#!/bin/bash

VERBOSITY=0
TEMP_D=""
DEF_DISK_FORMAT="raw"
DEF_FILESYSTEM="iso9660"

error() { echo "$@" 1>&2; }
errorp() { printf "$@" 1>&2; }
fail() { [ $# -eq 0 ] || error "$@"; exit 1; }
failp() { [ $# -eq 0 ] || errorp "$@"; exit 1; }

Usage() {
	cat <<EOF
Usage: ${0##*/} [ options ] output user-data [meta-data]

   Create a disk for cloud-init to utilize nocloud

   options:
     -h | --help            show usage
     -d | --disk-format D   disk format to output. default: raw
     -f | --filesystem  F   filesystem format (vfat or iso), default: iso9660

     -i | --interfaces  F   write network interfaces file into metadata
     -m | --dsmode      M   add 'dsmode' ('local' or 'net') to the metadata
                            default in cloud-init is 'net', meaning network is
                            required.

   Example:
    * cat my-user-data
      #cloud-config
      password: passw0rd
      chpasswd: { expire: False }
      ssh_pwauth: True
    * echo "instance-id: \$(uuidgen || echo i-abcdefg)" > my-meta-data
    * ${0##*/} my-seed.img my-user-data my-meta-data
    * kvm -net nic -net user,hostfwd=tcp::2222-:22 \\
         -drive file=disk1.img,if=virtio -drive file=my-seed.img,if=virtio
    * ssh -p 2222 ubuntu@localhost
EOF
}

bad_Usage() { Usage 1>&2; [ $# -eq 0 ] || error "$@"; exit 1; }
cleanup() {
	[ -z "${TEMP_D}" -o ! -d "${TEMP_D}" ] || rm -Rf "${TEMP_D}"
}

debug() {
	local level=${1}; shift;
	[ "${level}" -gt "${VERBOSITY}" ] && return
	error "${@}"
}

short_opts="hi:d:f:m:o:v"
long_opts="disk-format:,dsmode:,filesystem:,help,interfaces:,output:,verbose"
getopt_out=$(getopt --name "${0##*/}" \
	--options "${short_opts}" --long "${long_opts}" -- "$@") &&
	eval set -- "${getopt_out}" ||
	bad_Usage

## <<insert default variables here>>
output=""
userdata=""
metadata=""
filesystem=$DEF_FILESYSTEM
diskformat=$DEF_DISK_FORMAT
interfaces=_unset
dsmode=""


while [ $# -ne 0 ]; do
	cur=${1}; next=${2};
	case "$cur" in
		-h|--help) Usage ; exit 0;;
		-v|--verbose) VERBOSITY=$((${VERBOSITY}+1));;
		-d|--disk-format) diskformat=$next; shift;;
		-f|--filesystem) filesystem=$next; shift;;
		-m|--dsmode) dsmode=$next; shift;;
		-i|--interfaces) interfaces=$next; shift;;
		--) shift; break;;
	esac
	shift;
done

## check arguments here
## how many args do you expect?
[ $# -ge 2 ] || bad_Usage "must provide output, userdata"
[ $# -le 3 ] || bad_Usage "confused by additional args"

output=$1
userdata=$2
metadata=$3

[ -n "$metadata" -a "${interfaces}" != "_unset" ] &&
	fail "metadata and --interfaces are incompatible"
[ -n "$metadata" -a -n "$dsmode" ] &&
	fail "metadata and dsmode are incompatible"
[ "$interfaces" = "_unset" -o -r "$interfaces" ] ||
	fail "$interfaces: not a readable file"

TEMP_D=$(mktemp -d "${TMPDIR:-/tmp}/${0##*/}.XXXXXX") ||
	fail "failed to make tempdir"
trap cleanup EXIT

if [ -n "$metadata" ]; then
	cp "$metadata" "$TEMP_D/meta-data" || fail "$metadata: failed to copy"
else
	iface_data=""
	dsmode_data=""
	[ "$interfaces" != "_unset" ] &&
		iface_data=$(sed ':a;N;$!ba;s/\n/\\n/g' "$interfaces") &&
		iface_data="\"interfaces\": '$iface_data'"
	[ -n "$dsmode" ] && dsmode_data="\"dsmode\": \"$dsmode\""

	# write json formatted user-data (json is a subset of yaml)
	printf "{\n%s\n%s\n%s\n}" "\"instance-id\": \"iid-local01\"" \
		"${iface_data}" "${dsmode_data}" > "${TEMP_D}/meta-data"
fi

if [ "$userdata" = "-" ]; then
	cat > "$TEMP_D/user-data" || fail "failed to read from stdin"
else
	cp "$userdata" "$TEMP_D/user-data" || fail "$userdata: failed to copy"
fi

## alternatively, create a vfat filesystem with same files
img="$TEMP_D/seed.img"
truncate --size 100K "$img" || fail "failed truncate image"

case "$filesystem" in
	iso9660|iso)
		genisoimage  -output "$img" -volid cidata \
			-joliet -rock "$TEMP_D/user-data" "$TEMP_D/meta-data" \
			> "$TEMP_D/err" 2>&1 ||
			{ cat "$TEMP_D/err" 1>&2; fail "failed to genisoimage"; }
		;;
	vfat)
		mkfs.vfat -n cidata "$img" || fail "failed mkfs.vfat"
		mcopy -oi "$img" "$TEMP_D/user-data" "$TEMP_D/meta-data" :: ||
			fail "failed to copy user-data, meta-data to img"
		;;
	*) fail "unknown filesystem $filesystem";;
esac

[ "$output" = "-" ] && output="$TEMP_D/final"
qemu-img convert -f raw -O "$diskformat" "$img" "$output" ||
	fail "failed to convert to disk format $diskformat"

[ "$output" != "$TEMP_D/final" ] || { cat "$output" && output="-"; } ||
	fail "failed to write to -"

error "wrote ${output} with filesystem=$filesystem and diskformat=$diskformat"
# vi: ts=4 noexpandtab