/*
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * The Original Code is Copyright (C) Blender Foundation
 * All rights reserved.
 */

#pragma once

/** \file
 * \ingroup sim
 */

#if defined(__GNUC__) && !defined(__clang__)
#  pragma GCC diagnostic push
/* XXX suppress verbose warnings in eigen */
#  pragma GCC diagnostic ignored "-Wlogical-op"
#endif

#include <Eigen/Sparse>
#include <Eigen/src/Core/util/DisableStupidWarnings.h>

#ifdef __GNUC__
#  pragma GCC diagnostic pop
#endif

#include "BLI_utildefines.h"
#include "implicit.h"

typedef float Scalar;

/* slightly extended Eigen vector class
 * with conversion to/from plain C float array
 */
class Vector3 : public Eigen::Vector3f {
 public:
  typedef float *ctype;

  Vector3()
  {
  }

  Vector3(const ctype &v)
  {
    for (int k = 0; k < 3; k++) {
      coeffRef(k) = v[k];
    }
  }

  Vector3 &operator=(const ctype &v)
  {
    for (int k = 0; k < 3; k++) {
      coeffRef(k) = v[k];
    }
    return *this;
  }

  operator ctype()
  {
    return data();
  }
};

/* slightly extended Eigen matrix class
 * with conversion to/from plain C float array
 */
class Matrix3 : public Eigen::Matrix3f {
 public:
  typedef float (*ctype)[3];

  Matrix3()
  {
  }

  Matrix3(const ctype &v)
  {
    for (int k = 0; k < 3; k++) {
      for (int l = 0; l < 3; l++) {
        coeffRef(l, k) = v[k][l];
      }
    }
  }

  Matrix3 &operator=(const ctype &v)
  {
    for (int k = 0; k < 3; k++) {
      for (int l = 0; l < 3; l++) {
        coeffRef(l, k) = v[k][l];
      }
    }
    return *this;
  }

  operator ctype()
  {
    return (ctype)data();
  }
};

typedef Eigen::VectorXf lVector;

/* Extension of dense Eigen vectors,
 * providing 3-float block access for blenlib math functions
 */
class lVector3f : public Eigen::VectorXf {
 public:
  typedef Eigen::VectorXf base_t;

  lVector3f()
  {
  }

  template<typename T> lVector3f &operator=(T rhs)
  {
    base_t::operator=(rhs);
    return *this;
  }

  float *v3(int vertex)
  {
    return &coeffRef(3 * vertex);
  }

  const float *v3(int vertex) const
  {
    return &coeffRef(3 * vertex);
  }
};

typedef Eigen::Triplet<Scalar> Triplet;
typedef std::vector<Triplet> TripletList;

typedef Eigen::SparseMatrix<Scalar> lMatrix;

/* Constructor type that provides more convenient handling of Eigen triplets
 * for efficient construction of sparse 3x3 block matrices.
 * This should be used for building lMatrix instead of writing to such lMatrix directly (which is
 * very inefficient). After all elements have been defined using the set() method, the actual
 * matrix can be filled using construct().
 */
struct lMatrix3fCtor {
  lMatrix3fCtor()
  {
  }

  void reset()
  {
    m_trips.clear();
  }

  void reserve(int numverts)
  {
    /* reserve for diagonal entries */
    m_trips.reserve(numverts * 9);
  }

  void add(int i, int j, const Matrix3 &m)
  {
    i *= 3;
    j *= 3;
    for (int k = 0; k < 3; k++) {
      for (int l = 0; l < 3; l++) {
        m_trips.push_back(Triplet(i + k, j + l, m.coeff(l, k)));
      }
    }
  }

  void sub(int i, int j, const Matrix3 &m)
  {
    i *= 3;
    j *= 3;
    for (int k = 0; k < 3; k++) {
      for (int l = 0; l < 3; l++) {
        m_trips.push_back(Triplet(i + k, j + l, -m.coeff(l, k)));
      }
    }
  }

  inline void construct(lMatrix &m)
  {
    m.setFromTriplets(m_trips.begin(), m_trips.end());
    m_trips.clear();
  }

 private:
  TripletList m_trips;
};

typedef Eigen::ConjugateGradient<lMatrix, Eigen::Lower, Eigen::DiagonalPreconditioner<Scalar>>
    ConjugateGradient;

using Eigen::ComputationInfo;

BLI_INLINE void print_lvector(const lVector3f &v)
{
  for (int i = 0; i < v.rows(); i++) {
    if (i > 0 && i % 3 == 0) {
      printf("\n");
    }

    printf("%f,\n", v[i]);
  }
}

BLI_INLINE void print_lmatrix(const lMatrix &m)
{
  for (int j = 0; j < m.rows(); j++) {
    if (j > 0 && j % 3 == 0) {
      printf("\n");
    }

    for (int i = 0; i < m.cols(); i++) {
      if (i > 0 && i % 3 == 0) {
        printf("  ");
      }

      implicit_print_matrix_elem(m.coeff(j, i));
    }
    printf("\n");
  }
}