/* SPDX-License-Identifier: GPL-2.0-or-later */

/** \file
 * \ingroup freestyle
 * \brief Classes to define an Extended Winged Edge data structure.
 */

#include "WXEdge.h"
#include "BKE_global.h"

namespace Freestyle {

/**********************************
 *                                *
 *                                *
 *             WXFace             *
 *                                *
 *                                *
 **********************************/

uint WXFaceLayer::Get0VertexIndex() const
{
  int i = 0;
  int nEdges = _pWXFace->numberOfEdges();
  for (i = 0; i < nEdges; ++i) {
    if (_DotP[i] == 0.0f) {  // TODO: this comparison is weak, check if it actually works
      return i;
    }
  }
  return -1;
}
uint WXFaceLayer::GetSmoothEdgeIndex() const
{
  int i = 0;
  int nEdges = _pWXFace->numberOfEdges();
  for (i = 0; i < nEdges; ++i) {
    if ((_DotP[i] == 0.0f) && (_DotP[(i + 1) % nEdges] == 0.0f)) {  // TODO: ditto
      return i;
    }
  }
  return -1;
}

void WXFaceLayer::RetrieveCuspEdgesIndices(vector<int> &oCuspEdges)
{
  int i = 0;
  int nEdges = _pWXFace->numberOfEdges();
  for (i = 0; i < nEdges; ++i) {
    if (_DotP[i] * _DotP[(i + 1) % nEdges] < 0.0f) {
      // we got one
      oCuspEdges.push_back(i);
    }
  }
}

WXSmoothEdge *WXFaceLayer::BuildSmoothEdge()
{
  // if the smooth edge has already been built: exit
  if (_pSmoothEdge) {
    return _pSmoothEdge;
  }
  float ta, tb;
  WOEdge *woea(nullptr), *woeb(nullptr);
  bool ok = false;
  vector<int> cuspEdgesIndices;
  int indexStart, indexEnd;
  uint nedges = _pWXFace->numberOfEdges();
  if (_nNullDotP == nedges) {
    _pSmoothEdge = nullptr;
    return _pSmoothEdge;
  }
  if ((_nPosDotP != 0) && (_nPosDotP != _DotP.size()) && (_nNullDotP == 0)) {
    // that means that we have a smooth edge that starts from an edge and ends at an edge
    //-----------------------------
    // We retrieve the 2 edges for which we have opposite signs for each extremity
    RetrieveCuspEdgesIndices(cuspEdgesIndices);
    if (cuspEdgesIndices.size() != 2) {  // we necessarily have 2 cusp edges
      return nullptr;
    }

    // let us determine which cusp edge corresponds to the starting:
    // We can do that because we defined that a silhouette edge had the back facing part on its
    // right. So if the WOEdge woea is such that woea[0].dotp > 0 and woea[1].dotp < 0, it is the
    // starting edge.
    //-------------------------------------------

    if (_DotP[cuspEdgesIndices[0]] > 0.0f) {
      woea = _pWXFace->GetOEdge(cuspEdgesIndices[0]);
      woeb = _pWXFace->GetOEdge(cuspEdgesIndices[1]);
      indexStart = cuspEdgesIndices[0];
      indexEnd = cuspEdgesIndices[1];
    }
    else {
      woea = _pWXFace->GetOEdge(cuspEdgesIndices[1]);
      woeb = _pWXFace->GetOEdge(cuspEdgesIndices[0]);
      indexStart = cuspEdgesIndices[1];
      indexEnd = cuspEdgesIndices[0];
    }

    // Compute the interpolation:
    ta = _DotP[indexStart] / (_DotP[indexStart] - _DotP[(indexStart + 1) % nedges]);
    tb = _DotP[indexEnd] / (_DotP[indexEnd] - _DotP[(indexEnd + 1) % nedges]);
    ok = true;
  }
  else if (_nNullDotP == 1) {
    // that means that we have exactly one of the 2 extremities of our silhouette edge is a vertex
    // of the mesh
    if (ELEM(_nPosDotP, 2, 0)) {
      _pSmoothEdge = nullptr;
      return _pSmoothEdge;
    }
    RetrieveCuspEdgesIndices(cuspEdgesIndices);
    // We should have only one EdgeCusp:
    if (cuspEdgesIndices.size() != 1) {
      if (G.debug & G_DEBUG_FREESTYLE) {
        cout << "Warning in BuildSmoothEdge: weird WXFace configuration" << endl;
      }
      _pSmoothEdge = nullptr;
      return nullptr;
    }
    uint index0 = Get0VertexIndex();  // retrieve the 0 vertex index
    uint nedges = _pWXFace->numberOfEdges();
    if (_DotP[cuspEdgesIndices[0]] > 0.0f) {
      woea = _pWXFace->GetOEdge(cuspEdgesIndices[0]);
      woeb = _pWXFace->GetOEdge(index0);
      indexStart = cuspEdgesIndices[0];
      ta = _DotP[indexStart] / (_DotP[indexStart] - _DotP[(indexStart + 1) % nedges]);
      tb = 0.0f;
    }
    else {
      woea = _pWXFace->GetOEdge(index0);
      woeb = _pWXFace->GetOEdge(cuspEdgesIndices[0]);
      indexEnd = cuspEdgesIndices[0];
      ta = 0.0f;
      tb = _DotP[indexEnd] / (_DotP[indexEnd] - _DotP[(indexEnd + 1) % nedges]);
    }
    ok = true;
  }
  else if (_nNullDotP == 2) {
    // that means that the silhouette edge is an edge of the mesh
    int index = GetSmoothEdgeIndex();
    if (!_pWXFace->front()) {  // is it in the right order ?
      // the order of the WOEdge index is wrong
      woea = _pWXFace->GetOEdge((index + 1) % nedges);
      woeb = _pWXFace->GetOEdge((index - 1) % nedges);
      ta = 0.0f;
      tb = 1.0f;
      ok = true;
    }
    else {
      // here it's not good, our edge is a single point -> skip that face
      ok = false;
#if 0
      // the order of the WOEdge index is good
      woea = _pWXFace->GetOEdge((index - 1) % nedges);
      woeb = _pWXFace->GetOEdge((index + 1) % nedges);
      ta = 1.0f;
      tb = 0.0f;
#endif
    }
  }
  if (ok) {
    _pSmoothEdge = new WXSmoothEdge;
    _pSmoothEdge->setWOeA(woea);
    _pSmoothEdge->setWOeB(woeb);
    _pSmoothEdge->setTa(ta);
    _pSmoothEdge->setTb(tb);
    if (_Nature & Nature::SILHOUETTE) {
      if (_nNullDotP != 2) {
        if (_DotP[_ClosestPointIndex] + 0.01f > 0.0f) {
          _pSmoothEdge->setFront(true);
        }
        else {
          _pSmoothEdge->setFront(false);
        }
      }
    }
  }

