#!/usr/bin/env bash

set -o pipefail

cleanup()
{
  rm -f "${tmp_container[@]}"
}

insert_date()
{
  while read
  do
    local date_value
    date_value="$(date +"%b %d %T %s.%N")"
    echo "${date_value} ${REPLY}"
  done
}

fatal_error_handler()
{
  local result="$?"
  local p_message="$1"
  local pid="${BASHPID}"
  (exit "${result}") ||
  {
    (
      cd "$(dirname "${BASH_SOURCE[1]}")"
      echo -n "${FUNCNAME[0]}: $(echo | insert_date)${PWD}/${BASH_SOURCE[1]##*/}:${BASH_LINENO[0]} ${FUNCNAME[1]}() PID(${pid})"
    )
    [ "${p_message}" != "" ] && echo -n " ${p_message}"
    echo
    return "${result}"
  } >&2
}

version_test_gt()
{
  local version_a="$1"
  local version_b="$2"
  dpkg --compare-versions "${version_a}" gt "${version_b}"
}

get_current_kernel_version()
{
  local p_dpkg_output="$1"
  local current_kernel_version
  current_kernel_version="linux-image-$(uname -r)"
  current_kernel_version="$(awk '$2=="'${current_kernel_version}'" {print $3}' <<< "${p_dpkg_output}")" || fatal_error_handler || return
  [ "${current_kernel_version}" != "" ] || fatal_error_handler || return
  echo "${current_kernel_version}"
}

is_gui_required()
{
  if ! tty &> /dev/null
  then
    echo "true"
  else
    echo "false"
  fi
}

main()
{
  local dpkg_output
  dpkg_output="$(dpkg -l 'linux-image-[0-9]*' | awk '$1=="ii"')" || fatal_error_handler || return
  [ "${dpkg_output}" != "" ] || fatal_error_handler || return
  local version_to_keep_container
  version_to_keep_container=($(awk '{print $3}' <<< "${dpkg_output}")) || fatal_error_handler || return
  [ 0 -lt "${#version_to_keep_container[@]}" ] || fatal_error_handler || return
  local idx1
  for ((idx1=0; idx1<${#version_to_keep_container[@]}-1; ++idx1))
  do
    local idx2
    for ((idx2=idx1+1; idx2<${#version_to_keep_container[@]}; ++idx2))
    do
      if version_test_gt "${version_to_keep_container[idx1]}" "${version_to_keep_container[idx2]}"
      then
        local tmp="${version_to_keep_container[idx1]}"
        version_to_keep_container[idx1]="${version_to_keep_container[idx2]}"
        version_to_keep_container[idx2]="${tmp}"
      fi
    done
  done
  version_to_keep_container=($(
  {
    (
      IFS=$'\n'
      echo "${version_to_keep_container[*]}"
    ) | tail -2 || fatal_error_handler || return
    get_current_kernel_version "${dpkg_output}" || fatal_error_handler || return
  } | sort -u)) || fatal_error_handler || return
  ((1 <= "${#version_to_keep_container[@]}" && "${#version_to_keep_container[@]}" <= 3)) || fatal_error_handler || return
  dpkg_output="$(dpkg -l 'linux-headers-*' 'linux-image-*' | awk '$1=="ii"')" || fatal_error_handler || return
  [ "${dpkg_output}" != "" ] || fatal_error_handler || return
  for ((idx1=0; idx1<${#version_to_keep_container[@]}; ++idx1))
  do
    dpkg_output="$(awk '$3!="'${version_to_keep_container[idx1]}'"' <<< "${dpkg_output}")" || fatal_error_handler || return
  done
  dpkg_output="$(awk '$2!="linux-headers-generic"' <<< "${dpkg_output}")" || fatal_error_handler || return
  dpkg_output="$(awk '$2!="linux-image-generic"' <<< "${dpkg_output}")" || fatal_error_handler || return
  local package_to_remove_container
  if [ "${dpkg_output}" != "" ]
  then
    package_to_remove_container+=($(awk '{print $2}' <<< "${dpkg_output}")) || fatal_error_handler || return
  fi
  dpkg_output="$(dpkg -l | awk '$1=="rc"')" || fatal_error_handler || return
  if [ "${dpkg_output}" != "" ]
  then
    package_to_remove_container+=($(awk '{print $2}' <<< "${dpkg_output}")) || fatal_error_handler || return
  fi
  if [ 0 -lt "${#package_to_remove_container[@]}" ]
  then
    if [ "${gui_required}" = "true" ]
    then
      (IFS=$'\n';echo "${package_to_remove_container[*]}") | LANG="${language}" zenity --list --title "${title}" --text "${text}" --column "${column}" &> /dev/null || return 0
    else
      echo "${text}"
      (IFS=$'\n';echo "${package_to_remove_container[*]}")
      echo -n "${choice}"
      read
      [ "${REPLY}" != "y" ] && [ "${REPLY}" != "o" ] && return 0
    fi
    if [ "${gui_required}" = "true" ]
    then
      local password
      password="$(LANG="${language}" zenity --title "${title}" --password)" || return 0
      sudo -S -- apt-get -y purge "${package_to_remove_container[@]}" <<< "${password}" || fatal_error_handler || return
      sudo -S -- apt-get -y autoclean                                 <<< "${password}" || fatal_error_handler || return
      sudo -S -- apt-get -y clean                                     <<< "${password}" || fatal_error_handler || return
      sudo -S -- apt-get -y autoremove                                <<< "${password}" || fatal_error_handler || return
      unset password
    else
      sudo -- apt-get -y purge "${package_to_remove_container[@]}" || fatal_error_handler || return
      sudo -- apt-get -y autoclean                                 || fatal_error_handler || return
      sudo -- apt-get -y clean                                     || fatal_error_handler || return
      sudo -- apt-get -y autoremove                                || fatal_error_handler || return
    fi
    if [ "${gui_required}" = "true" ]
    then
      LANG="${language}" zenity --title "${title}" --info --text "${text2}" --no-wrap
    else
      echo "${text2}"
    fi
  fi
}

if [ "$0" = "${BASH_SOURCE[0]}" ]
then
  trap cleanup EXIT
  declare -r gui_required="$(is_gui_required)"
  if [ "${gui_required}" = "true" ]
  then
    tmp_container+=("$(mktemp -u)")
    declare -r logfile="${tmp_container[${#tmp_container[@]}-1]}"
    exec &> "${logfile}"
  fi
  declare -r language="${LANG}"
  if [ "${language:0:5}" = "fr_FR" ]
  then
    declare -r title="Nettoyeur du système"
    declare -r text="Voulez vous supprimer les paquets ci-dessous ?"
    declare -r text2="Le système a été nettoyé avec succès."
    declare -r column="Nom du paquet"
    declare -r choice="Choix (o/n) : "
    declare -r text3="Contenu du fichier : \"${logfile}\""
  else
    declare -r title="System cleaner"
    declare -r text="Do you want to remove packages below?"
    declare -r text2="System has been successfully cleaned."
    declare -r column="Package name"
    declare -r choice="Choice (y/n): "
    declare -r text3="Content of file: \"${logfile}\""
  fi
  if [ "${gui_required}" = "true" ]
  then
    echo "${text3}"
  fi
  LANG="C"
  main "$@" || fatal_error_handler || [ "${gui_required}" = "false" ] || LANG="${language}" zenity --title "${title}" --text-info --filename "${logfile}"
fi