#!/usr/bin/env bash


working_dir="$(dirname $(realpath $0))"
conf_file="${working_dir}/conf/bind.conf"

log_file="$(mktemp)"

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

_serial_new=`date +%Y%m%d01`


#---------------------------------------
#-----------------------------
# Base Function(s)
#-----------------------------
#---------------------------------------

clean_up() {

   # Perform program exit housekeeping
   rm $log_file
   exit $1
}

echononl(){
   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$$
}

fatal(){
   echo ""
   echo -e "[ \033[31m\033[1mError\033[m ]: $*"
   echo ""
   echo -e "\t\033[31m\033[1mScript is canceled\033[m\033[m"
   echo ""
   clean_up 1
}

warn (){
   echo ""
   echo -e "\t[ \033[33m\033[1mWarning\033[m ]: $*"
   echo ""
}

info (){
   echo ""
   echo -e "\t[ \033[33m\033[1mInfo\033[m ]: $*"
   echo ""
}

ok (){
   echo ""
   echo -e "\t[ \033[36m\033[1mOk\033[m ]: $*"
   echo ""
}

error(){
   echo ""
   echo -e "\t[ \033[31m\033[1mFehler\033[m ]: $*"
   echo ""
}

echo_ok() {
   echo -e "\033[75G[ \033[32mok\033[m ]"
}
echo_done() {
   echo -e "\033[75G[ \033[32mdone\033[m ]"
}
echo_failed(){
   echo -e "\033[75G[ \033[1;31mfailed\033[m ]"
}
echo_skipped() {
   echo -e "\033[75G[ \033[33m\033[1mskipped\033[m ]"
}

containsElement () {
   local e
   for e in "${@:2}"; do [[ "$e" == "$1" ]] && return 0; done
   return 1
}


## - Test of valid IPv4 Address
## -
## -    Returns 0 if valid, > 0 otherwise
## -
is_valid_ipv4() {
  local -a octets=( ${1//\./ } )
  local RETURNVALUE=0

  # return an error if the IP doesn't have exactly 4 octets
  [[ ${#octets[@]} -ne 4 ]] && return 1

  for octet in ${octets[@]}
  do
    if [[ ${octet} =~ ^[0-9]{1,3}$ ]]
    then # shift number by 8 bits, anything larger than 255 will be > 0
      ((RETURNVALUE += octet>>8 ))
    else # octet wasn't numeric, return error
      return 1
    fi
  done
  return ${RETURNVALUE}
}

is_valid_ipv6() {
   local _ipv6=$1

   if [ "$1" != "${1#[0-9a-f]*:}" ] \
      && [ "$1" = "${1#*[^0-9a-f:]}" ] \
      && [ "${1#*[0-9A-Fa-f][0-9A-Fa-f][0-9A-Fa-f][0-9A-Fa-f][0-9A-Fa-f]}" = "${1#*:*:*:*:*:*:*:*:*:}" ]; then
      return 0
   else
      return 1
   fi
}

trap clean_up SIGHUP SIGINT SIGTERM



#---------------------------------------
#-----------------------------
# Setting Defaults
#-----------------------------
#---------------------------------------

DEFAULT_CONF_FILE_DIR="/etc/bind"
DEFAULT_BIND_CACHE_DIR="/var/cache/bind"



#---------------------------------------
#-----------------------------
# Load default values from bind.conf
#
# Overwrites the settings above
# 
#-----------------------------
#---------------------------------------

#clear
echo ""
echo ""
echononl "   Loading default Configuration values from $(basename ${conf_file}).."
if [[ ! -f "$conf_file" ]]; then
   echo_skipped
else
   source "${conf_file}" > $log_file 2>&1
   if [[ $? -eq 0 ]]; then
      echo_ok
   else
      echo_failed
      fatal "$(cat $log_file)"
   fi
fi

[[ -n "$CONF_FILE_DIR" ]] && DEFAULT_CONF_FILE_DIR="$CONF_FILE_DIR"

