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/* Author: Ioan Sucan */

#ifndef OMPL_GEOMETRIC_GENETIC_SEARCH_
#define OMPL_GEOMETRIC_GENETIC_SEARCH_

#include "ompl/base/SpaceInformation.h"
#include "ompl/base/goals/GoalRegion.h"
#include "ompl/geometric/HillClimbing.h"
#include "ompl/util/Console.h"

namespace ompl
{

    namespace geometric
    {

        /**
           @anchor GeneticSearch

           @par Short description

           GeneticSearch does search for valid states using a genetic algorithm

           @par External documentation
        */

        /** \brief Genetic Algorithm for searching valid states */
        class GeneticSearch
        {
        public:

            /** \brief Construct an instance of a genetic algorithm for inverse kinematics given the space information to search within */
            GeneticSearch(const base::SpaceInformationPtr &si);
            ~GeneticSearch();

            /** \brief Find a state that fits the request */
            bool solve(double solveTime, const base::GoalRegion &goal, base::State *result,
                       const std::vector<base::State*> &hint = std::vector<base::State*>());

            /** \brief Set the number of steps to perform when using hill climbing to improve an individual in the population */
            void setMaxImproveSteps(unsigned int maxSteps)
            {
                hc_.setMaxImproveSteps(maxSteps);
            }

            /** \brief Get the number of steps to perform when using hill climbing to improve an individual in the population */
            unsigned int getMaxImproveSteps() const
            {
                return hc_.getMaxImproveSteps();
            }

            /** \brief Set the state validity flag; if this is false, states are not checked for validity */
            void setValidityCheck(bool valid)
            {
                checkValidity_ = valid;
                hc_.setValidityCheck(valid);
            }

            /** \brief Get the state validity flag; if this is false, states are not checked for validity */
            bool getValidityCheck() const
            {
                return checkValidity_;
            }

            /** \brief Set the flag that determines whether improvements using hill climbing should be attempted for solutions generated by the genetic algorithm. */
            void setTryImprove(bool flag)
            {
                tryImprove_ = flag;
            }

            /** \brief Returns true if improvements using hill climbing should be attempted for solutions generated by the genetic algorithm. Returns false otherwise. */
            bool getTryImprove() const
            {
                return tryImprove_;
            }

            /** \brief Set the number of individuals in the population */
            void setPoolSize(unsigned int size)
            {
                poolSize_ = size;
            }

            /** \brief Get the number number of individuals in the population */
            unsigned int getPoolSize() const
            {
                return poolSize_;
            }

            /** \brief Set the number of individuals to mutate at each generation. */
            void setPoolMutationSize(unsigned int size)
            {
                poolMutation_ = size;
            }

            /** \brief Get the number of individuals that are mutated at each generation */
            unsigned int getPoolMutationSize() const
            {
                return poolMutation_;
            }

            /** \brief Set the number of individuals to randomly sample at each generation */
            void setPoolRandomSize(unsigned int size)
            {
                poolRandom_ = size;
            }

            /** \brief Get the number of individuals to randomly sample at each generation */
            unsigned int getPoolRandomSize() const
            {
                return poolRandom_;
            }

            /** \brief Set the range (distance) to be used when sampling around a state */
            void setRange(double distance)
            {
                maxDistance_ = distance;
            }

            /** \brief Get the range GeneticSearch is using */
            double getRange() const
            {
                return maxDistance_;
            }

            /** \brief Clear the pool of samples */
            void clear();

        private:

            /** \brief Use hill climbing to attempt to get a state closer to the goal */
            void tryToImprove(const base::GoalRegion &goal, base::State *state, double distance);

            /** \brief Return true if the state is to be considered valid. This function always returns true if checking of validity is disabled. */
            bool valid(const base::State *state) const
            {
                return checkValidity_ ? si_->isValid(state) : true;
            }

            struct Individual
            {
                base::State *state;
                double       distance;
                bool         valid;
            };

            struct IndividualSort
            {
                bool operator()(const Individual& a, const Individual& b)
                {
                    if (a.valid == b.valid)
                        return a.distance < b.distance;
                    return a.valid;
                }
            };

            HillClimbing                                 hc_;
            base::SpaceInformationPtr                    si_;
            base::StateSamplerPtr                        sampler_;
            std::vector<Individual>                      pool_;
            unsigned int                                 poolSize_;
            unsigned int                                 poolMutation_;
            unsigned int                                 poolRandom_;
            unsigned int                                 generations_;
            bool                                         checkValidity_;
            bool                                         tryImprove_;

            double                                       maxDistance_;
        };

    }
}

#endif
