#!/usr/bin/env perl
# +-======-+ 
#  Copyright (c) 2003-2018 United States Government as represented by 
#  the Admistrator of the National Aeronautics and Space Administration.  
#  All Rights Reserved.
#  
#  THIS OPEN  SOURCE  AGREEMENT  ("AGREEMENT") DEFINES  THE  RIGHTS  OF USE,
#  REPRODUCTION,  DISTRIBUTION,  MODIFICATION AND REDISTRIBUTION OF CERTAIN 
#  COMPUTER SOFTWARE ORIGINALLY RELEASED BY THE UNITED STATES GOVERNMENT AS 
#  REPRESENTED BY THE GOVERNMENT AGENCY LISTED BELOW ("GOVERNMENT AGENCY").  
#  THE UNITED STATES GOVERNMENT, AS REPRESENTED BY GOVERNMENT AGENCY, IS AN 
#  INTENDED  THIRD-PARTY  BENEFICIARY  OF  ALL  SUBSEQUENT DISTRIBUTIONS OR 
#  REDISTRIBUTIONS  OF THE  SUBJECT  SOFTWARE.  ANYONE WHO USES, REPRODUCES, 
#  DISTRIBUTES, MODIFIES  OR REDISTRIBUTES THE SUBJECT SOFTWARE, AS DEFINED 
#  HEREIN, OR ANY PART THEREOF,  IS,  BY THAT ACTION, ACCEPTING IN FULL THE 
#  RESPONSIBILITIES AND OBLIGATIONS CONTAINED IN THIS AGREEMENT.
#  
#  Government Agency: National Aeronautics and Space Administration
#  Government Agency Original Software Designation: GSC-15354-1
#  Government Agency Original Software Title:  GEOS-5 GCM Modeling Software
#  User Registration Requested.  Please Visit http://opensource.gsfc.nasa.gov
#  Government Agency Point of Contact for Original Software:  
#  			Dale Hithon, SRA Assistant, (301) 286-2691
#  
# +-======-+ 

#-----------------------------------------------------------------------------
# !DESCRIPTION:
#
#    Uses L. Takacs utilities to convert ECMWF analysis to GEOS eta grid
#
# !REVISION HISTORY:
#
#  18Feb2014  Todling   Initial code
#
#-----------------------------------------------------------------------------

use Cwd;                 # current directory
use Env;                 # make env vars readily available
use FindBin;             # so we can find where this script resides
use File::Basename;      # for basename(), dirname()
use Shell qw(rm);        # rm commands
use Getopt::Long;        # command line options

# look for perl packages in the following locations
#--------------------------------------------------
use lib ( "$FindBin::Bin", "$SHARE/dasilva/opengrads/Contents", "/discover/nobackup/rtodling/M2Plus/GEOSadas/src/GMAO_Shared/GEOS_Util/plots/grads_util", "$ESMADIR/$ARCH/bin" );

# FVROOT is where the binaries have been installed
# ------------------------------------------------
$fvroot  = dirname($FindBin::Bin);
$fvroot  =~ s|/u/.realmounts/share|/share|;   # for portability across
                                              # NAS machines
# Command line options
# --------------------
GetOptions( "h", "prs", "o=s", "rc=s" );

usage() if $opt_h;

$user = getlogin();

$rc=init();

# get positioned in local directory
my $mydir = getcwd;
chdir("$mydir");

grads_fix();

if (! $rc ) {
   e2g();
}
if (! $rc ) {
   g2p();
}

exit ($rc);

#=======================================================================
## name - init
##=======================================================================
sub init {


  if ( $#ARGV < 1 ) {
       print STDERR "missing nymd, nhms and/or expid; see usage";
       usage();
  } else {              # required command lile args
       $nymd    = $ARGV[0];
       $nhms    = sprintf("%6.6d",$ARGV[1]);
       $yyyy    = substr($nymd,0,4);
       $mm      = substr($nymd,4,2);
       $dd      = substr($nymd,6,2);
       $hh      = substr($nhms,0,2);
       $nymdhhz = "${nymd}_${hh}z";
  }

  if ( $ENV{NCSUFFIX} ) {
     $ncsuffix = $ENV{NCSUFFIX};
  } else {
     $ncsuffix = "nc4";
  }

  if( $opt_rc ) { # rc file required by odsstats
      $rcfile = $opt_rc;
  } else {
     if ( $ENV{FVHOME} ) {
         if ( -e "$FVHOME/run/blendrs.rc" ) {
             $rcfile = "$FVHOME/run/blendrs.rc";
         } else {
           if ( -e "$FVHOME/fcst/blendrs.rc" ) {
             $rcfile = "$FVHOME/fcst/blendrs.rc";
           } else {
             print "Error: User must specify location of blendrs.rc file \n";
             $rc = 1;
             exit ($rc);
           }
         }
     } else {
       print "Error: User must specify location of blendrs.rc file \n";
       $rc = 1;
       exit ($rc);
     }
  }

  if( $opt_o ) { # ouput filename
    $outetafile =  $opt_o;
  } else {
    $outetafile =  "ecmwf.ana.eta.${nymd}_${hh}z.$ncsuffix";
  }
  $outprstag = "ecmwf.inst3_3d_ana_Np"; # this is only the type (tag) for the filename