[[ -n "$BIND_CACHE_DIR" ]] && DEFAULT_BIND_CACHE_DIR="$BIND_CACHE_DIR"

if [[ -n "$ZONE_FILE_MASTER_DIR" ]] ; then
   DEFAULT_ZONE_FILE_MASTER_DIR="$ZONE_FILE_MASTER_DIR"
else
   DEFAULT_ZONE_FILE_MASTER_DIR="${DEFAULT_CONF_FILE_DIR}/master"
fi

if [[ -n "$ZONE_FILE_SLAVE_DIR" ]] ; then
   DEFAULT_ZONE_FILE_SLAVE_DIR="$ZONE_FILE_SLAVE_DIR"
else
   DEFAULT_ZONE_FILE_SLAVE_DIR="$DEFAULT_BIND_CACHE_DIR"
fi

if [[ -n "$ZONE_FILE_SUFFIX" ]] ; then
   DEFAULT_ZONE_FILE_SUFFIX="$ZONE_FILE_SUFFIX"
else
   DEFAULT_ZONE_FILE_SUFFIX='zone'
fi

if [[ -n "$ZONES_DECLARATION_FILE" ]] ; then
   DEFAULT_ZONES_DECLARATION_FILE="$ZONES_DECLARATION_FILE"
else
   DEFAULT_ZONES_DECLARATION_FILE="${CONF_FILE_DIR}/named.conf.local"
fi


echo ""
echo -e "\033[32m--\033[m"
echo ""
echo "Insert IPv4-Address(es) for which TTL should be set to zone-file default."
echo ""
echo "For multiple IPv4 Addresses, insert a blank separated list"
echo ""
echo -e "Type \"\033[33mNone\033[m\" if no IPv4 address should be changed."
echo ""
IPv4_ADDRESS=
_set_ipv4=true
while [ "X$IPv4_ADDRESS" = "X" ]; do
   echononl "IPv4-Address: "
   read IPv4_ADDRESS
   ## - To lower case
   IPv4_ADDRESS=${IPv4_ADDRESS,,}
   if [ "X$IPv4_ADDRESS" = "X" ]; then
      echo -e "\n\t\033[33m\033[1mAn entry is required!\033[m\n"
      IPv4_ADDRESS=""
      continue
   fi
   if [ "$IPv4_ADDRESS" = "none" ];then
      _set_ipv4=false
      break
   fi
   if ! is_valid_ipv4 $IPv4_ADDRESS ; then
      echo -e "\n\t\033[33m\033[1m$IPv4_ADDRESS\033[m is NOT a valid IPv4 Address\n"
      IPv4_ADDRESS=""
      continue
   fi
done


echo ""
echo -e "\033[32m--\033[m"
echo ""
echo "Insert IPv6-Address(es) for which TTL should be set to zone-file default."
echo ""
echo "For multiple IPv6 Addresses, insert a blank separated list"
echo ""
echo -e "Type \"\033[33mNone\033[m\" if no IPv6 address should be changed."
echo ""
IPv6_ADDRESS=
_set_ipv6=true
while [ "X$IPv6_ADDRESS" = "X" ]; do
   echononl "IPv6-Address: "
   read IPv6_ADDRESS
   ## - To lower case
   IPv6_ADDRESS=${IPv6_ADDRESS,,}
   if [ "X$IPv6_ADDRESS" = "X" ]; then
      echo -e "\n\t\033[33m\033[1mAn entry is required!\033[m\n"
      IPv6_ADDRESS=""
      continue
   fi
   if [ "$IPv6_ADDRESS" = "none" ];then
      _set_ipv6=false
      break
   fi
   if ! is_valid_ipv6 $IPv6_ADDRESS ; then
      echo -e "\n\t\033[33m\033[1m$IPv6_ADDRESS\033[m is NOT a valid IPv6 Address\n"
      IPv6_ADDRESS=""
      continue
   fi
done

if ! $_set_ipv6 && ! $_set_ipv4 ; then
   fatal "No IP-Adresses given for changing their TTL to the zone-file default.."
fi


echo ""
echo ""
echo -e "\033[32m--\033[m"
echo "Common parameters"
echo -e "\033[32m--\033[m"


echo ""
echo "Insert directory containing the bind configuration files."
echo ""
CONF_FILE_DIR=""
if [[ -n "$DEFAULT_CONF_FILE_DIR" ]] ; then
   echononl "Bind Configuration Directory [${DEFAULT_CONF_FILE_DIR}]: "
   read CONF_FILE_DIR
   if [[ "X$CONF_FILE_DIR" = "X" ]]; then
      CONF_FILE_DIR="$DEFAULT_CONF_FILE_DIR"
   fi
else
   echononl "Bind Configuration Directory: "
   read CONF_FILE_DIR
   while [ "X$CONF_FILE_DIR" = "X" ] ; do
      echo -e "\n\t\033[33m\033[1mSetting 'Bind Configuration Directory' is required!\033[m\n"
      echononl "Bind Configuration Directory: "
      read CONF_FILE_DIR
   done
fi

