/**
 *
 * \copyright
 * Copyright (c) 2012-2022, OpenGeoSys Community (http://www.opengeosys.org)
 *            Distributed under a Modified BSD License.
 *              See accompanying file LICENSE.txt or
 *              http://www.opengeosys.org/project/license
 *
 */

#include "GMSHPolygonTree.h"

#include <sstream>

#include "BaseLib/Algorithm.h"
#include "GMSHAdaptiveMeshDensity.h"
#include "GMSHFixedMeshDensity.h"
#include "GeoLib/AnalyticalGeometry.h"
#include "GeoLib/GEOObjects.h"
#include "GeoLib/Point.h"
#include "GeoLib/Polygon.h"
#include "GeoLib/PolygonWithSegmentMarker.h"
#include "GeoLib/PolylineWithSegmentMarker.h"
#include "GeoLib/Station.h"

namespace FileIO
{
namespace GMSH
{
GMSHPolygonTree::GMSHPolygonTree(GeoLib::PolygonWithSegmentMarker* polygon,
                                 GMSHPolygonTree* parent,
                                 GeoLib::GEOObjects& geo_objs,
                                 std::string const& geo_name,
                                 GMSHMeshDensityStrategy& mesh_density_strategy)
    : GeoLib::SimplePolygonTree(polygon, parent),
      _geo_objs(geo_objs),
      _geo_name(geo_name),
      _mesh_density_strategy(mesh_density_strategy)
{
}

GMSHPolygonTree::~GMSHPolygonTree()
{
    // the polylines are processed also by the children, but the root is
    // responsible to cleanup up
    if (isRoot())
    {  // root
        BaseLib::cleanupVectorElements(_plys);
    }
}

void GMSHPolygonTree::markSharedSegments()
{
    if (isRoot())
    {
        return;
    }

    for (auto& child : *this)
    {
        std::size_t const n_pnts(child->polygon().getNumberOfPoints());
        for (std::size_t k(1); k < n_pnts; k++)
        {
            if (GeoLib::containsEdge(parent()->polygon(),
                                     polygon().getPointID(k - 1),
                                     polygon().getPointID(k)))
            {
                static_cast<GeoLib::PolygonWithSegmentMarker&>(polygon())
                    .markSegment(k, true);
            }
        }
    }
}

bool GMSHPolygonTree::insertStation(GeoLib::Point const* station)
{
    if (polygon().isPntInPolygon(*station))
    {
        // try to insert station into the child nodes
        for (auto* child : *this)
        {
            if (child->polygon().isPntInPolygon(*station))
            {
                bool rval(dynamic_cast<GMSHPolygonTree*>(child)->insertStation(
                    station));
                // stop recursion if sub SimplePolygonTree is a leaf
                if (rval && child->getNumberOfChildren() == 0)
                {
                    _stations.push_back(station);
                }
                return rval;
            }
        }
        // station did not fit into child nodes -> insert the station into this
        // node
        _stations.push_back(station);
        return true;
    }
    return false;
}

void GMSHPolygonTree::insertPolyline(GeoLib::PolylineWithSegmentMarker* ply)
{
    if (!polygon().isPartOfPolylineInPolygon(*ply))
    {
        return;
    }

    // check if polyline segments are inside of the polygon, intersect the
    // polygon or are part of the boundary of the polygon
    for (auto* child : *this)
    {
        dynamic_cast<GMSHPolygonTree*>(child)->insertPolyline(ply);
    }

