http://blah/blah/blah.wmv
http://blah/blah/labh.wmv
http://foo/foo/foo%04i 23 40

##</code><code>##

use IO::Socket::INET;
use Data::Dumper;

use strict;
use warnings;

$| ++;

#@done is populated, but not really used in this version
#in the future, might retry failed ones base on done.
my (@page, @done);

open(PAGES, "<", "pages.txt");
while (<PAGES>) {
    chomp;
    my @data = split / /;
	if ($#data == 2) {
		for my $index ($data[1]..$data[2]) {
			push @page, sprintf($data[0], $index);
			push @done, 0;
		}
	} elsif ($#data == 0) {
		push @page, $data[0];
		push @done, 0;
	}
}
close(PAGES);

download(\@page, \@done);

sub download {
	my ($page, $done) = @_;
	for my $index (0..$#{@$page}) {
		$done[$index] = download_one_file($page[$index]);
	}
}

sub download_one_file {
	my ($page) = @_;
	my $host = get_host($page);
	my $file = get_file($page);

	my $percentage;
	my $header = {};
	my $return_code;
	
	print "Trying $host... ";
	my $connection = IO::Socket::INET->new(PeerAddr => $host,
					PeerPort => 80,
					Timeout => 30);
	if ($connection) {
        print "connected, download <$file>\n";
		binmode($connection);
		my $req = "GET $page HTTP/1.0\r\nHost: $host\r\n\r\n";
		print $connection $req;

		my $res;
		if (open(FILE, ">", $file)) {
			binmode(FILE);
			my $bytes_read = 0;
			while (1) {
				my $chunk;
				sysread($connection, $chunk, 4096);
				#stopped, just fail it
				if (!length($chunk)) {
					print " Connection dropped";
					$return_code = 0;
					last;
				}
				if (!exists($header->{"status_code"})) {
					$res .= $chunk;
					if (got_header($res)) {
						$res =~ m/(.*?)\r\n\r\n(.*)/s;
						if ($2) {
							syswrite(FILE, $2);
							$bytes_read += length($2);
						}
						parse_header($1, $header);
						if ($header->{"status_code"} eq '200') {
							$percentage = get_percentage($header->{"Content-Length"}, $bytes_read);
							print "Content Length = " . $header->{"Content-Length"} . ", Received = $percentage";
						} else {
							print "Status Code = " . $header->{"status_code"};
							$return_code = 1;
							last;
						}
					}
				} else {
					syswrite(FILE, $chunk); 
					$bytes_read += length($chunk);
					my $old_percentage = $percentage;
					$percentage = get_percentage($header->{"Content-Length"}, $bytes_read);
					if ($percentage != $old_percentage) {
						print $percentage;
					}
				}
				if ($header->{"Content Length"} && ($header->{"Content-Length"} <= $bytes_read)) {
					print "Read up to content length\n";
					$return_code = 1;
					last;
				}
				if ($res =~ m/\/html/) {
					print "reached /html tag\n";
					$return_code = 1;
					last;
				}
			}
			close(FILE);
			print "\n";
		} else {
			$return_code = 0;
			print "failed to open local file\n";
		}
	} else {
		$return_code = 0;
		print "failed, skip $file\n";
	}
	return $return_code;
}

sub get_host {
	my ($page) = @_;
	$page =~ m/\/\/(.*?)\//;
	return $1;
}

sub get_file {
	my ($page) = @_;
	return (split /\//, $page)[-1];
}

sub get_percentage {
	my ($total, $rcvd) = @_;
	return int(($rcvd / $total) * 10);
}

sub got_header {
	my $res = shift;
	if ($res =~ m/\r\n\r\n/s) {
		return 1;
	} else {
		return 0;
	}
}

sub parse_header {
	my ($res, $header) = @_;
	my @lines = split(/\r\n/, $res);
	$header->{"status_code"} = (split(/ /, $lines[0]))[1];
	for my $index (1 .. $#lines) {
		my ($key, $value) = split(/: /, $lines[$index]);
		$header->{$key} = $value;
	}
}