#include <petsc/private/dmpleximpl.h> /*I      "petscdmplex.h"   I*/

#if !defined(ANSI_DECLARATORS)
  #define ANSI_DECLARATORS
#endif
#include <triangle.h>

static PetscErrorCode InitInput_Triangle(struct triangulateio *inputCtx)
{
  PetscFunctionBegin;
  inputCtx->numberofpoints             = 0;
  inputCtx->numberofpointattributes    = 0;
  inputCtx->pointlist                  = NULL;
  inputCtx->pointattributelist         = NULL;
  inputCtx->pointmarkerlist            = NULL;
  inputCtx->numberofsegments           = 0;
  inputCtx->segmentlist                = NULL;
  inputCtx->segmentmarkerlist          = NULL;
  inputCtx->numberoftriangleattributes = 0;
  inputCtx->trianglelist               = NULL;
  inputCtx->numberofholes              = 0;
  inputCtx->holelist                   = NULL;
  inputCtx->numberofregions            = 0;
  inputCtx->regionlist                 = NULL;
  PetscFunctionReturn(PETSC_SUCCESS);
}

static PetscErrorCode InitOutput_Triangle(struct triangulateio *outputCtx)
{
  PetscFunctionBegin;
  outputCtx->numberofpoints        = 0;
  outputCtx->pointlist             = NULL;
  outputCtx->pointattributelist    = NULL;
  outputCtx->pointmarkerlist       = NULL;
  outputCtx->numberoftriangles     = 0;
  outputCtx->trianglelist          = NULL;
  outputCtx->triangleattributelist = NULL;
  outputCtx->neighborlist          = NULL;
  outputCtx->segmentlist           = NULL;
  outputCtx->segmentmarkerlist     = NULL;
  outputCtx->numberofedges         = 0;
  outputCtx->edgelist              = NULL;
  outputCtx->edgemarkerlist        = NULL;
  PetscFunctionReturn(PETSC_SUCCESS);
}

static PetscErrorCode FiniOutput_Triangle(struct triangulateio *outputCtx)
{
  PetscFunctionBegin;
  free(outputCtx->pointlist);
  free(outputCtx->pointmarkerlist);
  free(outputCtx->segmentlist);
  free(outputCtx->segmentmarkerlist);
  free(outputCtx->edgelist);
  free(outputCtx->edgemarkerlist);
  free(outputCtx->trianglelist);
  free(outputCtx->neighborlist);
  PetscFunctionReturn(PETSC_SUCCESS);
}

PETSC_EXTERN PetscErrorCode DMPlexGenerate_Triangle(DM boundary, PetscBool interpolate, DM *dm)
{
  MPI_Comm             comm;
  DM_Plex             *mesh             = (DM_Plex *)boundary->data;
  PetscInt             dim              = 2;
  const PetscBool      createConvexHull = PETSC_FALSE;
  const PetscBool      constrained      = PETSC_FALSE;
  const char          *labelName        = "marker";
  const char          *labelName2       = "Face Sets";
  struct triangulateio in;
  struct triangulateio out;
  DMLabel              label, label2;
  PetscInt             vStart, vEnd, v, eStart, eEnd, e;
  PetscMPIInt          rank;
  PetscBool            flg;
  char                 opts[64];

  PetscFunctionBegin;
  PetscCall(PetscObjectGetComm((PetscObject)boundary, &comm));
  PetscCallMPI(MPI_Comm_rank(comm, &rank));
  PetscCall(InitInput_Triangle(&in));
  PetscCall(InitOutput_Triangle(&out));
  PetscCall(DMPlexGetDepthStratum(boundary, 0, &vStart, &vEnd));
  PetscCall(DMGetLabel(boundary, labelName, &label));
  PetscCall(DMGetLabel(boundary, labelName2, &label2));
  PetscCall(PetscOptionsGetString(((PetscObject)boundary)->options, ((PetscObject)boundary)->prefix, "-dm_plex_generate_triangle_opts", opts, sizeof(opts), &flg));
  if (flg) PetscCall(DMPlexTriangleSetOptions(boundary, opts));

