/////////////////////////////////////////////////////////////////////////////////
//
//  Copyright (C) 2015-     Statoil ASA
//  Copyright (C) 2015-     Ceetron Solutions AS
//
//  ResInsight is free software: you can redistribute it and/or modify
//  it under the terms of the GNU General Public License as published by
//  the Free Software Foundation, either version 3 of the License, or
//  (at your option) any later version.
//
//  ResInsight is distributed in the hope that it will be useful, but WITHOUT ANY
//  WARRANTY; without even the implied warranty of MERCHANTABILITY or
//  FITNESS FOR A PARTICULAR PURPOSE.
//
//  See the GNU General Public License at <http://www.gnu.org/licenses/gpl.html>
//  for more details.
//
/////////////////////////////////////////////////////////////////////////////////

#pragma once

#include <algorithm>
#include <climits>
#include <vector>

class RigFemFaceComparator
{
public:
    RigFemFaceComparator()
        : m_minMainFaceNodeIdx( std::numeric_limits<int>::max() )
        , m_faceIdxToMinMainFaceNodeIdx( 0 )
    {
    }

    void setMainFace( const int* elmNodes, const int* localFaceIndices, int faceNodeCount )
    {
        m_canonizedMainFaceIdxes.resize( faceNodeCount );
        m_minMainFaceNodeIdx          = std::numeric_limits<int>::max();
        m_faceIdxToMinMainFaceNodeIdx = 0;

        for ( int fnIdx = 0; fnIdx < faceNodeCount; ++fnIdx )
        {
            int nodeIdx                     = elmNodes[localFaceIndices[fnIdx]];
            m_canonizedMainFaceIdxes[fnIdx] = nodeIdx;
            if ( nodeIdx < m_minMainFaceNodeIdx )
            {
                m_minMainFaceNodeIdx          = nodeIdx;
                m_faceIdxToMinMainFaceNodeIdx = fnIdx;
            }
        }
    }

    bool isSameButOposite( const int* elmNodes, const int* localFaceIndices, int faceNodeCount )
    {
        if ( faceNodeCount != static_cast<int>( m_canonizedMainFaceIdxes.size() ) ) return false;

        // Find min node index in face
        int minNodeIdx          = std::numeric_limits<int>::max();
        int faceIdxToMinNodeIdx = 0;

        for ( int fnIdx = 0; fnIdx < faceNodeCount; ++fnIdx )
        {
            int nodeIdx = elmNodes[localFaceIndices[fnIdx]];
            if ( nodeIdx < minNodeIdx )
            {
                minNodeIdx          = nodeIdx;
                faceIdxToMinNodeIdx = fnIdx;
            }
        }

        // Compare faces
        {
            if ( minNodeIdx != m_minMainFaceNodeIdx ) return false;

            int canFaceIdx = m_faceIdxToMinMainFaceNodeIdx;
            int fnIdx      = faceIdxToMinNodeIdx;
            int count      = 0;

            for ( ; count < faceNodeCount; --fnIdx, ++canFaceIdx, ++count )
            {
                if ( fnIdx < 0 ) fnIdx = faceNodeCount - 1;
                if ( canFaceIdx == faceNodeCount ) canFaceIdx = 0;

                if ( elmNodes[localFaceIndices[fnIdx]] != m_canonizedMainFaceIdxes[canFaceIdx] ) return false;
            }

            return true;
        }
    }

private:
    std::vector<int> m_canonizedMainFaceIdxes;
    int              m_minMainFaceNodeIdx;
    int              m_faceIdxToMinMainFaceNodeIdx;
};