/* ************************************************************************
 * 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 "base_amg.hpp"
#include "../../utils/def.hpp"
#include "../../utils/types.hpp"

#include "../../base/global_matrix.hpp"
#include "../../base/global_vector.hpp"
#include "../../base/local_matrix.hpp"
#include "../../base/local_vector.hpp"
#include "../iter_ctrl.hpp"

#include "../krylov/cg.hpp"
#include "../preconditioners/preconditioner.hpp"

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

#include <list>

namespace rocalution
{

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

        this->coarse_size_ = 300;

        // manual smoothers and coarse solver
        this->set_sm_ = false;
        this->set_s_  = false;

        // default smoother format
        this->sm_format_ = CSR;
        // default operator format
        this->op_format_ = CSR;

        // since hierarchy has not been built yet
        this->hierarchy_ = false;

        // initialize temp default smoother pointer
        this->sm_default_ = NULL;
    }

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

        this->Clear();
    }

    template <class OperatorType, class VectorType, typename ValueType>
    void BaseAMG<OperatorType, VectorType, ValueType>::SetCoarsestLevel(int coarse_size)
    {
        log_debug(this, "BaseAMG::SetCoarsestLevel()", coarse_size);

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

        this->coarse_size_ = coarse_size;
    }

    template <class OperatorType, class VectorType, typename ValueType>
    void BaseAMG<OperatorType, VectorType, ValueType>::SetManualSmoothers(bool sm_manual)
    {
        log_debug(this, "BaseAMG::SetManualSmoothers()", sm_manual);

        assert(this->build_ == false);

        this->set_sm_ = sm_manual;
    }

    template <class OperatorType, class VectorType, typename ValueType>
    void BaseAMG<OperatorType, VectorType, ValueType>::SetManualSolver(bool s_manual)
    {
        log_debug(this, "BaseAMG::SetManualSolver()", s_manual);

        assert(this->build_ == false);

        this->set_s_ = s_manual;
    }

    template <class OperatorType, class VectorType, typename ValueType>
    void BaseAMG<OperatorType, VectorType, ValueType>::SetDefaultSmootherFormat(
        unsigned int op_format)
    {
        log_debug(this, "BaseAMG::SetDefaultSmootherFormat()", op_format);

        assert(this->build_ == false);

        this->sm_format_ = op_format;
    }

    template <class OperatorType, class VectorType, typename ValueType>
    void BaseAMG<OperatorType, VectorType, ValueType>::SetOperatorFormat(unsigned int op_format)
    {
        log_debug(this, "BaseAMG::SetOperatorFormat()", op_format);

        this->op_format_ = op_format;
    }

    template <class OperatorType, class VectorType, typename ValueType>
    int BaseAMG<OperatorType, VectorType, ValueType>::GetNumLevels(void)
    {
        assert(this->hierarchy_ != false);

        return this->levels_;
    }

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

        if(this->build_ == true)
        {
            this->Clear();
        }

        assert(this->build_ == false);

        this->BuildHierarchy();

        this->build_ = true;

        log_debug(this, "BaseAMG::Build()", "#*# allocate data");

        this->d_level_ = new VectorType*[this->levels_];
        this->r_level_ = new VectorType*[this->levels_];
        this->t_level_ = new VectorType*[this->levels_];
        this->s_level_ = new VectorType*[this->levels_];

        // Extra structure for K-cycle
        if(this->cycle_ == 2)
        {
            this->p_level_ = new VectorType*[this->levels_ - 2];
            this->q_level_ = new VectorType*[this->levels_ - 2];
            this->k_level_ = new VectorType*[this->levels_ - 2];
            this->l_level_ = new VectorType*[this->levels_ - 2];

            for(int i = 0; i < this->levels_ - 2; ++i)
            {
                this->p_level_[i] = new VectorType;
                this->p_level_[i]->CloneBackend(*this->op_level_[i]);
                this->p_level_[i]->Allocate("p", this->op_level_[i]->GetM());

