/**
 * @copyright
 * Copyright (c) 2012-2021, 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 "TINInterface.h"

#include <fstream>
#include <limits>

#include "BaseLib/FileTools.h"
#include "BaseLib/Logging.h"
#include "BaseLib/StringTools.h"
#include "GeoLib/AnalyticalGeometry.h"
#include "GeoLib/Surface.h"
#include "GeoLib/Triangle.h"
#include "MathLib/GeometricBasics.h"

namespace GeoLib
{
namespace IO
{
GeoLib::Surface* TINInterface::readTIN(std::string const& fname,
                                       GeoLib::PointVec& pnt_vec,
                                       std::vector<std::string>* errors)
{
    // open file
    std::ifstream in(fname.c_str());
    if (!in)
    {
        WARN("readTIN(): could not open stream from {:s}.", fname);
        if (errors)
        {
            errors->push_back("readTINFile error opening stream from " + fname);
        }
        return nullptr;
    }

    auto* sfc = new GeoLib::Surface(*(pnt_vec.getVector()));
    std::size_t id;
    MathLib::Point3d p0;
    MathLib::Point3d p1;
    MathLib::Point3d p2;
    std::string line;
    while (std::getline(in, line).good())
    {
        // allow empty lines
        if (line.empty())
        {
            continue;
        }

        // parse line
        std::stringstream input(line);
        // read id
        if (!(input >> id))
        {
            in.close();
            delete sfc;
            return nullptr;
        }
        // read first point
        if (!(input >> p0[0] >> p0[1] >> p0[2]))
        {
            ERR("Could not read coords of 1st point of triangle {:d}.", id);
            if (errors)
            {
                errors->push_back(
                    std::string("readTIN error: ") +
                    std::string(
                        "Could not read coords of 1st point in triangle ") +
                    std::to_string(id));
            }
            in.close();
            delete sfc;
            return nullptr;
        }
        // read second point
        if (!(input >> p1[0] >> p1[1] >> p1[2]))
        {
            ERR("Could not read coords of 2nd point of triangle {:d}.", id);
            if (errors)
            {
                errors->push_back(
                    std::string("readTIN error: ") +
                    std::string(
                        "Could not read coords of 2nd point in triangle ") +
                    std::to_string(id));
            }
            in.close();
            delete sfc;
            return nullptr;
        }
        // read third point
        if (!(input >> p2[0] >> p2[1] >> p2[2]))
        {
            ERR("Could not read coords of 3rd point of triangle {:d}.", id);
            if (errors)
            {
                errors->push_back(
                    std::string("readTIN error: ") +
                    std::string(
                        "Could not read coords of 3rd point in triangle ") +
                    std::to_string(id));
            }
            in.close();
            delete sfc;
            return nullptr;
        }

        // check area of triangle
        double const d_eps(std::numeric_limits<double>::epsilon());
        if (MathLib::calcTriangleArea(p0, p1, p2) < d_eps)
        {
            ERR("readTIN: Triangle {:d} has zero area.", id);
            if (errors)
            {
                errors->push_back(std::string("readTIN: Triangle ") +
                                  std::to_string(id) +
                                  std::string(" has zero area."));
            }
            delete sfc;
            return nullptr;
        }

        // determine size pnt_vec to insert the correct ids
        std::size_t const s(pnt_vec.getVector()->size());

        std::size_t const pnt_pos_0(
            pnt_vec.push_back(new GeoLib::Point(p0, s)));
        std::size_t const pnt_pos_1(
            pnt_vec.push_back(new GeoLib::Point(p1, s + 1)));
        std::size_t const pnt_pos_2(
            pnt_vec.push_back(new GeoLib::Point(p2, s + 2)));
        // create new Triangle
        if (pnt_pos_0 != std::numeric_limits<std::size_t>::max() &&
            pnt_pos_1 != std::numeric_limits<std::size_t>::max() &&
            pnt_pos_2 != std::numeric_limits<std::size_t>::max())
        {
            sfc->addTriangle(pnt_pos_0, pnt_pos_1, pnt_pos_2);
        }
    }

    if (sfc->getNumberOfTriangles() == 0)
    {
        WARN("readTIN(): No triangle found.", fname);
        if (errors)
        {
            errors->push_back("readTIN error because of no triangle found");
        }
        delete sfc;
        return nullptr;
    }

    return sfc;
}

void TINInterface::writeSurfaceAsTIN(GeoLib::Surface const& surface,
                                     std::string const& file_name)
{
    std::ofstream os(file_name.c_str());
    if (!os)
    {
        WARN("writeSurfaceAsTIN(): could not open stream to {:s}.", file_name);
        return;
    }
    os.precision(std::numeric_limits<double>::digits10);
    const std::size_t n_tris(surface.getNumberOfTriangles());
    for (std::size_t l(0); l < n_tris; l++)
    {
        GeoLib::Triangle const& tri(*(surface[l]));
        os << l << " " << *(tri.getPoint(0)) << " " << *(tri.getPoint(1)) << " "
           << *(tri.getPoint(2)) << "\n";
    }
    os.close();
}
}  // end namespace IO
}  // end namespace GeoLib