    // calculate possible intersection points between the node polygon and the
    // given polyline ply
    // pay attention: loop bound is not fix!
    GeoLib::Point tmp_pnt;
    GeoLib::PointVec& pnt_vec(*(_geo_objs.getPointVecObj(_geo_name)));
    for (auto segment_it(ply->begin()); segment_it != ply->end(); ++segment_it)
    {
        if (ply->isSegmentMarked(segment_it.getSegmentNumber()))
        {
            continue;
        }

        if (polygon().containsSegment(*segment_it))
        {
            ply->markSegment(segment_it.getSegmentNumber(), true);
            continue;
        }

        std::size_t seg_num(0);
        GeoLib::Point intersection_pnt;
        while (polygon().getNextIntersectionPointPolygonLine(
            *segment_it, intersection_pnt, seg_num))
        {
            // insert the intersection point to point vector of GEOObjects
            // instance
            const std::size_t pnt_vec_size(pnt_vec.size());
            std::size_t pnt_id(
                pnt_vec.push_back(new GeoLib::Point(intersection_pnt)));
            if (pnt_vec_size < pnt_vec.size())
            {  // case: new point
                // modify the polygon
                polygon().insertPoint(seg_num + 1, pnt_id);
                // modify the polyline
                ply->insertPoint(segment_it.getSegmentNumber(), pnt_id);
            }
            else
            {  // case: existing point
                // check if point id is within the polygon
                if (!polygon().isPointIDInPolyline(pnt_id))
                {
                    polygon().insertPoint(seg_num + 1, pnt_id);
                }

                // check if point id is in polyline
                if (!ply->isPointIDInPolyline(pnt_id))
                {
                    ply->insertPoint(segment_it.getSegmentNumber() + 1, pnt_id);
                }
            }

            std::size_t tmp_seg_num(seg_num + 1);
            if (!polygon().getNextIntersectionPointPolygonLine(
                    *segment_it, tmp_pnt, tmp_seg_num))
            {
                // check a point of the segment except the end points
                for (std::size_t i(0); i < 3; i++)
                {
                    tmp_pnt[i] = ((*segment_it).getBeginPoint()[i] +
                                  (*segment_it).getEndPoint()[i]) /
                                 2;
                }
                if (polygon().isPntInPolygon(tmp_pnt))
                {
                    ply->markSegment(segment_it.getSegmentNumber(), true);
                    // insert line segment as constraint
                    _gmsh_lines_for_constraints.push_back(
                        new GMSHLine((*segment_it).getBeginPoint().getID(),
                                     (*segment_it).getEndPoint().getID()));
                }
            }
            seg_num++;

            // check a point of the segment except the end points
            for (std::size_t i(0); i < 3; i++)
            {
                tmp_pnt[i] = ((*segment_it).getBeginPoint()[i] +
                              (*segment_it).getEndPoint()[i]) /
                             2;
            }

            checkIntersectionsSegmentExistingPolylines(ply, segment_it);

            if (polygon().isPntInPolygon(tmp_pnt))
            {
                ply->markSegment(segment_it.getSegmentNumber(), true);
                // insert line segment as constraint
                _gmsh_lines_for_constraints.push_back(
                    new GMSHLine((*segment_it).getBeginPoint().getID(),
                                 (*segment_it).getEndPoint().getID()));
            }
        }
    }

    _plys.push_back(ply);
}

void GMSHPolygonTree::checkIntersectionsSegmentExistingPolylines(
    GeoLib::PolylineWithSegmentMarker* ply,
    GeoLib::Polyline::SegmentIterator const& seg_it)
{
    std::size_t const ply_segment_number(seg_it.getSegmentNumber());
    for (GeoLib::PolylineWithSegmentMarker* const p : _plys)
    {
        GeoLib::PointVec& pnt_vec(*(_geo_objs.getPointVecObj(_geo_name)));
        for (auto seg_it_p(p->begin()); seg_it_p != p->end(); ++seg_it_p)
        {
            GeoLib::Point s;  // intersection point
            if (GeoLib::lineSegmentIntersect(*seg_it, *seg_it_p, s))
            {
                const std::size_t pnt_vec_size(pnt_vec.size());
                // point id of new point in GEOObjects instance
                const std::size_t pnt_id(
                    pnt_vec.push_back(new GeoLib::Point(s)));
                if (pnt_vec_size < pnt_vec.size())
                {  // case: new point
                    // modify polyline already in this node
                    p->insertPoint(seg_it_p.getSegmentNumber() + 1, pnt_id);
                    // modify polyline
                    ply->insertPoint(ply_segment_number + 1, pnt_id);
                }
                else
                {  // case: point exists already in geometry
                    // check if point is not already in polyline p
                    std::size_t const k(seg_it_p.getSegmentNumber());
                    if (p->getPointID(k) != pnt_id &&
                        p->getPointID(k + 1) != pnt_id)
                    {
                        p->insertPoint(k + 1, pnt_id);
                    }
                    // check if point is not already in polyline ply
                    if (ply->getPointID(ply_segment_number) != pnt_id &&
                        ply->getPointID(ply_segment_number + 1) != pnt_id)
                    {
                        ply->insertPoint(ply_segment_number + 1, pnt_id);
                    }
                }
            }
        }
    }
}

