpoptSolver;

  /// \brief
  virtual ~DartTNLP();

  //------------------------- Ipopt::TNLP --------------------------------------
  /// \brief Method to return some info about the nlp
  bool get_nlp_info(
      Ipopt::Index& n,
      Ipopt::Index& m,
      Ipopt::Index& nnz_jac_g,
      Ipopt::Index& nnz_h_lag,
      Ipopt::TNLP::IndexStyleEnum& index_style) override;

  /// \brief Method to return the bounds for my problem
  bool get_bounds_info(
      Ipopt::Index n,
      Ipopt::Number* x_l,
      Ipopt::Number* x_u,
      Ipopt::Index m,
      Ipopt::Number* g_l,
      Ipopt::Number* g_u) override;

  /// \brief Method to return the starting point for the algorithm
  bool get_starting_point(
      Ipopt::Index n,
      bool init_x,
      Ipopt::Number* x,
      bool init_z,
      Ipopt::Number* z_L,
      Ipopt::Number* z_U,
      Ipopt::Index m,
      bool init_lambda,
      Ipopt::Number* lambda) override;

  /// \brief Method to return the objective value
  bool eval_f(
      Ipopt::Index _n,
      const Ipopt::Number* _x,
      bool _new_x,
      Ipopt::Number& _obj_value) override;

  /// \brief Method to return the gradient of the objective
  bool eval_grad_f(
      Ipopt::Index _n,
      const Ipopt::Number* _x,
      bool _new_x,
      Ipopt::Number* _grad_f) override;

  /// \brief Method to return the constraint residuals
  bool eval_g(
      Ipopt::Index _n,
      const Ipopt::Number* _x,
      bool _new_x,
      Ipopt::Index _m,
      Ipopt::Number* _g) override;

  /// \brief Method to return:
  ///        1) The structure of the jacobian (if "values" is nullptr)
  ///        2) The values of the jacobian (if "values" is not nullptr)
  bool eval_jac_g(
      Ipopt::Index _n,
      const Ipopt::Number* _x,
      bool _new_x,
      Ipopt::Index _m,
      Ipopt::Index _nele_jac,
      Ipopt::Index* _iRow,
      Ipopt::Index* _jCol,
      Ipopt::Number* _values) override;

  /// \brief Method to return:
  ///        1) The structure of the hessian of the lagrangian (if "values" is
  ///           nullptr)
  ///        2) The values of the hessian of the lagrangian (if "values" is not
  ///           nullptr)
  bool eval_h(
      Ipopt::Index _n,
      const Ipopt::Number* _x,
      bool _new_x,
      Ipopt::Number _obj_factor,
      Ipopt::Index _m,
      const Ipopt::Number* _lambda,
      bool _new_lambda,
      Ipopt::Index _nele_hess,
      Ipopt::Index* _iRow,
      Ipopt::Index* _jCol,
      Ipopt::Number* _values) override;

  /// \brief This method is called when the algorithm is complete so the TNLP
  ///        can store/write the solution
  void finalize_solution(
      Ipopt::SolverReturn _status,
      Ipopt::Index _n,
      const Ipopt::Number* _x,
      const Ipopt::Number* _z_L,
      const Ipopt::Number* _z_U,
      Ipopt::Index _m,
      const Ipopt::Number* _g,
      const Ipopt::Number* _lambda,
      Ipopt::Number _obj_value,
      const Ipopt::IpoptData* _ip_data,
      Ipopt::IpoptCalculatedQuantities* _ip_cq) override;

private:
  /// \brief
  explicit DartTNLP(IpoptSolver* _solver);

  /// \brief DART optimization problem
  IpoptSolver* mSolver;

  /// \brief Objective value
  Ipopt::Number mObjValue;

  /// \brief Objective gradient
  Eigen::VectorXd mObjGradient;

  /// \brief Objective Hessian
  Eigen::MatrixXd mObjHessian;
};

} // namespace optimizer
} // namespace dart

#endif // DART_OPTIMIZER_IPOPT_IPOPTSOLVER_HPP_
