#!/bin/bash
# Author: Stefan Kuhn <woudan@pentoo.ch>
#
# toggles touchpads on/off
# Supported are both Synaptics and Elantech touchpads

# error handling
exiterror() {
	if [ "$1" == "" ]; then
		echo "Error: Something went wrong!"
	else
		echo "$1"
	fi
	exit 1
}

# xinput: extract the device id for the supplied touch device name
xi_getTouchDeviceId() {
	xinput list | sed -nr "s|.*$1.*id=([0-9]+).*|\1|p"
}

# xinput: toggle touchpad on/off
xi_toggletouchpad() {
	# Get the xinput device number and enabling property for the touchpad
	local xinputnum=$(getTouchDeviceId "SynPS/2 Synaptics TouchPad")
	local enableprop="Synaptics Off"
	if [ -z "$xinputnum" ]; then
		xinputnum=$(getTouchDeviceId "PS/2 Elantech Touchpad")
		enableprop="Device Enabled"
	fi

	# if we failed to get an input, exit
	[ -z "$xinputnum" ] && exiterror

	# get the current state of the touchpad
	local tpstatus=$(xinput list-props $xinputnum | awk "/$enableprop/ { print \$NF }")

	# if getting the status failed, exit
	[ -z "$tpstatus" ] && exiterror

	if [ $tpstatus = 0 ]; then
		xinput set-prop $xinputnum "$enableprop" 1
	else
		xinput set-prop $xinputnum "$enableprop" 0
	fi
}

# synclient: toggle touchpad on/off
sc_toggletouchpad() {
	# get the status
	local tpstatus=$(synclient | grep TouchpadOff | sed 's/^\s*TouchpadOff\s*=\s*//')

	# if getting the status failed, exit
	[ -z "$tpstatus" ] && exiterror

	if [ $tpstatus = 0 ]; then
		synclient TouchpadOff=1
	else
		synclient TouchpadOff=0
	fi	
}

# sanity check
if [ -x /usr/bin/synclient ]; then
	sc_toggletouchpad
elif [ -x /usr/bin/xinput ]; then
	xi_toggletouchpad
else 
	exiterror "Error: /usr/bin/synclient and /usr/bin/xinput not found.\nOne of them must be installed!"
fi