void GMSHPolygonTree::initMeshDensityStrategy()
{
    if (auto* adaptive_mesh_density =
            dynamic_cast<GMSHAdaptiveMeshDensity*>(&_mesh_density_strategy))
    {
        // collect points
        std::vector<GeoLib::Point const*> pnts;
        const std::size_t n_pnts_polygon(polygon().getNumberOfPoints());
        for (std::size_t k(0); k < n_pnts_polygon; k++)
        {
            pnts.push_back(polygon().getPoint(k));
        }
        getPointsFromSubPolygons(pnts);

        const std::size_t n_plys(_plys.size());
        for (std::size_t k(0); k < n_plys; k++)
        {
            const std::size_t n_pnts_in_kth_ply(_plys[k]->getNumberOfPoints());
            for (std::size_t j(0); j < n_pnts_in_kth_ply; j++)
            {
                pnts.push_back(_plys[k]->getPoint(j));
            }
        }

        // give collected points to the mesh density strategy
        adaptive_mesh_density->initialize(pnts);
        // insert constraints
        adaptive_mesh_density->addPoints(_stations);
        std::vector<GeoLib::Point const*> stations;
        getStationsInsideSubPolygons(stations);
        adaptive_mesh_density->addPoints(stations);
    }
}

void GMSHPolygonTree::createGMSHPoints(std::vector<GMSHPoint*>& gmsh_pnts) const
{
    const std::size_t n_pnts_polygon(polygon().getNumberOfPoints());
    for (std::size_t k(0); k < n_pnts_polygon - 1; k++)
    {
        const std::size_t id(polygon().getPointID(k));
        GeoLib::Point const* const pnt(polygon().getPoint(k));
        // if this point was already part of another polyline
        if (gmsh_pnts[id] != nullptr)
        {
            continue;
        }
        gmsh_pnts[id] = new GMSHPoint(
            *pnt, id, _mesh_density_strategy.getMeshDensityAtPoint(pnt));
    }

    const std::size_t n_plys(_plys.size());
    std::stringstream error_messages;
    error_messages.precision(std::numeric_limits<double>::digits10);
    for (std::size_t k(0); k < n_plys; k++)
    {
        const std::size_t n_pnts_in_ply(_plys[k]->getNumberOfPoints());
        for (std::size_t j(0); j < n_pnts_in_ply; j++)
        {
            if (polygon().isPntInPolygon(*(_plys[k]->getPoint(j))))
            {
                const std::size_t id(_plys[k]->getPointID(j));
                // if this point was already part of another polyline
                if (gmsh_pnts[id] != nullptr)
                {
                    continue;
                }
                GeoLib::Point const* const pnt(_plys[k]->getPoint(j));
                gmsh_pnts[id] = new GMSHPoint(
                    *pnt, id,
                    _mesh_density_strategy.getMeshDensityAtPoint(pnt));
            }
            else
            {
                auto const& p = *(_plys[k]->getPoint(j));
                error_messages << "\n\tpoint with id " << p.getID()
                               << " and coordinates (" << p[0] << ", " << p[1]
                               << ", " << p[2]
                               << ") is outside of the polygon.";
            }
        }
    }
    if (!parent())
    {
        auto const error_message = error_messages.str();
        if (!error_message.empty())
        {
            OGS_FATAL("{}", error_message);
        }
    }

