#pragma once

#include "storm/solver/StandardMinMaxLinearEquationSolver.h"

namespace storm {

    class Environment;

    namespace solver {

        /*!
         * This solver can be used on equation systems that are known to be acyclic.
         * It is optimized for solving many instances of the equation system with the same underlying matrix.
         */
        template<typename ValueType>
        class AcyclicMinMaxLinearEquationSolver : public StandardMinMaxLinearEquationSolver<ValueType> {
        public:
            AcyclicMinMaxLinearEquationSolver();
            AcyclicMinMaxLinearEquationSolver(storm::storage::SparseMatrix<ValueType> const& A);
            AcyclicMinMaxLinearEquationSolver(storm::storage::SparseMatrix<ValueType>&& A);

            virtual ~AcyclicMinMaxLinearEquationSolver() {
            }

            virtual void clearCache() const override;

            virtual MinMaxLinearEquationSolverRequirements getRequirements(Environment const& env, boost::optional<storm::solver::OptimizationDirection> const& direction = boost::none, bool const& hasInitialScheduler = false) const override ;

        protected:

            virtual bool internalSolveEquations(storm::Environment const& env, OptimizationDirection d, std::vector<ValueType>& x, std::vector<ValueType> const& b) const override;

        private:
            // cached multiplier either with original matrix or ordered matrix
            mutable std::unique_ptr<storm::solver::Multiplier<ValueType>> multiplier;
            // cached matrix for the multiplier (only if different from original matrix)
            mutable boost::optional<storm::storage::SparseMatrix<ValueType>> orderedMatrix;
            // cached row group ordering (only if not identity)
            mutable boost::optional<std::vector<uint64_t>> rowGroupOrdering; // A.rowGroupCount() entries
            // can be used if the entries in 'b' need to be reordered
            mutable boost::optional<std::vector<ValueType>> auxiliaryRowVector; // A.rowCount() entries
            // contains factors applied to scale the entries of the 'b' vector
            mutable std::vector<std::pair<uint64_t, ValueType>> bFactors;

        };
    }
}