#!/usr/bin/env bash


#---------------------------------------
#-----------------------------
# Predifined Variables
#-----------------------------
#---------------------------------------

conf_file="/etc/ddclient.conf"
ddclient_script="/usr/bin/ddclient"

_SKIP_IP=false


#---------------------------------------
#-----------------------------
# Functions
#-----------------------------
#---------------------------------------

usage() {

        echo

        if [ -n "$1" ];then
           echo -e "Error: $1\n"
        fi
        echo -e ""
        echo -e "\tusage: `basename $0` < dyndns-name>\n"
        exit 1
}


fatal(){
   echo ""
   echo -e "   [ Fatal ] $*"
   echo ""
   echo -e "\tScript terminated.."
   echo ""
   exit 1
}
info (){
   echo ""
   echo -e "   [ Info ]  $*"
   echo ""
}

ok (){
   echo ""
   echo -e "   [ Ok ]    $*"
   echo ""
}


#---------------------------------------
#-----------------------------
# Evaluate command line
#-----------------------------
#---------------------------------------

[ $# -eq "0" -o $# -gt "2" ] && usage "wrong number of arguments"

DYNDNS_NAME=$1


#---------------------------------------
#-----------------------------
# Some checks
#-----------------------------
#---------------------------------------

# - Only run ddclient, if it is installed
# -
if [[ ! -x "$ddclient_script" ]]; then
   fatal "Script '${ddclient_script}' not found!"
fi

# - Configuration present?
# - 
if [[ ! -f "$conf_file" ]]; then
   fatal "ddclient Configuration '${conf_file}' not found!"
fi

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

# - Check, if ddclient uses a local interface (variable "if")
# -
# -    if true, interface name will be stored into variable 'if'
# -
eval `sed -n 's/\(if=[^       ,]*\)/\1/p' /etc/ddclient.conf`

# - Check if interface used by dyndns is present
#
if [ -n "$if" ];then
   for _IFACE in `ifconfig | grep -e"^ppp" | cut -d" " -f1 `; do
      if [ "$_IFACE" = $if ];then
         PPP_IFACE=$_IFACE
         break
      fi
   done

   ## - exit if no connection for dydns interface exists
   ## -
   if [ "X" = "X$PPP_IFACE" ]; then
      fatal "No interface for dydns exists."
   fi

else
   _SKIP_IP=true
fi


#---------------------------------------
#-----------------------------
# Update DynDNS IP-Address if needed
#-----------------------------
#---------------------------------------

if ! $_SKIP_IP ; then

   PPP_REMOTE=`ifconfig  $PPP_IFACE 2>/dev/null | grep -e "P-[tz]-P" | cut -d":" -f3 | cut -d " " -f1`
   PPP_LOCAL=`ifconfig  $PPP_IFACE 2>/dev/null | grep -e "P-[tz]-P" | cut -d":" -f2 | cut -d " " -f1`

   if [ "X$PPP_REMOTE" != "X" -a "X$PPP_LOCAL" != "X" ] ; then

      DYNDNS_IP=`dig $DYNDNS_NAME +short`

      if [ "$DYNDNS_IP" != "$PPP_LOCAL" ] ; then

         # - Run ddclient with the IP address of the ppp device
         # -
         info "Try to update ip-adress entry at dyndns.org.."
         /usr/sbin/ddclient -syslog -ip $PPP_LOCAL
      else
         if $LOGGING ; then
            ok "DynDNS IP is up-to-date"
         fi
      fi

   fi

else

   # - Load defaults
   source /etc/default/ddclient
   if $(ps -e f | grep -E "[[:digit:]]\ .*ddclient" | grep -q -v grep) || [[ "$run_daemon" = "true" ]]; then
      if $LOGGING ; then
         info "'ddclient' is configured to run as daemon. So nothing to do here."
      fi
   else
      if $LOGGING ; then
         info "Going to run '${ddclient_script}'.."
      fi
      /usr/sbin/ddclient -file $conf_file
   fi

fi


exit 0;