use strict;
use threads;
use threads::shared;
use IO::Socket;
use IO::Socket::Socks ':constants';
use IO::Select;

my ($listenaddr, $listenport) = ("localhost", "12593");
my $filename = "proxies.txt";
my $useproxy :shared = 1;
my @proxylist :shared;

sub readlist {
    lock @proxylist;
    open F, "<$filename";
    chomp(@proxylist = <F>);
    close F;
}

&readlist;

threads->create(sub {
    sleep(5);
    \&readlist;
});

my $sc_srv = IO::Socket::Socks->new(ProxyAddr => $listenaddr,
                                    ProxyPort => $listenport,
                                    Listen => 1,
                                    SocksResolve => 1,
                                    SocksVersion => 4);
my $sel_srv = IO::Select->new($sc_srv);
my $ss;

while(1) {
    if ($sel_srv->can_read()) {
        $ss = $sc_srv->accept();
        if (!defined($ss)) {
            next;
        }
        threads->create(\&do_client, $ss);
    }
}

sub do_client {
    my $sc_in = shift;
    my $sc_out;
    my ($command, $remoteaddr, $remoteport, $type) = @{$sc_in->command()};
    my ($proxyaddr, $proxyport);

    if($useproxy) {
        lock @proxylist;
        my $proxystr = shift @proxylist;
        ($proxyaddr, $proxyport) = split(':', $proxystr);
        push @proxylist, $proxystr;
    }

    if ($command != CMD_CONNECT) {
        $sc_in->command_reply(REQUEST_FAILED, $remoteaddr, $remoteport);
        $sc_in->close;
        return;
    }

    print "connecting to $remoteaddr:$remoteport...\n";

    if(!$useproxy) {
        $sc_out = IO::Socket::INET->new(PeerAddr => $remoteaddr,
                                    PeerPort => $remoteport,
                                    Proto => 'tcp');
    }
    else {
        print "using proxy $proxyaddr:$proxyport\n";
        $sc_out = IO::Socket::Socks->new(ProxyAddr => $proxyaddr,
                                    ProxyPort => $proxyport,
                                    ConnectAddr => $remoteaddr,
                                    ConnectPort => $remoteport,
                                    Timeout => 10);
    }

    if(!$sc_out) {
        $sc_in->command_reply(REQUEST_FAILED, $remoteaddr, $remoteport);
        $sc_in->close;
        return;
    }

    $sc_in->command_reply(REQUEST_GRANTED, $remoteaddr, $remoteport);

    print "connected!\n";

    my $data;
    my $size = 2048;
    my $f = 1;

    while($f != 0) {
        my ($sel_in, $sel_out) = (IO::Select->new($sc_in),IO::Select->new($sc_out));

        while($f && $sel_in->can_read(0.01)) {
            $data = '';
            $sc_in->recv($data, $size);
            if(!$data) {
                $f = 0;
            }
            else {
                $sc_out->send($data);
            }
        }

        while($f && $sel_out->can_read(0.01)) {
            $data = '';
            $sc_out->recv($data, $size);
            if(!$data) {
                $f = 0;
            }
            else {
                $sc_in->send($data);
            }
        }
    }

    print "disconnected\n";

    $sc_out->close;
    $sc_in->close;
}