#! /bin/sh

# Copyright © 2022 Adam Spragg
# SPDX-License-Identifier: LGPL-3.0-or-later
#
# This file is part of apt-desktop-upgrades
#
# apt-desktop-upgrades is free software: you can redistribute it and/or modify
# under the terms of the GNU Lesser General Public License as published by the
# Free Software Foundation, either version 3 of the License, or (at your option)
# any later version.
#
# apt-desktop-upgrades 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 Lesser General Public License
# for more details.
#
# You should have received a copy of the GNU Lesser General Public License along
# with apt-desktop-upgrades.  If not, see <https://www.gnu.org/licenses/>.

set -e

SBINDIR=/usr/local/sbin

UPDATE_SYMLINK="/system-update"
UPDATE_TARGET="${SBINDIR}/adu-upgrade"

apt-get -qq update

upgrades=$(apt -qq list --upgradeable 2>/dev/null | wc -l)
if [ "$upgrades" -eq 0 ]; then
	exit 0
fi

apt-get -q -y --with-new-pkgs --download-only upgrade | grep "^Get:"

ln -s -- "${UPDATE_TARGET}" "${UPDATE_SYMLINK}" 2>/dev/null || true

# Notify logged-in users that updates are available
if command -v notify-send >/dev/null; then
	# Disable shellcheck's "For loops over find output are fragile" warning here
	# because filenames in `/run/user` are safe, and doing it The Right Way is a
	# pain because of the environment variable.
	# shellcheck disable=SC2044
	for addr in $(find /run/user -type s -name bus 2>/dev/null); do
		export DBUS_SESSION_BUS_ADDRESS="unix:path=$addr";
		runuser -u "$(stat -c "%U" "$addr")" -- \
			notify-send --app-name=apt-desktop-upgrades \
			"$upgrades system updates available" \
			"Reboot when it is convenient to install them"
	done
fi

echo "$upgrades updates available"