#!/bin/sh -e
# -*- mode: sh; indent-tabs-mode: t -*-
#
# 2021 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/>.
#

postgres_user=$("${__type_explorer:?}/postgres_user")

conf_name=${__object_id:?}

su - "${postgres_user}" -c 'psql postgres -c "SELECT 1"' >/dev/null || {
	echo 'Connection to PostgreSQL server failed' >&2
	exit 1
}

if su - "${postgres_user}" -c "psql postgres -twAc 'SHOW ${conf_name}'" \
	| cmp -s "${__object:?}/parameter/value" -
then
	echo present
else
	# NOTE: SHOW/SET are case-insentitive, so this command should also be.
	case $(su - "${postgres_user}" -c "psql postgres -tAwc \"SELECT CASE WHEN source = 'default' OR setting = boot_val THEN 'default' ELSE source END FROM pg_settings WHERE lower(name) = lower('${conf_name}')\"")
	in
		('')
			# invalid configuration parameter
			# (error message was already printed by SHOW command above.
			#  Yes, it's a hack)
			exit 1
			;;
		(default)
			echo absent
			;;
		(*)
			echo different
			;;
	esac
fi