#!/bin/bash

# blacklist-diffs - locates the upstream repo in which each blacklist entry exists;
# and identifies blacklist entries which do not exist upstream
#
# Copyright (C) 2023 bill-auger <bill-auger@programmer.net>
#
# SPDX-License-Identifier: AGPL-3.0-or-later
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero 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 Affero General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.
#
#
# TODO: determine which non-existing packages should exist on a per-arch basis,
#       perhaps with a cross-arch compare filter, or per-arch supplemental blacklists
#       (eg: blacklist.txt (all arches) , blacklist-armv7h.txt (armv7h only) , ...)


## constants ##

readonly DEBUG=0

readonly BLACKLIST=/usr/share/doc/your-freedom/blacklist.txt
readonly ARCH_MIRROR=http://mirror.cyberbits.eu/archlinux
readonly ARCH_REPOS=( community{,-testing} core extra testing multilib{,-testing} )
readonly TEMP_DB_NAME=blacklist-diffs

readonly BLACKLIST_ERR_MSG="this script requires the 'your-freedom' package"
readonly UNPRIVILEGED_ERR_MSG="this script requires super-user privileges"
readonly CBLUE='\033[0;36m'
readonly CRED='\033[0;31m'
readonly CYELLOW='\033[0;33m'
readonly CEND='\033[0m'

BlacklistedPkgs=( $(sed 's|:.*||' ${BLACKLIST}) )
DbTempdirs=() # Init()


## helpers ##

DBG() # (log_fmt [fmt_args]*)
{
  local log_fmt=$1
  local fmt_args=( "${@:2}" )

  (( DEBUG )) && printf "${CYELLOW}${log_fmt}${CEND}\n" "${fmt_args[@]}" >&2 || :
}

Log() # (log_fmt [fmt_args]*)
{
  local log_fmt=$1
  local fmt_args=( "${@:2}" )

  printf "${CBLUE}${log_fmt}${CEND}\n" "${fmt_args[@]}" >&2
}

LogError() # (log_fmt [fmt_args]*)
{
  local log_fmt=$1
  local fmt_args=( "${@:2}" )

  printf "${CRED}ERROR: ${log_fmt}${CEND}\n" "${fmt_args[@]}" >&2
}

Exit() # (log_fmt [fmt_args]*)
{
  LogError "$@" ; exit 1 ;
}

PacmanOpts() # (db_tempdir)
{
  local db_tempdir=$1

  echo "--dbpath=${db_tempdir} --config=${db_tempdir}/pacman.conf"
}


## business ##

Init() # (upstream_arch mirror_url repos*)
{
  local upstream_arch=$1
  local mirror_url=$2
  local repos=( ${@:3} )

  # Setup the temporary directory
  local db_tempdir="$(mktemp --tmpdir -d "${TEMP_DB_NAME}-${upstream_arch}.XXXXXXXXXX")"
  DbTempdirs+=( ${db_tempdir} )

  # populate the temporary package database
  Log "updating database ...."
  cd ${db_tempdir}
  printf "[options]\nArchitecture = ${upstream_arch}\n"              > pacman.conf
  for repo in ${repos[@]}
  do  printf "[${repo}]\nServer = ${mirror_url}/\$repo/os/\$arch\n" >> pacman.conf
  done
  sudo pacman $(PacmanOpts ${db_tempdir}) -Sy &> /dev/null

  echo ${db_tempdir}


DBG "Init() db_tempdir=${db_tempdir}=$(printf "\n\t%s" $(ls ${db_tempdir}))"
}

Compare() # (db_tempdir)
{
  local db_tempdir=$1
  local upstream_arch=$(sed "s|.*/${TEMP_DB_NAME}-\([^\.]*\)\..*|\1|" <<<${db_tempdir})
  local upstream_pkgs=( $(pacman $(PacmanOpts ${db_tempdir}) -Ss | cut -d ' ' -f 1) )
  local blacklisted_pkg upstream_pkg


DBG "Compare() db_tempdir=${db_tempdir}"
DBG "Compare() PacmanOpts=$(PacmanOpts ${db_tempdir})"
DBG "Compare() upstream_arch=${upstream_arch}"
DBG "Compare() upstream_pkgs=${upstream_pkgs[*]:0:4}"
DBG "Compare() n_blacklisted_pkgs=${#BlacklistedPkgs[*]}"
DBG "Compare() n_upstream_pkgs=${#upstream_pkgs[*]}"


  Log "comparing (${#BlacklistedPkgs[*]}) blacklisted packages to (${#upstream_pkgs[*]}) ${upstream_arch} packages ...."
  for blacklisted_pkg in ${BlacklistedPkgs[*]}
  do  upstream_pkg="$(grep ^[^/]*/${blacklisted_pkg}$ <(printf "%s\n" ${upstream_pkgs[*]}) || \
                      echo '<NONE>' | cut -d ' ' -f 1               )"
      echo "${upstream_pkg} ${blacklisted_pkg}"
  done | sort | column -t
}


trap "for tmpdir in ${DbTempdirs[*]} ; do rm -rf -- ${tmpdir} ; done ;" EXIT


[[ -f "${BLACKLIST}"             ]] || Exit "${BLACKLIST_ERR_MSG}"
(( ${#BlacklistedPkgs[*]}        )) || Exit "${BLACKLIST_ERR_MSG}"
sudo pacman -Ss pacman &> /dev/null || Exit "${UNPRIVILEGED_ERR_MSG}"


Compare $(Init x86_64 ${ARCH_MIRROR} ${ARCH_REPOS[*]})