  PetscCall(PetscCIntCast(vEnd - vStart, &in.numberofpoints));
  if (in.numberofpoints > 0) {
    PetscSection coordSection;
    Vec          coordinates;
    PetscScalar *array;

    PetscCall(PetscMalloc1(in.numberofpoints * dim, &in.pointlist));
    PetscCall(PetscMalloc1(in.numberofpoints, &in.pointmarkerlist));
    PetscCall(DMGetCoordinatesLocal(boundary, &coordinates));
    PetscCall(DMGetCoordinateSection(boundary, &coordSection));
    PetscCall(VecGetArray(coordinates, &array));
    for (v = vStart; v < vEnd; ++v) {
      const PetscInt idx = v - vStart;
      PetscInt       val, off, d;

      PetscCall(PetscSectionGetOffset(coordSection, v, &off));
      for (d = 0; d < dim; ++d) in.pointlist[idx * dim + d] = PetscRealPart(array[off + d]);
      if (label) {
        PetscCall(DMLabelGetValue(label, v, &val));
        PetscCall(PetscCIntCast(val, &in.pointmarkerlist[idx]));
      }
    }
    PetscCall(VecRestoreArray(coordinates, &array));
  }
  PetscCall(DMPlexGetHeightStratum(boundary, 0, &eStart, &eEnd));
  PetscCall(PetscCIntCast(eEnd - eStart, &in.numberofsegments));
  if (in.numberofsegments > 0) {
    PetscCall(PetscMalloc1(in.numberofsegments * 2, &in.segmentlist));
    PetscCall(PetscMalloc1(in.numberofsegments, &in.segmentmarkerlist));
    for (e = eStart; e < eEnd; ++e) {
      const PetscInt  idx = e - eStart;
      const PetscInt *cone;
      PetscInt        val;

      PetscCall(DMPlexGetCone(boundary, e, &cone));

      PetscCall(PetscCIntCast(cone[0] - vStart, &in.segmentlist[idx * 2 + 0]));
      PetscCall(PetscCIntCast(cone[1] - vStart, &in.segmentlist[idx * 2 + 1]));

      if (label) {
        PetscCall(DMLabelGetValue(label, e, &val));
        PetscCall(PetscCIntCast(val, &in.segmentmarkerlist[idx]));
      }
    }
  }
#if 0 /* Do not currently support holes */
  PetscReal *holeCoords;
  PetscInt   h, d;

  PetscCall(DMPlexGetHoles(boundary, &in.numberofholes, &holeCords));
  if (in.numberofholes > 0) {
    PetscCall(PetscMalloc1(in.numberofholes*dim, &in.holelist));
    for (h = 0; h < in.numberofholes; ++h) {
      for (d = 0; d < dim; ++d) in.holelist[h*dim+d] = holeCoords[h*dim+d];
    }
  }
#endif
  if (rank == 0) {
    char args[32];

    /* Take away 'Q' for verbose output */
    PetscCall(PetscStrncpy(args, "pqezQ", sizeof(args)));
    if (createConvexHull) PetscCall(PetscStrlcat(args, "c", sizeof(args)));
    if (constrained) PetscCall(PetscStrncpy(args, "zepDQ", sizeof(args)));
    if (mesh->triangleOpts) {
      triangulate(mesh->triangleOpts, &in, &out, NULL);
    } else {
      triangulate(args, &in, &out, NULL);
    }
  }
  PetscCall(PetscFree(in.pointlist));
  PetscCall(PetscFree(in.pointmarkerlist));
  PetscCall(PetscFree(in.segmentlist));
  PetscCall(PetscFree(in.segmentmarkerlist));
  PetscCall(PetscFree(in.holelist));

