#!/usr/bin/env bash

script_name="$(basename $(realpath $0))"
working_dir="$(dirname $(realpath $0))"

conf_file="${working_dir}/conf/${script_name%%.*}.conf"

log_file="$(mktemp)"
random_prefix="$(head -c 300 /dev/urandom | tr -cd 'a-zA-Z0-9' | head -c  8)"

backup_date=$(date +%Y-%m-%d-%H%M)


# =============
# --- Some functions
# =============

clean_up() {


   if [[ -f "$_backup_crontab_file" ]]; then

      blank_line
      echononl "   (Re)Install Crontab from previously saved crontab file
      '$_backup_crontab_file'.."

      crontab $_backup_crontab_file >> $log_file 2>&1

      if [[ $? -eq 0 ]]; then
         echo_ok
      else
         echo_failed
         error "$(cat $log_file)"
      fi

   fi

   # Perform program exit housekeeping
   rm -f $log_file
   rm -rf /tmp/*.${random_prefix}
   blank_line
   exit $1
}

echononl(){
   if $terminal ; then
      echo X\\c > /tmp/shprompt$$
      if [ `wc -c /tmp/shprompt$$ | awk '{print $1}'` -eq 1 ]; then
         echo -e -n "  $*\\c" 1>&2
      else
         echo -e -n "  $*" 1>&2
      fi
      rm /tmp/shprompt$$
   fi
}
echo_done() {
   if $terminal ; then
      echo -e "\033[80G[ \033[32mdone\033[m ]"
   fi
}
echo_ok() {
   if $terminal ; then
      echo -e "\033[80G[ \033[32mok\033[m ]"
   fi
}
echo_ignore() {
   if $terminal ; then
      echo -e "\033[80G[ \033[33mignore\033[m ]"
   fi
}
echo_warning() {
   if $terminal ; then
      echo -e "\033[80G[ \033[33m\033[1mwarn\033[m ]"
   fi
}
echo_failed(){
   if $terminal ; then
      echo -e "\033[80G[ \033[1;31mfailed\033[m ]"
   fi
}
echo_skipped() {
   if $terminal ; then
      echo -e "\033[80G[ \033[37mskipped\033[m ]"
   fi
}

fatal (){
   blank_line
   if $terminal ; then
      echo -e "  [ \033[31m\033[1mFatal\033[m ]: \033[37m\033[1m$*\033[m"
      echo ""
      echo -e "  \033[31m\033[1m           Script will be interrupted..\033[m\033[m"
   else
      echo "fatal: $*"
      echo "Script will be interrupted.."
   fi
   clean_up 1
}
error(){
   blank_line
   if $terminal ; then
      echo -e "  [ \033[31m\033[1mFehler\033[m ]: $*"
   else
      echo "Error: $*"
   fi
   blank_line
}

warn (){
   if $terminal ; then
      echo ""
      echo -e "  [ \033[33m\033[1mWarning\033[m ]: $*"
      echo ""
   fi
}

info (){
   if $terminal ; then
      echo ""
      echo -e "  [ \033[32m\033[1mInfo\033[m ]: $*"
      echo ""
   fi
}

## - Check if a given array (parameter 2) contains a given string (parameter 1)
## -
containsElement () {
   local e
   for e in "${@:2}"; do [[ "$e" == "$1" ]] && return 0; done
   return 1
}

trim() {
    local var="$*"
    var="${var#"${var%%[![:space:]]*}"}"   # remove leading whitespace characters
    var="${var%"${var##*[![:space:]]}"}"   # remove trailing whitespace characters
    echo -n "$var"
}

blank_line() {
   if $terminal ; then
      echo ""
   fi
}



# ----------
# - Jobhandling
# ----------

# - Run 'clean_up' for signals SIGHUP SIGINT SIGTERM
# -
trap clean_up SIGHUP SIGINT SIGTERM


# =============
# --- Some 
# =============

# - Support systemd ?
# -
if [[ "X$(which systemd)" = "X" ]]; then
   SYSTEMD_EXISTS=false
else
   SYSTEMD_EXISTS=true
fi

