/* ***********************************************************************
//
//   Copyright (C) 2025 -- The 4D-STAR Collaboration
//   File Author: Emily Boudreaux
//   Last Modified: March 19, 2025
//
//   4DSSE is free software; you can use it and/or modify
//   it under the terms and restrictions the GNU General Library Public
//   License version 3 (GPLv3) as published by the Free Software Foundation.
//
//   4DSSE is distributed in the hope that it will be useful,
//   but WITHOUT ANY WARRANTY; without even the implied warranty of
//   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
//   See the GNU Library General Public License for more details.
//
//   You should have received a copy of the GNU Library General Public License
//   along with this software; if not, write to the Free Software
//   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
//
// *********************************************************************** */
#ifndef POLYMFEMUTILS_H
#define POLYMFEMUTILS_H

#include "mfem.hpp"
#include <string>
#include <vector>
#include "config.h"
#include "probe.h"



/**
 * @file polyMFEMUtils.h
 * @brief A collection of utilities for working with MFEM and solving the lane-emden equation.
 */


/**
 * @namespace polyMFEMUtils
 * @brief A namespace for utilities for working with MFEM and solving the lane-emden equation.
 */
namespace polyMFEMUtils {
  /**
   * @brief A class for nonlinear power integrator.
   */
  class NonlinearPowerIntegrator: public mfem::NonlinearFormIntegrator {
  private: 
    Config& config = Config::getInstance();
    mfem::Coefficient &coeff_;
    double polytropicIndex;
  public:
    /**
     * @brief Constructor for NonlinearPowerIntegrator.
     * 
     * @param coeff The function coefficient.
     * @param n The polytropic index.
     */
    NonlinearPowerIntegrator(mfem::Coefficient &coeff, double n);

    /**
     * @brief Assembles the element vector.
     * 
     * @param el The finite element.
     * @param Trans The element transformation.
     * @param elfun The element function.
     * @param elvect The element vector to be assembled.
     */
    virtual void AssembleElementVector(const mfem::FiniteElement &el, mfem::ElementTransformation &Trans, const mfem::Vector &elfun, mfem::Vector &elvect) override;

    /**
     * @brief Assembles the element gradient.
     * 
     * @param el The finite element.
     * @param Trans The element transformation.
     * @param elfun The element function.
     * @param elmat The element matrix to be assembled.
     */
    virtual void AssembleElementGrad (const mfem::FiniteElement &el, mfem::ElementTransformation &Trans, const mfem::Vector &elfun, mfem::DenseMatrix &elmat) override;
  };

  /**
   * @brief A wrapper class for bilinear integrator.
   */
  class BilinearIntegratorWrapper : public mfem::NonlinearFormIntegrator
  {
  private:
    mfem::BilinearFormIntegrator *integrator;
  public:
    /**
      * @brief Constructor for BilinearIntegratorWrapper.
      * 
      * @param integratorInput The bilinear form integrator input.
      */
    BilinearIntegratorWrapper(mfem::BilinearFormIntegrator *integratorInput);

    /**
      * @brief Destructor for BilinearIntegratorWrapper.
      */
    virtual ~BilinearIntegratorWrapper();

    /**
      * @brief Assembles the element vector.
      * 
      * @param el The finite element.
      * @param Trans The element transformation.
      * @param elfun The element function.
      * @param elvect The element vector to be assembled.
      */
    virtual void AssembleElementVector(const mfem::FiniteElement &el, mfem::ElementTransformation &Trans, const mfem::Vector &elfun, mfem::Vector &elvect) override;

    /**
      * @brief Assembles the element gradient.
      * 
      * @param el The finite element.
      * @param Trans The element transformation.
      * @param elfun The element function.
      * @param elmat The element matrix to be assembled.
      */
    virtual void AssembleElementGrad(const mfem::FiniteElement &el, mfem::ElementTransformation &Trans, const mfem::Vector &elfun, mfem::DenseMatrix &elmat) override;
  };

  /**
   * @brief A class for composite nonlinear integrator.
   */
  class CompositeNonlinearIntegrator: public mfem::NonlinearFormIntegrator {
    private:
      std::vector<mfem::NonlinearFormIntegrator*> integrators;
    public:
      /**
       * @brief Constructor for CompositeNonlinearIntegrator.
       */
      CompositeNonlinearIntegrator();

      /**
       * @brief Destructor for CompositeNonlinearIntegrator.
       */
      virtual ~CompositeNonlinearIntegrator();

      /**
       * @brief Adds an integrator to the composite integrator.
       * 
       * @param integrator The nonlinear form integrator to add.
       */
      void add_integrator(mfem::NonlinearFormIntegrator *integrator);

      /**
       * @brief Assembles the element vector.
       * 
       * @param el The finite element.
       * @param Trans The element transformation.
       * @param elfun The element function.
       * @param elvect The element vector to be assembled.
       */
      virtual void AssembleElementVector(const mfem::FiniteElement &el, mfem::ElementTransformation &Trans, const mfem::Vector &elfun, mfem::Vector &elvect) override;

      /**
       * @brief Assembles the element gradient.
       * 
       * @param el The finite element.
       * @param Trans The element transformation.
       * @param elfun The element function.
       * @param elmat The element matrix to be assembled.
       */
      virtual void AssembleElementGrad(const mfem::FiniteElement &el, mfem::ElementTransformation &Trans, const mfem::Vector &elfun, mfem::DenseMatrix &elmat) override;
  };

  class ConstraintIntegrator: public mfem::BilinearFormIntegrator {
  private:
    Config& m_config = Config::getInstance();
    Probe::LogManager& logManager = Probe::LogManager::getInstance();
    quill::Logger* m_logger = logManager.getLogger("log");
    const double m_gamma;
    mfem::Array<int> m_originElementIDs;
    mfem::Array<mfem::IntegrationPoint> m_originIntegrationPoints;
    mfem::DenseMatrix m_originCoordinateMatrix;
    mfem::Mesh* m_mesh;
    std::vector<int> m_originConnectedElementIds;
  public:
    ConstraintIntegrator(const double gamma, mfem::Mesh* mesh);
    ~ConstraintIntegrator() = default;

    void AssembleElementMatrix(const mfem::FiniteElement &el, mfem::ElementTransformation &Trans, mfem::DenseMatrix &elmat) override;

  };

} // namespace polyMFEMUtils

#endif // POLYMFEMUTILS_H