  {
    DMLabel        glabel      = NULL;
    DMLabel        glabel2     = NULL;
    const PetscInt numCorners  = 3;
    const PetscInt numCells    = out.numberoftriangles;
    const PetscInt numVertices = out.numberofpoints;
    PetscInt      *cells;
    PetscReal     *meshCoords;

    if (sizeof(PetscReal) == sizeof(out.pointlist[0])) {
      meshCoords = (PetscReal *)out.pointlist;
    } else {
      PetscInt i;

      PetscCall(PetscMalloc1(dim * numVertices, &meshCoords));
      for (i = 0; i < dim * numVertices; i++) meshCoords[i] = (PetscReal)out.pointlist[i];
    }
    if (sizeof(PetscInt) == sizeof(out.trianglelist[0])) {
      cells = (PetscInt *)out.trianglelist;
    } else {
      PetscInt i;

      PetscCall(PetscMalloc1(numCells * numCorners, &cells));
      for (i = 0; i < numCells * numCorners; i++) cells[i] = (PetscInt)out.trianglelist[i];
    }
    PetscCall(DMPlexCreateFromCellListPetsc(comm, dim, numCells, numVertices, numCorners, interpolate, cells, dim, meshCoords, dm));
    if (sizeof(PetscReal) != sizeof(out.pointlist[0])) PetscCall(PetscFree(meshCoords));
    if (sizeof(PetscInt) != sizeof(out.trianglelist[0])) PetscCall(PetscFree(cells));
    if (label) {
      PetscCall(DMCreateLabel(*dm, labelName));
      PetscCall(DMGetLabel(*dm, labelName, &glabel));
    }
    if (label2) {
      PetscCall(DMCreateLabel(*dm, labelName2));
      PetscCall(DMGetLabel(*dm, labelName2, &glabel2));
    }
    /* Set labels */
    for (v = 0; v < numVertices; ++v) {
      if (out.pointmarkerlist[v]) {
        if (glabel) PetscCall(DMLabelSetValue(glabel, v + numCells, out.pointmarkerlist[v]));
      }
    }
    if (interpolate) {
      for (e = 0; e < out.numberofedges; e++) {
        if (out.edgemarkerlist[e]) {
          const PetscInt  vertices[2] = {out.edgelist[e * 2 + 0] + numCells, out.edgelist[e * 2 + 1] + numCells};
          const PetscInt *edges;
          PetscInt        numEdges;

          PetscCall(DMPlexGetJoin(*dm, 2, vertices, &numEdges, &edges));
          PetscCheck(numEdges == 1, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Two vertices must cover only one edge, not %" PetscInt_FMT, numEdges);
          if (glabel) PetscCall(DMLabelSetValue(glabel, edges[0], out.edgemarkerlist[e]));
          if (glabel2) PetscCall(DMLabelSetValue(glabel2, edges[0], out.edgemarkerlist[e]));
          PetscCall(DMPlexRestoreJoin(*dm, 2, vertices, &numEdges, &edges));
        }
      }
    }
    PetscCall(DMPlexSetRefinementUniform(*dm, PETSC_FALSE));
  }
#if 0 /* Do not currently support holes */
  PetscCall(DMPlexCopyHoles(*dm, boundary));
#endif
  PetscCall(FiniOutput_Triangle(&out));
  PetscFunctionReturn(PETSC_SUCCESS);
}

PETSC_EXTERN PetscErrorCode DMPlexRefine_Triangle(DM dm, PetscReal *inmaxVolumes, DM *dmRefined)
{
  MPI_Comm             comm;
  PetscInt             dim       = 2;
  const char          *labelName = "marker";
  struct triangulateio in;
  struct triangulateio out;
  DMLabel              label;
  PetscInt             vStart, vEnd, v, gcStart, cStart, cEnd, c, depth, depthGlobal;
  PetscMPIInt          rank;
  double              *maxVolumes;

