// Created on: 2004-05-10
// Created by: Michael SAZONOV
// Copyright (c) 2004-2014 OPEN CASCADE SAS
//
// This file is part of Open CASCADE Technology software library.
//
// This library is free software; you can redistribute it and/or modify it under
// the terms of the GNU Lesser General Public License version 2.1 as published
// by the Free Software Foundation, with special exception defined in the file
// OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT
// distribution for complete text of the license and disclaimer of any warranty.
//
// Alternatively, this file may be used under the terms of Open CASCADE
// commercial license or contractual agreement.

#include <MeshTest_CheckTopology.hxx>
#include <BRep_Tool.hxx>
#include <TopExp.hxx>
#include <TopExp_Explorer.hxx>
#include <TopoDS.hxx>
#include <TopoDS_Face.hxx>
#include <TopLoc_Location.hxx>
#include <TopTools_ShapeMapHasher.hxx>
#include <NCollection_IndexedMap.hxx>
#include <TopoDS_Shape.hxx>
#include <NCollection_List.hxx>
#include <NCollection_IndexedDataMap.hxx>
#include <Poly_Triangulation.hxx>
#include <Poly_PolygonOnTriangulation.hxx>
#include <Poly_Connect.hxx>
#include <Precision.hxx>

//=======================================================================
// function : ComputeArea
// purpose  : Computes area of the triangle given by its three points (either 2D or3D)
//=======================================================================
static double ComputeArea(const gp_XYZ& theP1, const gp_XYZ& theP2, const gp_XYZ& theP3)
{
  return 0.5 * (theP3 - theP1).Crossed(theP2 - theP1).Modulus();
}

//=======================================================================
// function : ComputeArea
// purpose  : Computes area of the triangle given by its three points (either 2D or3D)
//=======================================================================
static double ComputeArea(const gp_XY& theP1, const gp_XY& theP2, const gp_XY& theP3)
{
  return 0.5 * std::abs((theP3 - theP1).Crossed(theP2 - theP1));
}

//=================================================================================================

void MeshTest_CheckTopology::Perform(Draw_Interpretor& di)
{
  NCollection_IndexedMap<TopoDS_Shape, TopTools_ShapeMapHasher> aMapF;
  NCollection_IndexedDataMap<TopoDS_Shape, NCollection_List<TopoDS_Shape>, TopTools_ShapeMapHasher>
    aMapEF;
  TopExp::MapShapes(myShape, TopAbs_FACE, aMapF);
  TopExp::MapShapesAndAncestors(myShape, TopAbs_EDGE, TopAbs_FACE, aMapEF);

  // check polygons
  int ie;
  for (ie = 1; ie <= aMapEF.Extent(); ie++)
  {
    const TopoDS_Edge&                    aEdge  = TopoDS::Edge(aMapEF.FindKey(ie));
    const NCollection_List<TopoDS_Shape>& aFaces = aMapEF(ie);
    if (aFaces.Extent() < 2)
    {
      continue;
    }

    // get polygon on first face
    const TopoDS_Face&                       aFace1 = TopoDS::Face(aFaces.First());
    TopLoc_Location                          aLoc1;
    occ::handle<Poly_Triangulation>          aT1 = BRep_Tool::Triangulation(aFace1, aLoc1);
    occ::handle<Poly_PolygonOnTriangulation> aPoly1 =
      BRep_Tool::PolygonOnTriangulation(aEdge, aT1, aLoc1);
    if (aPoly1.IsNull() || aT1.IsNull())
    {
#ifdef OCCT_DEBUG
      std::cout << "problem getting PolygonOnTriangulation of edge " << ie << std::endl;
#endif
      continue;
    }
    const NCollection_Array1<int>& aNodes1 = aPoly1->Nodes();

    // cycle on other polygons
    NCollection_List<TopoDS_Shape>::Iterator it(aFaces);
    it.Next();
    for (; it.More(); it.Next())
    {
      const TopoDS_Face&                       aFace2 = TopoDS::Face(it.Value());
      TopLoc_Location                          aLoc2;
      occ::handle<Poly_Triangulation>          aT2 = BRep_Tool::Triangulation(aFace2, aLoc2);
      occ::handle<Poly_PolygonOnTriangulation> aPoly2 =
        BRep_Tool::PolygonOnTriangulation(aEdge, aT2, aLoc2);
      if (aPoly2.IsNull() || aT2.IsNull())
      {
#ifdef OCCT_DEBUG
        std::cout << "problem getting PolygonOnTriangulation of edge " << ie << std::endl;
#endif
        continue;
      }
      const NCollection_Array1<int>& aNodes2 = aPoly2->Nodes();

      // check equality of polygons lengths
      if (aNodes2.Length() != aNodes1.Length())
      {
        myAsyncEdges.Append(ie);
        break;
      }

      // check distances between corresponding points
      double aSqDefle = BRep_Tool::Tolerance(aEdge);
      aSqDefle *= aSqDefle;
      int            iF1    = aMapF.FindIndex(aFace1);
      int            iF2    = aMapF.FindIndex(aFace2);
      int            i1     = aNodes1.Lower();
      int            i2     = aNodes2.Lower();
      const gp_Trsf& aTrsf1 = aFace1.Location().Transformation();
      const gp_Trsf& aTrsf2 = aFace2.Location().Transformation();
      for (; i1 <= aNodes1.Upper(); i1++, i2++)
      {
        const gp_Pnt aP1     = aT1->Node(aNodes1[i1]).Transformed(aTrsf1);
        const gp_Pnt aP2     = aT2->Node(aNodes2[i2]).Transformed(aTrsf2);
        const double aSqDist = aP1.SquareDistance(aP2);
        if (aSqDist > aSqDefle)
        {
          myErrors.Append(iF1);
          myErrors.Append(i1);
          myErrors.Append(iF2);
          myErrors.Append(i2);
          myErrorsVal.Append(std::sqrt(aSqDist));
        }
      }
    }
  }

