function sf_print { builtin printf '%s' "$*"; }

function sf_println { builtin printf '%s\n' "$*"; }

function sf_print2 { sf_print "$@" >&2; }

function sf_println2 { sf_println "$@" >&2; }

function sf_error_unknown_option { sf_println2 "Error: Unknown option -${OPTARG}"; }

function sf_error_missing_argument { sf_println2 "Error: Option -${OPTARG} requires an argument"; }

function sf_fields
{
	local skip=0 delimiter=" " input_delimiter="$IFS"
	local OPTIND=1 OPTARG OPTERR opt
	while getopts ":s:d:D:" opt; do
		case "$opt" in
			s)
				skip=$OPTARG
				if ! sf_integer -v -- "$skip"; then
					return 1
				fi
			;;
			D) delimiter=$OPTARG ;;
			d) input_delimiter=$OPTARG ;;
			[?])
				sf_error_unknown_option
				return 1
			;;
			:)
				sf_error_missing_argument
				return 1
			;;
		esac
	done
	shift $((OPTIND-1))
	if [[ "${1:-}" = "--" ]]; then shift; fi

	local f_min=() f_max=()
	local opt
	for opt; do
		if [[ "$opt" =~ ^-?[0-9]+$ ]]; then
			f_min+=( $((opt-1)) )
			f_max+=( $((opt-1)) )
		elif [[ "$opt" =~ ^[[:digit:]]+-$ ]]; then
			opt=${opt%"-"}
			f_min+=( $((opt-1)) )
			f_max+=( "" )
		elif [[ "$opt" =~ ^[[:digit:]]+-[[:digit:]]+$ ]]; then
			local lower=${opt%%-*}
			f_min+=( $((lower-1)) )
			local upper=${opt##*-}
			f_max+=( $((upper-1)) )
		else
			sf_println2 "Error: ${FUNCNAME}: Invalid field specification: $opt"
			return 1
		fi
	done

	while (( skip-- > 0 )); do
		read -r
	done

	local fields=()
	while IFS="$input_delimiter" read -ra fields; do
		local cnt="${#fields[@]}"
		local i=0
		for ((; i<$#; i++)); do
			local j=${f_min[i]}
			local k=${f_max[i]:-$((cnt-1))}
			for ((; j<=k; j++)); do
				if (( j < cnt )) && (( j >= -cnt )); then
					sf_print "${fields[j]}"
				fi
				if (( i+1 < $# )) || (( j+1 <= k )); then
					sf_print "$delimiter"
				fi
			done
		done
		sf_println
	done
}

function sf_integer { sf_number -i "$@"; }

function sf_number
{
	local decimal=true
	local negative=false
	local complain=false
	local OPTIND=1 OPTARG OPTERR opt
	while getopts ":cC:de:int:vq" opt; do
		case "$opt" in
			i) decimal=false ;;
			n) negative=true ;;
			v) complain=true ;;
			[?])
				sf_error_unknown_option
				return 1
			;;
			:)
				sf_error_missing_argument
				return 1
			;;
			*) sf_println2 "Warning: Deprecated option passed to ${FUNCNAME}: $opt" ;;
		esac
	done
	shift $((OPTIND-1))
	if [[ "${1:-}" = "--" ]]; then shift; fi
	
	local regex=""
	if $negative; then
		regex='-?'
	fi
	if $decimal; then
		regex='^('"$regex"'[[:digit:]]+(\.[[:digit:]]*)?|'"$regex"'\.[[:digit:]]+)$'
	else
		regex='^'"$regex"'[[:digit:]]+$'
	fi
	if [[ "$*" =~ $regex ]]; then
		return 0
	fi
	if $complain; then
		local error
		case "${FUNCNAME[1]}" in
			sf_integer) printf '`%s` is not a valid integer!\n' "$*" >&2 ;;
			sf_decimal) printf '`%s` is not a valid decimal!\n' "$*" >&2 ;;
			*) printf '`%s` is not a valid number!\n' "$*" >&2 ;;
		esac
	fi
	return 1
}

function sf_killtree
{
	local pids ppid=$1 sig=${2:-"TERM"}
	if ! kill -0 "$ppid"; then
		sf_println2 "killtree: ($ppid) - No such process"
		return 1
	fi
	(( ppid == $$ )) || kill -STOP "$ppid" 2>/dev/null || :
	mapfile -t pids < <( { pgrep -P "$ppid" || ps -o pid= --ppid "$ppid" || :; } 2>/dev/null )
	if [[ -n "${pids[*]:-}" ]]; then
		for pid in "${pids[@]}"; do
			sf_killtree "$pid" "$sig" 2>/dev/null || :
		done
	fi
	kill "-${sig}" "$ppid" 2>/dev/null || :
	(( ppid == $$ )) || kill -CONT "$ppid" 2>/dev/null || :
	wait "$ppid" 2>/dev/null || :
}

