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

  Copyright (C) 2003-2015 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.
*/

#include <ctype.h>

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


#define  MAX_VARS   6


static
void init_vars(int vlistID, int gridID, int zaxisID, int nvars)
{
  int  code[]  = {11, 17, 33, 34, 1, 2/*, 3*/};
  char *name[]  = {"temp", "depoint", "u", "v", "height", "pressure" /*, "station"*/};
  char *units[] = {"Celsius", "", "m/s", "m/s", "m", "hPa" /*, ""*/};
  int i, varID;

  for ( i = 0; i < nvars; ++i )
    {
      varID = vlistDefVar(vlistID, gridID, zaxisID, TSTEP_INSTANT);
      vlistDefVarCode(vlistID, varID, code[i]);
      vlistDefVarName(vlistID, varID, name[i]);
      vlistDefVarUnits(vlistID, varID, units[i]);
      vlistDefVarDatatype(vlistID, varID, DATATYPE_FLT32);
    }
}

static
void init_data(int vlistID, int nvars, double *data[])
{
  int varID, i, gridsize;
  double missval;

  for ( varID = 0; varID < nvars; ++varID )
    {
      gridsize = gridInqSize(vlistInqVarGrid(vlistID, varID));
      missval  = vlistInqVarMissval(vlistID, varID);
      
      for ( i = 0; i < gridsize; ++i )
	{
	  data[varID][i] = missval;
	}
    } 
}

static
void write_data(int streamID, int vlistID, int nvars, double *data[])
{
  int i;
  int varID;
  int nmiss;
  int gridsize;
  double missval;

  for ( varID = 0; varID < nvars; ++varID )
    {
      gridsize = gridInqSize(vlistInqVarGrid(vlistID, varID));
      missval  = vlistInqVarMissval(vlistID, varID);
      
      streamDefRecord(streamID, varID, 0);

      nmiss = 0;
      for ( i = 0; i < gridsize; ++i )
	if ( DBL_IS_EQUAL(data[varID][i], missval) ) nmiss++;
      
      streamWriteRecord(streamID, data[varID], nmiss);
    }
}

static
int getDate(const char *name)
{
  int date = 0;
  char *pname;

  pname = strchr(name, '_');

  if ( pname ) date = atoi(pname+1);

  return(date);
}

#define  MAX_LINE_LEN  4096

void *Importobs(void *argument)
{
  int operatorID;
  char line[MAX_LINE_LEN];
  int streamID;
  int tsID;
  int gridID, zaxisID, taxisID, vlistID;
  int i, j;
  int nvars = MAX_VARS;
  int vdate = 0, vtime = 0;
  int vdate0 = 0, vtime0 = 0;
  int gridsize, xsize, ysize;
  double *xvals = NULL, *yvals = NULL;
  double *data[MAX_VARS];
  FILE *fp;
  char dummy[32], station[32], datetime[32];
  float lat, lon, height1, pressure, height2, value;
  double latmin = 90, latmax = -90, lonmin = 360, lonmax = -360;
  int code;
  int index;
  double dx, dy;
  char *pstation;

  cdoInitialize(argument);

  cdoOperatorAdd("import_obs",     0, 0, "grid description file or name");

  operatorID = cdoOperatorID();

  operatorInputArg(cdoOperatorEnter(operatorID));  

  gridID = cdoDefineGrid(operatorArgv()[0]);

  if ( gridInqType(gridID) != GRID_LONLAT ) 
    cdoAbort("Unsupported grid type: %s", gridNamePtr(gridInqType(gridID)));

  gridsize = gridInqSize(gridID);
  xsize = gridInqXsize(gridID);
  ysize = gridInqYsize(gridID);

  // printf("gridsize=%d, xsize=%d, ysize=%d\n", gridsize, xsize, ysize);

  xvals = (double*) malloc(gridsize*sizeof(double));
  yvals = (double*) malloc(gridsize*sizeof(double));

  gridInqXvals(gridID, xvals);
  gridInqYvals(gridID, yvals);

