// Gmsh - Copyright (C) 1997-2019 C. Geuzaine, J.-F. Remacle
//
// See the LICENSE.txt file for license information. Please report all
// issues on https://gitlab.onelab.info/gmsh/gmsh/issues.

#include <sstream>
#include "GModel.h"
#include "GFace.h"
#include "gmshEdge.h"
#include "Geo.h"
#include "GeoInterpolation.h"
#include "GmshMessage.h"
#include "Context.h"
#include "decasteljau.h"

gmshEdge::gmshEdge(GModel *m, Curve *edge, GVertex *v1, GVertex *v2)
  : GEdge(m, edge->Num, v1, v2), c(edge)
{
  resetMeshAttributes();
}

void gmshEdge::resetNativePtr(Curve *edge, GVertex *_v1, GVertex *_v2)
{
  c = edge;
  v0 = _v1;
  v1 = _v2;
  if(v0) v0->addEdge(this);
  if(v1 && v1 != v0) v1->addEdge(this);
}

bool gmshEdge::degenerate(int dim) const
{
  if(c->beg == c->end && c->Typ == MSH_SEGM_LINE &&
     List_Nbr(c->Control_Points) == 0) {
    Msg::Info("Model Edge %d is degenerate", tag());
    return true;
  }
  return false;
}

void gmshEdge::resetMeshAttributes()
{
  meshAttributes.method = c->Method;
  meshAttributes.nbPointsTransfinite = c->nbPointsTransfinite;
  meshAttributes.typeTransfinite = c->typeTransfinite;
  meshAttributes.coeffTransfinite = c->coeffTransfinite;
  meshAttributes.extrude = c->Extrude;
  meshAttributes.reverseMesh = c->ReverseMesh;
}

Range<double> gmshEdge::parBounds(int i) const
{
  return Range<double>(c->ubeg, c->uend);
}

GPoint gmshEdge::point(double par) const
{
  Vertex a = InterpolateCurve(c, par, 0);
  return GPoint(a.Pos.X, a.Pos.Y, a.Pos.Z, this, par);
}

SVector3 gmshEdge::firstDer(double par) const
{
  Vertex a = InterpolateCurve(c, par, 1);
  return SVector3(a.Pos.X, a.Pos.Y, a.Pos.Z);
}

SVector3 gmshEdge::secondDer(double par) const
{
  Vertex a = InterpolateCurve(c, par, 2);
  return SVector3(a.Pos.X, a.Pos.Y, a.Pos.Z);
}

GEntity::GeomType gmshEdge::geomType() const
{
  switch(c->Typ) {
  case MSH_SEGM_LINE: return Line;
  case MSH_SEGM_CIRC:
  case MSH_SEGM_CIRC_INV: return Circle;
  case MSH_SEGM_ELLI:
  case MSH_SEGM_ELLI_INV: return Ellipse;
  case MSH_SEGM_BSPLN:
  case MSH_SEGM_BEZIER:
  case MSH_SEGM_NURBS:
  case MSH_SEGM_SPLN: return Nurb;
  case MSH_SEGM_BND_LAYER: return BoundaryLayerCurve;
  case MSH_SEGM_DISCRETE: return DiscreteCurve;
  default: return Unknown;
  }
}

std::string gmshEdge::getAdditionalInfoString(bool multline)
{
  if(List_Nbr(c->Control_Points) > 0) {
    std::ostringstream sstream;
    sstream << "Control points: ";
    for(int i = 0; i < List_Nbr(c->Control_Points); i++) {
      if(i) sstream << ", ";
      Vertex *v;
      List_Read(c->Control_Points, i, &v);
      sstream << v->Num;
    }

    if(meshAttributes.method == MESH_TRANSFINITE || meshAttributes.extrude ||
       meshAttributes.reverseMesh) {
      if(multline)
        sstream << "\n";
      else
        sstream << " ";
      sstream << "Mesh attributes:";
      if(meshAttributes.method == MESH_TRANSFINITE) {
        sstream << " transfinite (" << meshAttributes.nbPointsTransfinite;
        int type = meshAttributes.typeTransfinite;
        if(std::abs(type) == 1)
          sstream << ", progression "
                  << gmsh_sign(type) * meshAttributes.coeffTransfinite;
        else if(std::abs(type) == 2)
          sstream << ", bump " << meshAttributes.coeffTransfinite;
        sstream << ")";
      }
      if(meshAttributes.extrude) sstream << " extruded";
      if(meshAttributes.reverseMesh) sstream << " reversed";
    }
    return sstream.str();
  }
  else
    return GEdge::getAdditionalInfoString();
}

