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/* Author: Ioan Sucan */

#ifndef OMPL_BASE_STATE_
#define OMPL_BASE_STATE_

#include <boost/concept_check.hpp>

namespace ompl
{
    namespace base
    {
        /** \brief Definition of an abstract state.

            See \ref stateAlloc and \ref stateOps. */
        class State
        {
        private:
            /** \brief Disable copy-constructor */
            State(const State &);

            /** \brief Disable copy operator */
            const State &operator=(const State &);

        protected:
            State() = default;

            virtual ~State() = default;

        public:
            /** \brief Cast this instance to a desired type. */
            template <class T>
            const T *as() const
            {
                /** \brief Make sure the type we are allocating is indeed a state */
                BOOST_CONCEPT_ASSERT((boost::Convertible<T *, State *>));

                return static_cast<const T *>(this);
            }

            /** \brief Cast this instance to a desired type. */
            template <class T>
            T *as()
            {
                /** \brief Make sure the type we are allocating is indeed a state */
                BOOST_CONCEPT_ASSERT((boost::Convertible<T *, State *>));

                return static_cast<T *>(this);
            }
        };

        /** \brief Definition of a compound state */
        class CompoundState : public State
        {
        public:
            CompoundState() : State(), components(nullptr)
            {
            }

            ~CompoundState() override = default;

            /** \brief Cast a component of this instance to a desired type. */
            template <class T>
            const T *as(const unsigned int index) const
            {
                /** \brief Make sure the type we are allocating is indeed a state */
                BOOST_CONCEPT_ASSERT((boost::Convertible<T *, State *>));

                return static_cast<const T *>(components[index]);
            }

            /** \brief Cast a component of this instance to a desired type. */
            template <class T>
            T *as(const unsigned int index)
            {
                /** \brief Make sure the type we are allocating is indeed a state */
                BOOST_CONCEPT_ASSERT((boost::Convertible<T *, State *>));

                return static_cast<T *>(components[index]);
            }

            /** \brief Access const element i<sup>th</sup> component. This
                does not check whether the index is within bounds. */
            const State *operator[](unsigned int i) const
            {
                return components[i];
            }

            /** \brief Access element i<sup>th</sup> component. This
                does not check whether the index is within bounds. */
            State *operator[](unsigned int i)
            {
                return components[i];
            }

            /** \brief The components that make up a compound state */
            State **components;
        };
    }
}

#endif
