#!/usr/bin/env bash

# - Bind configuration file containing zone definitions
# -
ZONE_CONF_FILE=/etc/bind/named.conf.local

## --
## -- End: Variable definitions

## ***
## *** Don't make changes after this line ***
## ***

## --- some functions
## ---
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$$
}

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

info (){
   echo ""
   echo -e "\t[ \033[32m\033[1mInfo\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_failed(){
   echo -e "\033[75G[ \033[1;31mfailed\033[m ]"
}
echo_skipped() {
   echo -e "\033[75G[ \033[33m\033[1mskipped\033[m ]"
}

## ---
## --- END: functions

hostname=$1

# - 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

$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]))*$"
$verbose && echononl "\tValidate syntax of given hostname/domain.."
if [[ $hostname =~ $valid_domain_regex ]]; then
   if [[ ! $hostname =~ \. ]]; then
       $verbose && echo_failed
       $verbose && error "Invalid hostname/domain given!"
       exit 10
   else
      $verbose && echo_ok
   fi
else
   $verbose && echo_failed
   $verbose && error "Invalid hostname/domain given!"
   exit 10
fi

_failed=false
_hostname=$(echo ${hostname//\./\\.})
while ! grep -e "$_hostname" $ZONE_CONF_FILE > /dev/null 2>&1 ; do
   hostname=${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 "Domain: $domain"
   else
      echo "$domain"
   fi
fi

$verbose && echo
exit 0