#!/usr/local/bin/perl

use IO::Socket;
use Time::localtime;

$port = 7654;
$maxspoj = SOMAXCONN;

sub calc {
	$oper = shift;
	$op1 = shift;
	$op2 = shift;

	if ($oper eq "+") {
		$vysl = $op1 + $op2;
	} elsif ($oper eq "-") {
		$vysl = $op1 - $op2;
	} elsif ($oper eq "*") {
		$vysl = $op1 * $op2;
	} elsif ($oper eq "/") {
		$vysl = $op1 / $op2;
	} else {
		$vysl = "ERR";
	}
	return $vysl;
}
	

$server = IO::Socket::INET->new(Proto=>"tcp", LocalPort=>$port, Listen=>$maxspoj, Reuse=>1)
	or die "Nelze vytvorit server.\n\n";

print "SER: [",ctime,"] Inicializace. Port: $port. Max. spojeni: $maxspoj\n";
binmode(STDOUT);

while ($klient = $server->accept) {
	print "SER: [",ctime,"] Socket klienta vytvoren.\n";
	$klient->autoflush(1);
	# ocekava se pozadavek ve forme "CALC klientID x[+-*/]y"
	@poz = split(' ',<$klient>);
	$prefix = $poz[0];
	$klID = $poz[1];
	$vyraz = $poz[2];

	# platny prefix? reaguj jen na CALC!
	if ($prefix eq "CALC" &&
	    $vyraz !~ /^$/) {
		$vyraz =~ /(.+)([\+\-\*\/])(.+)/;
		$op1 = $1;
		$oper = $2;
		$op2 = $3;
		print "SER: [",ctime," Klient $klID] Pozadavek: $op1 $oper $op2\n";

		sleep(5);
		$vysl = calc($oper,$op1,$op2);
		print "SER: [",ctime," Klient $klID] Vysledek: $vysl. Odesilam klientovi.\n";
		print $klient "RSLT $vysl\n";
	} else {
		# Spatny pozadavek	
		print "SER: [",ctime," Klient $klID] Zaslan spatny pozadavek. Odesilam chybovou zpravu.\n";
		print $klient "RSLT ERR\n";
	}
	print "SER: [",ctime," Klient $klID] Zaviram socket klienta.\n";
	close $klient;
}

print "SER: [",ctime," Klient $klID] Konec\n\n\n";
close $server;