int gmshEdge::minimumMeshSegments() const
{
  int np;
  if(geomType() == Line) {
    np = GEdge::minimumMeshSegments();
    // FIXME FOR QUADS
    if(List_Nbr(c->Control_Points) > 2) {
      np = 3 * (List_Nbr(c->Control_Points)) + 1;
    }
  }
  else if(geomType() == Circle || geomType() == Ellipse)
    np = (int)(0.99 + fabs(c->Circle.t1 - c->Circle.t2) *
                        ((double)CTX::instance()->mesh.minCircPoints - 1.0) /
                        (2 * M_PI));
  else
    np = CTX::instance()->mesh.minCurvPoints - 1;
  return std::max(np, meshAttributes.minimumMeshSegments);
}

int gmshEdge::minimumDrawSegments() const
{
  int n = List_Nbr(c->Control_Points) - 1;
  if(!n) n = GEdge::minimumDrawSegments();

  if(geomType() == Line && !c->geometry)
    return n;
  else
    return CTX::instance()->geom.numSubEdges * n;
}

SPoint2 gmshEdge::reparamOnFace(const GFace *face, double epar, int dir) const
{
  Surface *s = (Surface *)face->getNativePtr();

  bool periodic = (c->end == c->beg);
  if(s->geometry) {
    switch(c->Typ) {
    case MSH_SEGM_LINE: {
      Vertex *v[3];
      List_Read(c->Control_Points, 0, &v[1]);
      List_Read(c->Control_Points, 1, &v[2]);
      SPoint2 p = v[1]->pntOnGeometry +
                  (v[2]->pntOnGeometry - v[1]->pntOnGeometry) * epar;
      return p;
    }
    case MSH_SEGM_BSPLN:
    case MSH_SEGM_BEZIER: {
      int NbControlPoints = List_Nbr(c->Control_Points);
      int NbCurves = NbControlPoints + (periodic ? -1 : 1);
      int iCurve = (int)floor(epar * (double)NbCurves);
      if(iCurve >= NbCurves)
        iCurve = NbCurves - 1;
      else if(iCurve < 0) // ? does it happen ?
        iCurve = 0;
      double t1 = (double)(iCurve) / (double)(NbCurves);
      double t2 = (double)(iCurve + 1) / (double)(NbCurves);
      double t = (epar - t1) / (t2 - t1);
      Vertex *v[4];
      for(int j = 0; j < 4; j++) {
        int k = iCurve - (periodic ? 1 : 2) + j;
        if(k < 0) k = periodic ? k + NbControlPoints - 1 : 0;
        if(k >= NbControlPoints)
          k = periodic ? k - NbControlPoints + 1 : NbControlPoints - 1;
        List_Read(c->Control_Points, k, &v[j]);
      }
      return InterpolateCubicSpline(v, t, c->mat, t1, t2, c->geometry, 0);
    }
    case MSH_SEGM_SPLN: {
      Vertex temp1, temp2;
      int N = List_Nbr(c->Control_Points);
      int i = (int)((double)(N - 1) * epar);
      if(i < 0) i = 0;
      if(i >= N - 1) i = N - 2;
      double t1 = (double)(i) / (double)(N - 1);
      double t2 = (double)(i + 1) / (double)(N - 1);
      double t = (epar - t1) / (t2 - t1);
      Vertex *v[4];
      List_Read(c->Control_Points, i, &v[1]);
      List_Read(c->Control_Points, i + 1, &v[2]);
      if(!i) {
        if(c->beg == c->end) {
          List_Read(c->Control_Points, N - 2, &v[0]);
        }
        else {
          v[0] = &temp1;
          v[0]->pntOnGeometry = v[1]->pntOnGeometry * 2. - v[2]->pntOnGeometry;
        }
      }
      else {
        List_Read(c->Control_Points, i - 1, &v[0]);
      }
      if(i == N - 2) {
        if(c->beg == c->end) {
          List_Read(c->Control_Points, 1, &v[3]);
        }
        else {
          v[3] = &temp2;
          v[3]->pntOnGeometry = v[2]->pntOnGeometry * 2. - v[1]->pntOnGeometry;
        }
      }
      else {
        List_Read(c->Control_Points, i + 2, &v[3]);
      }
      return InterpolateCubicSpline(v, t, c->mat, t1, t2, c->geometry, 0);
    }
    default: Msg::Error("Unknown edge type in reparamOnFace"); return SPoint2();
    }
  }

