/*
  Copyright 2014 SINTEF ICT, Applied Mathematics.
  Copyright 2014 IRIS AS

  This file is part of the Open Porous Media project (OPM).

  OPM 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 3 of the License, or
  (at your option) any later version.

  OPM 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 OPM.  If not, see <http://www.gnu.org/licenses/>.
*/

#ifndef OPM_DUNEMATRIX_HEADER_INCLUDED
#define OPM_DUNEMATRIX_HEADER_INCLUDED

#ifdef DUNE_BCRSMATRIX_HH
#error This header must be included before any bcrsmatrix.hh is included (directly or indirectly)
#endif

#include <opm/core/utility/platform_dependent/disable_warnings.h>

#include <Eigen/Eigen>
#include <Eigen/Sparse>

#include <dune/common/fmatrix.hh>
#include <dune/common/version.hh>

// Include matrix header with hackery to make it possible to inherit.
#define private protected
#include <dune/istl/bcrsmatrix.hh>
#undef private

#include <opm/core/utility/platform_dependent/reenable_warnings.h>

namespace Opm
{

    class DuneMatrix : public Dune::BCRSMatrix< Dune::FieldMatrix<double, 1, 1> >
    {
    public:
        DuneMatrix(const int rows, const int cols, const int* ia, const int* ja, const double* sa)
        {
            // create BCRSMatrix from given CSR storage
            init( rows, cols, ia, ja, sa );
        }

        /// \brief create an ISTL BCRSMatrix from a Eigen::SparseMatrix
        DuneMatrix( const Eigen::SparseMatrix<double, Eigen::RowMajor>& matrix )
        {
            // Create ISTL matrix.
            const int rows = matrix.rows();
            const int cols = matrix.cols();
            const int* ia = matrix.outerIndexPtr();
            const int* ja = matrix.innerIndexPtr();
            const double* sa = matrix.valuePtr();
            // create BCRSMatrix from Eigen matrix
            init( rows, cols, ia, ja, sa );
        }

    protected:
        void init(const int rows, const int cols, const int* ia, const int* ja, const double* sa)
        {
            typedef Dune::BCRSMatrix< Dune::FieldMatrix<double, 1, 1> > Super;
            typedef Super::block_type block_type;
            this->build_mode = Super::unknown;
            this->ready = Super::built;
            this->n = rows;
            this->m = cols;
            this->nnz = ia[rows];

#if DUNE_VERSION_NEWER(DUNE_ISTL, 2, 3)
            this->allocationSize = this->nnz;
            this->avg = 0;
            this->overflowsize = -1.0;
#endif

            // make sure to use the allocators of this matrix 
            // because the same allocators are used to deallocate the data
            this->a = this->allocator_.allocate(this->nnz);
            static_assert(sizeof(block_type) == sizeof(double), "This constructor requires a block type that is the same as a double.");
            std::copy(sa, sa + this->nnz, reinterpret_cast<double*>(this->a));
            this->j.reset(this->sizeAllocator_.allocate(this->nnz));
            std::copy(ja, ja +this-> nnz, this->j.get());
            this->r = rowAllocator_.allocate(rows);
            for (int row = 0; row < rows; ++row) {
                this->r[row].set(ia[row+1] - ia[row], this->a + ia[row], this->j.get() + ia[row]);
            }
        }
    };

} // namespace Opm

#endif // OPM_DUNEMATRIX_HEADER_INCLUDED