#!/bin/bash

usage() {
	echo >&2 "Usage: $0 <start|stop|status|restart|enable|disable|pid|rotate|respawn>"
	exit 1
}

cmd="$1"; shift

[ -z "${cmd}" ] && usage

service="unicorn"
sig_rotate="USR1"
sig_respawn="USR2"

get_pid() {
	echo $(systemctl show -pMainPID $service|cut -d= -f2)
}

case "$cmd" in
status|start|stop|restart|enable|disable)
	exec systemctl $cmd $service
	;;
rotate|respawn)
	pid=$(get_pid)
	if [ "${pid}" -eq 0 ]; then
		exec systemctl start $service
	else
		signal="sig_${cmd}"
		/sbin/start-stop-daemon --stop --pid "$pid" --signal "${!signal}" --quiet
		# Wait for Main PID to change on respawn
		while [ "${pid}" -eq $(get_pid) -a "${cmd}" = "respawn" ]; do
			sleep 1
		done
	fi
	;;
pid)
	exec systemctl show -pMainPID $service|cut -d= -f2
	;;
*)
	usage
	;;
esac