  if(s->Typ == MSH_SURF_REGL) {
    Curve *C[4];
    for(int i = 0; i < 4; i++) List_Read(s->Generatrices, i, &C[i]);

    double U, V;
    if(C[0]->Num == c->Num) {
      U = (epar - C[0]->ubeg) / (C[0]->uend - C[0]->ubeg);
      V = 0;
    }
    else if(C[0]->Num == -c->Num) {
      U = (C[0]->uend - epar - C[0]->ubeg) / (C[0]->uend - C[0]->ubeg);
      V = 0;
    }
    else if(C[1]->Num == c->Num) {
      V = (epar - C[1]->ubeg) / (C[1]->uend - C[1]->ubeg);
      U = 1;
    }
    else if(C[1]->Num == -c->Num) {
      V = (C[1]->uend - epar - C[1]->ubeg) / (C[1]->uend - C[1]->ubeg);
      U = 1;
    }
    else if(C[2]->Num == c->Num) {
      U = 1 - (epar - C[2]->ubeg) / (C[2]->uend - C[2]->ubeg);
      V = 1;
    }
    else if(C[2]->Num == -c->Num) {
      U = 1 - (C[2]->uend - epar - C[2]->ubeg) / (C[2]->uend - C[2]->ubeg);
      V = 1;
    }
    else if(C[3]->Num == c->Num) {
      V = 1 - (epar - C[3]->ubeg) / (C[3]->uend - C[3]->ubeg);
      U = 0;
    }
    else if(C[3]->Num == -c->Num) {
      V = 1 - (C[3]->uend - epar - C[3]->ubeg) / (C[3]->uend - C[3]->ubeg);
      U = 0;
    }
    else {
      Msg::Info("Reparameterizing edge %d on face %d", c->Num, s->Num);
      return GEdge::reparamOnFace(face, epar, dir);
    }
    return SPoint2(U, V);
  }
  else if(s->Typ == MSH_SURF_TRIC) {
    Curve *C[3];
    for(int i = 0; i < 3; i++) List_Read(s->Generatrices, i, &C[i]);
    double U, V;
    if(CTX::instance()->geom.oldRuledSurface) {
      if(C[0]->Num == c->Num) {
        U = (epar - C[0]->ubeg) / (C[0]->uend - C[0]->ubeg);
        V = 0;
      }
      else if(C[0]->Num == -c->Num) {
        U = (C[0]->uend - epar - C[0]->ubeg) / (C[0]->uend - C[0]->ubeg);
        V = 0;
      }
      else if(C[1]->Num == c->Num) {
        V = (epar - C[1]->ubeg) / (C[1]->uend - C[1]->ubeg);
        U = 1;
      }
      else if(C[1]->Num == -c->Num) {
        V = (C[1]->uend - epar - C[1]->ubeg) / (C[1]->uend - C[1]->ubeg);
        U = 1;
      }
      else if(C[2]->Num == c->Num) {
        U = 1 - (epar - C[2]->ubeg) / (C[2]->uend - C[2]->ubeg);
        V = 1;
      }
      else if(C[2]->Num == -c->Num) {
        U = 1 - (C[2]->uend - epar - C[2]->ubeg) / (C[2]->uend - C[2]->ubeg);
        V = 1;
      }
      else {
        Msg::Info("Reparameterizing edge %d on face %d", c->Num, s->Num);
        return GEdge::reparamOnFace(face, epar, dir);
      }
    }
    else {
      // FIXME: workaround for exact extrusions
      bool hack = false;
      if(CTX::instance()->geom.exactExtrusion && s->Extrude &&
         s->Extrude->geo.Mode == EXTRUDED_ENTITY && s->Typ != MSH_SURF_PLAN)
        hack = true;
      if(C[0]->Num == c->Num) {
        U = (epar - C[0]->ubeg) / (C[0]->uend - C[0]->ubeg);
        V = 0;
      }
      else if(C[0]->Num == -c->Num) {
        U = (C[0]->uend - epar - C[0]->ubeg) / (C[0]->uend - C[0]->ubeg);
        V = 0;
      }
      else if(C[1]->Num == c->Num) {
        V = (epar - C[1]->ubeg) / (C[1]->uend - C[1]->ubeg);
        U = 1;
      }
      else if(C[1]->Num == -c->Num) {
        V = (C[1]->uend - epar - C[1]->ubeg) / (C[1]->uend - C[1]->ubeg);
        U = 1;
      }
      else if(C[2]->Num == c->Num) {
        U = 1 - (epar - C[2]->ubeg) / (C[2]->uend - C[2]->ubeg);
        V = hack ? 1 : U;
      }
      else if(C[2]->Num == -c->Num) {
        U = 1 - (C[2]->uend - epar - C[2]->ubeg) / (C[2]->uend - C[2]->ubeg);
        V = hack ? 1 : U;
      }
      else {
        Msg::Info("Reparameterizing edge %d on face %d", c->Num, s->Num);
        return GEdge::reparamOnFace(face, epar, dir);
      }
    }
    return SPoint2(U, V);
  }
  else {
    return GEdge::reparamOnFace(face, epar, dir);
  }
}