function sf_killchildren
{
	local _term
	_term=$(builtin trap -p TERM)
	builtin trap : TERM
	sf_killtree $$ TERM;
	builtin trap - TERM
	builtin eval "$_term"
}

function sf_printable
{
	if (( $# )); then
		printf '%s' "$*" | sf_printable
	else
		sed -e 's/[^[:print:]]//g'
	fi
}

function sf_crlf
{
	if (( $# )); then
		sf_crlf <<<"$@"
		return $?
	fi
	perl -e '
		$| = 1;
		while ((my $c = getc) ne undef)
		{
			if ("$c" eq "\r") { next; }
			if ("$c" eq "\n") { print "\r\n"; next; }
			print "$c";
		}
	'
}

function sf_tn_init
{
	_sf_tn_mode=${1:-"default"}

	local cmd
	for cmd in iconv perl pv stdbuf xxd; do
		if ! type "$cmd" >/dev/null 2>&1; then
			sf_println2 "Error: ${FUNCNAME}: Required command not found: \`${cmd}\`"
			return 1
		fi
	done

	exec {_sf_tn_raw_fd}>&1
	exec > >( { sf_crlf; } 2>/dev/null )

	# shellcheck disable=SC2059
	function printf { { builtin printf "$@"; } 2>/dev/null; }
	function echo { { builtin echo "$@"; } 2>/dev/null; }
	function println { { builtin printf '%s\r\n' "$*" >&"${_sf_tn_raw_fd}"; } 2>/dev/null; }
	function tn_raw { { builtin printf '%s' "$*" >&"${_sf_tn_raw_fd}"; } 2>/dev/null; }
	function read { { builtin read -r "$@"; } 2>/dev/null; }
	function cat { { command cat "$@"; } 2>/dev/null; }
	function pv { { command pv "$@"; } 2>/dev/null; }
	function xxd { { command xxd "$@"; } 2>/dev/null; }

	function _sf_tn_autostar
	{
		local _text="$*"
		if $__password; then
			_text=$(_sf_tn_iconv "$_text" | sed -e 's/./*/g')
		fi
		tn_raw "$_text"
	}

	function _sf_tn_iconv
	{
		{
			if (( $# )); then
				printf '%s' "$*"
			else
				cat
			fi
		} | {
			if $_sf_tn_client_linux; then
				iconv -c -f "UTF8" || :
			else
				iconv -c -f "CP850" || : # IBM850
			fi
		} 2>/dev/null
	}

	trap : PIPE

	case "$_sf_tn_mode" in
		echo)
			tn_raw $'\xff\xfb\x01' # will echo
			tn_raw $'\xff\xfb\x03' # will suppress go-ahead
			tn_raw $'\xff\xfd\x18' # do termtype
			_sf_tn_echo=true
			_sf_tn_raw=false
		;;
		raw)
			_sf_tn_echo=false
			_sf_tn_raw=true
		;;
		*)
			_sf_tn_echo=false
			_sf_tn_raw=false
		;;
	esac

	# hacks
	_sf_tn_first_read=true
	_sf_tn_skip_newline=false

	# sub negotiation
	_sf_tn_subnegotiate=""
	_sf_tn_sub_data=""
	_sf_tn_client_linux=true
}

function sf_tn_flush_input
{
	local c
	while read -r -t 0; do
		LC_ALL=C IFS='' read -r -n 1 -t 1 c 2>/dev/null || :
	done
}

function sf_tn_iconv
{
	{
		if (( $# )); then
			printf '%s' "$*"
		else
			cat
		fi
	} | {
		if $_sf_tn_client_linux; then
			iconv -c -t "UTF8" || :
		else
			iconv -c -t "CP850" || : # IBM850
		fi
	} 2>/dev/null
}