# - Running in a terminal?
# -
if [[ -t 1 ]] ; then
   terminal=true
else
   terminal=false
fi
#terminal=false


# ----------
#  Read Configurations from $conf_file
# ----------


# - Give your default values here
# -
DEFAULT_QUARANTINE_BASE_DIR="/var/QUARANTINE"
DEFAULT_CLAMAV_VIRUS_WHITE_LIST="/var/lib/clamav/my_whitelist.ign2"
DEFAULT_WHITE_LIST_STRINGS="google.com"

blank_line
echononl "Include Configuration file.."
if [[ ! -f $conf_file ]]; then
   echo_skipped
   warn  "No configuration file '$conf_file' found!\n
               Loading default values.."
else
   source $conf_file
   echo_done
fi
blank_line

[[ -z "$QUARANTINE_BASE_DIR" ]] && QUARANTINE_BASE_DIR="$DEFAULT_QUARANTINE_BASE_DIR"

Q_VIRUS_DIR="${QUARANTINE_BASE_DIR}/virus"

[[ -z "$CLAMAV_VIRUS_WHITE_LIST" ]] && CLAMAV_VIRUS_WHITE_LIST="$DEFAULT_CLAMAV_VIRUS_WHITE_LIST"

[[ -z "$WHITE_LIST_STRINGS" ]] && WHITE_LIST_STRINGS="$DEFAULT_WHITE_LIST_STRINGS"

# List of strings to be whitelisted
#
declare -a whitelist_string_arr=()
for _str in $WHITE_LIST_STRINGS ; do
   whitelist_string_arr+=("$_str")
done
   

# -----
# - Doing some pre-script tasks
# -----

if $terminal ; then
   echo ""
   echo ""
   echo -e "\033[37m\033[1mDoing some pre-script tasks..\033[m"
   echo ""
fi

if $terminal ; then
   echo -e "  \033[32mFind/Manage signatures that have already whitelistet\033[m..\n"
fi

# - List of already whitelistet signatures
# -
_found=false
declare -a white_list=()
if [[ ! -f "$CLAMAV_VIRUS_WHITE_LIST" ]] ; then
   if $terminal ; then
      echo -e "  \033[33mNo whitelist file present\033[m..\n"
   fi
else
   for _sig in $(grep -E "^MBL_" $CLAMAV_VIRUS_WHITE_LIST | sort -u) ; do

      _found=true
      _failed=false

      # Decode Signatures, save output in file
      #
      echononl "Decode Signature \033[1m$_sig\033[m .."
      sigtool --find-sigs=$_sig |  sigtool --decode-sigs > /tmp/${_sig}.${random_prefix} 2> $log_file
      [[ $? -ne 0 ]] && _failed=true

      # Remove blank lines and lines that only contain whitespaces
      #
      sed -i '/^[[:space:]]*$/d' /tmp/${_sig}.${random_prefix} >> $log_file 2>&1
      [[ $? -ne 0 ]] && _failed=true

      if $_failed ; then
         echo_failed
         error "$(cat $log_file)"
         continue
      else
         echo_ok
      fi

      if [[ -s "/tmp/${_sig}.${random_prefix}" ]]; then
         echononl "Add signature '$_sig' to whitelist array.."
         white_list+=("$_sig")
         if [[ $? -eq 0 ]]; then
            echo_ok
         else
            echo_failed
            error "$(cat $log_file)"
         fi
      else
         echononl "Signature '$_sig' is NOT decodable.."
         echo_ignore
         rm -f /tmp/${_sig}.${random_prefix} > /dev/null 2>&1
         #echononl "Delete '$_sig' from whitelist '$CLAMAV_VIRUS_WHITE_LIST'.."
         #sed -i "/$_sig/d" "$CLAMAV_VIRUS_WHITE_LIST" > $log_file 2>&1
         #if [[ $? -eq 0 ]]; then
         #   echo_ok
         #else
         #   echo_failed
         #   error "$(cat $log_file)"
         #fi
      fi
      blank_line
   done

   if ! $_found ; then
      if $terminal ; then
         echo -e "  \033[33mNo already whitelistet signature present\033[m..\n"
      fi
   fi
fi


blank_line


if $terminal ; then
   echo -e "  \033[32mGathering/Manage signatures starting with 'MBL_' from quarantined e-mails\033[m..\n"
fi

