#! perl.exe

########################################################################################
##
##			Server Service
##
########################################################################################

use Win32;
use Win32::Daemon;	#Manipulate the Win32 Service
use Socket;		#Create and Manipulate Sockets
use IO::Socket;		#Create and Manipulate Sockets
use IO::Select;		#Use for Non-Blocking Sockets

use strict;
use warnings;

########################################################################################
#Service Variables
my ($Result, $PrevState, $State);
#Socket Variables
my ($remote, $port, $sock, @client_list, $sel);
#Misc Variables
my ($VERSION, $logfile, $timeout);
########################################################################################

$VERSION 	= "1.0";
$logfile 		= "c:/Logs/SockSrv.log";
$port 		= 54321;
$timeout 		= 2;

#Open Log File
if (open( LOG, ">>$logfile" ) ) {
	my $TempSelect = select( LOG );
	$| = 1;
	select( $TempSelect );
	print LOG "\n# Date: " . localtime() . "\n================================\n";
}

if( ! Win32::Daemon::StartService()) {
	if( fileno( LOG ) ) {
		&Update_Log("Failed to start this script as a Win32 service.\n");
		&Update_Log("Error: " . GetError());
		close($sock);
        		close( LOG );
	}
    	exit();
}

$PrevState = "SERVICE_STARTING";

while( SERVICE_STOPPED != ( $State = Win32::Daemon::State() ) ) {
	if( SERVICE_START_PENDING == $State ) {
        # Initialization code
		Win32::Daemon::State( SERVICE_RUNNING );

		@client_list = ();
		&Create_Socket();

		&Debug_Log("DEBUG - Service is Running\n");

		$PrevState = SERVICE_RUNNING;
	} elsif( SERVICE_PAUSE_PENDING == $State ) {
        # "Pausing...";
		Win32::Daemon::State( SERVICE_PAUSED );
		&Debug_Log("DEBUG - Service is Paused\n");

		#Clean Up Memory and Sockets
		if ($remote) { close($remote); }
		close($sock);

		&Debug_Log("DEBUG - Socket Closed\n");
        		$PrevState = SERVICE_PAUSED;
		next;
	} elsif( SERVICE_CONTINUE_PENDING == $State ) {
        # "Resuming...";
		Win32::Daemon::State( SERVICE_RUNNING );
		&Debug_Log("DEBUG - Service Continue\n");

		#Setup Socket
		&Create_Socket();

		&Debug_Log("DEBUG - Socket RE-Created\n");
        		$PrevState = SERVICE_RUNNING;
		next;
	} elsif ( SERVICE_STOP_PENDING == $State ) {
        # "Stopping...";
		Win32::Daemon::State( SERVICE_STOPPED );
		$PrevState = SERVICE_STOPPED;

		#Clean Up Memory and Sockets
		if ($remote) { close($remote); }
		close($sock);

		#Backup ExistCalls into ExistCalls File

		&Debug_Log("DEBUG - Socket Closed\n");
		&Update_Log("Service is Stoped\n");
		next;
	} elsif( SERVICE_RUNNING == $State ) {
        # The service is running as normal...
		$PrevState = SERVICE_RUNNING;

		my $read_buffer = 1024;

		while (@client_list = $sel->can_read(1)) {

			foreach $remote(@client_list) {
				if ($remote == $sock) {
					my $new_remote = $sock->accept;
					$sel->add($new_remote) if ($new_remote);
					&Update_Log("Accepted new Client\n");
				} else {
					my $msg = <$remote>;
					chomp($msg);

					#Look at what we received from the Client
					&Update_Log("\nRECEIVED FROM CLIENT - $msg\n");

					$sel->remove($remote) or Debug_Log("Could Not Clean Up the Select:$!\n");
					close($remote);
				}
			}
		}
	} else {
        # We have some unknown state...
        # reset it back to what we last knew the state to be...
		Win32::Daemon::State( $PrevState );
		sleep( $timeout );
	}
}
#Stop the Service
Win32::Daemon::StopService();
if( fileno( LOG ) )
{
	&Update_Log("================================\n");
	&Update_Log("Service Stopped.\n" . localtime());
	close LOG;
}

########################################################################################
##
##		SUB ROUTINES
##
########################################################################################

#Create a Socket to listen on
sub Create_Socket
{
	&Update_Log("Socket Created");

	my $max_length = 1024;
	my $max_clients = 10;

	$sock = IO::Socket::INET->new(
			LocalPort => $port,
			Proto => 'tcp',
			Listen => $max_clients
			) or die &Debug_Log("...Failed\nCould Not Create Socket: $@\n");

	$sel = IO::Select->new($sock);

	&Update_Log(" ... Successful\n");
	&Update_Log("Awaiting messages on: $port\n");
	return(0);
}

#Update Log file
sub Update_Log
{
	if (! $_[0]) { return (0); }

	print LOG "$_[0]";
	return(0);
}