#if 0
  // check bording edges to see if they have different dotp values in bording faces.
  for (int i = 0; i < numberOfEdges(); i++) {
    WSFace *bface = (WSFace *)GetBordingFace(i);
    if (bface) {
      if ((front()) ^
          (bface->front())) {  // fA->front XOR fB->front (true if one is 0 and the other is 1)
        // that means that the edge i of the face is a silhouette edge
        // CHECK FIRST WHETHER THE EXACTSILHOUETTEEDGE HAS
        // NOT YET BEEN BUILT ON THE OTHER FACE (1 is enough).
        if (((WSExactFace *)bface)->exactSilhouetteEdge()) {
          // that means that this silhouette edge has already been built
          return ((WSExactFace *)bface)->exactSilhouetteEdge();
        }
        // Else we must build it
        WOEdge *woea, *woeb;
        float ta, tb;
        if (!front()) {  // is it in the right order ?
          // the order of the WOEdge index is wrong
          woea = _OEdgeList[(i + 1) % numberOfEdges()];
          if (0 == i) {
            woeb = _OEdgeList[numberOfEdges() - 1];
          }
          else {
            woeb = _OEdgeList[(i - 1)];
          }
          ta = 0.0f;
          tb = 1.0f;
        }
        else {
          // the order of the WOEdge index is good
          if (0 == i) {
            woea = _OEdgeList[numberOfEdges() - 1];
          }
          else {
            woea = _OEdgeList[(i - 1)];
          }
          woeb = _OEdgeList[(i + 1) % numberOfEdges()];
          ta = 1.0f;
          tb = 0.0f;
        }

        _pSmoothEdge = new ExactSilhouetteEdge(ExactSilhouetteEdge::VERTEX_VERTEX);
        _pSmoothEdge->setWOeA(woea);
        _pSmoothEdge->setWOeA(woeb);
        _pSmoothEdge->setTa(ta);
        _pSmoothEdge->setTb(tb);

        return _pSmoothEdge;
      }
    }
  }
#endif
  return _pSmoothEdge;
}

void WXFace::ComputeCenter()
{
  vector<WVertex *> iVertexList;
  RetrieveVertexList(iVertexList);
  Vec3f center;
  for (vector<WVertex *>::iterator wv = iVertexList.begin(), wvend = iVertexList.end();
       wv != wvend;
       ++wv) {
    center += (*wv)->GetVertex();
  }
  center /= float(iVertexList.size());
  setCenter(center);
}

/**********************************
 *                                *
 *                                *
 *             WXShape            *
 *                                *
 *                                *
 **********************************/

WFace *WXShape::MakeFace(vector<WVertex *> &iVertexList,
                         vector<bool> &iFaceEdgeMarksList,
                         uint iMaterialIndex)
{
  WFace *face = WShape::MakeFace(iVertexList, iFaceEdgeMarksList, iMaterialIndex);
  if (!face) {
    return nullptr;
  }

  Vec3f center;
  for (vector<WVertex *>::iterator wv = iVertexList.begin(), wvend = iVertexList.end();
       wv != wvend;
       ++wv) {
    center += (*wv)->GetVertex();
  }
  center /= float(iVertexList.size());
  ((WXFace *)face)->setCenter(center);

  return face;
}

WFace *WXShape::MakeFace(vector<WVertex *> &iVertexList,
                         vector<Vec3f> &iNormalsList,
                         vector<Vec2f> &iTexCoordsList,
                         vector<bool> &iFaceEdgeMarksList,
                         uint iMaterialIndex)
{
  WFace *face = WShape::MakeFace(
      iVertexList, iNormalsList, iTexCoordsList, iFaceEdgeMarksList, iMaterialIndex);

#if 0
  Vec3f center;
  for (vector<WVertex *>::iterator wv = iVertexList.begin(), wvend = iVertexList.end();
       wv != wvend;
       ++wv) {
    center += (*wv)->GetVertex();
  }
  center /= (float)iVertexList.size();
  ((WXFace *)face)->setCenter(center);
#endif

  return face;
}

} /* namespace Freestyle */