  $gmaoprs ="";
  if( $opt_gmaoprs ) { # indicate that input is really GMAO prs file
    $gmaoprs = "-gmaoprs";
  }

  # get name of file from ECMWF
  $ecmwf_anal = `$fvroot/bin/echorc.x -template ecmwf $nymd $nhms -rc $rcfile ecmwf_anal_file`;
  chomp($ecmwf_anal);

  # determine resolution to go to from ECMWF to GEOS
  @geos_resol = (`$fvroot/bin/echorc.x -rc $rcfile geos_resolution`);
  chomp($geos_resol); split($geos_resol);
  $im = $geos_resol[0]; chomp($im);
  $jm = $geos_resol[1]; chomp($jm);

  # get positioned in local directory
  my $mydir = getcwd;
  chdir("$mydir");

  do "$fvroot/bin/g5_modules_perl_wrapper";

  $rc = 0;

} # end init

#=======================================================================
sub grads_fix {

  my $myname = "grads_fix";

# Apply grads fix to ECMWF file
  Assignfn("$ecmwf_anal","ecmwf.data");
  $cmd = "$fvroot/bin/ec2grd.csh $fvroot $mydir";
  print "$myname: $cmd \n";
  $rc = system($cmd);

}
#=======================================================================
sub e2g {

  my $myname = "e2g";

# Create ECMWF Gridded data from GDAS Spectral Analysis at specified resolution
# -----------------------------------------------------------------------------
   $cmd = "$fvroot/bin/flat2hdf.x -flat grads.fwrite -ctl ctlinfo -nymd $nymd -nhms $nhms -ndt 21600";
   print "$cmd \n";
   $rc = system($cmd);

   if ($rc) {return};

# Convert ECMWF analysis to GMAO eta coordinate system
# ----------------------------------------------------
   $cmd = "$fvroot/bin/ec_prs2eta.x $gmaoprs -im $im -jm $jm -ecmwf grads.fwrite.$ncsuffix";
   print "$myname: $cmd \n";
   $rc = system($cmd);
   if ( -e   "ec_prs2eta.${nymd}_${hh}z.$ncsuffix" ) {
      rename("ec_prs2eta.${nymd}_${hh}z.$ncsuffix","$outetafile");
   }

   $rc = 0;

   rm("ctlinfo");
   rm("ecmwf.data");
   rm("grads.fwrite");
   rm("grads.fwrite.$ncsuffix");

} # end e2g
#=======================================================================
sub g2p {

  return 0 unless $opt_prs;

  my $myname = "g2p";

  $cmd = "$fvroot/bin/eta2prs.x -eta  $outetafile -levs 1000 925 850 700 500 400 300 250 200 150 100 50 20 10 -ana -noquad -tag  $outprstag";
   print "$myname: $cmd \n";
   $rc = system($cmd);

  $rc = 0;

} # end g2p
#=======================================================================
sub Assignfn {

# Assignfn - assigns fn to given file name fname.
# fname = old file
# fn = new file (links to old)
  my ( $fname, $fn ) = @_;
  unlink($fn) if ( -e $fn ) ;
  symlink("$fname","$fn");

}
#
#=======================================================================
# name - usage
#=======================================================================
sub usage {

   print <<"EOF";

NAME
     ecmwf2geos - Convert ECMWF analysis files to GEOS eta grid
          
SYNOPSIS

     ecmwf2geos [...options...]  nymd nhms
          
DESCRIPTION

     The following parameter are required 

     nymd     Year-month-day, e.g., 19990901  for 01 Sept 1999 
     nhms     Hour-minutes-seconds, e.g., 120000

OPTIONS
 
 -h            prints this usage notice
 
 -o efname     sepecify name of output eta file 
                 (default: ecmwf.ana.eta.%y4%m2%d2_%h2z.nc4)

 -rc RCFILE    full path of RC file for odsstats
                 (default: FVHOME/run/blendrs.rc or FVHOME/fcst/blendrs.rc)

 -prs          convert eta file to and write fname
                 (default: do not convert to pressure)

 -gmaoprs      input file is actually GMAO prs file, not EC (used for testing only)

TO DO 

 1. look for ecmwf-eta file in archive if not found when create the file anew

ENVIRONMENT

   FVHOME      needed to local rc file in case -rc not specified
   NCSUFFIX    specify SDF file type (default: nc4)

EXAMPLE RC FILE

  The following is an example of what this program expects to be in the rc file

ecmwf_anal_file:/discover/nobackup/dao_ops/intermediate/flk/stage/ecmwf/ecmwf.inst3_3d_wxm_Np.%y4%m2%d2_%h2z+%y4%m2%d2_%h2z.nc
ecmwfeta_ana_file: ecmwf.ana.eta.%y4%m2%d2_%h2z.nc4
geos_resolution: 576 361

AUTHOR
      R. Todling (ricardo.todling\@nasa.gov), NASA/GSFC/GMAO
      Based on L. Takacs programs

EOF

  exit(1)

}