package Vz::DirTree;
use Data::Dumper;
use strict;
use threads ;
use threads::shared;

my @dirToFetch : shared ; 
my @isFile : shared;
my @isDir : shared;
my @warn : shared;
my $ModuleBusy; 

sub _fetchDir {
	my $root = shift;
	my $dir;
	eval { opendir $dir, $root or die "$! Can't open '$root'" };	
	if ( $@ ) {
		push @warn, $root ;
		return undef;
	}
	
	foreach my $file ( readdir $dir ) {
		next if $file =~/^\.{1,2}/;
		$file = "$root/$file"; 
		if ( -f $file ) {
			push @isFile, $file if -f $file;
		} elsif ( -d $file ) {
			push @isDir, $file;
			push @dirToFetch, $file;
		}
	}
	closedir $dir;	
}

sub setRoot {	
	my $c = shift;
	my $root = shift;
		$root = "./" unless $root;
	my $waitIfBusy = grep { /-WaitIfBusy/ } @_ ? 1 : 0 ;
	
	if ( $ModuleBusy && ! $waitIfBusy ) {
		die __PACKAGE__ . " is busy. Pass -WaitIfBusy as argv if you can wait ";	
	}
	elsif ( $ModuleBusy && $waitIfBusy ) {
		sleep 1 until ! $ModuleBusy
	}
	$ModuleBusy = 1;	
	
	my $self = bless {isDir => [],	isFile => [],	duration => undef}, $c;
	_fetchDir ($root); # first scan from root dir
	
	my $startTime = time;	
	
	my $walker = threads-> create ( sub {
		while ( @dirToFetch ) {
			my $t = scalar(threads->list);
			next if $t > @dirToFetch; 
				# so that threads will not empty @dirToFetch before 
				# other thread finish their result back to @dirToFetch.							
			threads->create ( sub { _fetchDir(shift(@dirToFetch))} ) ;
		}
	});	
	
	while (threads->list) {
		my $t = scalar(threads->list);		
		$self->{MaxThreadHit} = $t if $t > $self->{MaxThreadHit};
		$_ -> join foreach ( threads->list ( threads::joinable ) ) ;
	}
	
	my $endTime = time;
	$self -> {duration} = $endTime - $startTime ;
	@{$self->{isDir}} = @isDir;
	@{$self->{isFile}} = @isFile;
	@{$self->{failOpen}} = @warn;
	
	@isFile = (); @isDir=(); @warn=();	
	$ModuleBusy = 0;
	return $self;
}

1;

package main;
use Data::Dumper;

my $dir = Vz::DirTree->setRoot ( "M:/" ) ;
print Dumper $dir;