[[ -n "$ZONES_DECLARATION_FILE" ]] || DEFAULT_ZONES_DECLARATION_FILE="${CONF_FILE_DIR}/named.conf.local"


echo ""
echo -e "\033[32m--\033[m"

echo ""
echo "Insert zones declaration file."
echo ""
ZONES_DECLARATION_FILE=""
if [[ -n "$DEFAULT_ZONES_DECLARATION_FILE" ]] ; then
   echononl "Zones Declaration File [${DEFAULT_ZONES_DECLARATION_FILE}]: "
   read ZONES_DECLARATION_FILE
   if [[ "X$ZONES_DECLARATION_FILE" = "X" ]]; then
      ZONES_DECLARATION_FILE="$DEFAULT_ZONES_DECLARATION_FILE"
   fi
else
   echononl "Zones Declaration File: "
   read ZONES_DECLARATION_FILE
   while [ "X$ZONES_DECLARATION_FILE" = "X" ] ; do
      echo -e "\n\t\033[33m\033[1mSetting 'Zones Declaration File' is required!\033[m\n"
      echononl "Zones Declaration File: "
      read ZONES_DECLARATION_FILE
   done
fi


echo ""
echo -e "\033[32m--\033[m"

echo ""
echo "Insert the directory, where your zone-files resides."
echo ""
echo ""
ZONE_FILE_MASTER_DIR=""
if [[ -n "$DEFAULT_ZONE_FILE_MASTER_DIR" ]] ; then
   echononl "Zone File Directory (master) [${DEFAULT_ZONE_FILE_MASTER_DIR}]: "
   read ZONE_FILE_MASTER_DIR
   if [[ "X$ZONE_FILE_MASTER_DIR" = "X" ]]; then
      ZONE_FILE_MASTER_DIR="$DEFAULT_ZONE_FILE_MASTER_DIR"
   fi
else
   echononl "Zone File Directory (master): "
   read ZONE_FILE_MASTER_DIR
   while [ "X$ZONE_FILE_MASTER_DIR" = "X" ] ; do
      echo -e "\n\t\033[33m\033[1mSetting 'Zone File Directory (master)' is required!\033[m\n"
      echononl "Zone File Directory (master): "
      read ZONE_FILE_MASTER_DIR
   done
fi


clear
echo ""
echo ""
echo -e "\033[21G\033[32mChange TTL settings to the zonefile default value\033[m"
echo ""

echo ""
if $_set_ipv4 ; then
   echo "IPv4 Address(es)..................: $IPv4_ADDRESS"
else
   echo -e "IPv4 Address(es)..................: \033[33mNone\033[m"
fi
if $_set_ipv6 ; then
   echo "IPv6 Address(es)..................: $IPv6_ADDRESS"
else
   echo -e "IPv6 Address(es)..................: \033[33mNone\033[m"
fi
echo ""
echo "New TTL...........................: Zonefile default"
echo ""
echo "Bind Configuration Directory......: $CONF_FILE_DIR"
echo "Zones Declaration File............: $ZONES_DECLARATION_FILE"
echo "Zone File Directory...............: $ZONE_FILE_MASTER_DIR"
#echo "Zone File Suffix..................: $ZONE_FILE_SUFFIX"

echo ""
OK=
while [ "$OK" != "yes" -o "$OK" != "no" ] ; do
   echononl "Parameters ok? [yes/no]: "
   read OK
   ## - To lower case
   OK=${OK,,}
   if [ "X$OK" = "X" ]; then
      echo -e "\n\t\033[33m\033[1mAn entry is required!\033[m\n"
      OK=""
      continue
   fi
   if [ "$OK" = "yes" -o "$OK" = "no" ] ; then
      break
   else
      OK=""
      continue
   fi
   echo -e "\n\t\033[33m\033[1mWrong entry!\033[m\n"
done
[[ $OK = "yes" ]] || fatal Repeat execution with different parameters


