#!/usr/bin/perl -w

# Smackbook for Leopard Spaces
# ============================
# Last modified by Jason Shen
# iamreal2@hotmail.com
# 16 Nov 2007
#
# Based on Brian Jepson's Smaxpose2.command
#   http://www.jepstone.net/blog/2006/05/25/expose-smackbook-pro-style/
# Which is
# Based on Erling Ellingsen's SmackBook Pro scripts:
#   http://blog.medallia.com/2006/05/smacbook_pro.html
# 
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
# 
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.

# USAGE:
#
# Save this script into a file called smackleopard.command, and make 
# it executable with the Terminal command: 
#
#   chmod +x smackleopard.command
#
# Then, run it from the Terminal or double-click it in the Finder.


use strict;
my $switch = 0;
my $prevX = 0;

# Get AMSTracker from Amit Singh's site:
# http://www.osxbook.com/software/sms/amstracker/
# and put AMSTracker in same directory as smackleopard.command
#
open F,"./AMSTracker -s -u0.015 |"; #using a slower update time save CPU cycles
                                    #this is 5% cpu usage on a 2GHz dual core
                                    #but less frequent refreshes cause less predictable
                                    #behavior
while(<F>) {
    my @a = /(-?\d+)/g;
    print, next if @a != 3;

    # we get a signed short written as two unsigned bytes
    $a[0] += 256 if $a[0] < 0;
    my $x = $a[1]*256 + $a[0];

    my $change = abs($prevX) - abs($x); #check for bumb
    
    $prevX = $x; #retain previous X position

    if($switch > 0) { #reset switching capability
	$switch--; 
    } 

    # you can adjust sensitivity here. 30 is a light tap
    # 100 is a generous bump, 10 is remarkable stable but a toddler could switch spaces
     if(abs($change) > 25 && $switch == 0){ #if bump is bigger than desired value then switch
	$switch = 10; #approx time before next switch allowed
	
	# check if it is LEFT or RIGHT tap
	# I use ^ArrowKeys for Leopard Spaces to switch.
	if ($x < 0) {
        	`osascript -e 'tell application \"System Events\" to keystroke (ASCII character 29) using control down'`
	} else {
		`osascript -e 'tell application \"System Events\" to keystroke (ASCII character 28) using control down'`
	}
    }
}