# shellcheck shell=bash
# vim: ft=sh

# Support functions

function ssh_version() {
    ssh -V 2>&1 | perl -ne '/^OpenSSH_(\d+\.\d+)/ and print "$1";'
}

function ssh_back() {
    local remote="$1"
    local timeout=60
    local port=0
    shift

    case $(ssh_version) in
        5.*)
            port=55555
			# shellcheck disable=SC2029
            ssh -f -R "$port":127.0.0.1:22 "$remote" sleep "$timeout" >/dev/null 2>&1
            ;;
        *)
			# shellcheck disable=SC2029
            port="$(ssh -f -R 0:127.0.0.1:22 "$remote" sleep "$timeout" 2>&1 >/dev/null | head -1 | perl -ne '/Allocated port (\d+)/ and print "$1"')"
            ;;
    esac

    local args="-o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -p $port"
	# shellcheck disable=SC2029
    [[ -n "$port" ]] && ssh -A "$remote" "SSH_BACK_PORT=$port; SSH_BACK_USER=$USER; SSH_BACK_ARGS='$args'; $*" 2> >(grep -v "Permanently added")
}

# Fallback functions

if ! which systemctl >/dev/null; then
function systemctl() {
    case "$1" in
        start|stop|restart|reload)
            service "$2" "$1"
            ;;
        *)
            false
            ;;
    esac
}
fi