#!/usr/bin/perl -w

use HTTP::Daemon;
use HTTP::Status;
use HTTP::Response;
use IPC::Open2;
use LWP::UserAgent;

my $PORT = 8081;
if (@ARGV) { $PORT = shift; }

=comment

sub clean_child {
	wait;
	$SIG{'CHLD'} = \&clean_child;
}
$SIG{'CHLD'} = \&clean_child;

=cut

my $LOCAL = 'http://(nemesis|aisa)';
my $REMOTE = 'https://is.muni.cz/';

my $daemon = new HTTP::Daemon LocalPort => $PORT, Reuse => 1,
	Listen => 20;
if (not defined $daemon) { die "Cannot bind to $PORT: $@\n"; }

my $agent = new LWP::UserAgent;

my $myurl = $daemon->url;
warn "My URL is $myurl\n";

while (my $connection = $daemon->accept) {
	my $child = fork();
	unless (defined $child) { die "Fork failed: $!\n"; }
	if ($child) {
		# Rodič -- nic na práci, půjdeme zase poslouchat
		warn "Parent: forked child $child, fine. Will go to another accept.\n";
		### $connection->close;
		next;
		}
	$connection->autoflush;
	my $num_req = 1;
	# Potomek postupně přebírá požadavky (ovšem se s klientem
	# nedomluví na keep-alive spojení, bude proveden stejně jen jeden)
	while (my $request = $connection->get_request) {
                my $uri = $request->uri;
                $uri =~ s!^$LOCAL(\.[^:/]+)*(:\d+)*/!$REMOTE/!;
                print $request->uri, "\n";
                $request->uri($uri);

                my $response = $agent->request($request);
                if ($response->is_success) {
                        my $body = $response->content;
                        $body =~ s!$REMOTE!$myurl!gso;
                        $response->content($body);
                        }
		else {
			warn $response->error_as_HTML;
			}
                $connection->send_response($response);
		}
	continue {
		warn "Child $$: finished response, going back to wait.\n";
		}
	warn "Child $$: no more requests, exitting.\n";
##	$connection->close;
##	undef $connection;
	exit 0;
	}
undef $daemon;