#!/usr/bin/env bash

LOCAL_REAL_IP=$(hostname -I 2>/dev/null | awk '{for(i=1;i<=NF;i++) if($i !~ /^127\./) {print $i; exit}}')

# Split comma-separated list into array
IFS=',' read -ra HOSTS <<< "$1"

for host in "${HOSTS[@]}"; do
	# Resolve hostname to IP (IPv4)
	ip=$(getent hosts "$host" | awk '{print $1}')

	case "$ip" in
		127.*|::1)
			if [ -z "$LOCAL_REAL_IP" ]; then
				echo "$ip"
			else
				echo "$LOCAL_REAL_IP"
			fi
			;;
		"")
			echo "#$host (resolve failed)"
			;;
		*)
			echo "$ip"
			;;
	esac
done