/* ************************************************************************
 * Copyright (c) 2018 Advanced Micro Devices, Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 * ************************************************************************ */

#include "preconditioner_saddlepoint.hpp"
#include "../../utils/def.hpp"
#include "../solver.hpp"
#include "preconditioner.hpp"

#include "../../base/local_matrix.hpp"

#include "../../base/local_vector.hpp"

#include "../../utils/log.hpp"

#include <complex>

namespace rocalution
{

    template <class OperatorType, class VectorType, typename ValueType>
    DiagJacobiSaddlePointPrecond<OperatorType, VectorType, ValueType>::
        DiagJacobiSaddlePointPrecond()
    {
        log_debug(this,
                  "DiagJacobiSaddlePointPrecond::DiagJacobiSaddlePointPrecond()",
                  "default constructor");

        this->size_ = 0;

        this->K_solver_ = NULL;
        this->S_solver_ = NULL;

        this->K_nrow_ = 0;
        this->K_nnz_  = 0;
    }

    template <class OperatorType, class VectorType, typename ValueType>
    DiagJacobiSaddlePointPrecond<OperatorType, VectorType, ValueType>::
        ~DiagJacobiSaddlePointPrecond()
    {
        log_debug(
            this, "DiagJacobiSaddlePointPrecond::~DiagJacobiSaddlePointPrecond()", "destructor");

        this->Clear();
    }

    template <class OperatorType, class VectorType, typename ValueType>
    void DiagJacobiSaddlePointPrecond<OperatorType, VectorType, ValueType>::Clear(void)
    {
        log_debug(this, "DiagJacobiSaddlePointPrecond::Clear()", this->build_);

        if(this->build_ == true)
        {
            this->A_.Clear();
            this->K_.Clear();
            this->S_.Clear();

            this->A_.ConvertToCSR();
            this->K_.ConvertToCSR();
            this->S_.ConvertToCSR();

            this->K_nrow_ = 0;
            this->K_nnz_  = 0;

            this->x_.Clear();
            this->x_1_.Clear();
            this->x_2_.Clear();

            this->rhs_.Clear();
            this->rhs_1_.Clear();
            this->rhs_1_.Clear();

            this->permutation_.Clear();

            if(this->K_solver_ != NULL)
            {
                this->K_solver_->Clear();
            }

            if(this->S_solver_ != NULL)
            {
                this->S_solver_->Clear();
            }

            this->size_ = 0;

            this->K_solver_ = NULL;
            this->S_solver_ = NULL;

            this->build_ = false;
        }
    }

    template <class OperatorType, class VectorType, typename ValueType>
    void DiagJacobiSaddlePointPrecond<OperatorType, VectorType, ValueType>::Print(void) const
    {
        if(this->build_ == true)
        {
            LOG_INFO("DiagJacobiSaddlePointPrecond preconditioner with "
                     << " ; S solver:");

            this->S_solver_->Print();

            LOG_INFO("and K solver:")
            this->K_solver_->Print();
        }
        else
        {
            LOG_INFO("DiagJacobiSaddlePointPrecond (I)LU preconditioner");
        }
    }

    template <class OperatorType, class VectorType, typename ValueType>
    void DiagJacobiSaddlePointPrecond<OperatorType, VectorType, ValueType>::Set(
        Solver<OperatorType, VectorType, ValueType>& K_Solver,
        Solver<OperatorType, VectorType, ValueType>& S_Solver)
    {
        log_debug(this,
                  "DiagJacobiSaddlePointPrecond::Set()",
                  (const void*&)K_Solver,
                  (const void*&)S_Solver);

        this->K_solver_ = &K_Solver;
        this->S_solver_ = &S_Solver;
    }

    template <class OperatorType, class VectorType, typename ValueType>
    void DiagJacobiSaddlePointPrecond<OperatorType, VectorType, ValueType>::Build(void)
    {
        log_debug(this, "DiagJacobiSaddlePointPrecond::Build()", this->build_, " #*# begin");

        assert(this->build_ == false);
        this->build_ = true;

        assert(this->op_ != NULL);
        assert(this->K_solver_ != NULL);
        assert(this->S_solver_ != NULL);

        this->A_.CloneBackend(*this->op_);
        this->K_.CloneBackend(*this->op_);
        this->S_.CloneBackend(*this->op_);

        this->x_.CloneBackend(*this->op_);
        this->x_1_.CloneBackend(*this->op_);
        this->x_2_.CloneBackend(*this->op_);

        this->rhs_.CloneBackend(*this->op_);
        this->rhs_1_.CloneBackend(*this->op_);
        this->rhs_1_.CloneBackend(*this->op_);

        this->permutation_.CloneBackend(this->x_);

        this->A_.CloneFrom(*this->op_);

        //  this->A_.ConvertToCSR();

        this->A_.ZeroBlockPermutation(this->size_, &this->permutation_);

        this->A_.Permute(this->permutation_);

        this->A_.ExtractSubMatrix(0, 0, this->size_, this->size_, &this->K_);

        OperatorType E, F;
        VectorType   inv_K;

        E.CloneBackend(*this->op_);
        F.CloneBackend(*this->op_);
        inv_K.CloneBackend(*this->op_);

        this->A_.ExtractSubMatrix(
            0, this->size_, this->size_, this->A_.GetLocalN() - this->size_, &F);

        this->A_.ExtractSubMatrix(
            this->size_, 0, this->A_.GetLocalM() - this->size_, this->size_, &E);

        this->A_.Clear();

