#! /usr/bin/perl -w

use threads;
use threads::shared;
use IO::Socket;
use Device::SerialPort;
use DateTime;

$| = 1;

my $listen = IO::Socket::INET->new(
		ReuseAddr => 1,
		Reuse    => 1,
		Listen => SOMAXCONN,
		Proto     => 'tcp',
		LocalAddr => 'localhost:9927',
		Timeout => 1
	) or die "Failed to create socket!\n";

our $usb_lock : shared;

our $arduino = undef;

sub getArduinoConnection {
	#my $oldport = shift;
	#$arduino->close() if defined;
	my $arduino = Device::SerialPort->new("/dev/serial/by-id/usb-Arduino__www.arduino.cc__Arduino_Mega_2560_74136333033351011152-if00");
	if ( defined( $arduino ) ) {
		$arduino->baudrate(9600);
		$arduino->parity("none");
		$arduino->databits(8);
		$arduino->stopbits(1);

		$arduino->read_char_time(0);
		$arduino->read_const_time(500);
		$arduino->write_settings || undef $arduino;
		writelog( "server:[portSet]" );
	} else {
		writelog( "server:[portSet]: failed" );
	}
	return $arduino;
}

....
	
sub handle_connection {
	#sleep( 1 );
    my $socket = shift;
	my $local_arduino = shift;
	my $clientport = $socket->peerport();
	$socket->autoflush(1);
    while ( my $cmd = <$socket> ) {
		# get full command or die
		my $count = 0;
		while ( !cmd_complete($cmd) ) {
			$cmd .= <$socket>;
			$count++;
			if ( $count > 20 ) { 
				writelog( "server:" . $clientport . "[cmdInc]: no cmd end" );
				return 0;
			}
		}
		chomp($cmd);
		writelog( "server:" . $clientport . "[cmdInc]: " . decode_cmd( $cmd ) );
		{
			# send command to arduino
			lock( $usb_lock );
			writelog( "server:" . $clientport . "[lockusb]" );
			$local_arduino->write($cmd);
			
			# get arduinos answer
			my $answer = ".";
			while ( $answer ne "" ) {
				$answer = getLineFromArduino();
				writelog( "server:" . $clientport . "[cmdAnswer]: $answer" );
				#print $socket "$answer\n";
				if ( $answer eq "Command end" ) {
					last;
				}
			}
			# respond to client
			if ( $answer eq "Command end" ) {
				writelog( "server:" . $clientport . "[sendToClient]: \"ok\"" );
				print $socket "ok\n";
			} else {
				writelog( "server:" . $clientport . "[sendToClient]: \"fail\"" );
				print $socket "fail\n";
			}
			writelog( "server:" . $clientport . "[unlockusb]" );
		}
		return 1;
    }
}

my $last_validation = -10; #in the past
#main loop
while ( 1 ) {
	foreach $thr (threads->list) { 
		# Don't join the main thread or ourselves 
		#print $thr->tid;
		if ($thr->tid && $thr->is_joinable() ) { #&& !threads::equal($thr, threads->self)
			#$thr->join; 
		} 
	}
	# validate arduino every 10 seconds
	# sleep if arduino not alive
	if ( time > ( $last_validation + 30 ) ) {
		lock( $usb_lock );
		$last_validation = time;
		$arduino = validateArduinoConnection( $arduino );
		until ( defined( $arduino ) ) {
			$arduino = validateArduinoConnection( $arduino );
			sleep( 1 );
		}
		clearUSBdata();
	}
	if (my $socket = $listen->accept) {
		#async(\&handle_connection, $socket);
		threads->create(\&handle_connection, $socket, $arduino );
	}
}