#!usr/bin/perl

use strict;
use warnings;

use Tk;

my @directories = ( 'c:/test', 'c:/test/more', 'c:/test/less' );
my ( %object, %files );

my $interval = 5;    #seconds

my $mw = MainWindow->new(
    -relief => 'raised',
    -bd     => 2,
    -title  => "Directory Monitor"
);

$mw->geometry("800x600+4+25");

my $head_frame = $mw->Frame()->pack;

my $main_frame = $mw->Frame()->pack(
    -fill   => 'both',
    -expand => 1,
);

$head_frame->Button(
    -text    => "Salir",
    -command => sub { exit }
)->pack;

setup($_) for @directories;

$mw->repeat( $interval * 1000, sub { monitor(@directories) } );

MainLoop;

sub setup {
    my $dir = shift;
    $object{$dir}{frame} = $main_frame->Frame()->pack(
        -side   => 'left',
        -fill   => 'both',
        -expand => 1,
        -padx   => 2,
    );
    $object{$dir}{message} = $object{$dir}{frame}->Label( -text => ' ' )->pack;
    $object{$dir}{label}   = $object{$dir}{frame}->Label( -text => $dir )->pack;

    $object{$dir}{listbox} = $object{$dir}{frame}->Scrolled(
        'Listbox',
        -scrollbars => 'ose',
        -relief     => 'sunken',
        -height     => 5,
        -setgrid    => 0,
      )->pack(
        -fill   => 'both',
        -expand => 1
      );

    my ( $ok, @files ) = get_file_list($dir);

    if ($ok) {
        $files{$dir}{$_} = ( stat("$dir/$_") )[9],
          $object{$dir}{listbox}->insert( 'end', $_ )
          for @files;
    }
    else {
        $object{$dir}{message}
          ->configure( -text => '*** COULD NOT READ DIRECTORY ***' );
    }
}

sub monitor {
    my @directories = @_;
    for my $dir (@directories) {
        my @differences = file_lists_differ($dir);
        if (@differences) {
            $object{$dir}{message}->configure(
                -text => join "\n",
                @differences
            );
        }
    }
}

sub get_file_list {
    my $directory = shift;
    opendir( DIR, $directory ) or return 0;
    my @files = grep( !/^\.\.?$/, readdir(DIR) );
    closedir(DIR);
    return 1, @files;
}

sub file_lists_differ {
    my $dir = shift;
    my ( %new_files, %old_files, @modified );
    $object{$dir}{message}->configure( -text => ' ' );

    my ( $ok, @files ) = get_file_list($dir);

    if ($ok) {
        $new_files{$_} = ( stat("$dir/$_") )[9] for @files;
        %old_files = %{ $files{$dir} };
        for ( keys %new_files ) {
            if ( defined $old_files{$_} ) {
                if ( $new_files{$_} eq $old_files{$_} ) {
                    delete $old_files{$_};
                    next;
                }
                push @modified, "$_ modified";
                delete $old_files{$_};
            }
            else {
                push @modified, "$_ added";
            }
        }
        for ( keys %old_files ) {
            push @modified, "$_ deleted";
        }
        %{ $files{$dir} } = %new_files;
    }
    else {
        $object{$dir}{message}
          ->configure( -text => '*** COULD NOT READ DIRECTORY ***' );
    }
    my @view = $object{$dir}{listbox}->yview;
    $object{$dir}{listbox}->delete( 0, 'end' );
    $object{$dir}{listbox}->insert( 'end', $_ ) for @files;
    $object{$dir}{listbox}->yviewMoveto( $view[0] );
    return @modified;
}