/*
  This file is part of CDO. CDO is a collection of Operators to manipulate and analyse Climate model Data.

  Author: Uwe Schulzweida

*/

/*
   This module contains the following operators:

      Enlarge    enlarge         Enlarge fields
*/

#include <cdi.h>

#include "cdo_options.h"
#include "process_int.h"
#include "griddes.h"

class Enlarge : public Process
{
public:
  using Process::Process;
  inline static CdoModule module = {
    .name = "Enlarge",
    .operators = { { "enlarge", EnlargeHelp } },
    .aliases = {},
    .mode = EXPOSED,     // Module mode: 0:intern 1:extern
    .number = CDI_REAL,  // Allowed number type
    .constraints = { 1, 1, NoRestriction },
  };
  inline static RegisterEntry<Enlarge> registration = RegisterEntry<Enlarge>(module);

  CdoStreamID streamID1;
  CdoStreamID streamID2;

  size_t ysize2;
  size_t xsize2;

  int taxisID1;
  int taxisID2;

  int vlistID1;
  int vlistID2;

  size_t gridsize2;

  VarList varList1;

public:
  void
  init() override
  {
    operator_check_argc(1);

    auto gridID2 = cdo_define_grid(cdo_operator_argv(0));
    xsize2 = gridInqXsize(gridID2);
    ysize2 = gridInqYsize(gridID2);

    if (Options::cdoVerbose) fprintf(stderr, "gridID2 %d, xsize2 %zu, ysize2 %zu\n", gridID2, xsize2, ysize2);

    streamID1 = cdo_open_read(0);

    vlistID1 = cdo_stream_inq_vlist(streamID1);
    vlistID2 = vlistDuplicate(vlistID1);

    varList1 = VarList(vlistID1);

    taxisID1 = vlistInqTaxis(vlistID1);
    taxisID2 = taxisDuplicate(taxisID1);

    gridsize2 = gridInqSize(gridID2);
    if (gridsize2 < varList1.gridsizeMax()) cdo_abort("Gridsize of input stream is greater than new gridsize!");

    auto numGrids = vlistNumGrids(vlistID1);
    for (int index = 0; index < numGrids; ++index) vlistChangeGridIndex(vlistID2, index, gridID2);

    streamID2 = cdo_open_write(1);

    cdo_def_vlist(streamID2, vlistID2);
  }

  void
  run() override
  {
    bool linfo = true;
    Varray<double> array1(gridsize2);
    Varray<double> array2(gridsize2);

    int tsID = 0;
    while (true)
      {
        auto numFields = cdo_stream_inq_timestep(streamID1, tsID);
        if (numFields == 0) break;

        cdo_taxis_copy_timestep(taxisID2, taxisID1);
        cdo_def_timestep(streamID2, tsID);

        while (numFields--)
          {
            auto [varID, levelID] = cdo_inq_field(streamID1);
            size_t numMissVals;
            cdo_read_field(streamID1, array1.data(), &numMissVals);

            const auto &var = varList1.vars[varID];
            auto gridID1 = var.gridID;
            auto gridsize1 = var.gridsize;

            auto xsize1 = gridInqXsize(gridID1);
            auto ysize1 = gridInqYsize(gridID1);
            if (xsize1 == 0) xsize1 = 1;
            if (ysize1 == 0) ysize1 = 1;

            if (xsize1 == 1 && ysize1 == ysize2 && xsize1 * ysize1 == gridsize1)
              {
                if (linfo)
                  {
                    cdo_print("Enlarge zonal");
                    linfo = false;
                  }

                for (size_t iy = 0; iy < ysize2; iy++)
                  for (size_t ix = 0; ix < xsize2; ix++) array2[ix + iy * xsize2] = array1[iy];

                if (numMissVals) numMissVals *= xsize2;
              }
            else if (ysize1 == 1 && xsize1 == xsize2 && xsize1 * ysize1 == gridsize1)
              {
                if (linfo)
                  {
                    cdo_print("Enlarge meridional");
                    linfo = false;
                  }

                for (size_t iy = 0; iy < ysize2; iy++)
                  for (size_t ix = 0; ix < xsize2; ix++) array2[ix + iy * xsize2] = array1[ix];

                if (numMissVals) numMissVals *= ysize2;
              }
            else
              {
                varray_copy(gridsize1, array1, array2);
                for (size_t i = gridsize1; i < gridsize2; ++i) array2[i] = array1[gridsize1 - 1];

                if (numMissVals && fp_is_equal(array1[gridsize1 - 1], var.missval)) numMissVals += (gridsize2 - gridsize1);
              }

            cdo_def_field(streamID2, varID, levelID);
            cdo_write_field(streamID2, array2.data(), numMissVals);
          }

        tsID++;
      }
  }

  void
  close() override
  {
    cdo_stream_close(streamID2);
    cdo_stream_close(streamID1);
  }
};