  // check triangulations
  int iF;
  for (iF = 1; iF <= aMapF.Extent(); iF++)
  {
    const TopoDS_Face&              aFace = TopoDS::Face(aMapF.FindKey(iF));
    TopLoc_Location                 aLoc;
    occ::handle<Poly_Triangulation> aT = BRep_Tool::Triangulation(aFace, aLoc);
    if (aT.IsNull())
    {
      di << "face " << iF << " has no triangulation\n";
      continue;
    }

    const gp_Trsf& aTrsf = aLoc.Transformation();

    // remember boundary nodes
    TColStd_PackedMapOfInteger aMapBndNodes;
    TopExp_Explorer            ex(aFace, TopAbs_EDGE);
    for (; ex.More(); ex.Next())
    {
      const TopoDS_Edge&                       aEdge = TopoDS::Edge(ex.Current());
      occ::handle<Poly_PolygonOnTriangulation> aPoly =
        BRep_Tool::PolygonOnTriangulation(aEdge, aT, aLoc);
      if (aPoly.IsNull())
      {
        continue;
      }
      const NCollection_Array1<int>& aNodes = aPoly->Nodes();
      int                            i;
      for (i = aNodes.Lower(); i <= aNodes.Upper(); i++)
      {
        aMapBndNodes.Add(aNodes(i));
      }
    }

    TColStd_PackedMapOfInteger aUsedNodes;

    // check of free links and nodes
    Poly_Connect aConn(aT);
    int          nbTri = aT->NbTriangles(), i, j, n[3], t[3];
    for (i = 1; i <= nbTri; i++)
    {
      aT->Triangle(i).Get(n[0], n[1], n[2]);

      aUsedNodes.Add(n[0]);
      aUsedNodes.Add(n[1]);
      aUsedNodes.Add(n[2]);

      const gp_Pnt aPts[3] = {aT->Node(n[0]).Transformed(aTrsf),
                              aT->Node(n[1]).Transformed(aTrsf),
                              aT->Node(n[2]).Transformed(aTrsf)};

      double anArea = ComputeArea(aPts[0].XYZ(), aPts[1].XYZ(), aPts[2].XYZ());
      if (anArea < Precision::SquareConfusion())
      {
        mySmallTrianglesFaces.Append(iF);
        mySmallTrianglesTriangles.Append(i);
      }
      else if (aT->HasUVNodes())
      {
        const gp_XY aPUV[3] = {aT->UVNode(n[0]).XY(), aT->UVNode(n[1]).XY(), aT->UVNode(n[2]).XY()};
        anArea              = ComputeArea(aPUV[0], aPUV[1], aPUV[2]);
        if (anArea < Precision::SquarePConfusion())
        {
          mySmallTrianglesFaces.Append(iF);
          mySmallTrianglesTriangles.Append(i);
        }
      }

      aConn.Triangles(i, t[0], t[1], t[2]);
      for (j = 0; j < 3; j++)
      {
        if (t[j] == 0)
        {
          // free link found
          int k  = (j + 1) % 3; // the following node of the edge
          int n1 = n[j];
          int n2 = n[k];
          // skip if it is on boundary
          if (aMapBndNodes.Contains(n1) && aMapBndNodes.Contains(n2))
          {
            continue;
          }
          if (!myMapFaceLinks.Contains(iF))
          {
            occ::handle<NCollection_HSequence<int>> tmpSeq = new NCollection_HSequence<int>;
            myMapFaceLinks.Add(iF, tmpSeq);
          }
          occ::handle<NCollection_HSequence<int>>& aSeq = myMapFaceLinks.ChangeFromKey(iF);
          aSeq->Append(n1);
          aSeq->Append(n2);
        }
      }
    }

    // check of free nodes
    int aNbNodes = aT->NbNodes();
    for (int k = 1; k <= aNbNodes; k++)
    {
      if (!aUsedNodes.Contains(k))
      {
        myFreeNodeFaces.Append(iF);
        myFreeNodeNums.Append(k);
      }
    }
  }
}

//=======================================================================
// function : GetFreeLink
// purpose  : gets the numbers of nodes of a free link with the given index
//           in the face with the given index
//=======================================================================

void MeshTest_CheckTopology::GetFreeLink(const int theFaceIndex,
                                         const int theLinkIndex,
                                         int&      theNode1,
                                         int&      theNode2) const
{
  const occ::handle<NCollection_HSequence<int>>& aSeq = myMapFaceLinks(theFaceIndex);
  int                                            aInd = (theLinkIndex - 1) * 2 + 1;
  theNode1                                            = aSeq->Value(aInd);
  theNode2                                            = aSeq->Value(aInd + 1);
}

//=======================================================================
// function : GetCrossFaceError
// purpose  : gets the attributes of a cross face error with the given index
//=======================================================================

void MeshTest_CheckTopology::GetCrossFaceError(const int theIndex,
                                               int&      theFace1,
                                               int&      theNode1,
                                               int&      theFace2,
                                               int&      theNode2,
                                               double&   theValue) const
{
  int aInd = (theIndex - 1) * 4 + 1;
  theFace1 = myErrors(aInd);
  theNode1 = myErrors(aInd + 1);
  theFace2 = myErrors(aInd + 2);
  theNode2 = myErrors(aInd + 3);
  theValue = myErrorsVal(theIndex);
}
