#!/bin/bash

if [ "$TERM" != "xterm" ]; then
	echo "not tested on '${TERM}' mode"
fi

KEYINDEX=0
KEY=""

# "name" codenum code0 code1 code2 code3 code4 reserved
declare -r _ELMS_=8

oldifs=$IFS
IFS=

KEY_ENTER=( "ENTER"     1 $'\012'  "-" "-" "-" "-" 0 ) #FIXME
KEY_SPC=(   "SPACE"     1 $'\040'  "-" "-" "-" "-" 0 )
KEY_TAB=(   "TAB"       1 $'\011'  "-" "-" "-" "-" 0 )

_SEQ_O=( $'\E' "O" )
_SEQ_P=( $'\E' "[" )

KEY_HOME=( "HOME" 3 ${_SEQ_O[*]} "H" "-" "-" 0 )
KEY_END=(  "END"  3 ${_SEQ_O[*]} "F" "-" "-" 0 )

KEY_UP=(   "UP"    3 ${_SEQ_P[*]} "A" "-" "-" 0 )
KEY_DOWN=( "DOWN"  3 ${_SEQ_P[*]} "B" "-" "-" 0 )
KEY_RIGHT=("RIGHT" 3 ${_SEQ_P[*]} "C" "-" "-" 0 )
KEY_LEFT=( "LEFT"  3 ${_SEQ_P[*]} "D" "-" "-" 0 )

KEY_KHOME=("KP_HOME" 4 ${_SEQ_P[*]} "1" "~" "-" 0 ) # keypad HOME
KEY_INS=(  "INSERT"  4 ${_SEQ_P[*]} "2" "~" "-" 0 )
KEY_DEL=(  "DELETE"  4 ${_SEQ_P[*]} "3" "~" "-" 0 )
KEY_KEND=( "KP_END"  4 ${_SEQ_P[*]} "4" "~" "-" 0 ) # keypad END
KEY_PGUP=( "PGUP"    4 ${_SEQ_P[*]} "5" "~" "-" 0 )
KEY_PGDN=( "PGDN"    4 ${_SEQ_P[*]} "6" "~" "-" 0 )
KEY_CENTER=("CENTER" 3 ${_SEQ_P[*]} "E" "-" "-" 0 ) # keypad CENTER

KEY_FUNC7=( "FUNC7"  5 ${_SEQ_P[*]} "1" "8" "~" 0 )
KEY_FUNC8=( "FUNC8"  5 ${_SEQ_P[*]} "1" "9" "~" 0 )
                                                

KEYS=(
   ${KEY_ENTER[*]}  ${KEY_SPC[*]}  ${KEY_TAB[*]}
   ${KEY_HOME[*]}   ${KEY_END[*]}  ${KEY_UP[*]}    ${KEY_DOWN[*]}
   ${KEY_RIGHT[*]}  ${KEY_LEFT[*]} ${KEY_KHOME[*]} ${KEY_INS[*]}
   ${KEY_DEL[*]}    ${KEY_KEND[*]} ${KEY_PGUP[*]}  ${KEY_PGDN[*]}
   ${KEY_CENTER[*]}
   ${KEY_FUNC7[*]}  ${KEY_FUNC8[*]}
)

NR_KEYS=$(expr ${#KEYS[*]} / $_ELMS_)

IFS=$oldifs

function __check_key_one() {
	local ret=0
	local _i=0
	local _index=0

	[ $KEYINDEX -eq 1 ] && read -s -n 1 || read -s -t 1 -n 1
	if [ $? -ne 0 ]; then
		return 1
	fi

	if [ "$REPLY" == "" ]; then
		KEY="ENTER"
		return 1
	fi

	while ((_i < NR_KEYS))
	do
		((_index = _i * _ELMS_))
		((_i++))
		((_index_codenum = _index + 1))
		((_index_count = _index + 7))
		[ $KEYINDEX -eq 1 ] && let "KEYS[$_index_count] = 0"
		((_index_code = _index + 2 + $KEYINDEX - 1))
		[ $KEYINDEX -gt ${KEYS[$_index_codenum]} ] && continue
		[ $REPLY != ${KEYS[$_index_code]} ] && continue
		let "KEYS[$_index_count] = ${KEYS[$_index_count]} + 1"
		if [ ${KEYS[$_index_count]} -eq ${KEYS[$_index_codenum]} ]; then
			KEY="${KEYS[$_index]}"
			return 1
		fi
	done

	return 0
}

function check_key() {
	KEYINDEX=1
	oldifs=$IFS
	IFS=
	__check_key_one
	while [ $? == 0 ];
	do
		((KEYINDEX++))
		__check_key_one
	done
	IFS=$oldifs
}

KEY=""
check_key
: ${KEY:="unknown"}

echo "$KEY"