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

  Copyright (C) 2003-2018 Uwe Schulzweida, <uwe.schulzweida AT mpimet.mpg.de>
  See COPYING file for copying and redistribution conditions.

  This program is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation; version 2 of the License.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.
*/

/*
   This module contains the following operators:

      Monarith  monadd         Add monthly time series
      Monarith  monsub         Subtract monthly time series
      Monarith  monmul         Multiply monthly time series
      Monarith  mondiv         Divide monthly time series
*/

#include <cdi.h>

#include "cdo_int.h"
#include "pstream_int.h"

void *
Monarith(void *process)
{
  int nrecs, nrecs2, nlev;
  int varID, levelID;
  size_t nmiss;
  int yearmon2 = -1;

  cdoInitialize(process);

  cdoOperatorAdd("monadd", func_add, 0, NULL);
  cdoOperatorAdd("monsub", func_sub, 0, NULL);
  cdoOperatorAdd("monmul", func_mul, 0, NULL);
  cdoOperatorAdd("mondiv", func_div, 0, NULL);

  int operatorID = cdoOperatorID();
  int operfunc = cdoOperatorF1(operatorID);

  int streamID1 = cdoStreamOpenRead(cdoStreamName(0));
  int streamID2 = cdoStreamOpenRead(cdoStreamName(1));

  int vlistID1 = cdoStreamInqVlist(streamID1);
  int vlistID2 = cdoStreamInqVlist(streamID2);
  int vlistID3 = vlistDuplicate(vlistID1);

  vlistCompare(vlistID1, vlistID2, CMP_ALL);

  size_t gridsizemax = vlistGridsizeMax(vlistID1);

  Field field1, field2;
  field_init(&field1);
  field_init(&field2);
  field1.ptr = (double *) Malloc(gridsizemax * sizeof(double));
  field2.ptr = (double *) Malloc(gridsizemax * sizeof(double));

  int taxisID1 = vlistInqTaxis(vlistID1);
  int taxisID2 = vlistInqTaxis(vlistID2);
  int taxisID3 = taxisDuplicate(taxisID1);
  vlistDefTaxis(vlistID3, taxisID3);

  int streamID3 = cdoStreamOpenWrite(cdoStreamName(2), cdoFiletype());
  pstreamDefVlist(streamID3, vlistID3);

  int nvars = vlistNvars(vlistID2);

  std::vector<std::vector<double>> vardata2(nvars);
  std::vector<std::vector<size_t>> varnmiss2(nvars);

  for (varID = 0; varID < nvars; varID++)
    {
      size_t gridsize = gridInqSize(vlistInqVarGrid(vlistID2, varID));
      nlev = zaxisInqSize(vlistInqVarZaxis(vlistID2, varID));
      vardata2[varID].resize(nlev * gridsize);
      varnmiss2[varID].resize(nlev);
    }

  int tsID = 0;
  int tsID2 = 0;
  while ((nrecs = cdoStreamInqTimestep(streamID1, tsID)))
    {
      int64_t vdate = taxisInqVdate(taxisID1);
      int yearmon1 = vdate / 100;

      if (yearmon1 != yearmon2)
        {
          int year1 = yearmon1 / 100;
          int mon1 = yearmon1 - (yearmon1 / 100) * 100;

          if (cdoVerbose) cdoPrint("Process: Year = %4d  Month = %2d", year1, mon1);

          nrecs2 = cdoStreamInqTimestep(streamID2, tsID2);
          if (nrecs2 == 0) cdoAbort("Missing year=%4d mon=%2d in %s!", year1, mon1, cdoGetStreamName(1).c_str());

          vdate = taxisInqVdate(taxisID2);
          yearmon2 = vdate / 100;

          if (yearmon1 != yearmon2)
            {
              int year2 = yearmon2 / 100;
              int mon2 = yearmon2 - (yearmon2 / 100) * 100;
              cdoAbort("Timestep %d in %s has wrong date! Current year=%4d mon=%2d, expected year=%4d mon=%2d", tsID2 + 1,
                       cdoGetStreamName(1).c_str(), year2, mon2, year1, mon1);
            }

          for (int recID = 0; recID < nrecs2; recID++)
            {
              pstreamInqRecord(streamID2, &varID, &levelID);

              size_t gridsize = gridInqSize(vlistInqVarGrid(vlistID2, varID));
              size_t offset = gridsize * levelID;

              pstreamReadRecord(streamID2, &vardata2[varID][offset], &nmiss);
              varnmiss2[varID][levelID] = nmiss;
            }

          tsID2++;
        }

      taxisCopyTimestep(taxisID3, taxisID1);
      pstreamDefTimestep(streamID3, tsID);

      for (int recID = 0; recID < nrecs; recID++)
        {
          pstreamInqRecord(streamID1, &varID, &levelID);
          pstreamReadRecord(streamID1, field1.ptr, &nmiss);
          field1.nmiss = nmiss;
          field1.grid = vlistInqVarGrid(vlistID1, varID);
          field1.missval = vlistInqVarMissval(vlistID1, varID);

          size_t gridsize = gridInqSize(vlistInqVarGrid(vlistID2, varID));
          size_t offset = gridsize * levelID;
          arrayCopy(gridsize, &vardata2[varID][offset], field2.ptr);
          field2.nmiss = varnmiss2[varID][levelID];
          field2.grid = vlistInqVarGrid(vlistID2, varID);
          field2.missval = vlistInqVarMissval(vlistID2, varID);

          farfun(&field1, field2, operfunc);

          pstreamDefRecord(streamID3, varID, levelID);
          pstreamWriteRecord(streamID3, field1.ptr, field1.nmiss);
        }

      tsID++;
    }

  pstreamClose(streamID3);
  pstreamClose(streamID2);
  pstreamClose(streamID1);

  if (field1.ptr) Free(field1.ptr);
  if (field2.ptr) Free(field2.ptr);

  cdoFinish();

  return 0;
}
