_user="munge"

post_install() {
	# The installation process is described at https://github.com/dun/munge/wiki/Installation-Guide

	# Create munge /var/run/munge dir and secure it
	mkdir -p /var/run/munge
	chmod 0755 /var/run/munge

	getent group "${_user}" &>/dev/null
	if [ $? -ne 0 ]; then
		echo "Adding ${_user} system group..."
		groupadd -r ${_user} 1>/dev/null
	fi

	getent passwd "${_user}" &>/dev/null
	if [ $? -ne 0 ]; then
		echo "Adding ${_user} system user..."
		useradd -r -g ${_user} -d "/var/log/munge" -c "Munge Daemon" ${_user} 1>/dev/null
	fi

	echo "Locking Munge User Account..."
	passwd -l munge &>/dev/null

	# Create munge key
	if [[ ! -e /etc/munge/munge.key && -c /dev/urandom ]]; then
		echo "Creating random munge key at /etc/munge/munge.key ..."
		dd if=/dev/urandom bs=1 count=1024 of=/etc/munge/munge.key
		chmod 0400 /etc/munge/munge.key
	else
		if [[ -c /dev/urandom ]]; then
			echo "No munge key is generated since /etc/munge/munge.key already exists."
		else
			echo "Did not create /etc/munge/munge.key since /dev/urandom can not be found."
		fi
	fi

	# Set permissions
	chown ${_user}:${_user} -R /etc/munge
	chown ${_user}:${_user} -R /var/log/munge
	chown ${_user}:${_user} -R /var/lib/munge
	chown ${_user}:${_user} -R /var/run/munge
}

post_upgrade() {
	# Set permissions
	chown ${_user}:${_user} -R /etc/munge
	chown ${_user}:${_user} -R /var/log/munge
	chown ${_user}:${_user} -R /var/lib/munge
	chown ${_user}:${_user} -R /var/run/munge

	if [[ -e /etc/munge/munge.key ]]; then
		chmod 0400 /etc/munge/munge.key
	fi
}

pre_remove() {
	echo "Stopping and disabling munge using SystemD..."
	systemctl stop munge
	systemctl disable munge.service
}

post_remove() {
	# Removing obsolete directory
	rm -rf /var/run/munge

	# Notifying the user of kept dirs and change owner
	[[ -d /etc/munge ]] && chown root:root -R /etc/munge && echo "Custom configuration-file(s) in /etc/munge/ were kept on your system."
	[[ -d /var/log/munge ]] && chown root:root -R /var/log/munge && echo "Logfiles were preserved. They reside under /var/log/munge ."

	echo "Removing ${_user} system user and group..."
	if getent passwd ${_user} >/dev/null 2>&1; then
		userdel ${_user} 2>/dev/null
	fi
	if getent group ${_user} >/dev/null 2>&1; then
		groupdel ${_user}
	fi
}