/*
This Source Code Form is subject to the
terms of the Mozilla Public License, v.
2.0. If a copy of the MPL was not
distributed with this file, You can
obtain one at
http://mozilla.org/MPL/2.0/.
*/

#pragma once

#include <vector>

#include <glm/glm.hpp>

#include "world/TrackSleepers.h"

// the fastenings of the rails on the timbers: where a rail lies on a timber, the part of the model of the timbers which holds it
// there. a stock rail with the blade beside it lies in a slide chair, a rail with a check rail or another rail of the frog close
// beside it in a fastening of both, the blade on the chair of its stock rail, and the other rails each in a plate of its own
namespace track_sleepers {

// a fastening on a timber
struct fastening {
    int part { part_plate };
    glm::dvec3 point { 0.0 }; // under the middle of the rail, on the top of the timber
    glm::dvec2 across { 1.0, 0.0 }; // unit vector in plan square to the rail, the way the +x of the part goes
};

// the rails of the tracks around a track, which lie on its timbers
class fastened_rails {

public:
    explicit fastened_rails( TTrack &Track );
    // the fastenings of the rails on the timber, of the parts the model has
    std::vector<fastening> on( beam const &Beam, beam_model const &Model ) const;

private:
    // what a rail is where it lies on a timber
    enum class role {
        plain,
        blade, // a blade of a switch, which slides on the chair of its stock rail
        stock, // the stock rail of a switch with the blade beside it
        checked // a rail with a check rail beside it
    };
    // a rail by points along its middle
    struct rail {
        TTrack *track { nullptr };
        int path { 0 };
        int side { 1 };
        std::vector<glm::dvec2> points;
        std::vector<double> heights;
        std::vector<glm::dvec2> inward; // unit vectors in plan from the rail toward the middle of its path
        std::vector<double> distances;
        glm::dvec2 low { 0.0 };
        glm::dvec2 high { 0.0 };
        // the stretches along the path the rail is a blade, a stock rail with a chair, checked along
        glm::dvec2 blade { -1.0 };
        glm::dvec2 stock { -1.0 };
        std::vector<glm::dvec2> checks;
        role at( double const Distance ) const;
    };
    // where a rail crosses a timber
    struct hit {
        double at { 0.0 }; // along the timber, from its from end
        role kind { role::plain };
        glm::dvec2 inward { 1.0, 0.0 };
    };

    std::vector<rail> m_rails;
};

} // namespace track_sleepers