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/* Author: Javier V. Gómez */

#ifndef OMPL_BASE_SAMPLERS_CFOREST_STATE_SAMPLER_
#define OMPL_BASE_SAMPLERS_CFOREST_STATE_SAMPLER_

#include "ompl/base/StateSpace.h"

#include <mutex>
#include <utility>

namespace ompl
{
    namespace base
    {
        /** \brief Extended state sampler to use with the CForest planning algorithm. It wraps the user-specified
            state sampler.*/
        class CForestStateSampler : public StateSampler
        {
        public:
            /** \brief Constructor */
            CForestStateSampler(const StateSpace *space, StateSamplerPtr sampler)
              : StateSampler(space), sampler_(std::move(sampler))
            {
            }

            /** \brief Destructor */
            ~CForestStateSampler() override
            {
                clear();
            }

            /** \brief It will sample the next state of the vector StatesToSample_. If this is empty,
                it will call the sampleUniform() method of the specified sampler. */
            void sampleUniform(State *state) override;

            /** \brief It will sample the next state of the vector StatesToSample_. If this is empty,
                it will call the sampleUniformNear() method of the specified sampler. */
            void sampleUniformNear(State *state, const State *near, const double distance) override;

            /** \brief It will sample the next state of the vector StatesToSample_. If this is empty,
                it will call the sampleGaussian() method of the specified sampler. */
            void sampleGaussian(State *state, const State *mean, const double stdDev) override;

            const StateSpace *getStateSpace() const
            {
                return space_;
            }

            /** \brief Fills the vector StatesToSample_ of states to be sampled in the next
                calls to sampleUniform(), sampleUniformNear() or sampleGaussian(). */
            void setStatesToSample(const std::vector<const State *> &states);

            void clear();

        protected:
            /** \brief Extracts the next sample when statesToSample_ is not empty. */
            void getNextSample(State *state);

            /** \brief States to be sampled */
            std::vector<State *> statesToSample_;

            /** \brief Underlying, user-specified state sampler. */
            StateSamplerPtr sampler_;

            /** \brief Lock to control the access to the statesToSample_ vector. */
            std::mutex statesLock_;
        };
    }
}

#endif
