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

  Copyright (C) 2003-2008 Uwe Schulzweida, Uwe.Schulzweida@zmaw.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:

      Compc      eqc             Equal constant
      Compc      nec             Not equal constant
      Compc      lec             Less equal constant
      Compc      ltc             Less then constant
      Compc      gec             Greater equal constant
      Compc      gtc             Greater then constant
*/


#include "cdi.h"
#include "cdo.h"
#include "cdo_int.h"
#include "pstream.h"


void *Compc(void *argument)
{
  static char func[] = "Compc";
  int EQC, NEC, LEC, LTC, GEC, GTC;
  int operatorID;
  int streamID1, streamID2;
  int gridsize;
  int nrecs, recID;
  int tsID;
  int varID, levelID;
  int vlistID1, vlistID2;
  int nmiss, nmiss2;
  int i;
  double missval;
  double rc;
  double *array1, *array2;
  int taxisID1, taxisID2;
  int rc_is_missval;

  cdoInitialize(argument);

  EQC = cdoOperatorAdd("eqc", 0, 0, NULL);
  NEC = cdoOperatorAdd("nec", 0, 0, NULL);
  LEC = cdoOperatorAdd("lec", 0, 0, NULL);
  LTC = cdoOperatorAdd("ltc", 0, 0, NULL);
  GEC = cdoOperatorAdd("gec", 0, 0, NULL);
  GTC = cdoOperatorAdd("gtc", 0, 0, NULL);

  operatorID = cdoOperatorID();

  operatorInputArg("constant value");
  rc = atof(operatorArgv()[0]);

  streamID1 = streamOpenRead(cdoStreamName(0));
  if ( streamID1 < 0 ) cdiError(streamID1, "Open failed on %s", cdoStreamName(0));

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

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

  nospec(vlistID1);

  gridsize = vlistGridsizeMax(vlistID1);

  array1 = (double *) malloc(gridsize*sizeof(double));
  array2 = (double *) malloc(gridsize*sizeof(double));

  streamID2 = streamOpenWrite(cdoStreamName(1), cdoFiletype());
  if ( streamID2 < 0 ) cdiError(streamID2, "Open failed on %s", cdoStreamName(1));

  streamDefVlist(streamID2, vlistID2);

  tsID = 0;
  while ( (nrecs = streamInqTimestep(streamID1, tsID)) )
    {
      taxisCopyTimestep(taxisID2, taxisID1);

      streamDefTimestep(streamID2, tsID);

      for ( recID = 0; recID < nrecs; recID++ )
	{
	  streamInqRecord(streamID1, &varID, &levelID);
	  streamReadRecord(streamID1, array1, &nmiss);

	  missval  = vlistInqVarMissval(vlistID1, varID);
	  gridsize = gridInqSize(vlistInqVarGrid(vlistID1, varID));

	  rc_is_missval = DBL_IS_EQUAL(rc, missval);

	  if ( operatorID == EQC )
	    {
	      for ( i = 0; i < gridsize; i++ )
		array2[i] = DBL_IS_EQUAL(array1[i], missval) || rc_is_missval ? missval : DBL_IS_EQUAL(array1[i], rc);
	    }
	  else if ( operatorID == NEC )
	    {
	      for ( i = 0; i < gridsize; i++ )
		array2[i] = DBL_IS_EQUAL(array1[i], missval) || rc_is_missval ? missval : !DBL_IS_EQUAL(array1[i], rc);
	    }
	  else if ( operatorID == LEC )
	    {
	      for ( i = 0; i < gridsize; i++ )
		array2[i] = DBL_IS_EQUAL(array1[i], missval) || rc_is_missval ? missval : array1[i] <= rc;
	    }
	  else if ( operatorID == LTC )
	    {
	      for ( i = 0; i < gridsize; i++ )
		array2[i] = DBL_IS_EQUAL(array1[i], missval) || rc_is_missval ? missval : array1[i] < rc;
	    }
	  else if ( operatorID == GEC )
	    {
	      for ( i = 0; i < gridsize; i++ )
		array2[i] = DBL_IS_EQUAL(array1[i], missval) || rc_is_missval ? missval : array1[i] >= rc;
	    }
	  else if ( operatorID == GTC )
	    {
	      for ( i = 0; i < gridsize; i++ )
		array2[i] = DBL_IS_EQUAL(array1[i], missval) || rc_is_missval ? missval : array1[i] > rc;
	    }
	  else
	    {
	      cdoAbort("Operator not implemented!");
	    }

	  nmiss2 = 0;
	  for ( i = 0; i < gridsize; i++ )
	    if ( DBL_IS_EQUAL(array2[i], missval) ) nmiss2++;

	  streamDefRecord(streamID2, varID, levelID);
	  streamWriteRecord(streamID2, array2, nmiss2);
	}
      tsID++;
    }

  streamClose(streamID2);
  streamClose(streamID1);

  if ( array2 ) free(array2);
  if ( array1 ) free(array1);

  cdoFinish();

  return (0);
}