echo ""
echo ""
echononl "\tBackup directory '${ZONE_FILE_MASTER_DIR}'.."
cp -a "${ZONE_FILE_MASTER_DIR}" "${ZONE_FILE_MASTER_DIR}.${backup_date}" > $log_file 2>&1
if [[ $? -eq 0 ]]; then
   echo_ok
else
   echo_failed
   fatal "$(cat $log_file)"
fi

echo ""
echononl "\tCreate array of given IPv4 addresses"
ipv4_addresses_arr=()
for _ipv4_address in $IPv4_ADDRESS ; do
   containsElement "$_ipv4_address"  "${ipv4_addresses_arr[@]}" && continue
   ipv4_addresses_arr+=("$_ipv4_address")
done
echo_done

echononl "\tCreate array of given IPv6 addresses"
ipv6_addresses_arr=()
for _ipv6_address in $IPv6_ADDRESS ; do
   containsElement "$_ipv6_address"  "${ipv6_addresses_arr[@]}" && continue
   ipv6_addresses_arr+=("$_ipv6_address")
done
echo_done


echo ""
echo ""
echo -e "\033[37m\033[1mDetermine zone files conatining ip-adressse for which TTL time is requested to change..\033[m"

_found=false
_is_master=false
zonefiles_arr=()
zone_file=""
regex_master="type[[:space:]]+master"
regex_file="^[[:space:]]*file"
while IFS='' read -r _line || [[ -n $_line ]] ; do

   if [[ $_line  =~ ^[[:space:]]*zone[[:space:]]+ ]]; then
      _found=true
      zone="$(echo $_line | awk '{print$2}')"
      shopt -s extglob
      if [[ $zone =~ \; ]]; then
         zone=${zone%%*(\;)}
      fi
      if [[ $zone =~ ^\" ]]; then
         zone=${zone##*(\")}
         zone=${zone%%*(\")}
      fi
      shopt -u extglob
   fi
   if $_found ; then
      if [[ $_line  =~ $regex_file ]]; then
         zone_file=$(echo $_line | awk '{print$2}')
         shopt -s extglob
         if [[ $zone_file =~ \; ]]; then
            zone_file=${zone_file%%*(\;)}
         fi
         if [[ $zone_file =~ ^\" ]]; then
            zone_file=${zone_file##*(\")}
            zone_file=${zone_file%%*(\")}
         fi
         shopt -u extglob
      fi
      if [[ $_line  =~ $regex_master ]]; then
         _is_master=true
      fi
      if [[ "$_line"  =~ ^[[:space:]]*\}[[:space:]]*\; ]]; then
         if $_is_master && [[ -n "$zone_file" ]]; then


            if $_set_ipv4 ; then

               for _ipv4_address in "${ipv4_addresses_arr[@]}" ; do
                  if $(grep -q -E "IN\s+A\s+$_ipv4_address" "$zone_file") ; then
                     if [ ${#zonefiles_arr[@]} -eq 0 ] ; then
                        zonefiles_arr+=("${zone_file}:$zone")
                     else
                        if ! containsElement "${zone_file}:$zone"  "${zonefiles_arr[@]}" ; then
                           zonefiles_arr+=("${zone_file}:$zone")
                        fi
                     fi
                  fi
               done

            fi

            if $_set_ipv6 ; then

               for _ipv6_address in "${ipv6_addresses_arr[@]}" ; do
                  if $(grep -q -E "IN\s+AAAA\s+$_ipv6_address" "$zone_file") > /dev/null 2>&1 ; then
                     if [ ${#zonefiles_arr[@]} -eq 0 ] ; then
                        zonefiles_arr+=("${zone_file}:$zone")
                     else
                        if ! containsElement "${zone_file}:$zone"  "${zonefiles_arr[@]}" ; then
                           zonefiles_arr+=("${zone_file}:$zone")
                        fi
                     fi
                  fi
               done
            fi

         fi
         _is_master=false
         _found=false
         zone_file=""
      fi
   fi
done < "$ZONES_DECLARATION_FILE"

echo ""

for _val in ${zonefiles_arr[@]} ; do

   IFS=':' read -a _val_arr <<< "${_val}"

   zone_file="${_val_arr[0]}"
   zone="${_val_arr[1]}"

   echo -e "\n\tEditing \033[37m\033[1m$zone_file\033[m .."
      
