#!/usr/bin/perl
use Getopt::Long;
#
&GetOptions(
   "tgcmroot:s"   => \$tgcmroot,
   "h|help"       => \$help
) or usage();
if ($help) { usage(); } # provide usage if help was requested
#
# Order of precedence for determining tgcmroot is: 
#   1: Option to this program (-tgcmroot)
#   2: Environment variable $TGCMROOT
#   3: The default directory on hao or scd systems.
#  
$tgcmroot_default_hao = "/home/tgcm";
$tgcmroot_default_scd = "/fis/hao/tgcm";
if (! defined $tgcmroot or $tgcmroot eq "") {
  if (defined $ENV{TGCMROOT}) { $tgcmroot = $ENV{TGCMROOT}; 
    print "\n$0: Using tgcmroot from TGCMROOT env var: $tgcmroot\n";
  } elsif (-d $tgcmroot_default_hao) { $tgcmroot = $tgcmroot_default_hao;
    print "\n$0: Using default tgcmroot at HAO: $tgcmroot\n";
  } elsif (-d $tgcmroot_default_scd) { $tgcmroot = $tgcmroot_default_scd;
    print "\n$0: Using default tgcmroot at SCD: $tgcmroot\n"; 
  } else { 
    die "\n>>> $0: Could not determine tgcmroot (please use -tgcmroot option)\n\n";
  }
}
valid_models($tgcmroot);
exit;
#-------------------------------------------------------------------------
sub usage {
  die <<EOF;

$0 lists valid model directories under \$tgcmroot

SYNOPSIS
  $0 [options]

OPTIONS
  -tgcmroot  	TGCM root distribution.
                If tgcmroot is not provided, program will use env var 
                TGCMROOT. If env var is not set, program will use default 
                HAO or SCD tgcmroot directories. 

  -help		Print usage message and quit.

EOF
}
#-----------------------------------------------------------------------
sub validate_model {
#
# Return 1 if $tgcmroot/$model is valid, return 0 otherwise.
# A model is valid if the directory $tgcmroot/$model exists and
#   contains both src/ and scripts/ subdirectories.
#
  my ($tgcmroot,$model) = @_;
  if (-d "$tgcmroot/$model/src" and -d "$tgcmroot/$model/scripts") { 
    return 1;
  } 
  return 0;
}
#-----------------------------------------------------------------------
sub valid_models {
use Cwd;
#
# List valid models found in $tgcmroot (uses sub validate_model above):
#
  my ($tgcmroot) = @_;
  my $mycwd = cwd();
  if (! -d $tgcmroot) {
    die "\n$0: >>> Tgcmroot $tgcmroot does not exist as a directory.\n";
  }
  chdir($tgcmroot) || 
    die "\n$0: >>> Could not chdir to tgcmroot $tgcmroot\n";
  @list = `/bin/ls` ; chomp @list;
  foreach $file (@list) { 
    if (validate_model($tgcmroot,$file)) { push(@valid,$file); }
  }
  if (@valid) {
    print "\nList of valid model directories under tgcmroot $tgcmroot:\n";
    print "@valid\n\n";
  } else {
    print ">>> Could not find any valid model directories under tgcmroot $tgcmroot\n";
  }
  chdir($mycwd);
  return @valid;
}