#!/bin/sh

default_output=LVDS1

usage() {
	echo "Usage:
	rotate (left|right|invert) [output]
	rotate set (normal|right|inverted|left) [output]
Examples:
	rotate left LVDS1
	rotate set right HDMI2

Only the first letter of each command is checked (case-insensitive), so they
can be abbreviated or even cut to one letter each in lower or upper case.

For example, the following commands do the same thing:
	rotate set left
	rotate SET LeFt
	rotate s l
	rotate salad lasagna"
}

rot_to_num() {
	case $1 in
		# normal right invert left
		# convert to numbers to allow math to rotate
		[nN]*) rot0=0;;
		[rR]*) rot0=1;;
		[iI]*) rot0=2;;
		[lL]*) rot0=3;;
		*)     usage; exit 2;;
	esac
}
num_to_rot() {
	case $1 in
		# maps to rot_to_num output
		0) rot1=normal
		   rot2=none;;
		1) rot1=right
		   rot2=cw;;
		2) rot1=inverted
		   rot2=half;;
		3) rot1=left
		   rot2=ccw;;
	esac
}

case $1 in
	[sS]*)
		# set: rotate set (normal|right|inverted|left) [output]
		output=${3:-$default_output}
		rot_to_num $2
		;;
	*)
		# rotate (left|right|invert) [output]
		output=${2:-$default_output}
		rot_to_num `xrandr --query --verbose | grep $output | awk '{print $5}'`
		case $1 in
			[lL]*) rot0=$(($rot0 - 1));;
			[rR]*) rot0=$(($rot0 + 1));;
			[iI]*) rot0=$(($rot0 + 2));;
			*)    usage; exit 1;;
		esac
		;;
esac

# add 4 modulo 4 to prevent negatives and overflows
num_to_rot $((($rot0 + 4) % 4))

xrandr --output $output --rotation $rot1
# x220t
if command -v xsetwacom >/dev/null 2>&1; then
	xsetwacom --set stylus Rotate $rot2
	xsetwacom --set eraser Rotate $rot2
	xsetwacom --set touch  Rotate $rot2
fi

# reload bg
~/bin/wall