        // Construct solver for K
        this->K_solver_->SetOperator(this->K_);
        this->K_solver_->Build();

        // Construct solver for S
        // inv_K = inv(diag(K))
        this->K_.ExtractInverseDiagonal(&inv_K);

        // E = E * inv(diag(K))
        E.DiagonalMatrixMult(inv_K);

        // S = E * F
        this->S_.MatrixMult(E, F);

        this->S_solver_->SetOperator(this->S_);
        this->S_solver_->Build();

        this->x_.CloneBackend(*this->op_);
        this->x_.Allocate("Permuted solution vector", this->op_->GetM());

        this->rhs_.CloneBackend(*this->op_);
        this->rhs_.Allocate("Permuted RHS vector", this->op_->GetM());

        this->x_1_.CloneBackend(*this->op_);
        this->x_1_.Allocate("Permuted solution vector", this->size_);

        this->x_2_.CloneBackend(*this->op_);
        this->x_2_.Allocate("Permuted solution vector", this->op_->GetM() - this->size_);

        this->rhs_1_.CloneBackend(*this->op_);
        this->rhs_1_.Allocate("Permuted solution vector", this->size_);

        this->rhs_2_.CloneBackend(*this->op_);
        this->rhs_2_.Allocate("Permuted solution vector", this->op_->GetM() - this->size_);

        log_debug(this, "DiagJacobiSaddlePointPrecond::Build()", this->build_, " #*# end");
    }

    template <class OperatorType, class VectorType, typename ValueType>
    void DiagJacobiSaddlePointPrecond<OperatorType, VectorType, ValueType>::Solve(
        const VectorType& rhs, VectorType* x)
    {
        log_debug(
            this, "DiagJacobiSaddlePointPrecond::Solve()", " #*# begin", (const void*&)rhs, x);

        assert(this->build_ == true);

        this->rhs_.CopyFromPermute(rhs, this->permutation_);

        this->rhs_1_.CopyFrom(this->rhs_, 0, 0, this->size_);

        this->rhs_2_.CopyFrom(this->rhs_, this->size_, 0, this->rhs_.GetLocalSize() - this->size_);

        // Solve the first (K) block
        this->K_solver_->SolveZeroSol(this->rhs_1_, &this->x_1_);

        // Solve the second (S) block
        this->S_solver_->SolveZeroSol(this->rhs_2_, &this->x_2_);

        // Copy back
        this->x_.CopyFrom(this->x_1_, 0, 0, this->size_);

        this->x_.CopyFrom(this->x_2_, 0, this->size_, this->rhs_.GetLocalSize() - this->size_);

        x->CopyFromPermuteBackward(this->x_, this->permutation_);

        log_debug(this, "DiagJacobiSaddlePointPrecond::Solve()", " #*# end");
    }

    template <class OperatorType, class VectorType, typename ValueType>
    void DiagJacobiSaddlePointPrecond<OperatorType, VectorType, ValueType>::MoveToHostLocalData_(
        void)
    {
        log_debug(this, "DiagJacobiSaddlePointPrecond::MoveToHostLocalData_()", this->build_);

        this->A_.MoveToHost();
        this->K_.MoveToHost();
        this->S_.MoveToHost();

        this->x_.MoveToHost();
        this->x_1_.MoveToHost();
        this->x_2_.MoveToHost();

        this->rhs_.MoveToHost();
        this->rhs_1_.MoveToHost();
        this->rhs_2_.MoveToHost();

        this->permutation_.MoveToHost();

        if(this->K_solver_ != NULL)
        {
            this->K_solver_->MoveToHost();
        }

        if(this->S_solver_ != NULL)
        {
            this->S_solver_->MoveToHost();
        }
    }

    template <class OperatorType, class VectorType, typename ValueType>
    void DiagJacobiSaddlePointPrecond<OperatorType, VectorType, ValueType>::
        MoveToAcceleratorLocalData_(void)
    {
        log_debug(
            this, "DiagJacobiSaddlePointPrecond::MoveToAcceleratorLocalData_()", this->build_);

        this->A_.MoveToAccelerator();
        this->K_.MoveToAccelerator();
        this->S_.MoveToAccelerator();

        this->x_.MoveToAccelerator();
        this->x_1_.MoveToAccelerator();
        this->x_2_.MoveToAccelerator();

        this->rhs_.MoveToAccelerator();
        this->rhs_1_.MoveToAccelerator();
        this->rhs_2_.MoveToAccelerator();

        this->permutation_.MoveToAccelerator();

        if(this->K_solver_ != NULL)
        {
            this->K_solver_->MoveToAccelerator();
        }

        if(this->S_solver_ != NULL)
        {
            this->S_solver_->MoveToAccelerator();
        }
    }

    template class DiagJacobiSaddlePointPrecond<LocalMatrix<double>, LocalVector<double>, double>;
    template class DiagJacobiSaddlePointPrecond<LocalMatrix<float>, LocalVector<float>, float>;
#ifdef SUPPORT_COMPLEX
    template class DiagJacobiSaddlePointPrecond<LocalMatrix<std::complex<double>>,
                                                LocalVector<std::complex<double>>,
                                                std::complex<double>>;
    template class DiagJacobiSaddlePointPrecond<LocalMatrix<std::complex<float>>,
                                                LocalVector<std::complex<float>>,
                                                std::complex<float>>;
#endif

} // namespace rocalution