  /* Convert lat/lon units if required */
  {
    char units[CDI_MAX_NAME];
    gridInqXunits(gridID, units);
    grid_to_degree(units, gridsize, xvals, "grid center lon");
    gridInqYunits(gridID, units);
    grid_to_degree(units, gridsize, yvals, "grid center lat");
  }

  fp = fopen(cdoStreamName(0)->args, "r");
  if ( fp == NULL ) { perror(cdoStreamName(0)->args); exit(EXIT_FAILURE); }

  vdate = getDate(cdoStreamName(0)->args);
  if ( vdate <= 999999 ) vdate = vdate*100 + 1;

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

  zaxisID = zaxisCreate(ZAXIS_SURFACE, 1);

  taxisID = taxisCreate(TAXIS_ABSOLUTE);

  vlistID = vlistCreate();
  vlistDefTaxis(vlistID, taxisID);

    {
      for ( i = 0; i < nvars; ++i ) data[i] = (double*) malloc(gridsize*sizeof(double));

      init_vars(vlistID, gridID, zaxisID, nvars);

      streamDefVlist(streamID, vlistID);

      vdate0 = 0;
      vtime0 = 0;
      //ntime = 0;
      tsID = 0;
      while ( readline(fp, line, MAX_LINE_LEN) )
	{
	  sscanf(line, "%s %s %s %g %g %g %d %g %g %g", 
		 dummy, station, datetime, &lat, &lon, &height1, &code, &pressure, &height2, &value);
	  sscanf(datetime, "%d_%d", &vdate, &vtime);

	  if ( vdate != vdate0 || vtime != vtime0 )
	    {
	      if ( tsID > 0 ) write_data(streamID, vlistID, nvars, data);

	      vdate0 = vdate;
	      vtime0 = vtime;
	      /*
	      printf("%s %d %d %g %g %g %d %g %g %g\n", 
		     station, vdate, vtime, lat, lon, height1, code, pressure, height2, value);	    
	      */
	      taxisDefVdate(taxisID, vdate);
	      taxisDefVtime(taxisID, vtime);
	      streamDefTimestep(streamID, tsID);
      
	      init_data(vlistID, nvars, data);

	      tsID++;
	    }

	  if ( lon < lonmin ) lonmin = lon;
	  if ( lon > lonmax ) lonmax = lon;
	  if ( lat < latmin ) latmin = lat;
	  if ( lat > latmax ) latmax = lat;

	  dy =  yvals[1] - yvals[0];
	  for ( j = 0; j < ysize; ++j )
	    if ( lat >= (yvals[j]-dy/2) && lat < (yvals[j]+dy/2) )  break;

	  dx =  xvals[1] - xvals[0];
	  if ( lon < (xvals[0] - dx/2) && lon < 0 ) lon+=360;
	  for ( i = 0; i < xsize; ++i )
	    if ( lon >= (xvals[i]-dx/2) && lon < (xvals[i]+dx/2) )  break;
	  
	  index = -1;
	  if ( code == 11 ) index = 0;
	  if ( code == 17 ) index = 1;
	  if ( code == 33 ) index = 2;
	  if ( code == 34 ) index = 3;

	  //printf("%d %d %d %g %g %g %g\n", i, j, index, dx, dy, lon, lat);
	  if ( i < xsize && j < ysize && index >= 0 )
	    {
	      pstation = station;
	      while (isalpha(*pstation)) pstation++;
	      // printf("station %s %d\n", pstation, atoi(pstation));
	      data[index][j*xsize+i] = value;
	      data[    4][j*xsize+i] = height1;
	      data[    5][j*xsize+i] = pressure;
	      // data[    6][j*xsize+i] = atoi(pstation);
	    }

	  /*
	  printf("%s %d %d %g %g %g %d %g %g %g\n", 
		 station, vdate, vtime, lat, lon, height1, code, pressure, height2, value);
	  */
	}

      write_data(streamID, vlistID, nvars, data);

      for ( i = 0; i < nvars; ++i ) free(data[i]);
    }
  printf("lonmin=%g, lonmax=%g, latmin=%g, latmax=%g\n", lonmin, lonmax, latmin, latmax);

  processDefVarNum(vlistNvars(vlistID), streamID);

  streamClose(streamID);

  fclose(fp);

  vlistDestroy(vlistID);
  gridDestroy(gridID);
  zaxisDestroy(zaxisID);
  taxisDestroy(taxisID);

  free(xvals);
  free(yvals);

  cdoFinish();

  return (0);
}
