#!/bin/bash

set -e

# command to run a screen keyboard

KEYBOARD="coolkbd"

# arguments for the screen keyboard

KEYBOARD_ARGS="/dev/input/event1"

# name of an input device to configure (from xinput)

INPUTDEV="Elan Touchscreen"

# name of a transformation matrix property of the device

MATRIX_PROP="Coordinate Transformation Matrix"

# name of a dead edges sizes property of the device

# by this property you can disable keyboard area from taps

# use it if the screen keyboard handle touches by it self directly from a device

# just comment out this if you don't need this feature

EDGE_PROP="Trackpad Edge Sizes"

# height of a dead zone area at the bottom of the screen

# integer value - count of percents of the screen height

KEYAREA=20

function usage() {

    echo ""

    echo "Usage ./rotate.sh [command] ..."

    echo "  available commands:"

    echo "    kbon     - open screen keyboard"

    echo "    kboff    - close screen keyboard"

    echo "    kbtoggle - toggle screen keyboard"

    echo "    normal,left,inverted,right"

    echo "             - comma separated looped sequence of orientations"

    echo "               screen will be turned to the next state relative to current"

    echo "               if only one item is in sequence"

    echo "                   then screen will be turned into it"

    echo "               if current state is not present in the sequence"

    echo "                   then the first sequence item will be chosen"

    echo "  without args script will just configure the input device for the current orientation"

    echo ""

}

# function gets a next item from the looped sequence

# example: next normal,left,inverted,right left

# will be echoed: inverted

function next() {

    local res="$(echo "$1" | tr -s , '\n' | grep -i -x -A 1 "$2" | tail +2)"

    if [ -z "$res" ]; then

        res="$(echo "$1" | tr -s , '\n' | head -1)"

    fi

    echo "$res"

}

# always returns a valid name of the rotation (bad values will replaced with 'normal')

function fix_rotation_name() {

    case "$1" in

    right | inverted | left) echo "$1";;

    *) echo "normal";;

    esac

}

# check if the first arg is a comma separated sequence of valid rotation names

function is_rotation_sequence() {

    local s="$(echo "$1" | tr -s , ' ')"

    local x=

    for x in $s; do

        [ "$x" == "$(fix_rotation_name "$x")" ]

    done

}

# show the current screen rotation

function current_rotation() {

    fix_rotation_name "$(xrandr --screen 0 --current --query | head -2 | tail -1 | cut -d' ' -f5)"

}

# turn screen to chosen rotation

# possible values: normal, left, inverted and right

function rotate_screen() {

    xrandr -o "$1"

}

# keyboard functions

function is_keyboard_run() {

    [ -n "$KEYBOARD" ]

    pidof "$KEYBOARD" > /dev/null

}

function run_keyboard() {

    if ! is_keyboard_run; then

        nohup $KEYBOARD $KEYBOARD_ARGS &> /dev/null &

    fi

}

function stop_keyboard() {

    [ -z "$KEYBOARD" ] || killall -q "$KEYBOARD" || true

}

function toggle_keyboard() {

    [ -n "$KEYBOARD" ] || return

    if is_keyboard_run; then stop_keyboard; else run_keyboard; fi

}

# configure the input device for a specified rotation

function configure_input() {

    local rot="$(current_rotation)"

    local matrix=

    local edges=

    local area=0

    if is_keyboard_run; then area="$KEYAREA"; fi

    echo "configure the input device for orientation: $rot"

    case "$rot" in

    left)

        matrix="0 -1 1 1 0 0 0 0 1"

        edges="0 0 0 $area"

        ;;

    right)

        matrix="0 1 0 -1 0 1 0 0 1"

        edges="0 0 $area 0"

        ;;

    inverted)

        matrix="-1 0 1 0 -1 1 0 0 1"

        edges="$area 0 0 0"

        ;;

    *)

        matrix="1 0 0 0 1 0 0 0 1"

        edges="0 $area 0 0"

        ;;

    esac

    [ -z "$INPUTDEV" ] || [ -z "$MATRIX_PROP" ] || \

        xinput --set-prop "$INPUTDEV" "$MATRIX_PROP" $matrix

    [ -z "$INPUTDEV" ] || [ -z "$EDGE_PROP" ] || [ -z "$KEYAREA" ] || \

        xinput --set-prop "$INPUTDEV" "$EDGE_PROP" $edges

}

# parse arguments

SHOW_USAGE=

CHANGED=

while [ "$#" != "0" ]; do

  IS_CMD=1

  if [ "$1" = "kbon" ]; then

    echo "open screen keyboard"

    run_keyboard

  elif [ "$1" = "kboff" ]; then

    echo "close screen keyboard"

    stop_keyboard

  elif [ "$1" = "kbtoggle" ]; then

    echo "toggle screen keyboard"

    toggle_keyboard

  elif is_rotation_sequence "$1"; then

    ROT="$(current_rotation)"

    ROT="$(next "$1" "$ROT")"

    echo "turn screen to: $ROT"

    rotate_screen "$ROT"

  else

    echo "unknown command: $1"

    IS_CMD=

  fi

  if [ -n "$IS_CMD" ]; then CHANGED=1; else SHOW_USAGE=1; fi

  shift

done

[ -z "$SHOW_USAGE" ] || usage

( [ -n "$SHOW_USAGE" ] && [ -z "$CHANGED" ] ) || configure_input