///////////////////////////////////////////////////////////////////////////////

// BSD 3-Clause License

//

// Copyright (C) 2022-2023, LAAS-CNRS, University of Edinburgh,

//                          Heriot-Watt University

// Copyright note valid unless otherwise stated in individual files.

// All rights reserved.

///////////////////////////////////////////////////////////////////////////////

#ifndef CROCODDYL_MULTIBODY_RESIDUALS_STATE_HPP_

#define CROCODDYL_MULTIBODY_RESIDUALS_STATE_HPP_

#include "crocoddyl/core/fwd.hpp"

#include "crocoddyl/core/residual-base.hpp"

#include "crocoddyl/core/state-base.hpp"

#include "crocoddyl/multibody/fwd.hpp"

#include "crocoddyl/multibody/states/multibody.hpp"

namespace crocoddyl {

/**

 * @brief State residual

 *

 * This residual function defines the state tracking as

 * \f$\mathbf{r}=\mathbf{x}\ominus\mathbf{x}^*\f$, where

 * \f$\mathbf{x},\mathbf{x}^*\in~\mathcal{X}\f$ are the current and reference

 * states, respectively, which belong to the state manifold \f$\mathcal{X}\f$.

 * Note that the dimension of the residual vector is obtained from

 * `StateAbstract::get_ndx()`. Furthermore, the Jacobians of the residual

 * function are computed analytically.

 *

 * As described in `ResidualModelAbstractTpl()`, the residual value and its

 * derivatives are calculated by `calc` and `calcDiff`, respectively.

 *

 * \sa `ResidualModelAbstractTpl`, `calc()`, `calcDiff()`, `createData()`

 */

template <typename _Scalar>

class ResidualModelStateTpl : public ResidualModelAbstractTpl<_Scalar> {

 public:

  typedef _Scalar Scalar;

  typedef MathBaseTpl<Scalar> MathBase;

  typedef ResidualModelAbstractTpl<Scalar> Base;

  typedef StateMultibodyTpl<Scalar> StateMultibody;

  typedef ActivationModelAbstractTpl<Scalar> ActivationModelAbstract;

  typedef ResidualDataAbstractTpl<Scalar> ResidualDataAbstract;

  typedef ActivationDataAbstractTpl<Scalar> ActivationDataAbstract;

  typedef CostDataAbstractTpl<Scalar> CostDataAbstract;

  typedef DataCollectorAbstractTpl<Scalar> DataCollectorAbstract;

  typedef typename MathBase::VectorXs VectorXs;

  typedef typename MathBase::MatrixXs MatrixXs;

  /**

   * @brief Initialize the state residual model

   *

   * @param[in] state       State of the multibody system

   * @param[in] xref        Reference state

   * @param[in] nu          Dimension of the control vector

   */

  ResidualModelStateTpl(boost::shared_ptr<typename Base::StateAbstract> state,

                        const VectorXs& xref, const std::size_t nu);

  /**

   * @brief Initialize the state residual model

   *

   * The default `nu` value is obtained from `StateAbstractTpl::get_nv()`.

   *

   * @param[in] state       State of the multibody system

   * @param[in] xref        Reference state

   */

  ResidualModelStateTpl(boost::shared_ptr<typename Base::StateAbstract> state,

                        const VectorXs& xref);

  /**

   * @brief Initialize the state residual model

   *

   * The default reference state is obtained from `StateAbstractTpl::zero()`.

   *

   * @param[in] state  State of the multibody system

   * @param[in] nu     Dimension of the control vector

   */

  ResidualModelStateTpl(boost::shared_ptr<typename Base::StateAbstract> state,

                        const std::size_t nu);

  /**

   * @brief Initialize the state residual model

   *

   * The default state reference is obtained from `StateAbstractTpl::zero()`,

   * and `nu` from `StateAbstractTpl::get_nv()`.

   *

   * @param[in] state       State of the multibody system

   * @param[in] activation  Activation model

   */

  ResidualModelStateTpl(boost::shared_ptr<typename Base::StateAbstract> state);

  virtual ~ResidualModelStateTpl();

  /**

   * @brief Compute the state residual

   *

   * @param[in] data  State residual data

   * @param[in] x     State point \f$\mathbf{x}\in\mathbb{R}^{ndx}\f$

   * @param[in] u     Control input \f$\mathbf{u}\in\mathbb{R}^{nu}\f$

   */

  virtual void calc(const boost::shared_ptr<ResidualDataAbstract>& data,

                    const Eigen::Ref<const VectorXs>& x,

                    const Eigen::Ref<const VectorXs>& u);

  /**

   * @brief Compute the Jacobians of the state residual

   *

   * @param[in] data  State residual data

   * @param[in] x     State point \f$\mathbf{x}\in\mathbb{R}^{ndx}\f$

   * @param[in] u     Control input \f$\mathbf{u}\in\mathbb{R}^{nu}\f$

   */

  virtual void calcDiff(const boost::shared_ptr<ResidualDataAbstract>& data,

                        const Eigen::Ref<const VectorXs>& x,

                        const Eigen::Ref<const VectorXs>& u);

  /**

   * @brief Compute the derivative of the state-cost function and store it in

   * cost data

   *

   * This function assumes that the derivatives of the activation and residual

   * are computed via calcDiff functions.

   *

   * @param cdata     Cost data

   * @param rdata     Residual data

   * @param adata     Activation data

   * @param update_u  Update the derivative of the cost function w.r.t. to the

   * control if True.

   */

  virtual void calcCostDiff(

      const boost::shared_ptr<CostDataAbstract>& cdata,

      const boost::shared_ptr<ResidualDataAbstract>& rdata,

      const boost::shared_ptr<ActivationDataAbstract>& adata,

      const bool update_u = true);

  /**

   * @brief Return the reference state

   */

  const VectorXs& get_reference() const;

  /**

   * @brief Modify the reference state

   */

  void set_reference(const VectorXs& reference);

  /**

   * @brief Print relevant information of the state residual

   *

   * @param[out] os  Output stream object

   */

  virtual void print(std::ostream& os) const;

 protected:

  using Base::nr_;

  using Base::nu_;

  using Base::state_;

  using Base::u_dependent_;

 private:

  VectorXs xref_;  //!< Reference state

  boost::shared_ptr<typename StateMultibody::PinocchioModel>

      pin_model_;  //!< Pinocchio model

};

}  // namespace crocoddyl

/* --- Details -------------------------------------------------------------- */

/* --- Details -------------------------------------------------------------- */

/* --- Details -------------------------------------------------------------- */

#include "crocoddyl/multibody/residuals/state.hxx"

#endif  // CROCODDYL_MULTIBODY_RESIDUALS_STATE_HPP_