#!/usr/bin/perl -w
  
use strict;
use warnings;
use LWP::UserAgent;
use LWP::Simple;
use WWW::Mechanize;
use Digest::MD5    qw( md5_hex );
  
# Coded by Brendan Galvin from June 3rd 2013, to June 5th 2013.
# This product is open-source freeware, and credit to the original source must be given to Brendan Galvin upon re-distribution of the original source or any program, script or application made using the original source.
# http://www.linkedin.com/pub/brendan-galvin/26/267/94b
  
my $flag=0;
print"\n\nURL for mass-downloading (only download links using the <a href> tag, not images or other embedded elements): ";
chomp(my $url = <STDIN>);
print"\nExtensions to download (seperated by comma's): ";
chomp(my $extensions = <STDIN>);
$extensions =~ s/[.]//g;
print"\nLocation to store downloaded files: ";
chomp(my $location = <STDIN>);
  
print"\nHow many downloads would you like to skip starting from the first (in case you started this download earlier and have already downloaded some of the files)? ";
chomp(my $skips = <STDIN>);
  
print"\nAre you going to want to skip any files while the program is running (y/n)?";
chomp(my $skiporno = <STDIN>);
my $error = "";
  
my @extension = split(',', $extensions);
my %extens = map{$_ => 1} @extension;
  
sub GetFileSize{
        my $url=shift;
        my $ua = new LWP::UserAgent;
        $ua->agent("Mozilla/5.0");
        my $req = new HTTP::Request 'HEAD' => $url;
        $req->header('Accept' => 'text/html');
        my $res = $ua->request($req);
        if ($res->is_success) {
                 my $headers = $res->headers;
                 return $headers;
        }else{
        $flag = 1;
        $error .= "Error retrieving file information at $url ";
    }
return 0;
}
  
  
my $mech = WWW::Mechanize->new();
$mech->get($url);
my $base = $mech->base;
  
my @links = $mech->links();
  
  
for my $link ( @links ) {
    my $skip = 'n';
    if($link->url() =~ m/([^.]+)$/){
        my $ext = ($link->url() =~ m/([^.]+)$/)[0];
  
  
        if(exists($extens{$ext})){
            my $newurl = $link->url();
            if($newurl !~ /http::\/\/$/ig){
                my $baseurl = URI->new_abs($newurl, $base);
                $newurl = $baseurl;
            }
            my $filename = $newurl;
            $filename =~ m/.*\/(.*)$/;
            $filename = $1;
            if($skips > 0){
                $skips -= 1;
                print "\n\nSkipped $filename at " . $link->url();
                next;
            }else{
                my $header = GetFileSize($newurl);
                my $urlmech = WWW::Mechanize->new();
                $urlmech->show_progress("true");
                print"\n\n\n$filename at $newurl\n";
                print "File size: ".$header->content_length." bytes\n" unless $flag==1;
                print "Last modified: ".localtime($header->last_modified)."\n" unless $flag==1;
                if($skiporno eq 'y'){
                    print"Skip file (y/n)?";
                    chomp($skip = <STDIN>);
                }
                if($skip ne 'y'){
                    print " downloading...\n";
                    my $response = $urlmech->get($newurl, ':content_file' => "$filename", )->decoded_content;
                      
                }else{
                    print"\nSkipping...\n\n";
                    next or print"Error skipping.\n";
                }
            }
        }
    }
}
print"\n\n\nTasks completed.\n";
if($error ne ""){
    print"\nErrors: $error";
}else{
    print"No errors.\n";
}