  PetscFunctionBegin;
  PetscCall(PetscObjectGetComm((PetscObject)dm, &comm));
  PetscCallMPI(MPI_Comm_rank(comm, &rank));
  PetscCall(InitInput_Triangle(&in));
  PetscCall(InitOutput_Triangle(&out));
  PetscCall(DMPlexGetDepth(dm, &depth));
  PetscCallMPI(MPIU_Allreduce(&depth, &depthGlobal, 1, MPIU_INT, MPI_MAX, comm));
  PetscCall(DMPlexGetDepthStratum(dm, 0, &vStart, &vEnd));
  PetscCall(DMGetLabel(dm, labelName, &label));

  PetscCall(PetscCIntCast(vEnd - vStart, &in.numberofpoints));
  if (in.numberofpoints > 0) {
    PetscSection coordSection;
    Vec          coordinates;
    PetscScalar *array;

    PetscCall(PetscMalloc1(in.numberofpoints * dim, &in.pointlist));
    PetscCall(PetscMalloc1(in.numberofpoints, &in.pointmarkerlist));
    PetscCall(DMGetCoordinatesLocal(dm, &coordinates));
    PetscCall(DMGetCoordinateSection(dm, &coordSection));
    PetscCall(VecGetArray(coordinates, &array));
    for (v = vStart; v < vEnd; ++v) {
      const PetscInt idx = v - vStart;
      PetscInt       off, d, val;

      PetscCall(PetscSectionGetOffset(coordSection, v, &off));
      for (d = 0; d < dim; ++d) in.pointlist[idx * dim + d] = PetscRealPart(array[off + d]);
      if (label) {
        PetscCall(DMLabelGetValue(label, v, &val));
        PetscCall(PetscCIntCast(val, &in.pointmarkerlist[idx]));
      }
    }
    PetscCall(VecRestoreArray(coordinates, &array));
  }
  PetscCall(DMPlexGetHeightStratum(dm, 0, &cStart, &cEnd));
  PetscCall(DMPlexGetCellTypeStratum(dm, DM_POLYTOPE_FV_GHOST, &gcStart, NULL));
  if (gcStart >= 0) cEnd = gcStart;

  in.numberofcorners = 3;
  PetscCall(PetscCIntCast(cEnd - cStart, &in.numberoftriangles));

#if !defined(PETSC_USE_REAL_DOUBLE)
  PetscCall(PetscMalloc1(cEnd - cStart, &maxVolumes));
  for (c = 0; c < cEnd - cStart; ++c) maxVolumes[c] = (double)inmaxVolumes[c];
#else
  maxVolumes = inmaxVolumes;
#endif

  in.trianglearealist = (double *)maxVolumes;
  if (in.numberoftriangles > 0) {
    PetscCall(PetscMalloc1(in.numberoftriangles * in.numberofcorners, &in.trianglelist));
    for (c = cStart; c < cEnd; ++c) {
      const PetscInt idx     = c - cStart;
      PetscInt      *closure = NULL;
      PetscInt       closureSize;

      PetscCall(DMPlexGetTransitiveClosure(dm, c, PETSC_TRUE, &closureSize, &closure));
      PetscCheck(!(closureSize != 4) || !(closureSize != 7), comm, PETSC_ERR_ARG_WRONG, "Mesh has cell which is not a triangle, %" PetscInt_FMT " vertices in closure", closureSize);
      for (v = 0; v < 3; ++v) PetscCall(PetscCIntCast(closure[(v + closureSize - 3) * 2] - vStart, &in.trianglelist[idx * in.numberofcorners + v]));
      PetscCall(DMPlexRestoreTransitiveClosure(dm, c, PETSC_TRUE, &closureSize, &closure));
    }
  }
  /* TODO: Segment markers are missing on input */
#if 0 /* Do not currently support holes */
  PetscReal *holeCoords;
  PetscInt   h, d;

  PetscCall(DMPlexGetHoles(boundary, &in.numberofholes, &holeCords));
  if (in.numberofholes > 0) {
    PetscCall(PetscMalloc1(in.numberofholes*dim, &in.holelist));
    for (h = 0; h < in.numberofholes; ++h) {
      for (d = 0; d < dim; ++d) in.holelist[h*dim+d] = holeCoords[h*dim+d];
    }
  }
#endif
  if (rank == 0) {
    char args[32];