void gmshEdge::writeGEO(FILE *fp)
{
  if(!c || c->Num < 0 || c->Typ == MSH_SEGM_DISCRETE) return;
  switch(c->Typ) {
  case MSH_SEGM_LINE: fprintf(fp, "Line(%d) = ", c->Num); break;
  case MSH_SEGM_CIRC:
  case MSH_SEGM_CIRC_INV: fprintf(fp, "Circle(%d) = ", c->Num); break;
  case MSH_SEGM_ELLI:
  case MSH_SEGM_ELLI_INV: fprintf(fp, "Ellipse(%d) = ", c->Num); break;
  case MSH_SEGM_NURBS:
    fprintf(fp, "Nurbs(%d) = {", c->Num);
    for(int i = 0; i < List_Nbr(c->Control_Points); i++) {
      Vertex *v;
      List_Read(c->Control_Points, i, &v);
      if(!i)
        fprintf(fp, "%d", v->Num);
      else
        fprintf(fp, ", %d", v->Num);
      if(i % 8 == 7 && i != List_Nbr(c->Control_Points) - 1) fprintf(fp, "\n");
    }
    fprintf(fp, "}\n");
    fprintf(fp, "  Knots {");
    for(int j = 0; j < List_Nbr(c->Control_Points) + c->degre + 1; j++) {
      if(!j)
        fprintf(fp, "%.16g", c->k[j]);
      else
        fprintf(fp, ", %.16g", c->k[j]);
      if(j % 5 == 4 && j != List_Nbr(c->Control_Points) + c->degre)
        fprintf(fp, "\n        ");
    }
    fprintf(fp, "}\n");
    fprintf(fp, "  Order %d;\n", c->degre);
    return;
  case MSH_SEGM_SPLN: fprintf(fp, "Spline(%d) = ", c->Num); break;
  case MSH_SEGM_BSPLN: fprintf(fp, "BSpline(%d) = ", c->Num); break;
  case MSH_SEGM_BEZIER: fprintf(fp, "Bezier(%d) = ", c->Num); break;
  default: Msg::Error("Unknown curve type %d", c->Typ); return;
  }
  for(int i = 0; i < List_Nbr(c->Control_Points); i++) {
    Vertex *v;
    List_Read(c->Control_Points, i, &v);
    if(i)
      fprintf(fp, ", %d", v->Num);
    else
      fprintf(fp, "{%d", v->Num);
    if(i % 8 == 7) fprintf(fp, "\n");
  }
  fprintf(fp, "};\n");

  if(meshAttributes.method == MESH_TRANSFINITE) {
    fprintf(fp, "Transfinite Line {%d} = %d",
            tag() * (meshAttributes.typeTransfinite > 0 ? 1 : -1),
            meshAttributes.nbPointsTransfinite);
    if(meshAttributes.typeTransfinite) {
      if(std::abs(meshAttributes.typeTransfinite) == 1)
        fprintf(fp, "Using Progression ");
      else if(std::abs(meshAttributes.typeTransfinite) == 2)
        fprintf(fp, "Using Bump ");
      fprintf(fp, "%g", meshAttributes.coeffTransfinite);
    }
    fprintf(fp, ";\n");
  }

  if(meshAttributes.reverseMesh) fprintf(fp, "Reverse Line {%d};\n", tag());
}

static inline SPoint3 curveGetPoint(Curve *c, int i)
{
  Vertex *v;
  List_Read(c->Control_Points, i, &v);
  return SPoint3(v->Pos.X, v->Pos.Y, v->Pos.Z);
}