                this->q_level_[i] = new VectorType;
                this->q_level_[i]->CloneBackend(*this->op_level_[i]);
                this->q_level_[i]->Allocate("q", this->op_level_[i]->GetM());

                this->k_level_[i] = new VectorType;
                this->k_level_[i]->CloneBackend(*this->op_level_[i]);
                this->k_level_[i]->Allocate("k", this->op_level_[i]->GetM());

                this->l_level_[i] = new VectorType;
                this->l_level_[i]->CloneBackend(*this->op_level_[i]);
                this->l_level_[i]->Allocate("l", this->op_level_[i]->GetM());
            }
        }

        for(int i = 0; i < this->levels_; ++i)
        {
            this->r_level_[i] = new VectorType;
            this->t_level_[i] = new VectorType;
            this->s_level_[i] = new VectorType;
            if(i > 0)
            {
                this->d_level_[i] = new VectorType;
            }

            if(i > 0)
            {
                this->d_level_[i]->CloneBackend(*this->op_level_[i - 1]);
                this->r_level_[i]->CloneBackend(*this->op_level_[i - 1]);
                this->t_level_[i]->CloneBackend(*this->op_level_[i - 1]);
                this->s_level_[i]->CloneBackend(*this->op_level_[i - 1]);
            }
            else
            {
                this->r_level_[i]->CloneBackend(*this->op_);
                this->t_level_[i]->CloneBackend(*this->op_);
                this->s_level_[i]->CloneBackend(*this->op_);
            }
        }

        // Allocate temporary vectors for cycles
        for(int level = 0; level < this->levels_; ++level)
        {
            if(level > 0)
            {
                this->d_level_[level]->Allocate("defect correction",
                                                this->op_level_[level - 1]->GetM());
                this->r_level_[level]->Allocate("residual", this->op_level_[level - 1]->GetM());
                this->t_level_[level]->Allocate("temporary", this->op_level_[level - 1]->GetM());
                this->s_level_[level]->Allocate("temporary", this->op_level_[level - 1]->GetM());
            }
            else
            {
                this->r_level_[level]->Allocate("residual", this->op_->GetM());
                this->t_level_[level]->Allocate("temporary", this->op_->GetM());
                this->s_level_[level]->Allocate("temporary", this->op_->GetM());
            }
        }

        log_debug(this, "BaseAMG::Build()", "#*# setup smoothers");

        // Setup and build smoothers
        if(this->set_sm_ == false)
        {
            this->BuildSmoothers();
        }

        for(int i = 0; i < this->levels_ - 1; ++i)
        {
            if(i > 0)
            {
                this->smoother_level_[i]->SetOperator(*this->op_level_[i - 1]);
            }
            else
            {
                this->smoother_level_[i]->SetOperator(*this->op_);
            }

            this->smoother_level_[i]->Build();
        }

        log_debug(this, "BaseAMG::Build()", "#*# setup coarse solver");

        // Setup and build coarse grid solver
        if(this->set_s_ == false)
        {
            // Coarse Grid Solver
            CG<OperatorType, VectorType, ValueType>* cgs
                = new CG<OperatorType, VectorType, ValueType>;

            // set absolute tolerance to 0 to avoid issues with very small numbers
            cgs->Init(0.0, 1e-6, 1e+8, 1000000);
            // be quite
            cgs->Verbose(0);

            this->solver_coarse_ = cgs;
        }

        this->solver_coarse_->SetOperator(*this->op_level_[this->levels_ - 2]);
        this->solver_coarse_->Build();

        log_debug(this, "BaseAMG::Build()", "#*# convert operators");

        // Convert operator to op_format
        if(this->op_format_ != CSR)
        {
            for(int i = 0; i < this->levels_ - 1; ++i)
            {
                this->op_level_[i]->ConvertTo(this->op_format_);
            }
        }

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

    template <class OperatorType, class VectorType, typename ValueType>
    void BaseAMG<OperatorType, VectorType, ValueType>::BuildHierarchy(void)
    {
        log_debug(this, "BaseAMG::BuildHierarchy()", " #*# begin");

        if(this->hierarchy_ == false)
        {
            assert(this->build_ == false);
            this->hierarchy_ = true;

