###########################################################################
#
# ParallelInexport.pm -- useful class to support parallel_import.pl
# A component of the Greenstone digital library software
# from the New Zealand Digital Library Project at the 
# University of Waikato, New Zealand.
#
# Copyright (C) 1999 New Zealand Digital Library Project
#
# 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; either version 2 of the License, or
# (at your option) any later version.
#
# 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.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
#
###########################################################################

package ParallelInexport;

use strict;

# Randomize the order of files in the filelist
use List::Util qw( shuffle );

# index the files in parallel using MPI farmer to farm off multiple processes
# [hs, 1 july 2010]
sub farm_out_processes
{
   my ($jobs, $epoch, $importdir, $block_hash, $collection, $site) = @_;

   my $tmp_dir_path = &util::filename_cat($ENV{'GSDLCOLLECTDIR'}, 'tmp');
   if (!-d $tmp_dir_path)
   {
       mkdir($tmp_dir_path, 0777);
   }

   # create the list of files to import
   my $overwrite = 1;
   my $tmp_filelist = &util::filename_cat($tmp_dir_path, "filelist.txt");
   # - if the file is already there (which is should be during testing) then
   #   don't regenerate. This is especially important for imports of 1 million
   #   documents as just the directory scan can take several hours.
   if ($overwrite || !-f $tmp_filelist)
   {
     open (my $filelist, ">$tmp_filelist");
     my @filenames = keys %{$block_hash->{'all_files'}};
     @filenames = shuffle(@filenames);
     foreach my $filename (@filenames)
     {
       my $full_filename = &util::filename_cat($importdir,$filename);
       if ((! exists $block_hash->{'file_blocks'}->{$full_filename}) 
	   && ($filename !~ m/metadata\.xml$/))
       {
         print $filelist "$filename\n";
       }
     }
     close ($filelist); 
   }

   # Determine if we've been provided a mpi.conf file to indicate the other
   # machines (slave nodes) this parallizable process should run on
   my $mpi_conf_path = &util::filename_cat($ENV{'GSDLCOLLECTDIR'}, 'mpi.conf');
   my $mpi_flags = '';
   if (-f $mpi_conf_path)
   {
     print STDERR " ***** CLUSTER MODE *****\n";
     $mpi_flags .= '-machinefile "' . $mpi_conf_path . '" ';
     #$mpi_flags .= '-nolocal ';
   }
   else
   {
     print STDERR " ***** SINGLE COMPUTER MODE *****\n";
   }
   $mpi_flags .= ' --show-progress --timestamp-output --verbose';

   # invoke the farmer to start processing the files
   my $gsdlhome;

   if (defined $site) {
       $gsdlhome = $ENV{'GSDL3HOME'};
   }
   else {
       $site = "";
       $gsdlhome = $ENV{'GSDLHOME'};
   }

#   my $farmer_exe = $gsdlhome . '/ext/parallel-building/linux/bin/mpiimport';
   my $farmer_exe = 'mpiimport';

#   my $mpi_cmd = $gsdlhome . '/ext/parallel-building/linux/bin/mpirun ' . $mpi_flags . ' -n ' . $jobs . ' ' . $farmer_exe . ' ' . $tmp_filelist . ' ' . $epoch . ' ' . $gsdlhome . ' ' . $collection . ' ' . $site;
   my $mpi_cmd = 'mpirun ' . $mpi_flags . ' -n ' . $jobs . ' ' . $farmer_exe . ' ' . $tmp_filelist . ' ' . $epoch . ' ' . $gsdlhome . ' ' . $collection . ' ' . $site;
   print STDERR "MPI Command: \"" . $mpi_cmd . "\"\n";
#   system ($mpi_cmd);
   open(MPI, $mpi_cmd . " |") or die("Couldn't Execute MPI");
   while ( defined( my $line = <MPI> )  )
   {
     chomp($line);
     print "$line\n";
   }
   close(MPI);
}

1;