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

  Copyright (C) 2003-2012 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:

      Merstat    mermin          Meridional minimum
      Merstat    mermax          Meridional maximum
      Merstat    mersum          Meridional sum
      Merstat    mermean         Meridional mean
      Merstat    meravg          Meridional average
      Merstat    merstd          Meridional standard deviation
      Merstat    mervar          Meridional variance
      Merstat    merpctl         Meridional percentiles
*/


#include <cdi.h>
#include "cdo.h"
#include "cdo_int.h"
#include "grid.h"
#include "pstream.h"


void *Merstat(void *argument)
{
  int operatorID;
  int operfunc;
  int streamID1, streamID2;
  int vlistID1, vlistID2;
  int gridID1, gridID2 = -1, lastgrid = -1;
  int wstatus = FALSE;
  int code = 0, oldcode = 0;
  int nlonmax;
  int index, ngrids;
  int recID, nrecs;
  int tsID, varID, levelID;
  int lim;
  int ndiffgrids;
  int taxisID1, taxisID2;
  int needWeights = FALSE;
  field_t field1, field2;
  /* RQ */
  int pn = 0;
  /* QR */

  cdoInitialize(argument);

  cdoOperatorAdd("mermin",  func_min,  0, NULL);
  cdoOperatorAdd("mermax",  func_max,  0, NULL);
  cdoOperatorAdd("mersum",  func_sum,  0, NULL);
  cdoOperatorAdd("mermean", func_mean, 0, NULL);
  cdoOperatorAdd("meravg",  func_avg,  0, NULL);
  cdoOperatorAdd("mervar",  func_var,  0, NULL);
  cdoOperatorAdd("merstd",  func_std,  0, NULL);
  /* RQ */
  cdoOperatorAdd("merpctl", func_pctl, 0, NULL);
  /* QR */
 
  operatorID = cdoOperatorID();
  operfunc = cdoOperatorF1(operatorID);

  /* RQ */
  if ( operfunc == func_pctl )
    {
      operatorInputArg("percentile number");
      pn = atoi(operatorArgv()[0]);
      
      if ( pn < 1 || pn > 99 )
        cdoAbort("Illegal argument: percentile number %d is not in the range 1..99!", pn);
    }
  /* QR */

  if ( operfunc == func_mean || operfunc == func_avg ||
       operfunc == func_var  || operfunc == func_std )
    needWeights = TRUE;

  streamID1 = streamOpenRead(cdoStreamName(0));

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

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

  ngrids = vlistNgrids(vlistID1);
  ndiffgrids = 0;
  for ( index = 1; index < ngrids; index++ )
    if ( vlistGrid(vlistID1, 0) != vlistGrid(vlistID1, index))
      ndiffgrids++;

  if ( ndiffgrids > 0 ) cdoAbort("Too many different grids!");

  index = 0;
  gridID1 = vlistGrid(vlistID1, index);

  if ( gridInqType(gridID1) == GRID_LONLAT   ||
       gridInqType(gridID1) == GRID_GAUSSIAN ||
       gridInqType(gridID1) == GRID_GENERIC )
    {
      gridID2 = gridToMeridional(gridID1);
    }
  else
    {
      cdoAbort("Unsupported gridtype: %s", gridNamePtr(gridInqType(gridID1)));
    }

  vlistChangeGridIndex(vlistID2, index, gridID2);

  streamID2 = streamOpenWrite(cdoStreamName(1), cdoFiletype());

  streamDefVlist(streamID2, vlistID2);

  gridID1 = vlistInqVarGrid(vlistID1, 0);
  nlonmax = gridInqXsize(gridID1); /* max nlon ? */

  lim = vlistGridsizeMax(vlistID1);
  field1.ptr    = (double *) malloc(lim*sizeof(double));
  field1.weight = NULL;
  if ( needWeights )
    field1.weight = (double *) malloc(lim*sizeof(double));

  field2.ptr  = (double *) malloc(nlonmax*sizeof(double));
  field2.grid = gridID2;

  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, field1.ptr, &field1.nmiss);

	  field1.grid    = vlistInqVarGrid(vlistID1, varID);
	  if ( needWeights && field1.grid != lastgrid )
	    {
	      lastgrid = field1.grid;
	      wstatus = gridWeights(field1.grid, field1.weight);
	    }
	  code = vlistInqVarCode(vlistID1, varID);
	  if ( wstatus != 0 && tsID == 0 && code != oldcode )
	    cdoWarning("Using constant area weights for code %d!", oldcode=code);

	  field1.missval = vlistInqVarMissval(vlistID1, varID);
	  field2.missval = vlistInqVarMissval(vlistID1, varID);

	  /* RQ */
	  if ( operfunc == func_pctl )
	    merpctl(field1, & field2, pn);
	  else  
	    merfun(field1, &field2, operfunc);
	  /* QR */  

	  streamDefRecord(streamID2, varID,  levelID);
	  streamWriteRecord(streamID2, field2.ptr, field2.nmiss);
	}
      tsID++;
    }

  streamClose(streamID2);
  streamClose(streamID1);

  if ( field1.ptr )    free(field1.ptr);
  if ( field1.weight ) free(field1.weight);
  if ( field2.ptr )    free(field2.ptr);

  cdoFinish();

  return (0);
}