function _sf_tn_read_char
{
	_sf_tn_read_result=$(( 128 + 14 )) # bash read timeout => exit code >128, most often =142
	local __timeout=$((_sf_tn_read_timeout - SECONDS))
	if (( _sf_tn_read_timeout <= 0 )) || ((__timeout >= 0 )); then
		if (( _sf_tn_read_timeout > 0 )); then
			LC_ALL=C IFS='' read -r -n 1 -t "$__timeout" "$1" 2>/dev/null && _sf_tn_read_result=$? || _sf_tn_read_result=$?
		elif (( _sf_tn_read_timeout == 0 )); then
			LC_ALL=C IFS='' read -r -n 1 -t 0			 "$1" 2>/dev/null && _sf_tn_read_result=$? || _sf_tn_read_result=$?
		else
			LC_ALL=C IFS='' read -r -n 1				 "$1" 2>/dev/null && _sf_tn_read_result=$? || _sf_tn_read_result=$?
		fi
		(( _sf_tn_read_result )) || [[ -n "${!1}" ]] || printf -v "$1" '\n'
		if ! (( _sf_tn_read_result )) && ${_sf_tn_debug:-false}; then
			local what
			case "${!1}" in
				$'\xff') what="ESC" ;;
				$'\xf4') what="INT" ;;
				$'\xfb') what="WILL" ;;
				$'\xfc') what="WONT" ;;
				$'\xfd') what="DO" ;;
				$'\xfe') what="DONT" ;;
				$'\xfa') what="SUB BEG, SB" ;;
				$'\xf0') what="SUB END, SE" ;;
				$'\x01') what="ECHO" ;;
				$'\x02') what="RECONNECT" ;;
				$'\x03') what="SUPPRESS GO-AHEAD" ;;
				$'\x04') what="MESSAGE SIZE" ;;
				$'\x05') what="OPT STATUS" ;;
				$'\x06') what="TIMING" ;;
				$'\x07') what="RC PRINTER" ;;
				$'\x08') what="LINE WIDTH" ;;
				$'\x09') what="PAGE LENGTH" ;;
				$'\x0a') what="CARRIAGE RETURN USE" ;;
				$'\x0b') what="HORIZ TAB" ;;
				$'\x0c') what="HORIZ TAB USE" ;;
				$'\x0d') what="FORM FEEDS" ;;
				$'\x0e') what="VERT TAB" ;;
				$'\x0f') what="VERT TAB USE" ;;
				$'\x10') what="LINE FEED USE" ;;
				$'\x11') what="EXTENDED ASCII" ;;
				$'\x12') what="FORCED LOGOUT" ;;
				$'\x13') what="BYTE MACRO" ;;
				$'\x14') what="DATA TERM" ;;
				$'\x15') what="SIGDUP" ;;
				$'\x16') what="SIGDUP OUTPUT" ;;
				$'\x17') what="SEND LOCATE" ;;
				$'\x18') what="TERM TYPE" ;;
				$'\x19') what="END RECORD" ;;
				$'\x1a') what="TACACS ID" ;;
				$'\x1b') what="OUTPUT MARK" ;;
				$'\x1c') what="TERM LOC#" ;;
				$'\x1d') what="3270 REGIME" ;;
				$'\x1e') what="X.3 PAD" ;;
				$'\x1f') what="WINDOW SIZE" ;;
				$'\x20') what="TERMINAL SPEED" ;;
				$'\x21') what="REMOTE FLOW" ;;
				$'\x22') what="LINEMODE" ;;
				*) what='?' ;;
			esac
			printf 'telnet << %s (%s)\n' "$(printf '%s' "${!1}" | xxd -p)" "$what" >&2
		fi
	fi
	return $_sf_tn_read_result
}

function _sf_tn_assign
{
	local __i __input
	read -r __input || :
	for ((__i=0; __i<$#;)); do
		if (( ++__i == $# )); then
			read -r "${!__i}" <<<"$__input"
		else
			read -r "${!__i}" __input <<<"$__input"
		fi
	done
}

function sf_tn_read
{
	if [[ -z "${_sf_tn_raw_fd:-}" ]]; then
		sf_println2 "Error: ShellFunc telnet must be initialized before using $FUNCNAME!"
		return 1
	fi

	local __password=false
	local __unsafe=false
	local __timeout=60
	local OPTIND=1 OPTARG OPTERR opt
	while getopts ":pt:uP:" opt; do
		case "$opt" in
			P) printf '%s' "$OPTARG" ;;
			p) __password=true ;;
			u) __unsafe=true ;;
			t)
				__timeout=$OPTARG
				sf_integer -n -v -- "$__timeout" || return 1
			;;
			[?])
				sf_error_unknown_option
				return 1
			;;
			:)
				sf_error_missing_argument
				return 1
			;;
		esac
	done
	shift $((OPTIND-1))
	if [[ "${1:-}" = "--" ]]; then shift; fi

