#!/bin/bash
# Syncs Arch repos based on info contained in repo.db files
# License: GPLv3

# Principles
# * Get repo.db from an Arch-like repo
# * Generate a list of available packages
# * Create sync whitelist (based on package blacklist)
# * Get packages
# * Check package signatures
# * Check database signatures
# * Sync repo => repo

# TODO
# * make a tarball of files used for forensics

# Run as `V=true db-sync` to get verbose output
VERBOSE=${V}
extra=()
${VERBOSE} && extra+=(-v)

WORKDIR=$(mktemp -dt "${0##*/}.XXXXXXXXXX")
trap "rm -rf -- $(printf '%q' "${WORKDIR}")" EXIT

# Returns contents of a repo
get_repos() {
	# Exclude everything but db files
	rsync "${extra[@]}" --no-motd -mrtlH --no-p --include="*/" \
		--include="*.db" \
		--include="*${DBEXT}" \
		--include="*.files" \
		--include="*${FILESEXT}" \
		--exclude="*" \
		--delete-after \
		"rsync://${mirror}/${mirrorpath}/" "$WORKDIR"
}

get_repo_content() {
	# Return all contents
	bsdtar tf "${1}" | \
		cut -d "/" -f 1 | \
		sort -u
}

# Prints blacklisted packages
get_blacklist() {
	cut -d ':' -f 1 "${BLACKLIST_FILE}"
}

# repo
# arch
get_repo_file() {
	echo "${WORKDIR}/${2}/${1}/${1}"
}

# Process the databases and get the libre packages
init() {

	# Get the blacklisted packages
	blacklist=($(get_blacklist))
	# Store all the whitelist files
	whitelists=()

	msg "%d packages in blacklist" ${#blacklist[@]}

	test ${#blacklist[@]} -eq 0 && fatal_error "Empty blacklist"

	# Sync the repos databases
	get_repos

	# Traverse all repo-arch pairs
	local pkgpool
	for _arch in "${OURARCHES[@]}"; do
		for _repo in "${ARMREPOS[@]}"; do
			msg "Processing %s-%s" "${_repo}-${_arch}"

			db_file=$(get_repo_file "${_repo}" "${_arch}")${DBEXT}
			files_file=$(get_repo_file "${_repo}" "${_arch}")${FILESEXT}

			if [ ! -f "${db_file}" ]; then
				warning "%s doesn't exist, skipping this arch-repo" "${db_file}"
				continue
			fi
			if [ ! -f "${files_file}" ]; then
				warning "%s doesn't exist, skipping this arch-repo" "${files_file}"
				continue
			fi

			# Remove blacklisted packages and count them
			# TODO capture all removed packages for printing on debug mode
			msg2 "Removing blacklisted packages from %s database..." .db
			LC_ALL=C repo-remove "${db_file}" "${blacklist[@]}" \
			|& sed -n 's/-> Removing/	&/p'
			msg2 "Removing blacklisted packages from %s database..." .files
			LC_ALL=C repo-remove "${files_file}" "${blacklist[@]}" \
			|& sed -n 's/-> Removing/	&/p'
			# Get db contents
			db=($(get_repo_content "${db_file}"))

			msg2 "Process clean db for syncing..."

			# Create a whitelist, add * wildcard to end
			# TODO due to lack of -arch suffix, the pool sync retrieves every arch even if
			# we aren't syncing them
			# IMPORTANT: the . in the sed command is needed because an empty
			# whitelist would consist of a single * allowing any package to
			# pass through
			printf '%s\n' "${db[@]}" | sed "s|.$|&*|g" > "/tmp/${_repo}-${_arch}.whitelist"

			msg2 "%d packages in whitelist" "$(wc -l /tmp/${_repo}-${_arch}.whitelist | cut -d' ' -f1)"

			# Set pkgpool to sync packages
			if [ "${_repo}" = "community" ]; then
				pkgpool="pool/community"
			else
				pkgpool="pool/packages"
			fi

			# Sync excluding everything but whitelist
			rsync "${extra[@]}" --no-motd -rtlH \
				--delay-updates \
				--safe-links \
				--include-from="/tmp/${_repo}-${_arch}.whitelist" \
				--exclude="*" \
				"rsync://${mirror}/${mirrorpath}/${_arch}/${_repo}/" \
				"${FTP_BASE}/${pkgpool}/"

			msg "Putting databases back in place"
			rsync "${extra[@]}" --no-motd -rtlH \
				--delay-updates \
				--safe-links \
				"${WORKDIR}/${_arch}/${_repo}/" \
				"${FTP_BASE}/${_repo}/os/${_arch}/"

			# Search packages in whitelist to create symlinks
			sed -i 's/^/\^/' "/tmp/${_repo}-${_arch}.whitelist"

			ls ${FTP_BASE}/${pkgpool}/ | grep -w -f "/tmp/${_repo}-${_arch}.whitelist" \
			> "/tmp/${_repo}-${_arch}.pkgwhitelist"

			msg "Putting symlinks"
			while read _pkgfile; do
				ln -sf "../../../${pkgpool}/${_pkgfile}" "${FTP_BASE}/${_repo}/os/${_arch}"
			done < "/tmp/${_repo}-${_arch}.pkgwhitelist"

			# Cleanup
			unset db 
		done
	done

	date -u +%s > "${FTP_BASE}/lastsync"

	# Cleanup
	unset blacklist whitelists _arch _repo repo_file _pkgfile
}

trap_exit() {
	local signal=$1; shift
	echo
	error "$@"
	trap -- "$signal"
	kill "-$signal" "$$"
}

source "$(dirname "$(readlink -e "$0")")/config"
source "$(dirname "$(readlink -e "$0")")/db-sync-arm.conf"
source "$(dirname "$(readlink -e "$0")")/db-libremessages"

# Check variables presence
for var in DBEXT FILESEXT mirror mirrorpath WORKDIR BLACKLIST_FILE FTP_BASE ARCHSRCPOOLS ARCHPKGPOOLS; do
	test -z "${!var}" && fatal_error "Empty %s" "${var}"
done

# From makepkg
set -E
for signal in TERM HUP QUIT; do
	trap "trap_exit $signal '%s signal caught. Exiting...' $signal" "$signal"
done
trap 'trap_exit INT "Aborted by user! Exiting..."' INT
trap 'trap_exit USR1 "An unknown error has occurred. Exiting..."' ERR

init