    // walk through children
    for (auto* child : *this)
    {
        dynamic_cast<GMSHPolygonTree*>(child)->createGMSHPoints(gmsh_pnts);
    }
}

void GMSHPolygonTree::writeLineLoop(std::size_t& line_offset,
                                    std::size_t& sfc_offset, std::ostream& out,
                                    bool const write_physical) const
{
    const std::size_t n_pnts(polygon().getNumberOfPoints());
    for (std::size_t k(1), first_pnt_id(polygon().getPointID(0)); k < n_pnts;
         k++)
    {
        std::size_t const second_pnt_id = polygon().getPointID(k);
        out << "Line(" << line_offset + k - 1 << ") = {" << first_pnt_id << ","
            << second_pnt_id << "};\n";
        first_pnt_id = second_pnt_id;
    }
    out << "Line Loop(" << line_offset + n_pnts - 1 << ") = {";
    for (std::size_t k(0); k < n_pnts - 2; k++)
    {
        out << line_offset + k << ",";
    }
    out << line_offset + n_pnts - 2 << "};\n";
    out << "Plane Surface(" << sfc_offset << ") = {" << line_offset + n_pnts - 1
        << "};\n";
    if (write_physical)
    {
        out << "Physical Curve(" << sfc_offset << ") = {";
        for (std::size_t k(0); k < n_pnts - 2; k++)
        {
            out << line_offset + k << ",";
        }
        out << line_offset + n_pnts - 2 << "};\n";
        out << "Physical Surface(" << sfc_offset << ") = {" << sfc_offset
            << "};\n";
    }
    line_offset += n_pnts;
    sfc_offset++;
}

void GMSHPolygonTree::writeLineConstraints(std::size_t& line_offset,
                                           std::size_t sfc_number,
                                           std::ostream& out) const
{
    for (auto polyline : _plys)
    {
        const std::size_t n_pnts(polyline->getNumberOfPoints());
        std::size_t first_pnt_id(polyline->getPointID(0));
        for (std::size_t k(1); k < n_pnts; k++)
        {
            auto const second_pnt_id = polyline->getPointID(k);
            if (polyline->isSegmentMarked(k - 1) &&
                polygon().isPntInPolygon(*(polyline->getPoint(k))) &&
                !GeoLib::containsEdge(polygon(), first_pnt_id, second_pnt_id))
            {
                out << "Line(" << line_offset + k - 1 << ") = {" << first_pnt_id
                    << "," << second_pnt_id << "};\n";
                out << "Line { " << line_offset + k - 1 << " } In Surface { "
                    << sfc_number << " };\n";
            }
            first_pnt_id = second_pnt_id;
        }
        line_offset += n_pnts;
    }
}

void GMSHPolygonTree::writeSubPolygonsAsLineConstraints(
    std::size_t& line_offset, std::size_t sfc_number, std::ostream& out) const
{
    for (auto* child : *this)
    {
        dynamic_cast<GMSHPolygonTree*>(child)
            ->writeSubPolygonsAsLineConstraints(line_offset, sfc_number, out);
    }

    if (!isRoot())
    {
        const std::size_t n_pnts(polygon().getNumberOfPoints());
        std::size_t first_pnt_id(polygon().getPointID(0));
        for (std::size_t k(1); k < n_pnts; k++)
        {
            auto const second_pnt_id = polygon().getPointID(k);
            out << "Line(" << line_offset + k - 1 << ") = {" << first_pnt_id
                << "," << second_pnt_id << "};\n";
            first_pnt_id = second_pnt_id;
            out << "Line { " << line_offset + k - 1 << " } In Surface { "
                << sfc_number << " };\n";
        }
        line_offset += n_pnts;
    }
}

