#!/usr/bin/env bash

: "
  * This script is stupid and slow.  You probably shouldn't use it.
  "

. "$(dirname $0)/util/logging.bash"

command -v pacman > /dev/null \
  || die 'ERROR:  This script only works on systems with the "pacman" package' \
         ' manager!'


read -d '' usage <<EOUSAGE
$0 allows you to prune files in a directory tree that aren't managed by
Pacman.  Without the "-r" option it will just print files that aren't managed by
Pacman to standard output and logging information to standard error.

Usage:  $0 [-r|-h] [-i IGNORE_LIST] PATH ... PATH_N

Options:
    -r              -  Remove files instead of just printing them to standard
                       output. (Potentially dangerous!)
    -i IGNORE_LIST  -  Newline-delimited file containing files that should be
                       left alone by pacpruner.
    -h              -  Display this help.
EOUSAGE

rm=0

[ -z "$1" ] && dedcat "$usage"

while getopts 'rhi:' opt; do
  case "${opt}" in
    r)
      rm=1
      ;;
    i)
      export ignore_files=$(<$OPTARG) || exit 1
      ;;
    h)
      excat "$usage"
      ;;
  esac
done

shift $((OPTIND-1))

export packages=$(pacman -Qqn)
export rm

_prune() {
  matching_pkgs=$(pacman -F "$1" | awk '{print $5}' | sed 's/.*\///')
  if [ -z "$matching_pkgs" ]; then
    [ $rm -eq 1 ] && sudo rm -rv "$1" || errcho "PRUNE: \"$1\"" && echo "$1"
  else
    errcho "matching \"$matching_pkgs\""
    if [ $(grep -F "$matching_pkgs" <<<"$packages" | wc -l) -eq 0 ]; then
      [ $rm -eq 1 ] && sudo rm -rv "$1" || errcho "PRUNE: \"$1\"" && echo "$1"
    else
      errcho "Ignoring \"$1\""
    fi
  fi
}

prune() {
  for file in ${@}; do
    errcho "FILE: $file"
    if [ -n "$ignore_files" ]; then
      [ $(grep -F "$file" <<<"$ignore_files" | wc -l) -eq 0 ] \
        && _prune "$file" \
        || errcho "Ignoring \"$file\" from IGNORE_LIST."
    else
      _prune "$file"
    fi
  done
}

[ $rm -eq 1 ] && sudo -v

export -f errcho die _prune prune

while [ -n "$1" ]; do
  find $(dirname "${1}") -name $(basename "${1}") -print0 | xargs -0 -I '{}' bash -c 'prune {}'
  shift
done