# - Get signarures starting with "MBL_" found
# -
echononl "Gather signatures from quarantined e-mails .."
found_sigs="$(grep -o -E " MBL_[[:digit:]]*" ${Q_VIRUS_DIR}/* 2> $log_file | cut -d ' ' -f2 | sort -u)"
if [[ $? -eq 0 ]]; then
   echo_done
else
   echo_failed
   error "$(cat $log_file)"
fi

blank_line

declare -a whitelist_sig_arr=()
declare -A virus_emails=()
if [[ -z "$found_sigs" ]]; then
   if $terminal ; then
      echononl "\033[33mNo quarantined e-mails with  \033[1mMBL_*\033[ signatures found.\033[m\n"
   fi
else
   _failed=false
   for _sig in $found_sigs ; do
      for _str in ${whitelist_string_arr[@]} ; do
         if $(sigtool --find-sigs=$_sig | sigtool --decode-sigs | grep -q "$_str" 2> $log_file) ; then
            if containsElement "$_sig"  "${white_list[@]}" ; then
               echononl "Signature \033[1m$_sig\033[m already whitelisted.."
               echo_ignore
            else
               blank_line
               echononl "Mark signatur \033[1m$_sig\033[m containing \033[1m$_str\033[m for whitelisting.."
               whitelist_sig_arr+=("$_sig")
               if [[ $? -eq 0 ]]; then
                  echo_ok

                  echononl "Decode Signature \033[1m$_sig\033[m .."
                  sigtool --find-sigs=$_sig |  sigtool --decode-sigs > /tmp/${_sig}.${random_prefix} 2> $log_file
                  [[ $? -ne 0 ]] && _failed=true

                  # Remove blank lines and lines that only contain whitespaces
                  #
                  sed -i '/^[[:space:]]*$/d' /tmp/${_sig}.${random_prefix} >> $log_file 2>&1
                  [[ $? -ne 0 ]] && _failed=true

                  if $_failed ; then
                     echo_failed
                     error "$(cat $log_file)"
                     _failed=false
                     continue
                  else
                     echo_ok
                  fi

               else
                  echo_failed
                  error "Adding signatur \033[1m$_sig\033[m to array 'whitelist_sig_arr' failed!"
               fi
               blank_line
            fi
         else
            echononl "Signature \033[1m$_sig\033[m does not affect \033[1m$_str\033[m.."
            echo_ignore
         fi
      done
   done
fi


blank_line
if [[ ${#whitelist_sig_arr[@]} -lt 1 ]]; then
   if $terminal ; then
      info "No quarantined e-mails with whitelist signature(s) found.

            Nothing do to, exit now.."
   fi
   clean_up 0
fi


if $terminal ; then
   echo -e "  \033[32mGather/Manage quarantined e-mails with detected whitelist signature(s)\033[m..\n"
fi

for _sig in ${whitelist_sig_arr[@]}; do
   #_emails="$(grep INFECTED ${Q_VIRUS_DIR}/* | grep "$_sig" | cut -d ':' -f1 | sed -e "s#^${QUARANTINE_BASE_DIR}/##")"
   #_emails="$(grep INFECTED ${Q_VIRUS_DIR}/* | grep "$_sig" | cut -d ':' -f1)"
   _emails="$(grep "$_sig" ${Q_VIRUS_DIR}/* | cut -d ':' -f1)"
   for _email in $_emails ; do
      _email="${_email#"${QUARANTINE_BASE_DIR}/virus/"}"
      echononl "Add \033[1m$_email\033[m with signatur \033[1m$_sig\033[m to list.." 
      virus_emails+=(["$_email"]="$_sig")
      if [[ $? -eq 0 ]]; then
         echo_ok
      else
         echo_failed
         error "$(cat $log_file)"
      fi
      echononl "Add signature \033[1m$_sig\033[m to whitelist array.." 
      if containsElement "$_sig" "${white_list[@]}" ; then
         echo_skipped
      else
         white_list+=("$_sig")
         if [[ $? -eq 0 ]]; then
            echo_ok
         else
            echo_failed
            error "$(cat $log_file)"
         fi
      fi
   done
done