   _replaced=false

   if $_set_ipv4 ; then

      for _ipv4_address in "${ipv4_addresses_arr[@]}" ; do
         if $(grep -q -E "IN\s+A\s+$_ipv4_address" "$zone_file") ; then

            ## - setze neue ttl für ipv4 address
            ## -
            echononl "\t   Set default TTL for IPv4 '${_ipv4_address}'.."

            if grep -e "\s*[0-9][0-9]\s*IN\s*A\s*$_ipv4_address" $zone_file > /dev/null 2>&1 ; then
               perl -i -n -p -e "s/^(.+\s+)[0-9]{2,}\s+(IN\s+A\s+$_ipv4_address)/\1\2/" $zone_file
               if [ "$?" = "0" ]; then
                  echo_ok
                  _replaced=true
               else
                  echo_failed
                  error "Setting TTL to the zonfile default for $_ipv4_address in zone file \"$zone_file\" failed!"
               fi
            else
               echo_skipped
            fi

         fi
      done
   fi

   if $_set_ipv6 ; then

      for _ipv6_address in "${ipv6_addresses_arr[@]}" ; do
         if $(grep -q -E "IN\s+AAAA\s+$_ipv6_address" "$zone_file") > /dev/null 2>&1 ; then

            ## - setze neue ttl für ipv6 address
            ## -
            echononl "\t   Set default TTL for IPv6 '${_ipv6_address}'.."
            
            if grep -e "\s*[0-9][0-9]\s*IN\s*AAAA\s*$_ipv6_address" $zone_file > /dev/null 2>&1 ; then
               perl -i -n -p -e "s/^(.+\s+)[0-9]{2,}\s+(IN\s+AAAA\s+$_ipv6_address)/\1\2/" $zone_file
               if [ "$?" = "0" ]; then
                  echo_ok
                  _replaced=true
               else
                  echo_failed
                  error "Setting TTL to the zonfile default for $_ipv6_address in zone file \"$zone_file\" failed!"
               fi
            else
               echo_skipped
            fi
         fi
      done
   fi

   # - Calculate new serial
   # -
   echo ""
   echononl "\t   Calculate new serial"
   if $_replaced ; then
      declare -i __serial=`grep -e "[0-9]\{10\}" $zone_file | grep serial | awk '{print$1}'`
      while [ ! $_serial_new -gt $__serial ]; do
         let _serial_new++
      done
      echo_done
   else
      echo_skipped
   fi

   # - Set new serial
   # -
   echononl "\t   Increase Serial for zone file \"`basename $zone_file`\""
   if $_replaced ; then
      perl -i -n -p -e "s#^(\s*)\s$__serial(.*)#\1 $_serial_new\2#" $zone_file > /dev/null 2>&1
      if [[ $? -eq 0 ]]; then
         echo_ok
      else
         echo_failed
         error "Increasing Serial for zone file \"`basename $zone_file`\" failed!"
      fi
   else
      echo_skipped
   fi

   # - Reload Zone
   # -
   echononl "\t   Reload zone '${zone}'"
   if $_replaced ; then
      /usr/sbin/rndc reload $zone > /dev/null 2>&1
      if [[ $? -gt 0 ]]; then
         echo_failed
      else
         echo_ok
      fi
   else
      echo_skipped
   fi

done


if [[ -d "${ZONE_FILE_MASTER_DIR}.${backup_date}" ]] ; then
   diff -Nur "${ZONE_FILE_MASTER_DIR}" "${ZONE_FILE_MASTER_DIR}.${backup_date}" > /dev/null 2>&1
   if [[ $? -eq 0 ]]; then
      info "No zone file has changed.\n\t          Removing previously created backup"
      echononl "\tDelete '${ZONE_FILE_MASTER_DIR}.${backup_date}'.."
      rm -rf "${ZONE_FILE_MASTER_DIR}.${backup_date}" > $log_file 2>&1
      if [[ $? -eq 0 ]]; then
         echo_ok
      else
         echo_failed
      fi
   fi
fi

echo ""
clean_up 0