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/* Author: Dave Coleman */

#ifndef OMPL_GEOMETRIC_PLANNERS_EXPERIENCE_LIGHTNING_RETRIEVE_REPAIR_
#define OMPL_GEOMETRIC_PLANNERS_EXPERIENCE_LIGHTNING_RETRIEVE_REPAIR_

#include "ompl/geometric/planners/PlannerIncludes.h"
#include "ompl/geometric/PathGeometric.h"
#include "ompl/geometric/PathSimplifier.h"
#include "ompl/datastructures/NearestNeighbors.h"

namespace ompl
{
    namespace tools
    {
        OMPL_CLASS_FORWARD(LightningDB);
    }

    namespace geometric
    {
        /// @cond IGNORE
        /** \brief Forward declaration of ompl::base::LightningRetrieveRepair */
        OMPL_CLASS_FORWARD(LightningRetrieveRepair);
        /// @endcond

        /** \class ompl::base::LightningRetrieveRepairPtr
            \brief A shared pointer wrapper for ompl::base::LightningRetrieveRepair */

        /**
           @anchor LightningRetrieveRepair - Lightning Retrieve and Repair
           @par Short description
           LightningRetrieveRepair is an experienced-based motion planner
           that recalls from a database of previous actions the most similar
           one to the current planning problem and attempts to repair it.
           @par External documentation
           Berenson, Dmitry, Pieter Abbeel, and Ken Goldberg: A robot path
           planning framework that learns from experience, in _IEEE Intl.
           Conf. Robotics and Automation (ICRA)_, 2012.
           [[PDF]](http://users.wpi.edu/~dberenson/lightning.pdf)
        */

        /** \brief The Lightning Framework's Retrieve-Repair component */
        class LightningRetrieveRepair : public base::Planner
        {
        public:
            /** \brief Constructor */
            LightningRetrieveRepair(const base::SpaceInformationPtr &si, tools::LightningDBPtr experienceDB);

            ~LightningRetrieveRepair() override;

            /** \brief Get information about the exploration data structure the planning from scratch motion planner
             * used. */
            void getPlannerData(base::PlannerData &data) const override;

            /**
             *  \brief Get debug information about the top recalled paths that were chosen for further filtering
             *  \return data - vector of PlannerData objects that each hold a single path
             */
            const std::vector<base::PlannerDataPtr> &getLastRecalledNearestPaths() const;

            /**
             *  \brief Get debug information about the top recalled paths that were chosen for further filtering
             *  \return chosenID - the index of the PlannerData object that was chosen for repair
             */
            std::size_t getLastRecalledNearestPathChosen() const;

            /**
             * \brief Get the chosen path used from database for repair
             * \return PlannerData of chosen path
             */
            base::PlannerDataPtr getChosenRecallPath() const;

            /** \brief Get information about the exploration data structure the repair motion planner used each call. */
            void getRepairPlannerDatas(std::vector<base::PlannerDataPtr> &data) const;

            base::PlannerStatus solve(const base::PlannerTerminationCondition &ptc) override;

            void clear() override;

            /** \brief Pass a pointer of the database from the lightning framework */
            void setLightningDB(const tools::LightningDBPtr &experienceDB);

            /** \brief Set the planner that will be used for repairing invalid paths recalled from experience */
            void setRepairPlanner(const base::PlannerPtr &planner);

            void setup() override;

            /**
             * \brief Repairs a path to be valid in the current planning environment
             * \param path - old from experience
             * \param ptc - when to stop attempting repair
             * \return true if no error
             */
            bool repairPath(const base::PlannerTerminationCondition &ptc, geometric::PathGeometric &path);

            /**
             * \brief Use our secondary planner to find a valid path between start and goal, and return that path
             * \param start
             * \param goal
             * \param newPathSegment - the solution
             * \return true if path found
             */
            bool replan(const base::State *start, const base::State *goal, geometric::PathGeometric &newPathSegment,
                        const base::PlannerTerminationCondition &ptc);

            /**
             * \brief Getter for number of 'k' close solutions to choose from database for further filtering
             */
            int getNumNearestSolutions() const
            {
                return nearestK_;
            }

            /**
             * \brief Setter for number of 'k' close solutions to choose from database for further filtering
             */
            void setNumNearestSolutions(int nearestK)
            {
                nearestK_ = nearestK;
            }

        protected:
            /**
             * \brief Count the number of states along the discretized path that are in collision
             *        Note: This is kind of an ill-defined score though. It depends on the resolution of collision
             * checking.
             *        I am more inclined to try to compute the percent of the length of the motion that is valid.
             *        That could go in SpaceInformation, as a utility function.
             */
            std::size_t checkMotionScore(const base::State *s1, const base::State *s2) const;

            /**
             * \brief Filters the top n paths in nearestPaths_ to the top 1, based on state validity with current
             * environment
             * \return true if no error
             */
            bool findBestPath(const base::State *startState, const base::State *goalState,
                              base::PlannerDataPtr &chosenPath);

            /** \brief The database of motions to search through */
            tools::LightningDBPtr experienceDB_;

            /** \brief Recall the nearest paths and store this in planner data for introspection later */
            std::vector<base::PlannerDataPtr> nearestPaths_;

            /** \brief the ID within nearestPaths_ of the path that was chosen for repair */
            std::size_t nearestPathsChosenID_;

            /** \brief A secondary planner for replanning */
            base::PlannerPtr repairPlanner_;

            /** \brief A secondary problem definition for the repair planner to use */
            base::ProblemDefinitionPtr repairProblemDef_;

            /** \brief Debug the repair planner by saving its planner data each time it is used */
            std::vector<base::PlannerDataPtr> repairPlannerDatas_;

            /** \brief The instance of the path simplifier */
            geometric::PathSimplifierPtr psk_;

            /** \brief Number of 'k' close solutions to choose from database for further filtering */
            int nearestK_;
        };
    }
}

#endif