	if [[ -z "${1:-}" ]]; then
		local __garbage
		set -- "__garbage"
	fi

	_sf_tn_assign "$@" </dev/null

	local _sf_tn_read_timeout=$(( __timeout > 0 ? SECONDS + __timeout : __timeout ))
	local __pos=0
	local __cmd=""
	local __c
	local __i
	local __s
	local __mbPos=""
	while _sf_tn_read_char __c; do
		if $_sf_tn_first_read; then
			_sf_tn_first_read=false
			if [[ "$_sf_tn_mode" = "echo" ]] && [[ "$__c" != $'\xff' ]]; then
				# this client is not negotiating with us
				_sf_tn_mode="raw"
				_sf_tn_raw=true
				_sf_tn_echo=false
			fi
		fi
		if $_sf_tn_skip_newline; then
			_sf_tn_skip_newline=false
			[[ "$__c" != $'\n' ]] || continue
		fi
		if [[ -n $_sf_tn_subnegotiate ]] && [[ "$__c" != $'\xff' ]]; then
			_sf_tn_sub_data+="$__c"
			continue
		fi
		if $_sf_tn_raw; then
			case "$__c" in
				$'\r'|$'\n')
				   [[ "$__c" != $'\r' ]] || _sf_tn_skip_newline=true
					if $__password && ! $__unsafe; then
						_sf_tn_assign "$@" < <(_sf_tn_iconv "$__cmd" | sha256sum | sf_fields 1)
					else
						_sf_tn_assign "$@" < <(_sf_tn_iconv "$__cmd")
					fi
					return 0
				;;
				*) __cmd+="$__c";;
			esac
		else
			case "$__c" in
				$'\xff')
					local __action __code __response=""
					_sf_tn_read_char __action
					case "$__action" in
						$'\xfb') # 251, will
							_sf_tn_read_char __code
							if ! $_sf_tn_echo; then
								__response=$'\xff\xfe'"${__code}" # 254, dont
							else
								case "$__code" in
									$'\x18') # terminal type
										# IAC SB TERMINAL-TYPE SEND IAC SE
										__response=$'\xff\xfa\x18\x01\xff\xf0'
									;;
									*)
										__response=$'\xff\xfe'"${__code}" # 254, dont
									;;
								esac
							fi
						;;
						$'\xfd') # 253, do
							_sf_tn_read_char __code
							if ! $_sf_tn_echo || { [[ "$__code" != $'\x01' ]] && [[ "$__code" != $'\x03' ]]; }; then # allow echo and sga
								__response=$'\xff\xfc'"${__code}" # 252, wont
							fi
						;;
						$'\xfc') # 252, wont
							_sf_tn_read_char __code
						;;
						$'\xfe') # 254, dont
							_sf_tn_read_char __code
						;;
						$'\xf4') # 244, interrupt
							return 69
						;;
						$'\xfa') # 250, begin subnegotiation
							_sf_tn_read_char _sf_tn_subnegotiate # set sub type
							continue
						;;
						$'\xf0') # 240, end subnegotiation
							case "$_sf_tn_subnegotiate" in
								$'\x18') # terminal type
									case "${_sf_tn_sub_data,,}" in
										"ansi")
											_sf_tn_client_linux=false
										;;
									esac
								;;
							esac
							if ${_sf_tn_debug:-false}; then
								printf 'SUB DATA: %s (%s)\n' "$(printf '%s' "$_sf_tn_sub_data" | xxd -p)" "$_sf_tn_sub_data" >&2
							fi
							_sf_tn_subnegotiate=""
							_sf_tn_sub_data=""
							continue
						;;
						$'\xff') # 255, we actually meant to send 255
							:
						;;
						*)
							sf_println2 "Unknown action: $(printf '%s' "$__action" | xxd -p)"
							exit 1
						;;
					esac
					[[ -z "$__response" ]] || tn_raw "$__response"
				;;
				$'\r'|$'\n')
					[[ "$__c" != $'\r' ]] || _sf_tn_skip_newline=true
					if $_sf_tn_echo; then
						println
					fi
					if $__password && ! $__unsafe; then
						_sf_tn_assign "$@" < <(_sf_tn_iconv "$__cmd" | sha256sum | sf_fields 1)
					else
						_sf_tn_assign "$@" < <(_sf_tn_iconv "$__cmd")
					fi
					return 0
				;;
				$'\x03') # 3, windows interrupt
					return 69
				;;
				$'\x1b') # 27, arrows
					_sf_tn_read_char __action
					_sf_tn_read_char __code
					if [[ "$__action" = $'\x5b' ]] && $_sf_tn_echo; then
						case "$__code" in
							$'\x31'|$'\x37') # home
								_sf_tn_read_char __code
								for ((; __pos>0; __pos--)); do
									tn_raw $'\x1b\x5b\x44' # left
								done
							;;
							$'\x32') # insert
								_sf_tn_read_char __code
							;;
							$'\x33') # delete
								_sf_tn_read_char __code

