#!/usr/bin/env bash

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

log_file="$(mktemp)"

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

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

      cat<<EOF

   Usage: $(basename $0) [Options] <full-qualified-hostname>

      Script checks if a given hostname is supported by this nameserver. Hostname can
      alos be a TLD name.

      As result the Script returns the zone (domain) of the given hostname." In silent
      mode (-q), script returns an empty String, if the given hostname is not
      supported by this nameserver.

      Options:

      -h    
            Prints this help.

      -q
            Runs in silent mode.

EOF
clean_up 1
}

clean_up() {

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

echononl(){
   if $verbose ; 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
}

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

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

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

echo_ok() {
   if $verbose ; then
      echo -e "\033[75G[ \033[32mok\033[m ]"
   fi
}
echo_failed(){
   if $verbose ; then
      echo -e "\033[75G[ \033[1;31mfailed\033[m ]"
   fi
}
echo_skipped() {
   if $verbose ; then
      echo -e "\033[75G[ \033[33m\033[1mskipped\033[m ]"
   fi
}

# - Test whether stdout (file descriptor 1) is a terminal or not (e.g. cron
# - or if you pipe the output to some other program)
#
if [[ -t 1 ]] ; then
   verbose=true
else
   verbose=false
fi


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

shift $(expr $OPTIND - 1)
if [[ $# -ne 1 ]] ; then
   if $verbose ; then
      usage "wrong number of arguments"
   else
      clean_up 10
   fi
fi

hostname=$1


$verbose && echo ""

if [[ -z "$hostname" ]] ; then
   error "No hostname/domain given!"
   clean_up 10
fi


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

DEFAULT_CONF_FILE_DIR="/etc/bind"



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

if $verbose ; then
   clear
   echo ""
   echo -e "\033[32mRunning script \033[1m"$(basename $0)"\033[m .."
   echo ""
fi


info "Given hostname: \033[1m${hostname}\033[m"


echononl "\t   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 "$CONF_FILE_DIR" ]] || CONF_FILE_DIR="$DEFAULT_CONF_FILE_DIR"
[[ -n "$ZONES_DECLARATION_FILE" ]] || ZONES_DECLARATION_FILE="${CONF_FILE_DIR}/named.conf.local"

$verbose && echo ""



# - Validate Syntax of given domain
# -
valid_domain_regex="^([a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9\-]{0,61}[a-zA-Z0-9])(\.([a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9\-]{0,61}[a-zA-Z0-9]))*$"
echononl "\t   Validate syntax of given hostname/domain.."
if [[ $hostname =~ $valid_domain_regex ]]; then
   if [[ ! $hostname =~ \. ]]; then
       echo_failed
       error "Invalid hostname/domain given!"
       clean_up 10
   else
      echo_ok
   fi
else
   echo_failed
   error "Invalid hostname/domain given!"
   clean_up 10
fi

_failed=false
_hostname=$(echo ${hostname//\./\\.})
while ! grep -E "^\s*zone\s+\"?$_hostname" $ZONES_DECLARATION_FILE > /dev/null 2>&1 ; do
   hostname=${hostname#*.}
   _hostname=$(echo ${hostname//\./\\.})
   if [[ ! $_hostname =~ \. ]]; then
      _failed=true
      break
   fi
done

if $_failed ; then
   $verbose && error "hostname \"$1\" not supported by this nameserver!"
else
   domain=$hostname
   if $verbose  ; then
      info "Hosted Zone: \033[1m${domain}\033[m"
   else
      echo "$domain"
   fi
fi

$verbose && echo
clean_up 0