#!/bin/sh -e
#
# 2020 Dennis Camera (dennis.camera at ssrq-sds-fds.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/>.
#
# This explorer the "prefix" of the section matching --match.

squote_values() {
	sed -e '/=".*"$/{s/="/='\''/;s/"$/'\''/}' \
	    -e "/='.*'$/"'!{s/=/='\''/;s/$/'\''/}'
}

RS=$(printf '\036')

if ! test -e "${__object:?}/parameter/match"
then
	if echo "${__object_id:?}" | grep -qvE '^[^.]+\.[^.]+$'
	then
		echo 'Section identifiers are a package and section name separated by a "." (period).' >&2
		exit 1
	fi

	# If no --match is given, we take the __object_id as the section identifier.
	echo "${__object_id:?}"
	exit 0
fi

# shellcheck disable=SC2015
test -s "${__object:?}/parameter/match" && test -s "${__object:?}/parameter/type" \
|| {
	echo 'Parameters --match and --type must be used together.' >&2
	exit 1
}

# Find by match
match=$(cat "${__object:?}/parameter/match")
sect_type_filter=$(cat "${__object:?}/parameter/type")

package_filter=${sect_type_filter%%.*}
section_filter=${sect_type_filter##*.}
regex="^${package_filter}\.@${section_filter}\[[0-9]\{1,\}\]\.${match%%=*}="

matched_sections=$(
	uci -s -N -d "${RS}" show "${package_filter}" 2>/dev/null \
	| grep -e "${regex}" \
	| sed -e 's/\.[^.]*=.*$//')

if test "$(echo "${matched_sections}" | wc -l)" -gt 1
then
	printf 'Found multiple matching sections:\n%s\n' "${matched_sections}" >&2
	exit 1
fi

echo "${matched_sections}"