#!/bin/sh

# Linux GPIOs on XBee lines
XBEE_RESET_N_GPIO="##XBEE_RESET_N_GPIO##"
XBEE_SLEEP_RQ_GPIO="##XBEE_SLEEP_RQ_GPIO##"

# request_gpio <gpio_nr>
request_gpio_out() {
	local SG_GPIONR="${1}"
	local SG_GPIOPATH="/sys/class/gpio/gpio${SG_GPIONR}"

	[ -d "${SG_GPIOPATH}" ] || printf "%s" "${SG_GPIONR}" > /sys/class/gpio/export
	printf out > "${SG_GPIOPATH}/direction" && sleep .2
}

# free_gpio <gpio_nr>
free_gpio() {
	local SG_GPIONR="${1}"
	local SG_GPIOPATH="/sys/class/gpio/gpio${SG_GPIONR}"

	[ -d "${SG_GPIOPATH}" ] && printf "%s" "${SG_GPIONR}" > /sys/class/gpio/unexport
}

# set_gpio_value <gpio_nr> <value>
set_gpio_value() {
	local SG_GPIONR="${1}"
	local SG_GPIOVAL="${2}"
	local SG_GPIOPATH="/sys/class/gpio/gpio${SG_GPIONR}"

	printf out > "${SG_GPIOPATH}/direction" && sleep .2
	printf "${SG_GPIOVAL}" > "${SG_GPIOPATH}/value" && sleep .2
}

xbee_init() {
	# Power cycle XBEE_RESET_N
	request_gpio_out ${1}
	set_gpio_value ${1} 0
	set_gpio_value ${1} 1

	# Set low XBEE_SLEEP_RQ
	request_gpio_out ${2}
	set_gpio_value ${2} 0
}

xbee_stop() {
	free_gpio ${1}
	free_gpio ${2}
}

xbee_iterate_list() {
	i=0
	for RESET in $(echo ${XBEE_RESET_N_GPIO} | sed "s/,/ /g"); do
		j=0
		for SLEEP in $(echo ${XBEE_SLEEP_RQ_GPIO} | sed "s/,/ /g"); do
			if [ "${i}" = "${j}" ]; then
				if [ "${1}" = "start" ]; then
					xbee_init ${RESET} ${SLEEP}
				elif [ "${1}" = "stop" ]; then
					xbee_stop ${RESET} ${SLEEP}
				fi
			fi
			j="$((j + 1))"
		done
		i="$((i + 1))"
	done
}

case "$1" in
	start)
		echo -n "Starting XBee hardware: "
		xbee_iterate_list start
		echo "done."
		;;
	stop)
		echo -n "Stopping XBee hardware: "
		xbee_iterate_list stop
		echo "done."
		;;
	restart)
		$0 stop
		sleep 1
		$0 start
		;;
	*)
		echo "Usage: $0 {start|stop|restart}"
		exit 1
		;;
esac