/*=========================================================================
 *
 *  Copyright NumFOCUS
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *         https://www.apache.org/licenses/LICENSE-2.0.txt
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *=========================================================================*/
#ifndef itkQuadEdgeMeshEulerOperatorSplitVertexFunction_hxx
#define itkQuadEdgeMeshEulerOperatorSplitVertexFunction_hxx


namespace itk
{
template <typename TMesh, typename TQEType>
auto
QuadEdgeMeshEulerOperatorSplitVertexFunction<TMesh, TQEType>::Evaluate(QEType * h, QEType * g) -> OutputType
{
  if (!this->m_Mesh)
  {
    itkDebugMacro("No mesh present.");
    return (QEType *)nullptr;
  }

  if ((h == (QEType *)nullptr) || (g == (QEType *)nullptr))
  {
    itkDebugMacro("One or more argument(s) is(are) null.");
    return (QEType *)nullptr;
  }

  if (h == g)
  {
    itkDebugMacro("The two half-edges are the same. No antenna allowed.");
    return (QEType *)nullptr;
  }

  if (h->GetDestination() != g->GetDestination())
  {
    itkDebugMacro("The two half-edges must be incident to the same vertex.");
    return (QEType *)nullptr;
  }

  // delete the faces
  this->m_Mesh->DeleteFace(h->GetRight());
  this->m_Mesh->DeleteFace(g->GetRight());

  // splice to create a new point and disconnect the rings
  this->m_NewPoint = this->m_Mesh->Splice(h->GetSym(), g->GetSym());

  // then add a new edge
  QEType * ReturnedEdge = this->m_Mesh->AddEdge(g->GetDestination(), h->GetDestination());

  // Build two new faces
  this->m_Mesh->AddFace(h->GetSym());
  this->m_Mesh->AddFace(g->GetSym());
  this->m_Mesh->Modified();

  return ReturnedEdge;
}
} // end namespace itk

#endif
