#!/bin/bash

F=/tmp/out-$RANDOM
C=/etc/network/interfaces
H=/etc/hostname
R=/etc/resolv.conf
HN=$(hostname)
IP=$(ifconfig eth0 | grep inet\  | awk '{print $2}' | cut -f 2 -d :)
MSK=$(ifconfig eth0 | grep inet\  | awk '{print $4}' | cut -f 2 -d :)
GW=$(route -n|tail -1| awk '{print $2}')
NS=$(cat $R|grep nameserver|awk '{print $2}')
function c() { echo $1 | tr '.' '\n' | wc -l; }

function inp() {
  OK=1
  while [ $OK -eq 1 ] ; do
    dialog --no-collapse --nocancel --title "IP configuration" \
      --form "Please enter network settings"\
      0 0 0\
      "Hostname (FQDN)" 1 1 "$HN" 1 20 24 0 \
      "IP address" 2 1 "$IP" 2 20 20 0 \
      "Netmask" 3 1 "$MSK" 3 20 20 0 \
      "Gateway" 4 1 "$GW" 4 20 20 0 \
      "Name server" 5 1 "$NS" 5 20 20 0 \
      2> $F && {
    HN=$(cat $F | head -1)
    IP=$(cat $F | head -2 | tail -1)
    MSK=$(cat $F | head -3 | tail -1)
    GW=$(cat $F | head -4 | tail -1)
    NS=$(cat $F | head -5 | tail -1)
    OK=0
    [ $(c $HN) -lt 2 ] && { dialog --msgbox "Hostname must be FQDN" 6 32 ; OK=1; }
    [ $OK=0 -a $(c $IP) -lt 4 ] && { dialog --msgbox "Invalid IP address" 6 32 ; OK=1; }
    [ $OK=0 -a $(c $MSK) -lt 4 ] && { dialog --msgbox "Invalid network mask" 6 32  ; OK=1; }
    [ $OK=0 -a $(c $GW) -lt 4 ] && { dialog --msgbox "Invalid gateway address" 6 32  ; OK=1; }
    [ $OK=0 -a $(c $NS) -lt 4 ] && { dialog --msgbox "Invalid name server address" 6 32 ; OK=1; }
   }
   if [ $? -eq 255 ] ; then { rm $F ; return; } fi
  done

  echo -e "auto lo\niface lo inet loopback\n\nauto eth0\niface eth0 inet static" > $C
  echo "        address $IP">>$C
  echo "        netmask $MSK">>$C
  echo "        gateway $GW">>$C
  chgrp www-data $C
  chmod 664 $C

  echo $HN > $H
  hostname -F $H
  perl -p -i -e "s/^$IP\s.*/$IP $HN $(echo $HN|cut -f 1 -d .)/" /etc/hosts
  grep -q "$IP[         ]" /etc/hosts || echo "$IP $HN $(echo $HN|cut -f 1 -d .)" >>/etc/hosts
  perl -p -i -e "s/option domain-name \"[^\"]*\";/option domain-name \"`dnsdomainname`\";/" /etc/dhcpd.conf
  perl -p -i -e "s/option domain-name-servers .*/option domain-name-servers $NS;/" /etc/dhcpd.conf
  perl -p -i -e "s/option subnet-mask .*/option subnet-mask $MSK;/" /etc/dhcpd.conf
  perl -p -i -e "s/next-server .*/next-server $IP;/" /etc/dhcpd.conf
  perl -p -i -e "s/option routers .*/option routers $GW;/" /etc/dhcpd.conf
  echo search $(dnsdomainname) > $R
  echo nameserver $NS >> $R
  /etc/init.d/networking restart
  rm $F
}

[ -s /etc/network/interfaces ] || {
  inp
}

while [ true ]; do
  dialog --colors --no-collapse --nocancel --title Configuration --menu \
    "\nhostname: $(hostname)\n\nPlease connect to \n   http://$IP" 17 0 6 \
    "Access log" "" "Error log" "" Reconfigure "" Reboot "" Shutdown "" 2> $F
  O=$(head -1 $F)
  case $O in
  "Access log") dialog --title "scroll left/right with 'h' and 'l' or arrows" --tailbox /var/log/lighttpd/access.log 0 0;;
  "Error log") dialog --title "scroll left/right with 'h' and 'l' or arrows" --tailbox /var/log/lighttpd/error.log 0 0;;
  "Reconfigure") inp;;
  "Reboot") shutdown -r now;;
  "Shutdown") shutdown -h now;;
  *) sleep 1;;
  esac
done