/**
 * \file
 * \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 "QuadRule4.h"

#include "MathLib/GeometricBasics.h"

#include "MeshLib/Node.h"

namespace MeshLib {

const unsigned QuadRule4::edge_nodes[4][2] =
{
        {0, 1}, // Edge 0
        {1, 2}, // Edge 1
        {2, 3}, // Edge 2
        {3, 0}  // Edge 3
};

double QuadRule4::computeVolume(Node const* const* _nodes)
{
    return MathLib::calcTriangleArea(*_nodes[0], *_nodes[1], *_nodes[2])
         + MathLib::calcTriangleArea(*_nodes[2], *_nodes[3], *_nodes[0]);
}

bool QuadRule4::isPntInElement(Node const* const* nodes,
                               MathLib::Point3d const& pnt,
                               double eps)
{
    return (
        MathLib::isPointInTriangle(pnt, *nodes[0], *nodes[1], *nodes[2], eps) ||
        MathLib::isPointInTriangle(pnt, *nodes[0], *nodes[2], *nodes[3], eps));
}

unsigned QuadRule4::identifyFace(Node const* const* _nodes, Node* nodes[3])
{
    for (unsigned i=0; i<4; i++)
    {
        unsigned flag(0);
        for (unsigned j = 0; j < 2; j++)
        {
            for (unsigned k = 0; k < 2; k++)
            {
                if (_nodes[edge_nodes[i][j]] == nodes[k])
                {
                    flag++;
                }
            }
        }
        if (flag == 2)
        {
            return i;
        }
    }
    return std::numeric_limits<unsigned>::max();
}

ElementErrorCode QuadRule4::validate(const Element* e)
{
    ElementErrorCode error_code;
    error_code[ElementErrorFlag::ZeroVolume] = hasZeroVolume(*e);
    Node const* const* _nodes = e->getNodes();
    error_code[ElementErrorFlag::NonCoplanar] =
        (!MathLib::isCoplanar(*_nodes[0], *_nodes[1], *_nodes[2], *_nodes[3]));
    // for collapsed quads (i.e. reduced to a line) this test might result
    // "false" as all four points are actually located on a line.
    if (!error_code[ElementErrorFlag::ZeroVolume])
    {
        error_code[ElementErrorFlag::NonConvex] =
            (!(MathLib::dividedByPlane(
                   *_nodes[0], *_nodes[2], *_nodes[1], *_nodes[3]) &&
               MathLib::dividedByPlane(
                   *_nodes[1], *_nodes[3], *_nodes[0], *_nodes[2])));
    }
    error_code[ElementErrorFlag::NodeOrder] = !e->testElementNodeOrder();
    return error_code;
}

} // end namespace MeshLib