void GMSHPolygonTree::writeStations(std::size_t& pnt_id_offset,
                                    std::size_t sfc_number,
                                    std::ostream& out) const
{
    for (auto const* station : _stations)
    {
        out << "Point(" << pnt_id_offset << ") = {" << (*station)[0] << ", "
            << (*station)[1] << ", 0.0, "
            << _mesh_density_strategy.getMeshDensityAtStation(station)
            << "}; // Station "
            << static_cast<GeoLib::Station const*>(station)->getName() << " \n";
        out << "Point { " << pnt_id_offset << " } In Surface { " << sfc_number
            << " };\n";
        ++pnt_id_offset;
    }
}

void GMSHPolygonTree::writeAdditionalPointData(std::size_t& pnt_id_offset,
                                               std::size_t sfc_number,
                                               std::ostream& out) const
{
    if (auto* adaptive_mesh_density =
            dynamic_cast<GMSHAdaptiveMeshDensity*>(&_mesh_density_strategy))
    {
        std::vector<GeoLib::Point*> steiner_pnts;
        adaptive_mesh_density->getSteinerPoints(steiner_pnts, 0);
        const std::size_t n(steiner_pnts.size());
        for (std::size_t k(0); k < n; k++)
        {
            if (polygon().isPntInPolygon(*(steiner_pnts[k])))
            {
                out << "Point(" << pnt_id_offset + k << ") = {"
                    << (*(steiner_pnts[k]))[0] << "," << (*(steiner_pnts[k]))[1]
                    << ", 0.0, ";
                out << _mesh_density_strategy.getMeshDensityAtPoint(
                           steiner_pnts[k])
                    << "};\n";
                out << "Point { " << pnt_id_offset + k << " } In Surface { "
                    << sfc_number << " };\n";
            }
            delete steiner_pnts[k];
        }
        pnt_id_offset += n;
    }

#ifndef NDEBUG
    if (auto* adaptive_mesh_density =
            dynamic_cast<GMSHAdaptiveMeshDensity*>(&_mesh_density_strategy))
    {
        std::vector<GeoLib::Point*> pnts;
        std::vector<GeoLib::Polyline*> plys;
        adaptive_mesh_density->getQuadTreeGeometry(pnts, plys);
        std::string quad_tree_geo("QuadTree");
        _geo_objs.addPointVec(std::move(pnts), quad_tree_geo,
                              GeoLib::PointVec::NameIdMap{});
        std::vector<std::size_t> const& id_map(
            (_geo_objs.getPointVecObj(quad_tree_geo))->getIDMap());
        for (std::size_t k(0); k < plys.size(); k++)
        {
            for (std::size_t j(0); j < plys[k]->getNumberOfPoints(); j++)
            {
                (plys[k])->setPointID(j, id_map[(plys[k])->getPointID(j)]);
            }
        }
        _geo_objs.addPolylineVec(std::move(plys), quad_tree_geo,
                                 GeoLib::PolylineVec::NameIdMap{});
    }
#endif
}

void GMSHPolygonTree::getPointsFromSubPolygons(
    std::vector<GeoLib::Point const*>& pnts) const
{
    for (auto const* child : *this)
    {
        dynamic_cast<GMSHPolygonTree const*>(child)->getPointsFromSubPolygons(
            pnts);
    }
}

void GMSHPolygonTree::getStationsInsideSubPolygons(
    std::vector<GeoLib::Point const*>& stations) const
{
    const std::size_t n_stations(_stations.size());
    for (std::size_t k(0); k < n_stations; k++)
    {
        stations.push_back(_stations[k]);
    }

    for (auto const* child : *this)
    {
        dynamic_cast<GMSHPolygonTree const*>(child)
            ->getStationsInsideSubPolygons(stations);
    }
}

}  // end namespace GMSH
}  // end namespace FileIO