								# position must be less than the length of the current command
								(( __pos < ${#__cmd} )) || continue

								# erase character from command
								__cmd="${__cmd:0:__pos}${__cmd:__pos+1}"

								# write to end of command, space, then backpedal
								_sf_tn_autostar "${__cmd:__pos}"
								tn_raw " "
								for ((__c=${#__cmd} + 1; __c>__pos; __c--)); do
									tn_raw $'\x1b\x5b\x44' # left
								done
							;;
							$'\x34'|$'\x38') # end
								_sf_tn_read_char __code
								for ((; __pos<${#__cmd}; __pos++)); do
									tn_raw $'\x1b\x5b\x43' # right
								done
							;;
							$'\x35') # page up
								_sf_tn_read_char __code
							;;
							$'\x36') # page down
								_sf_tn_read_char __code
							;;
							$'\x43') # C, right
								if (( __pos < ${#__cmd} )); then
									(( ++__pos ))
									tn_raw "${__c}${__action}${__code}"
								fi
							;;
							$'\x44') # D, left
								if (( __pos )); then
									(( __pos-- ))
									tn_raw "${__c}${__action}${__code}"
								fi
							;;
						esac
					fi
				;;
				$'\x08') # backspace
					if (( __pos )) && $_sf_tn_echo; then

						# reduce position
						(( __pos-- ))
						tn_raw $'\x1b\x5b\x44' # left

						# erase character from command
						__cmd="${__cmd:0:__pos}${__cmd:__pos+1}"

						# write to end of command, space, then backpedal
						_sf_tn_autostar "${__cmd:__pos}"
						tn_raw " "
						for ((__c=${#__cmd} + 1; __c>__pos; __c--)); do
							tn_raw $'\x1b\x5b\x44' # left
						done
					fi
				;;
				$'\x7f') # delete
					if (( ${#__cmd} )) && $_sf_tn_echo; then

						# linux client? if so, act like backspace
						if $_sf_tn_client_linux; then
							(( __pos )) || continue
							(( __pos-- ))
							tn_raw $'\x1b\x5b\x44' # left
						fi

						# position must be less than the length of the current command
						(( __pos < ${#__cmd} )) || continue

						# erase character from command
						__cmd="${__cmd:0:__pos}${__cmd:__pos+1}"

						# write to end of command, space, then backpedal
						_sf_tn_autostar "${__cmd:__pos}"
						tn_raw " "
						for ((__c=${#__cmd} + 1; __c>__pos; __c--)); do
							tn_raw $'\x1b\x5b\x44' # left
						done
					fi
				;;
				*)
					__c=$(sf_printable "$__c")
					if [[ -n "$__c" ]]; then
						if ! $_sf_tn_echo; then
							__cmd="${__cmd:0:__pos}${__c}${__cmd:__pos}" && (( ++__pos ))
						else
							# get old length
							__s="$(_sf_tn_iconv "$__cmd")"
							__i="${#__s}"

							# add new byte
							__cmd="${__cmd:0:__pos}${__c}${__cmd:__pos}" && (( ++__pos ))

							# if length didn't change, we're writing a multibyte
							__s="$(_sf_tn_iconv "$__cmd")"
							if (( ${#__s} == __i )); then
								# consider setting the end position of the multibyte
								if [[ -z "$__mbPos" ]]; then
									__mbPos="$((__pos))"
								fi
							else
								# did we just end a multibyte?
								if [[ -n "$__mbPos" ]]; then
									__pos="$__mbPos"
									__mbPos=""
								fi

								# write to end of command, then backpedal
								_sf_tn_autostar "${__cmd:__pos-1}"
								for ((__c=${#__cmd}; __c>__pos; __c--)); do
									tn_raw $'\x1b\x5b\x44' # left
								done
							fi
						fi
					fi
				;;
			esac
		fi
	done
	return "$_sf_tn_read_result"
}



# vim: tabstop=4:softtabstop=4:shiftwidth=4:noexpandtab