#!/usr/bin/env sh

# a simple beep implementation for the "Hinweiston nach 1 TR 110-1, Kap. 8.8", also called "Sonderinformationston" or - shorthand - SIT.

# if you cannot beep :-), here's a hint or two:
# udev pcspkr beep rules: [...] GROUP="beep" MODE="0620", then rmmod, insmod and a udevadm control --reload

function zuhuelf {
	printf "USAGE: %b [ -l ]\\n\\n" "$(basename "$0")"
	printf "DESCRIPTION: Hinweiston nach 1 TR 110-1, Kap. 8.8 / SonderInformationsTon\\n\\n"
	(
		printf -- "-h:;This help\\n"
		printf -- "-l:;Loop the tone. Delays between loops are also implemented according to\\n"
		printf " ;1 TR 110-1 Kap. 8.8.\\n"
	)|column -ts\;
	printf "\\n"
}

LOOPADOOP=0
while getopts :hl SHOPT;do
	case "$SHOPT" in
		"h") zuhuelf;exit 0;;
		"l") LOOPADOOP=1;;
	esac
done

function sittone {
	# chain the tones to avoid kernel delays between tones
	beep -l 330 -f 950 -n -l 330 -f 1400 -n -l 330 -f 1800
}

if [ "$LOOPADOOP" -eq 1 ];then
	# TR 110-1 specifies a delay of 1000ms between repetitions
	while true; do sittone; sleep 1; done
else
	sittone
fi