!/usr/bin/perl

use warnings;
use strict;
use Data::Dumper;
use Sys::Syslog;

# Let's get some syslog action goin
openlog('SYNERGY-LOCATION','', 'local0');



# Servers to connect to
my $home_server = "192.168.0.50";
my $work_server = "10.240.220.50";

# SSIDs we care about
my $home_ssid = "HOME_SSID";
my $work_ssid = "WORK_SSID";

# Synergy Options
my $synergy_app = "/Applications/Synergy.app/Contents/MacOS/synergyc";
my $synergy_server_port = "24800";
my $screen_name = "LOCALHOSTNAME";

# Airport Utility
my $airport_app = "/System/Library/PrivateFrameworks/Apple80211.framework/Versions/A/Resources/airport -I";


############
# MAIN
############

my ($synergy_status, $synergy_location) = getSynergyStatus();
#print "Synergy Status: $synergy_status @ $synergy_location\n";

my $current_ssid = getSSID();
#print "Current SSID: $current_ssid\n";


# Are we at work?
if ( $current_ssid =~ /$work_ssid/ )
{
    # Is synergy running?
    if ( $synergy_status )
    {
        # Is synergy running for work?
        if ( $synergy_location =~ /$work_server/ )
        {
            #print "We're good!\n";
            syslog('notice', "SSID:$current_ssid and location $synergy_location, doing nothing...");
        }
        # The assumption is, if it's running but not in the right place, kill
        # the current process and restart it with the right info
        else
        {
            syslog('notice', "restarting synergy:$synergy_status and connecting to $work_server");
            controlSynergy("restart", $work_server, $synergy_status);
        }
        exit;
    }
    else
    {
        syslog('notice', "starting synergy and connecting to $work_server");
        controlSynergy("start", $work_server);
    }
}
# Are we at home?
elsif ( $current_ssid =~ /$home_ssid/ )
{
    # Is synergy running?
    if ( $synergy_status )
    {
        # Is synergy running for home?
        if ( $synergy_location =~ /$home_server/ )
        {
            #print "We're good!\n";
            syslog('notice', "SSID:$current_ssid and location $synergy_location, doing nothing...");
        }
        # The assumption is, if it's running but not in the right place, kill
        # the current process and restart it with the right info
        else
        {
            syslog('notice', "restarting synergy:$synergy_status and connecting to $home_server");
            controlSynergy("restart", $home_server, $synergy_status);
        }
        exit;
    }
    else
    {
        syslog('notice', "starting synergy and connecting to $home_server");
        controlSynergy("start", $home_server);
    }
    
}
# Otherwise don't connect to anything and stop the process
else
{
    syslog('notice', "stopping synergy:$synergy_status");
    controlSynergy("stop");
}

exit;

############
# Subs
############

sub controlSynergy
{
    # We could have 1,2, or 3 arguments to this
    # the controlling operation, start, stop, or restart
    # the ip to use if we're starting or restarting
    # the current PID if we're stopping or restarting
    # if we have a "stop" but no PID
    #print Dumper @_;
    
    my ($command) = grep /(^start$|^stop$|^restart$)/i, @_;
    my ($pid)     = grep /^(\d+)$/, @_;
    my ($host)    = grep /^(\d+\.\d+\.\d+\.\d+)$/, @_;
    
    #print "$command\n" if $command;
    #print "$pid\n" if $pid;
    #print "$host\n" if $host;
    
    if ( $command =~ /^start$/i && defined $host )
    {
        my $cmd = "$synergy_app -n $screen_name" . " " .  $host  . ":" . $synergy_server_port;
        #print "CMD: $cmd\n";
        exec $cmd;
        
    }
    
    if ( $command =~ /^stop$/i && defined $pid )
    {
        my $cmd = "kill -9 $pid";
        #print "CMD: $cmd\n";
        exec $cmd;
    }
    
    if ( $command =~ /^restart$/i && defined $pid && defined $host )
    {
        my $cmd = "kill -9 $pid";
        #print "CMD: $cmd\n";
        system $cmd;
        $cmd = "$synergy_app -n $screen_name" . " " .  $host  . ":" . $synergy_server_port;
        #print "CMD: $cmd\n";
        exec $cmd;
    }
    
}


sub getSynergyStatus
{

    my $synergy_running  = 0;
    my $synergy_location = 0;
    
    # Get a list of all processes
    my @full_proc_list = `ps -e`;
    my @synergy_process_list = grep /synergyc\s/, @full_proc_list;
    #print Dumper @synergy_process_list;
    
    #Did we find synergy in the process list?
    if ( @synergy_process_list )
    {
        # Do a little error checking...sorta
        if ( scalar @synergy_process_list > 1)
        {
            print STDERR "Found multiple process runnning, taking the first\n";
            print STDERR Dumper @synergy_process_list;
        }
        
        # Split the line into parts to find the PID
        my $process_line = shift @synergy_process_list;
        chomp $process_line;
        my @process_line_parts = split /\s+/, $process_line, 5;
        
        # Make sure we have all the parts
        if ( scalar @process_line_parts <5 )
        {
            print STDERR "Couldn't identify all the parts of the process line\n";
            print STDERR Dumper @process_line_parts;
        }
        
        # Get the PID for the synergy job
	my $synergy_pid;
	if ( $process_line_parts[0] =~ /\d+/ ) {
	        $synergy_pid = $process_line_parts[0];
	}
	else {
		$synergy_pid = $process_line_parts[1];
	}
        print "PID = $synergy_pid\n";
        
        # If we have a PID, we can assume its running and that value is > 0, so let's just shove it in here
        $synergy_running = $synergy_pid;
        
        # Get the options to the synergy executed command to determine how/where it's running
        my $synergy_command_line = $process_line_parts[4];
        #print "$synergy_command_line\n";
        
        if ( $synergy_command_line =~ /\s(\S+):24800$/ )
        {
            #print "Synergy running at work\n";
            $synergy_location = $1;
            chomp $synergy_location;
        }
        
    }
    
    # This will return 0 if not running and 0 for the location if it can be found
    return $synergy_running, $synergy_location;

}



sub getSSID
{

    # Let's figure out what SSID we're currently connected to
    my $current_ssid = 0;
    
    # Run the airport tool
    my @airport_output = `$airport_app`;
    
    # Get the SSID line
    my @airport_ssid = grep /^\s+SSID:/, @airport_output;
    
    # This will be false if no SSID is found or Wifi is disabled
    if ( @airport_ssid )
    {
        
        my $ssid_line = shift @airport_ssid;
        my ($blank, $label, $ssid) = split /\s+/, $ssid_line;
        #print "Current SSID: $ssid\n";
        return $ssid;
        
    }
    else
    {
        #print STDERR "No associated SSID found\n";
        return 0;
    }

}