#!/usr/bin/env bash

# Copyright (C) 2011-2012 Michał Masłowski <mtjm@mtjm.eu>
# Copyright (C) 2012 Daniel Molina (lluvia)
# Copyright (C) 2017, 2024 Luke T. Shumaker <lukeshu@parabola.nu>
#
# License: GNU GPLv3+
#
# 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 3 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 Affero General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

set -e

. "$(librelib messages)"
. "$(librelib conf)"

usage() {
	print 'Usage: %s [OPTIONS] REPO [ARCH]' "${0##*/}"
	print 'Diff between pacman databases and abslibre.git.'
	echo
	prose "This script outputs a diff of package names and versions
	       in repo between pacman's sync db and abslibre checkout."
	echo
	print 'Options:'
	flag \
		'-h, --help' 'Show this message'
}

main() {
	local args mode=run
	if ! args="$(getopt -n "${0##*/}" -o 'h' -l 'help' -- "$@")"; then
		mode=errusage
	else
		eval "set -- $args"
		local flag
		while true; do
			flag=$1
			shift
			case "$flag" in
				-h | --help) mode=usage ;;
				--) break ;;
				*) panic 'unhandled flag: %q' "$flag" ;;
			esac
		done
		if [[ $mode == run && $# -ne 1 && $# -ne 2 ]]; then
			gnuerror 'expected 1 or 2 non-flag arguments, got %d' "$#"
			mode=errusage
		fi
	fi
	case "$mode" in
		errusage)
			print "Try '%s --help' for more information." "${0##*/}" >&2
			return $EXIT_INVALIDARGUMENT
			;;
		usage)
			usage
			return $EXIT_SUCCESS
			;;
		run) : ;;
		*) panic 'invalid mode: %q' "$mode" ;;
	esac

	load_conf libretools.conf WORKDIR || exit

	# The repo to find missing packages in.
	local repo=$1
	# The arch to check in Arch repos, other will have all arches checked.
	local arch=${2:-mips64el}

	diff -U0 \
		<(pacman_list_packages "$repo" "$arch" | sort) \
		<(abslibre_list_packages "$repo" "$arch" | sort) |
		sed -En 's/^[+-][^+-].+$/&/p'
}

pacman_list_packages() {
	local repo=$1
	local arch=$2

	# A Python tuple of repos which don't have arch=any packages.
	local archrepos='("core", "extra", "community")'

	tar xOf "/var/lib/pacman/sync/$repo.db" | python -c '
		import sys


		arch = None
		name = None
		version = None
		it = iter(sys.stdin)
		try:
		    while True:
		        line = next(it)
		        if line == "%ARCH%\n":
		            arch = next(it)
		            if arch == "'"$arch"'\n" or "'"$repo"'" not in '"$archrepos"':
		                print("%s-%s" % (name.strip(), version.strip()))
		        if line == "%NAME%\n":
		            name = next(it)
		        if line == "%VERSION%\n":
		            version = next(it)
		except StopIteration:
		    pass
		'
}

abslibre_list_packages() {
	local repo=$1
	local arch=$2

	local CARCH=$arch
	local f name
	for f in "${WORKDIR}/abslibre/$repo"/*; do
		load_PKGBUILD "$f/PKGBUILD" || continue
		if in_array 'any' "${arch[@]}" || in_array "$CARCH" "${arch[@]}"; then
			for name in "${pkgname[@]}"; do
				if [[ -z $epoch ]]; then
					echo "$name-$pkgver-$pkgrel"
				else
					echo "$name-$epoch:$pkgver-$pkgrel"
				fi
			done
		fi
	done
}

main "$@"
