#autoload

# Usage: _deb_packages expl... avail|installed|uninstalled

_deb_packages_updage_avail () {
  if (( ! $+_deb_packages_cache_uninstalled )); then
    _deb_packages_cache_avail=(
      ${(f)"$(apt-cache dumpavail | awk '/^Package:/ { print $2 }')"}
    )
  fi
  cachevar=_deb_packages_cache_avail
}

_deb_packages_updage_installed () {
  if (( ! $+_deb_packages_cache_installed )); then
    _deb_packages_cache_installed=(
      ${${${(f)"$(dpkg --get-selections)"}:#*deinstall}%%	*}
    )
  fi
  cachevar=_deb_packages_cache_installed
}

_deb_packages_updage_uninstalled () {
  _deb_packages_updage_avail
  _deb_packages_updage_installed
  if (( ! $+_deb_packages_cache_uninstalled )); then
    _deb_packages_cache_uninstalled=(
      ${_deb_packages_cache_avail:#${(j:|:)~${_deb_packages_cache_installed:q}}}
    )
  fi
  cachevar=_deb_packages_cache_uninstalled
}

_deb_packages () {
  local command="$argv[$#]" expl cachevar

  [[ "$command" = (installed|uninstalled|avail) ]] || {
    _message "_deb_packages:unknown command: $command"
    return
  }

  expl=("${(@)argv[1,-2]}")

  _deb_packages_updage_$command

  _tags packages && compadd "$expl[@]" - "${(e):-"\${(@)$cachevar}"}"
}

_deb_packages "$@"