#!/bin/sh

# Copyright (C) 2010-2023 Pädagogisches Landesinstitut Rheinland-Pfalz
# Copyright (C) 2022-2023 Mike Gabriel <mike.gabriel@das-netzwerkteam.de>
#
# This program 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 2 of the License, or
# (at your option) any later version.
#
# This program 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 this program; if not, write to the
# Free Software Foundation, Inc.,
# 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.

# Sync FAI config space files from DATADIR/fai/config/ to
# /srv/fai/config. For this, the 'ucf' tool is used, three-way
# patching is supported for this.

set -e

LC_ALL=C
export LC_ALL

if [ -z "$1" ]; then
	echo "usage: $(basename $0) <FAI_CONFIGDIR>"
	exit 1
fi

# first parameter is the configspace's target dir
FAI_CONFIGDIR="$1"

FAI_CONFIGDIR_REAL="${FAI_CONFIGDIR}"
# if FAI_CONFIGDIR is a symlink, we need to find the real location...
if [ -h ${FAI_CONFIGDIR} ]; then
	FAI_CONFIGDIR_REAL="$(readlink ${FAI_CONFIGDIR})"
fi

# Copy FAI config space into /srv/fai/config if not already present
if [ "${FAI_CONFIGDIR_REAL}" = "/usr/share/debian-edu-fai/fai/config" ]; then
	echo "ERROR: FAI_CONFIGDIR points to '${FAI_CONFIGDIR_REAL}'."
	echo "ERROR: Such a setup is not supported..."
	exit 1
elif command -v git 1>/dev/null && [ "$(cd "${FAI_CONFIGDIR_REAL}"; git rev-parse --is-inside-work-tree 2>/dev/null)" = "true" ]; then
	# FAI config space is managed by Git, don't do anything then...
	:
else
	# create config space's base directory if it does not yet exist
	if [ ! -d "${FAI_CONFIGDIR_REAL}" ]; then
		mkdir -p "${FAI_CONFIGDIR_REAL}"
	fi

	# remove obsolete files used in previous FAI configspace versions
	cd "${FAI_CONFIGDIR_REAL}"
	cat /usr/share/debian-edu-fai/fai/config/_obsolete-files.d/*.removed | while read obsolete_configspace_file; do
		rm -fv "${obsolete_configspace_file}"
		# purge file's hash from ucf hash list
		ucf -p "${FAI_CONFIGDIR_REAL}/${obsolete_configspace_file}"
		# try to remove non-used / empty directories
		if [ -d "$(dirname ${obsolete_configspace_file})" ]; then
			rmdir --parents --ignore-fail-on-non-empty "$(dirname ${obsolete_configspace_file})"
		fi
	done
	cd - 1>/dev/null

	# managed FAI config space with 'ucf'...
	cd "/usr/share/debian-edu-fai/fai/config"
	find . -type f | grep -v "_obsolete-files.d/" | while read new_configspace_file; do
		# handle files that shall become a directory gracefully
		target_dir="${FAI_CONFIGDIR_REAL}/$(dirname "${new_configspace_file}")"
		if [ -e "${target_dir}" ] && [ ! -d "${target_dir}" ]; then
			mv -v "${target_dir}" "${target_dir}.moved-out-of-the-way"
		fi
		mkdir -p "${FAI_CONFIGDIR_REAL}/$(dirname "${new_configspace_file}")"
		if [ -e "${target_dir}.moved-out-of-the-way" ]; then
			mv -v "${target_dir}.moved-out-of-the-way" "${target_dir}/OBSOLETE"
		fi
		# install/update configspace file via ucf
		ucf --state-dir "/var/lib/debian-edu-fai/ucf/" --three-way "$new_configspace_file" "${FAI_CONFIGDIR_REAL}/${new_configspace_file}"
	done
	cd - 1>/dev/null

	# clean-up ucf backup files... (they confuse FAI)
	cd "${FAI_CONFIGDIR_REAL}"
	find . -name "*.ucf-*" -delete
	cd - 1>/dev/null
fi