#ifndef MEDUSA_BITS_DOMAINS_GENERALFILL_FWD_HPP_
#define MEDUSA_BITS_DOMAINS_GENERALFILL_FWD_HPP_

/**
 * @file
 * Declaration of the general node placing algorithm.
 *
 * @example test/domains/GeneralFill_test.cpp
 */

#include <medusa/Config.hpp>

/**
 * @file
 * Declaration of GeneralFill class.
 */

namespace mm
{

    template <typename vec_t>
    class DomainDiscretization;

    /**
     * Implements general `n`-d node placing algorithm, as described in https://arxiv.org/abs/1812.03160
     * If you specifically use this algorithm, we would appreciate if you cite the above publication.
     *
     * The algorithm starts from existing nodes, usually the boundary discretization nodes.
     * They are processed in a queue and for each node, new candidates are generated around it on
     * a circle with radius defined by a supplied density function. Candidates are then checked
     * and some are accepted and added to the queue. This is repeated until no more nodes
     * can be generated or the maximal number of points has been reached.
     *
     * Usage example:
     * @snippet domains/GeneralFill_test.cpp PDS usage example
     *
     * Using background grid:
     * @snippet domains/GeneralFill_test.cpp Background grid
     *
     * @sa GrainDropFill, BasicRelax
     * @ingroup domains
     */
    template <typename vec_t>
    class GeneralFill
    {
    public:
        typedef typename vec_t::scalar_t scalar_t; ///< Scalar type;
        typedef vec_t vector_t;                    ///< Vector type.
        /// Store dimension of the domain.
        enum
        { /** Dimensionality of the domain. */ dim = vec_t::dim };

    private:
        int max_points = 5000000;  ///< Maximal number of points generated.
        int seed_;                 ///<  Seed for the random number generator.
        int n_samples = 15;        ///< Number of samples.
        scalar_t zeta = 1 - 1e-10; ///< Proximity tolerance.

    public:
        GeneralFill();

        /** Maximal number of points generated
         * @warning The actual upper bound for number of points generated is maxPoints @f$\pm@f$
         * numSamples.
         */
        GeneralFill &maxPoints(int max_points)
        {
            this->max_points = max_points;
            return *this;
        }
        /// Set custom seed for the random number generator.
        GeneralFill &seed(int seed)
        {
            seed_ = seed;
            return *this;
        }
        /// Set proximity tolerance. A new candidate mush be at least `zeta*h(p)` away. It should hold
        /// that `0 < zeta < 1`.
        GeneralFill &proximityTolerance(scalar_t zeta);
        /**
         * Controls the number of generated candidates from each point. For 2-D it is the actual number
         * of candidates, for 3-D it is the number of candidates on the great circle. Its value
         * is ignored in 1-D.
         */
        GeneralFill &numSamples(int n_samples)
        {
            this->n_samples = n_samples;
            return *this;
        }

        /// Fills given domain according to the nodal spacing function `h`.
        template <typename func_t>
        void operator()(DomainDiscretization<vec_t> &domain, const func_t &h, int type = 0) const;

        /**
         * Fills domain with a quality node distribution.
         * @param domain Domain to fill with nodes. Can be partially filled.
         * @param h Nodal spacing function.
         * @param search Spatial search structure to be used, e.g. a KDTree or KDGrid.
         * @param contains_function Function taking a point and returning `True` if it is contained in
         * the domain and `False` otherwise.
         * @param type Type of the nodes. If 0 the engines default value is used.
         *
         * @warning Header <code> \#include <medusa/bits/domains/GeneralFill.hpp></code> must be
         * included additionally to <code> \#include <medusa/Medusa_fwd.hpp></code>.
         */
        template <typename func_t, typename search_structure_t, typename contains_function_t>
        void operator()(DomainDiscretization<vec_t> &domain, const func_t &h,
                        search_structure_t &search, contains_function_t &contains_function,
                        int type = 0) const;

        /// Overload for constant function.
        template <typename search_structure_t, typename contains_function_t>
        void operator()(DomainDiscretization<vec_t> &domain, const scalar_t &h,
                        search_structure_t &search, contains_function_t &contains_function,
                        int type = 0) const
        {
            this->operator()(
                domain, [=](const vector_t &)
                { return h; },
                search, contains_function,
                type);
        }

        /// Overload for constant function and default search and contains structures.
        void operator()(DomainDiscretization<vec_t> &domain, const scalar_t &h, int type = 0) const
        {
            this->operator()(
                domain, [=](const vector_t &)
                { return h; },
                type);
        }

        /// Overload without providing contains_function, using the default
        /// DomainDiscretization::contains.
        template <typename func_t, typename search_structure_t>
        void operator()(DomainDiscretization<vec_t> &domain, const func_t &h,
                        search_structure_t &search, int type = 0) const;
    };

} // namespace mm

#endif // MEDUSA_BITS_DOMAINS_GENERALFILL_FWD_HPP_