            // AMG will use operators for inter grid transfers
            assert(this->op_ != NULL);
            assert(this->coarse_size_ > 0);

            if(this->op_->GetM() <= (IndexType2)this->coarse_size_)
            {
                LOG_INFO("Problem size too small for AMG, use Krylov solver instead");
                FATAL_ERROR(__FILE__, __LINE__);
            }

            // Lists for the building procedure
            std::list<OperatorType*> op_list_;
            std::list<OperatorType*> restrict_list_;
            std::list<OperatorType*> prolong_list_;

            this->levels_ = 1;

            // Build finest hierarchy
            op_list_.push_back(new OperatorType);
            restrict_list_.push_back(new OperatorType);
            prolong_list_.push_back(new OperatorType);

            op_list_.back()->CloneBackend(*this->op_);
            restrict_list_.back()->CloneBackend(*this->op_);
            prolong_list_.back()->CloneBackend(*this->op_);

            // Create prolongation and restriction operators
            this->Aggregate_(
                *this->op_, prolong_list_.back(), restrict_list_.back(), op_list_.back());

            ++this->levels_;

            while(op_list_.back()->GetM() > (IndexType2)this->coarse_size_)
            {
                // Add new list elements
                restrict_list_.push_back(new OperatorType);
                prolong_list_.push_back(new OperatorType);
                OperatorType* prev_op_ = op_list_.back();
                op_list_.push_back(new OperatorType);

                op_list_.back()->CloneBackend(*this->op_);
                restrict_list_.back()->CloneBackend(*this->op_);
                prolong_list_.back()->CloneBackend(*this->op_);

                this->Aggregate_(
                    *prev_op_, prolong_list_.back(), restrict_list_.back(), op_list_.back());

                ++this->levels_;

                if(this->levels_ > 19)
                {
                    LOG_VERBOSE_INFO(2,
                                     "*** warning: BaseAMG::Build() Current number of levels: "
                                         << this->levels_);
                }
            }

            // Allocate data structures
            this->op_level_          = new OperatorType*[this->levels_ - 1];
            this->restrict_op_level_ = new Operator<ValueType>*[this->levels_ - 1];
            this->prolong_op_level_  = new Operator<ValueType>*[this->levels_ - 1];

            typename std::list<OperatorType*>::iterator op_it  = op_list_.begin();
            typename std::list<OperatorType*>::iterator pro_it = prolong_list_.begin();
            typename std::list<OperatorType*>::iterator res_it = restrict_list_.begin();

            for(int i = 0; i < this->levels_ - 1; ++i)
            {
                this->op_level_[i] = *op_it;
                this->op_level_[i]->Sort();
                ++op_it;

                this->restrict_op_level_[i] = *res_it;
                ++res_it;

                this->prolong_op_level_[i] = *pro_it;
                ++pro_it;
            }
        }

        log_debug(this, "BaseAMG::BuildHierarchy()", " #*# end");
    }

    template <class OperatorType, class VectorType, typename ValueType>
    void BaseAMG<OperatorType, VectorType, ValueType>::BuildSmoothers(void)
    {
        log_debug(this, "BaseAMG::BuildSmoothers()", " #*# begin");

        // Smoother for each level
        this->smoother_level_
            = new IterativeLinearSolver<OperatorType, VectorType, ValueType>*[this->levels_ - 1];
        this->sm_default_ = new Solver<OperatorType, VectorType, ValueType>*[this->levels_ - 1];

        for(int i = 0; i < this->levels_ - 1; ++i)
        {
            FixedPoint<OperatorType, VectorType, ValueType>* sm
                = new FixedPoint<OperatorType, VectorType, ValueType>;
            Jacobi<OperatorType, VectorType, ValueType>* jac
                = new Jacobi<OperatorType, VectorType, ValueType>;

            sm->SetRelaxation(static_cast<ValueType>(0.67));
            sm->SetPreconditioner(*jac);
            sm->Verbose(0);
            this->smoother_level_[i] = sm;
            this->sm_default_[i]     = jac;
        }

