#!/bin/sh -e
#
# 2021 Joachim Desroches (joachim.desroches@epfl.ch)
#
# This file is part of cdist.
#
# cdist is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# cdist is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with cdist. If not, see <http://www.gnu.org/licenses/>.
#


os=$(cat "${__global:?}/explorer/os")

CFG_DIR="/etc/opendkim"
user="opendkim"
group="opendkim"
case "$os" in
'alpine')
	:
;;
'freebsd')
	CFG_DIR="/usr/local/etc/mail"
	user="mailnull"
	group="mailnull"
;;
*)
	cat <<- EOF >&2
	__opendkim_genkey currently only supports Alpine Linux. Please
	contribute an implementation for $os if you can.
	EOF
	exit 1
;;
esac

# Logic to simplify the type as documented in
# https://code.ungleich.ch/ungleich-public/cdist-contrib/issues/20#issuecomment-14711
DOMAIN="$(cat "${__object:?}/parameter/domain" 2>/dev/null || true)"
SELECTOR="$(cat "${__object:?}/parameter/selector" 2>/dev/null || true)"
if [ -z "${DOMAIN}${SELECTOR}" ]; then
	# Neither SELECTOR nor DOMAIN were passed, try to use __object_id
	if echo "${__object_id:?}" | \
			grep -qE '^[^/[:space:]]+/[^/[:space:]]+$'; then
		# __object_id matches, let's get the data
		DOMAIN="$(echo "${__object_id:?}" | cut -d '/' -f 1)"
		SELECTOR="$(echo "${__object_id:?}" | cut -d '/' -f 2)"
	else
		# It doesn't match the pattern, this is sad
		cat <<- EOF >&2
		The arguments --domain and --selector were not used.
		So __object_id must match DOMAIN/SELECTOR.
		But instead the type got: ${__object_id:?}
		EOF
		exit 1
	fi
elif [ -z "${DOMAIN}" ] || [ -z "${SELECTOR}" ]; then
	# Only one was passed, this is sad :-(
	cat <<- EOF >&2
	You must pass either both --selector and --domain or none of them.
	If these arguments are absent, __object_id must match: DOMAIN/SELECTOR.
	EOF
	exit 1
# else: both were passed
fi

# Persist data for gencode-remote
printf '%s' "${user:?}" > "${__object:?}/user"
printf '%s' "${group:?}" > "${__object:?}/group"
printf '%s' "${DOMAIN:?}" > "${__object:?}/domain"
printf '%s' "${SELECTOR:?}" > "${__object:?}/selector"

DIRECTORY="/var/db/dkim/"
if [ -f "${__object:?}/parameter/directory" ];
then
	# Be forgiving about a lack of trailing slash
	DIRECTORY="$(sed -E 's!([^/])$!\1/!' < "${__object:?}/parameter/directory")"
fi

SIGKEY="${DOMAIN:?}"
if [ -f "${__object:?}/parameter/sigkey" ];
then
	SIGKEY="$(cat "${__object:?}/parameter/sigkey")"
fi
SIGDOMAIN="${DOMAIN:?}"
if [ -f "${__object:?}/parameter/sigdomain" ];
then
	SIGDOMAIN="$(cat "${__object:?}/parameter/sigdomain")"
fi

# Ensure the key-container directory exists with the proper permissions
__directory "${DIRECTORY}" \
	--mode 0750 \
	--owner "${user}" --group "${group}"

# OS-specific code
case "$os" in
'alpine')
	# This is needed for opendkim-genkey
	__package opendkim-utils
;;
esac

key_table="${CFG_DIR}/KeyTable"
signing_table="${CFG_DIR}/SigningTable"

KEY_STATE="$(cut -f 1 "${__object:?}/explorer/key-state")"
KEY_LOCATION="$(cut -f 2- "${__object:?}/explorer/key-state")"

__line "__opendkim_genkey/${__object_id:?}" \
	--file "${key_table}" \
	--line "${__object_id:?} ${SIGDOMAIN:?}:${SELECTOR:?}:${KEY_LOCATION:?}" \
	--regex "^${__object_id:?}[[:space:]]" \
	--state 'replace'

sigtable_block() {
	for sigkey in ${SIGKEY:?}; do
		echo "${sigkey:?} ${__object_id:?}"
	done
}
__block "__opendkim_genkey/${__object_id:?}" \
	--file "${signing_table}" \
	--text "$(sigtable_block)"

if [ "${KEY_STATE:?}" = "present" ]; then
	# Ensure proper permissions for the key file
	__file "${KEY_LOCATION}" \
		--owner "${user}" \
		--group "${group}" \
		--mode 0600
fi