#!/bin/sh
# License : GPLv3

# Variables that change behaviour
SLOP_CURRENT_WINDOW=false
EXIT_ON_RESET=false

# Arg parsing
while [ "$1" ]; do
  case "$1" in
    -h|--help)
      echo "Usage: $0 [current|reset] [<key>=<val> ..]"
      echo " current                  skip window selection (useful for keybinding)"
      echo " reset                    reset zone to draw to fullscreen"
      echo " <key>=<val>              add settings applyable to xsetwacom (val can be empty)"
      echo "Examples :"
      echo " $0 current              # select the rectangle zone to draw" 
      echo " $0 reset mode=relative  # reset the zone to draw and apply mode relative"
      exit 0
    ;;
    debug)
      set -x
      ;;
    current)
      SLOP_CURRENT_WINDOW=true
      ;;
    reset)
      EXIT_ON_RESET=true
      ;;
    *=*)
      OTHER_SETTINGS="${OTHER_SETTINGS} $1"
      ;;
  esac
  shift
done

PENTABLET_LIST="$(xsetwacom --list | sed 's/^.*\sid:\s*//;s/\s*type:.*//')"
PENTABLET_ID=$(echo $PENTABLET_LIST | cut -d' ' -f1)

_xsetwacom(){
  for dev in $PENTABLET_LIST; do 
    xsetwacom set $dev $*
  done
}

#reset and apply other settings
_xsetwacom MapToOutput $(xwininfo -root | sed -n 's/.*geometry//p')
for i in $OTHER_SETTINGS; do
  _xsetwacom $(echo "$i" | tr '=' ' ')
done 
if $EXIT_ON_RESET; then
  exit 0
fi

#get tablet size
_setup_tablet_area_vars() {
  DEFAULT_W=$3
  DEFAULT_H=$4
}
_setup_tablet_area_vars $(xsetwacom get ${PENTABLET_ID} area)

# select the window
if ! $SLOP_CURRENT_WINDOW; then
  xmessage -timeout 2 -default "Setting Screen Area" -buttons "" "Select window with Alt-Tab and click on it" &
  xwininfo 2> /dev/null 1>&2 # only to select the right window
fi

# select the area
xmessage -timeout 2 -default "Setting Screen Area" -buttons "" "Select region" &
_ret=$(slop -f '%w %x %y')
if [ -n "${_ret}" ] ; then 
  # setup the draw rect
  _xsetwacom mode absolute
  _set_draw_rect(){
    _w=$1
    _x=$2
    _y=$3
    _h=$(( _w * DEFAULT_H / DEFAULT_W ))
    _xsetwacom MapToOutput "${_w}x${_h}+${_x}+${_y}"
  }
  _set_draw_rect $_ret
fi