void gmshEdge::discretize(double tol, std::vector<SPoint3> &pts,
                          std::vector<double> &ts)
{
  switch(c->Typ) {
  case MSH_SEGM_LINE: {
    int NPt = List_Nbr(c->Control_Points);
    pts.resize(NPt);
    ts.resize(NPt);
    for(int i = 0; i < NPt; ++i) {
      pts[i] = curveGetPoint(c, i);
      ts[i] = i / (double)(NPt - 1);
    }
    return;
  }
  case MSH_SEGM_BEZIER: {
    int NbCurves = (List_Nbr(c->Control_Points) - 1) / 3;
    for(int iCurve = 0; iCurve < NbCurves; ++iCurve) {
      double t1 = (iCurve) / (double)(NbCurves);
      double t2 = (iCurve + 1) / (double)(NbCurves);
      SPoint3 pt[4];
      for(int i = 0; i < 4; i++) {
        pt[i] = curveGetPoint(c, iCurve * 3 + i);
      }
      std::vector<double> lts;
      std::vector<SPoint3> lpts;
      decasteljau(tol, pt[0], pt[1], pt[2], pt[3], lpts, lts);
      for(size_t i = (iCurve == 0 ? 0 : 1); i < lpts.size(); ++i) {
        pts.push_back(lpts[i]);
        ts.push_back(t1 + lts[i] * (t2 - t1));
      }
    }
    break;
  }
  case MSH_SEGM_BSPLN: {
    bool periodic = (c->end == c->beg);
    int NbControlPoints = List_Nbr(c->Control_Points);
    int NbCurves = NbControlPoints + (periodic ? -1 : 1);
    SPoint3 pt[4];
    for(int iCurve = 0; iCurve < NbCurves; ++iCurve) {
      double t1 = (iCurve) / (double)(NbCurves);
      double t2 = (iCurve + 1) / (double)(NbCurves);
      for(int i = 0; i < 4; i++) {
        int k;
        if(periodic) {
          k = (iCurve - 1 + i) % (NbControlPoints - 1);
          if(k < 0) k += NbControlPoints - 1;
        }
        else {
          k = std::max(0, std::min(iCurve - 2 + i, NbControlPoints - 1));
        }
        pt[i] = curveGetPoint(c, k);
      }
      SPoint3 bpt[4] = {(pt[0] + pt[1] * 4 + pt[2]) * (1. / 6.),
                        (pt[1] * 2 + pt[2]) * (1. / 3.),
                        (pt[1] + pt[2] * 2) * (1. / 3.),
                        (pt[1] + pt[2] * 4 + pt[3]) * (1. / 6.)};
      std::vector<double> lts;
      std::vector<SPoint3> lpts;
      decasteljau(tol, bpt[0], bpt[1], bpt[2], bpt[3], lpts, lts);
      for(size_t i = (iCurve == 0 ? 0 : 1); i < lpts.size(); ++i) {
        pts.push_back(lpts[i]);
        ts.push_back(t1 + lts[i] * (t2 - t1));
      }
    }
    break;
  }
  case MSH_SEGM_SPLN: {
    int NbCurves = List_Nbr(c->Control_Points) - 1;
    SPoint3 pt[4];
    for(int iCurve = 0; iCurve < NbCurves; ++iCurve) {
      double t1 = (iCurve) / (double)(NbCurves);
      double t2 = (iCurve + 1) / (double)(NbCurves);
      pt[1] = curveGetPoint(c, iCurve);
      pt[2] = curveGetPoint(c, iCurve + 1);
      if(iCurve == 0) {
        if(c->beg == c->end)
          pt[0] = curveGetPoint(c, NbCurves - 1);
        else
          pt[0] = SPoint3(pt[1] * 2 - pt[2]);
      }
      else
        pt[0] = curveGetPoint(c, iCurve - 1);
      if(iCurve == NbCurves - 1) {
        if(c->beg == c->end)
          pt[3] = curveGetPoint(c, 1);
        else
          pt[3] = SPoint3(2 * pt[2] - pt[1]);
      }
      else
        pt[3] = curveGetPoint(c, iCurve + 2);
      SPoint3 bpt[4] = {pt[1], (pt[1] * 6 + pt[2] - pt[0]) * (1. / 6.),
                        (pt[2] * 6 - pt[3] + pt[1]) * (1. / 6.), pt[2]};
      std::vector<double> lts;
      std::vector<SPoint3> lpts;
      decasteljau(tol, bpt[0], bpt[1], bpt[2], bpt[3], lpts, lts);
      for(size_t i = (iCurve == 0 ? 0 : 1); i < lpts.size(); ++i) {
        pts.push_back(lpts[i]);
        ts.push_back(t1 + lts[i] * (t2 - t1));
      }
    }
    break;
  }
  default: GEdge::discretize(tol, pts, ts);
  }
}
