#!/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)"


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

usage() {
   echo 
      [ -n  "$1" ] && echo -e "Error: $1\n"

      cat<<EOF

   Usage: $(basename $0) [Options]

      Script changes nameserver and admin e-mail entry in SOA Records of all
      master zonefiles .

      If running in a terminal and NOT '-q' is used, script acts in
      interactive mode. Script uses defaults either reading from file
      ${conf_file}, or if not present, bei hardcoded default settings.
      You will be asked to confirm or override the default setting.

      If not running in a terminal (i.e. used as cronjob) or flag '-q' (and 
      within '-d') is set, all configurations are read from file '${conf_file}'.
   

      Options:

      -h    
            Prints this help.

      -q
            Rund in silent mode.

EOF
clean_up 1
}

clean_up() {

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

echononl(){
   if $terminal && $LOGGING ; 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
}

fatal(){
   echo ""
   if $terminal ; then
      echo -e "[ \033[31m\033[1mError\033[m ]: $*"
      echo ""
      echo -e "\t\033[31m\033[1mScript was interupted\033[m!"
   else
      echo "   [ Fatal ]: $*"
      echo ""
      echo "              Script was terminated...."
   fi
   echo ""
   clean_up 1
}

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

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

error (){
   echo ""
   if $terminal ; then
      echo -e "\t[ \033[31m\033[1mError\033[m ]: $*"
   else
      echo "Error: $*"
   fi
   echo ""
}

echo_done() {
   if $terminal && $LOGGING ; then
      echo -e "\033[75G[ \033[32mdone\033[m ]"
   else
      if $LOGGING ; then
         echo " [ done ]"
      fi
   fi
}
echo_ok() {
   if $terminal && $LOGGING ; then
      echo -e "\033[75G[ \033[32mok\033[m ]"
   else
      if $LOGGING ; then
         echo " [ ok ]"
      fi
   fi
}
echo_failed(){
   if $terminal && $LOGGING ; then
      echo -e "\033[75G[ \033[1;31mfailed\033[m ]"
   else
      if $LOGGING ; then
         echo " [ failed ]"
      fi
   fi
}
echo_skipped() {
   if $terminal && $LOGGING ; then
      echo -e "\033[75G[ \033[33m\033[1mskipped\033[m ]"
   else
      if $LOGGING ; then
         echo " [ skipped ]"
      fi
   fi
}

trap clean_up SIGHUP SIGINT SIGTERM


#---------------------------------------
#-----------------------------
# Check some prerequisites
#-----------------------------
#---------------------------------------

if [[ -t 1 ]] ; then
      terminal=true
      LOGGING=true
else
   terminal=false
   LOGGING=false
fi

while getopts hq opt ; do
   case $opt in
      q) LOGGING=false
         ;;
      h) usage
          ;;
      *) usage
   esac
done



#---------------------------------------
#-----------------------------
# 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
# 
#-----------------------------
#---------------------------------------

if $LOGGING ; then
   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

   echo ""


   [[ -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
   [[ -n "$ZONES_DECLARATION_FILE" ]] && DEFAULT_ZONES_DECLARATION_FILE="$ZONES_DECLARATION_FILE"

   [[ -n "$SOA_PRIMARY_MASTER" ]] && DEFAULT_SOA_PRIMARY_MASTER=$SOA_PRIMARY_MASTER
   [[ -n "$SOA_ADMIN_EMAIL" ]] && DEFAULT_SOA_ADMIN_EMAIL=$SOA_ADMIN_EMAIL

   echo ""
   echo -e "\033[32m--\033[m"
   echo ""
   echo "Insert SOA primary master for all the zones."
   echo ""
   SOA_PRIMARY_MASTER=""

   if [[ -n "$DEFAULT_SOA_PRIMARY_MASTER" ]]; then
      echononl "Primary Master (SOA-Record) [${DEFAULT_SOA_PRIMARY_MASTER}]"
      read SOA_PRIMARY_MASTER
      if [[ "X${SOA_PRIMARY_MASTER}" = "X" ]]; then
         SOA_PRIMARY_MASTER="$DEFAULT_SOA_PRIMARY_MASTER"
      fi
   else
      echononl "Primary Master (SOA-Record): "
      read SOA_PRIMARY_MASTER
      while [ "X$SOA_PRIMARY_MASTER" = "X" ] ; do
         echo -e "\n\t\033[33m\033[1mSetting 'Primary Master' is required!\033[m\n"
         echononl "Primary Master (SOA-Record): "
         read SOA_PRIMARY_MASTER
      done
   fi

   echo ""
   echo -e "\033[32m--\033[m"
   echo ""
   echo "Insert SOA admin e-mail address for all the zones."
   echo ""
   SOA_ADMIN_EMAIL=""

   if [[ -n "$DEFAULT_SOA_ADMIN_EMAIL" ]]; then
      echononl "Admin E-Mail Address (SOA-Record) [${DEFAULT_SOA_ADMIN_EMAIL}]"
      read SOA_ADMIN_EMAIL
      if [[ "X${SOA_ADMIN_EMAIL}" = "X" ]]; then
         SOA_ADMIN_EMAIL="$DEFAULT_SOA_ADMIN_EMAIL"
      fi
   else
      echononl "Admin E-Mail Address (SOA-Record): "
      read SOA_ADMIN_EMAIL
      while [ "X$SOA_ADMIN_EMAIL" = "X" ] ; do
         echo -e "\n\t\033[33m\033[1mSetting 'Admin E-Mail Address' is required!\033[m\n"
         echononl "Admin E-Mail Address (SOA-Record): "
         read SOA_ADMIN_EMAIL
      done
   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"
   [[ -n "$ZONE_FILE_MASTER_DIR" ]] || ZONE_FILE_MASTER_DIR="${CONF_FILE_DIR}/master"