        log_debug(this, "BaseAMG::BuildSmoothers()", " #*# end");
    }

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

        if(this->build_ == true)
        {
            this->ClearLocal();

            for(int i = 0; i < this->levels_; ++i)
            {
                // Clear temporary VectorTypes
                if(i > 0)
                {
                    delete this->d_level_[i];
                }
                delete this->r_level_[i];
                delete this->t_level_[i];
                delete this->s_level_[i];
            }

            delete[] this->d_level_;
            delete[] this->r_level_;
            delete[] this->t_level_;
            delete[] this->s_level_;

            // Extra structure for K-cycle
            if(this->cycle_ == 2)
            {
                for(int i = 0; i < this->levels_ - 2; ++i)
                {
                    delete this->p_level_[i];
                    delete this->q_level_[i];
                    delete this->k_level_[i];
                    delete this->l_level_[i];
                }

                delete[] this->p_level_;
                delete[] this->q_level_;
                delete[] this->k_level_;
                delete[] this->l_level_;
            }

            for(int i = 0; i < this->levels_ - 1; ++i)
            {
                // Clear operator data structure
                delete this->op_level_[i];
                delete this->restrict_op_level_[i];
                delete this->prolong_op_level_[i];

                if(this->set_sm_ == false)
                {
                    delete this->smoother_level_[i];
                    delete this->sm_default_[i];
                }
                else
                    this->smoother_level_[i]->Clear();
            }

            // Clear coarse grid solver - we built it
            if(this->set_s_ == false)
            {
                delete this->solver_coarse_;
            }
            else
            {
                this->solver_coarse_->Clear();
            }

            delete[] this->op_level_;
            delete[] this->restrict_op_level_;
            delete[] this->prolong_op_level_;

            if(this->set_sm_ == false)
            {
                delete[] this->smoother_level_;
                delete[] this->sm_default_;
            }

            this->levels_ = -1;

            this->iter_ctrl_.Clear();

            this->build_     = false;
            this->hierarchy_ = false;
        }
    }

    // do nothing
    template <class OperatorType, class VectorType, typename ValueType>
    void BaseAMG<OperatorType, VectorType, ValueType>::ClearLocal(void)
    {
    }

    template <class OperatorType, class VectorType, typename ValueType>
    void BaseAMG<OperatorType, VectorType, ValueType>::SetRestrictOperator(OperatorType** op)
    {
        LOG_INFO(
            "BaseAMG::SetRestrictOperator() Perhaps you want to use the MultiGrid class to set "
            "external restriction operators");
        FATAL_ERROR(__FILE__, __LINE__);
    }

    template <class OperatorType, class VectorType, typename ValueType>
    void BaseAMG<OperatorType, VectorType, ValueType>::SetProlongOperator(OperatorType** op)
    {
        LOG_INFO("BaseAMG::SetProlongOperator() Perhaps you want to use the MultiGrid class to set "
                 "external prolongation operators");
        FATAL_ERROR(__FILE__, __LINE__);
    }

    template <class OperatorType, class VectorType, typename ValueType>
    void BaseAMG<OperatorType, VectorType, ValueType>::SetOperatorHierarchy(OperatorType** op)
    {
        LOG_INFO(
            "BaseAMG::SetOperatorHierarchy() Perhaps you want to use the MultiGrid class to set "
            "external operators");
        FATAL_ERROR(__FILE__, __LINE__);
    }

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

    template class BaseAMG<GlobalMatrix<double>, GlobalVector<double>, double>;
    template class BaseAMG<GlobalMatrix<float>, GlobalVector<float>, float>;
#ifdef SUPPORT_COMPLEX
    template class BaseAMG<GlobalMatrix<std::complex<double>>,
                           GlobalVector<std::complex<double>>,
                           std::complex<double>>;
    template class BaseAMG<GlobalMatrix<std::complex<float>>,
                           GlobalVector<std::complex<float>>,
                           std::complex<float>>;
#endif

} // namespace rocalution