#!/bin/sh
set -e

# based on https://github.com/carrot69/keep-presence/

test -n "$XJIGGLER_DELAY_ACTION" \
	|| XJIGGLER_DELAY_ACTION=300	# seconds
test -n "$XJIGGLER_DELAY_DETECTION" \
	|| XJIGGLER_DELAY_DETECTION=60	# seconds
test -n "$XJIGGLER_MOUSE_DIRECTION" \
	|| XJIGGER_MOUSE_DIRECTION=CIRCULAR # "CIRCULAR" "DIAGONAL"
test -n "$XJIGGLER_MOUSE_DISTANCE" \
	|| XJIGGLER_MOUSE_DISTANCE=1	# pixels

# eval is scary but this use was mentioned in the man page
getmouselocation(){
	eval $(xdotool getmouselocation --shell | sed 's/^/XJIGGLER_/g')
	XJIGGLER_T="$(date '+%s')"
}

jiggle(){
	case "$XJIGGLER_MOUSE_DIRECTION" in
	up)	xdotool mousemove_relative 0 -"$XJIGGLER_MOUSE_DISTANCE"
		return	;;
	right)	xdotool mousemove_relative "$XJIGGLER_MOUSE_DISTANCE" 0
		return	;;
	down)	xdotool mousemove_relative 0 "$XJIGGLER_MOUSE_DISTANCE"
		return	;;
	left)	xdotool mousemove_relative -"$XJIGGLER_MOUSE_DISTANCE" 0
		return	;;
	DIAGONAL)	xdotooltool mousemove_relative
				"$XJIGGLER_MOUSE_DISTANCE"
				"$XJIGGLER_MOUSE_DISTANCE"
		return	;;
	*)
		false	;;
	esac
}

pushmouselocation(){
	XJIGGLER_lastT="$XJIGGLER_T"
	XJIGGLER_lastX="$XJIGGLER_X"
	XJIGGLER_lastY="$XJIGGLER_Y"
}

printdebug(){
	printf "XJIGGLER_T=%s\n" "$XJIGGLER_T"	# seconds since epoch
	printf "XJIGGLER_X=%s\n" "$XJIGGLER_X"	# pixels
	printf "XJIGGLER_Y=%s\n" "$XJIGGLER_Y"	# pixels
	printf "XJIGGLER_lastT=%s\n" "$XJIGGLER_lastT"
	printf "XJIGGLER_lastX=%s\n" "$XJIGGLER_lastX"
	printf "XJIGGLER_lastY=%s\n" "$XJIGGLER_lastY"
}

rotatemousedirection(){
	case "$XJIGGLER_MOUSE_DIRECTION" in
	up)	XJIGGLER_MOUSE_DIRECTION=right;	return; ;;
	right)	XJIGGLER_MOUSE_DIRECTION=down;	return;	;;
	down)	XJIGGLER_MOUSE_DIRECTION=left;	return;	;;
	DIAGONAL)	return;	;;
	*)	XJIGGLER_MOUSE_DIRECTION=up;	return; ;;
	esac
}

usage(){
	printf 'Usage: %s (-ch) (-s [action delay seconds])\n' "$0">&2
	exit 64 # sysexits(3) EX_USAGE
}

while getopts :chs: OPTION
do
	case "$OPTION" in
	c)	XJIGGLER_MOUSE_DIRECTION=circular	;;
	s)	XJIGGLER_DELAY_ACTION="$(OPTARG)"	;;
	*)	usage	;;
	esac
done

getmouselocation; pushmouselocation

while true
do

	sleep "$XJIGGLER_DELAY_DETECTION"
	getmouselocation
	if test "$XJIGGLER_lastX" = "$XJIGGLER_X" \
			&& test "$XJIGGLER_lastY" = "$XJIGGLER_Y"
	then	# no movement
		test "$(printf '%s\n%s\n-\np\n' "$XJIGGLER_T" \
					"$XJIGGLER_lastT" \
				| dc)" -gt "$XJIGGLER_DELAY_ACTION" \
			|| continue	# hasn't been long enough
		rotatemousedirection; jiggle
		printf '%s: Jiggled:\n' "$0"
		printdebug | sed 's/^/\t/g'
	else	# movement
		pushmouselocation
		printf '%s: Movement detected:\n' "$0"
		printdebug | sed 's/^/\t/g'
	fi
done >&2