#!/tools/xgs/perl/5.8.8/bin/perl -w

use strict;
use lib '/home/fisusr/perl-packages/';
use Benchmark;
use Getopt::Long;
use Data::Dumper;
use POSIX ":sys_wait_h";
$| = 1;

my %children;
my $max = 16;
# monitor child processes
$SIG{CHLD} = sub {
					local ($!, $?);
					my $pid = waitpid(-1, WNOHANG);
					return if $pid == -1;
					return unless defined $children{$pid};
					delete $children{$pid};
					unless (kill 0 => $pid) {
						print "Killed child $pid\n";
					}
				};

my $dest = "/scratch/du/sb";
my @dirs;
my @skip;
my $help = 0;
my $limit;

GetOptions( 
			'max=i' => \$max,
			'dest=s' => \$dest,
			'limit=i' => \$limit,
			'dir=s' => \@dirs,
			'skip=s' => \@skip,
			'help' => \$help
			);

usage() if ($help);
if ($max > 16) {
	print "Maximum number of child processes has been set to $max; proceed? ";
	chomp(my $ans = <>);
	unless ($ans =~ /y|yes/i) {
		print "Exiting ...\n";
		exit(1);
	}
}
usage("$dest is not a directory") unless (-d $dest);
usage("-dir is required") unless (@dirs);

foreach my $dir (@dirs) {
	usage("$dir does not exist!") unless (-d $dir);
}

my %dirs = map { $_ => 1 } @dirs;

my %skip = map { $_ => 1 } @skip;
	
multi_dir(\%dirs,\%skip,$limit);

sub multi_dir {
	my ($dirs,$skip,$limit) = @_;
	foreach my $dir (keys %$dirs) {
		if(opendir(my $dh,$dir)) {
			(my $name = $dir) =~ s/\//_/g;
			mkdir "$dest/$name" unless (-e "$dest/$name");
			my @subs = sort grep { !/^\.+/ && -d "$dir/$_" } readdir($dh);
			closedir($dh);
			if ($limit) {
				@subs = @subs[1 .. $limit];
			}
			my $total = @subs;
			print "There are $total directories/files to evaluate ...\n";
			my $count = 0;
			foreach my $sub (@subs) {
				next if (exists $skip->{$sub});
				next if ($sub eq $dir);
				while (keys %children >= $max) {
				
				}
				$count++;
				die "Cannot fork: $!\n" unless defined(my $child_pid = fork());
				if ($child_pid > 0) {
					$children{$child_pid} = 1;
					print "There are currently ", scalar(keys %children), " child processes\n";
					next;
				}
				elsif ($child_pid == 0) {
system("/proj/fisdata/fisusr/sandboxes/sasi/tools/diskusagereports_v201/scripts/find.sh $dir/$sub -type d -o -type f > $dest/$name/$sub.dat");
					# print "/proj/fisdata/fisusr/sandboxes/sasi/tools/diskusagereports_v201/scripts/find.sh $dir/$sub -type d -o -type f > $dest/$name/$sub.dat";
					print "Child [$$] running find.sh on $sub	$count/$total\n";
				}
				exit;
			}
		}
		else {
			warn "Could not read $dir: $!\n";
		}
	}
}