#!/bin/sh

PROGRAM=setup-hostname
PREFIX=

. $PREFIX/lib/libalpine.sh

usage() {
        cat <<__EOF__
usage: setup-hostname [-h] [-n hostname]

Sets the system hostname.

options:
 -h  Show this help
 -n  Specify the hostname to set
__EOF__
        exit 1
}


# http://en.wikipedia.org/wiki/Hostname#Restrictions_on_valid_host_names
valid_hostname() {
	# check length
	if [ $(echo "$1" | wc -c) -gt 63 ]; then
		echo "Hostname '$1' is too long."
		return 1
	fi
	# check that it only contains valid chars
	if ! [ -z "$(echo $1 | sed 's/[0-9a-z-]//g')" ]; then
		echo "Hostname must only contain letters (a-z), digits (0-9) or -"
		return 1
	fi
	# must not start with -
	case "$1" in
		-*) echo "Hostname must not start with a '-'"; return 1;;
	esac
	return 0
}

while getopts "hn:" opt; do
        case $opt in
		h) usage;;
		n) HOSTNAME="$OPTARG";;
        esac
done


while true; do
	if [ -n "$HOSTNAME" ]; then
		HOST="$HOSTNAME"
	else
		HOST=`hostname`
		echon "Enter system hostname (short form, e.g. 'foo') [$HOST]: "
		default_read HOST `hostname`
	fi
	if valid_hostname "$HOST"; then
		break
	fi
done

mkdir -p "$ROOT/etc"
echo "$HOST" > "$ROOT/etc/hostname"