# -----
# -  Main Part of Script
# -----

if $terminal ; then
   echo ""
   echo ""
   echo -e "\033[37m\033[1mMain Part of Script.\033[m"
   echo ""
fi

if $terminal ; then
   echo -e "  \033[32mWrite new whitelist file\033[m..\n"
fi

tmp_whitelist_file="/tmp/$(basename "${CLAMAV_VIRUS_WHITE_LIST}").${random_prefix}"
:> "$tmp_whitelist_file"
for _sig in ${white_list[@]} ; do
   _failed=false
   echononl "Add signatur \033[1m$_sig\033[m to clamav's whitelist file"
   while IFS='' read -r line || [[ -n "$line" ]] ; do
      echo "# $line" >> "$tmp_whitelist_file" 2>> "$log_file"
      [[ $? -ne 0 ]] && _failed=true
   done < "/tmp/${_sig}.${random_prefix}"
   echo "$_sig" >> "$tmp_whitelist_file" 2>> "$log_file"
   [[ $? -ne 0 ]] && _failed=true
   if $_failed ; then
      echo_failed
      error "$(cat $log_file)"
      _failed=false
   else
      echo_ok
      if ! $terminal ; then
         echo ""
         echo "  Add Signatur "$_sig" to clamav's whitelist \"${CLAMAV_VIRUS_WHITE_LIST}\""
      fi
   fi
done

blank_line

echononl "Copy the temporary whitelist file to the designated location.."
cp "$tmp_whitelist_file" "${CLAMAV_VIRUS_WHITE_LIST}" > "$log_file" 2>&1
if [[ $? -eq 0 ]]; then
   echo_ok
else
   echo_failed
   error "$(cat $log_file)"
fi

# Remove blank lines and lines that only contain whitespaces
#
echononl "Remove empty lines from whitelist file.."
sed -i '/^[[:space:]]*$/d'  "${CLAMAV_VIRUS_WHITE_LIST}" > "$log_file" 2>&1
if [[ $? -eq 0 ]]; then
   echo_ok
else
   echo_failed
   error "$(cat $log_file)"
fi


blank_line

if $terminal ; then
   echo -e "  \033[32mResend quarantined e-mails with detected whitelist signature\033[m..\n"
fi

if [[ ${#virus_emails[@]} -lt 1 ]]; then
   error "No quarantined e-mails with detected whitelist signature found."
else
   for _virus_email in "${!virus_emails[@]}"; do
      _recipient="$(
         grep "X-Envelope-To-Blocked:" ${Q_VIRUS_DIR}/${_virus_email} 2> "$log_file" \
            | grep -o -E "\b[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,6}\b"
      )"

      echononl "Resend blocked e-mail with signatur \033[1m${virus_emails[$_virus_email]}\033[m
  to \033[1m$_recipient\033[m"

      amavisd-release virus/${_virus_email} > "$log_file" 2>&1
      if [[ $? -eq 0 ]]; then
         echo_ok

         if ! $terminal ; then
            echo ""
            echo "  Resend blocked e-mail with signatur ${virus_emails[$_virus_email]} to $_recipient"
         fi

         echononl "Remove \033[1mvirus/${_virus_email}\033[m from QUARANTINE directory.."
         rm "${Q_VIRUS_DIR}/${_virus_email}" > "$log_file" 2>&1
         if [[ $? -eq 0 ]]; then
            echo_ok
         else
            echo_failed
            error "$(cat $log_file)"
         fi
      else
         echo_failed
         error "$(cat $log_file)"
      fi
   blank_line

   done
fi


if $terminal ; then
   echo ""
   echo ""
   echo -e "\033[37m\033[1mDoing some post-script tasks..\033[m"
   echo ""
fi

echononl "Restart ClamAV Daemon"
if $SYSTEMD_EXISTS ; then
   systemctl restart clamav-daemon > "$log_file" 2>&1
   if [[ $? -eq 0 ]]; then
      echo_ok
   else
      echo_failed
      error "$(cat $log_file)"
   fi
else
   /etc/init.d/clamav-daemon restart > "$log_file" 2>&1
   if [[ $? -eq 0 ]]; then
      echo_ok
   else
      echo_failed
      error "$(cat $log_file)"
   fi
fi


blank_line

clean_up 1


# -----
# - Doing some post-script tasks
# -----