    /* Take away 'Q' for verbose output */
    PetscCall(PetscStrncpy(args, "pqezQra", sizeof(args)));
    triangulate(args, &in, &out, NULL);
  }
  PetscCall(PetscFree(in.pointlist));
  PetscCall(PetscFree(in.pointmarkerlist));
  PetscCall(PetscFree(in.segmentlist));
  PetscCall(PetscFree(in.segmentmarkerlist));
  PetscCall(PetscFree(in.trianglelist));

  {
    DMLabel        rlabel      = NULL;
    const PetscInt numCorners  = 3;
    const PetscInt numCells    = out.numberoftriangles;
    const PetscInt numVertices = out.numberofpoints;
    PetscInt      *cells;
    PetscReal     *meshCoords;
    PetscBool      interpolate = depthGlobal > 1 ? PETSC_TRUE : PETSC_FALSE;

    if (sizeof(PetscReal) == sizeof(out.pointlist[0])) {
      meshCoords = (PetscReal *)out.pointlist;
    } else {
      PetscInt i;

      PetscCall(PetscMalloc1(dim * numVertices, &meshCoords));
      for (i = 0; i < dim * numVertices; i++) meshCoords[i] = (PetscReal)out.pointlist[i];
    }
    if (sizeof(PetscInt) == sizeof(out.trianglelist[0])) {
      cells = (PetscInt *)out.trianglelist;
    } else {
      PetscInt i;

      PetscCall(PetscMalloc1(numCells * numCorners, &cells));
      for (i = 0; i < numCells * numCorners; i++) cells[i] = (PetscInt)out.trianglelist[i];
    }

    PetscCall(DMPlexCreateFromCellListPetsc(comm, dim, numCells, numVertices, numCorners, interpolate, cells, dim, meshCoords, dmRefined));
    if (label) {
      PetscCall(DMCreateLabel(*dmRefined, labelName));
      PetscCall(DMGetLabel(*dmRefined, labelName, &rlabel));
    }
    if (sizeof(PetscReal) != sizeof(out.pointlist[0])) PetscCall(PetscFree(meshCoords));
    if (sizeof(PetscInt) != sizeof(out.trianglelist[0])) PetscCall(PetscFree(cells));
    /* Set labels */
    for (v = 0; v < numVertices; ++v) {
      if (out.pointmarkerlist[v]) {
        if (rlabel) PetscCall(DMLabelSetValue(rlabel, v + numCells, out.pointmarkerlist[v]));
      }
    }
    if (interpolate) {
      PetscInt e;

      for (e = 0; e < out.numberofedges; e++) {
        if (out.edgemarkerlist[e]) {
          const PetscInt  vertices[2] = {out.edgelist[e * 2 + 0] + numCells, out.edgelist[e * 2 + 1] + numCells};
          const PetscInt *edges;
          PetscInt        numEdges;

          PetscCall(DMPlexGetJoin(*dmRefined, 2, vertices, &numEdges, &edges));
          PetscCheck(numEdges == 1, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Two vertices must cover only one edge, not %" PetscInt_FMT, numEdges);
          if (rlabel) PetscCall(DMLabelSetValue(rlabel, edges[0], out.edgemarkerlist[e]));
          PetscCall(DMPlexRestoreJoin(*dmRefined, 2, vertices, &numEdges, &edges));
        }
      }
    }
    PetscCall(DMPlexSetRefinementUniform(*dmRefined, PETSC_FALSE));
  }
#if 0 /* Do not currently support holes */
  PetscCall(DMPlexCopyHoles(*dm, boundary));
#endif
  PetscCall(FiniOutput_Triangle(&out));
#if !defined(PETSC_USE_REAL_DOUBLE)
  PetscCall(PetscFree(maxVolumes));
#endif
  PetscFunctionReturn(PETSC_SUCCESS);
}