   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

   # - replace '@' character with '.'
   # -
   SOA_ADMIN_EMAIL="${SOA_ADMIN_EMAIL/@/.}"

   echo ""
   echo ""
   echo -e "\033[1;32mSettings for \033[1;37mChange SOA Record\033[m Script"
   echo ""
   echo -e   "\tSOA Primary Master..................: $SOA_PRIMARY_MASTER"
   echo -e   "\tSOA Admin E-Mail Address............: $SOA_ADMIN_EMAIL"
   echo ""
   echo -e   "\tBind Configuration Directory........: $CONF_FILE_DIR"
   echo -e   "\tZones Declaration File..............: $ZONES_DECLARATION_FILE"

   echo ""
   info "Repace Primary Master \033[37m\033[1m${SOA_PRIMARY_MASTER}\033[m and Admin E-Mail \033[37m\033[1m${SOA_PRIMARY_MASTER}\033[m in all SOA Records"
   echo -n "To continue type uppercase 'YES': "
   read OK
   echo ""
   if [[ "$OK" != "YES" ]] ; then
      fatal "Abort by user request - Answer as not 'YES'"
   fi

else # if $LOGGING

   if [[ ! -f "$conf_file" ]]; then
      fatal "Configuration file '$conf_file' not found!"
   else
      echononl "   Loading default Configuration values from $(basename ${conf_file}).."
      source "${conf_file}" > $log_file 2>&1
      if [[ $? -eq 0 ]]; then
         echo_ok
      else
         echo_failed
         fatal "$(cat $log_file)"
      fi
   fi

   if [[ -z "$CONF_FILE_DIR" ]]; then
      CONF_FILE_DIR="$DEFAULT_CONF_FILE_DIR"
   fi
   if [[ ! -d "$CONF_FILE_DIR" ]] ; then
      fatal "Directory contaning bind configurations not found (see CONF_FILE_DIR)!"
   fi

   [[ -n "${ZONE_FILE_MASTER_DIR}" ]] || ZONE_FILE_MASTER_DIR="${CONF_FILE_DIR}/master"

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

   [[ -z "$SOA_ADMIN_EMAIL" ]] && fatal "Missing SOA Admin E-Mail Address (see SOA_ADMIN_EMAIL)"
   [[ -z "$SOA_PRIMARY_MASTER" ]] && fatal "Missing SOA Primary Master (see SOA_PRIMARY_MASTER)"

   # - replace '@' character with '.'
   # -
   SOA_ADMIN_EMAIL="${SOA_ADMIN_EMAIL/@/.}"

fi

if [[ ! -f "$ZONES_DECLARATION_FILE" ]]; then
   fatal "Zone declaration file '${ZONES_DECLARATION_FILE}' not found!"
fi

declare -a zone_file_arr=()

_found=false
_is_master=false
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
            zone_file_arr+=("${zone_file}:$zone")
         fi
         _is_master=false
         _found=false
         zone_file=""
      fi
   fi
done < "$ZONES_DECLARATION_FILE"


if [[ -d "$ZONE_FILE_MASTER_DIR" ]] ; then
   echononl "\tBackup directory '${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
fi


for _val in "${zone_file_arr[@]}" ; do

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

   declare -i _serial_new=`date +%Y%m%d01`

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

   if $LOGGING ; then
      echo ""
      echo -e "\tPreparing zone file \033[37m\033[1m${zone_file}\033[m"
   fi


   ## - calculate new serial
   ## -
   echononl "\tCalculate new serial.."
   declare -i __serial=$(grep -E "^\s*[0-9]{10}\s+;?(serial)?" $zone_file | awk '{print$1}')
   if [[ -z "$__serial" ]]; then
      echo_failed
      continue
   fi
   while [[ ! $_serial_new -gt $__serial ]]; do
      let _serial_new++
   done
   if [[ $? -gt 0 ]]; then
      echo_failed
   else
      echo_ok
   fi

   echononl "\tChanging SOA Record.."
   if ! $(grep -q -E "^.*IN\s+SOA\s+${SOA_PRIMARY_MASTER}\.\s+${SOA_ADMIN_EMAIL}\.\s+\(" $zone_file) ; then
      perl -i -n -p -e "s/^(.*IN\s+SOA).*$/\1 ${SOA_PRIMARY_MASTER}. ${SOA_ADMIN_EMAIL}. \(/" $zone_file
      if [[ $? -gt 0 ]]; then
         echo_failed
      else
         echo_ok
      fi
   else
      echo_skipped
      continue
   fi

   ## - Set new serial
   ## -
   echononl "\tRenew serial.."
   perl -i -n -p -e "s#^(\s*) $__serial(.*)#\1 $_serial_new\2#" $zone_file
   if [[ $? -gt 0 ]]; then
      echo_failed
   else
      echo_ok
   fi

   ## - Reload Zone
   ## -
   echononl "\tReload Zone ${zone}.."
   /usr/sbin/rndc reload $zone > /dev/null 2>&1
   if [[ $? -gt 0 ]]; then
      echo_failed
   else
      echo_ok
   fi

   sleep 1
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

$LOGGING && echo ""
clean_up 0