#!/bin/bash

#
# Variables
#
TEMP=/tmp/dnse/dnse.$$

#
# Remove temporary files and exit script
#
clean_up()
{
#  rm -f /tmp/dnse.*
#  rm -f /tmp/dnse_input.*
#  rm -f /tmp/dnse_input2.*
  rm -rf /tmp/dnse
  exit
}

#
# Edit the DNS settings
#
edit_dns()
{
  dialog --nocancel \
         --backtitle "DNS Editor v1.0" \
         --title "Edit DNS settings" \
	 --menu "Use [UP] [DOWN] to move, [ENTER] to select and [ESC] to exit. \
	         Doing this will over write your current /etc/resolv.conf. Only do these steps if you're sure you wish to do so" 20 40 4 \
	 Stored "Use stored settings" \
	 New "Change to new settings" \
	 Main "Go back to the main menu" \
	 Exit "Exit the script" 2>$TEMP
  OPT=$?
  SELECT=`cat $TEMP`
  case $OPT in
    0)
       case $SELECT in

         Stored)
                 if [ $(id -u) != "0" ]; then
		   dialog --backtitle "DNS Editor v1.0" \
		          --title "Alert : Root Required!" \
			  --yesno "You are currently not running as root! This feature is unavailable. Please exit and rerun this script to enable this feature. \
			           Would you like to exit?" 6 80
		    SEL=$?
		    case $SEL in
		      0)
		        clean_up;;
		      1)
		        edit_dns;;
		    esac
		 else
		   if [ -e $HOME/.dnseditor ] ; then
		     cp ~/.dnseditor /etc/resolv.conf
		     dialog --backtitle "DNS Editor v1.0" \
		 	    --title "Copying settings" \
			    --infobox "Copying stored DNS settings to /etc/resolv.conf" 5 40
	           else
		     dialog --backtitle "DNS Editor v1.0" \
		            --title "Error" \
		            --infobox "Could not find ~/.dnseditor. Please go to create new settings and select the save option!" 8 40 
		   fi
		 fi
		 sleep 1s
		 edit_dns;;
	 New) 
                 if [ $(id -u) != "0" ]; then
		   dialog --backtitle "DNS Editor v1.0" \
		          --title "Alert : Root Required!" \
			  --yesno "You are currently not running as root! This feature is unavailable. Please exit and rerun this script as root to enable this feature. \
			           Would you like to exit?" 6 80
		   SEL=$?
		   case $SEL in
		     0)
		       clean_up;;
		     1)
		       edit_dns;;
		   esac
		 else
		   dialog --nocancel \
		          --backtitle "DNS Editor v1.0" \
                          --title "DNS Server #1" \
		          --inputbox "Enter 1st DNS setting" 8 40 2>/tmp/dnse/input.$$
                   SEL=$?
		   NA=`cat /tmp/dnse/input.$$`
		   case $SEL in
		     0)
		       dialog --extra-button \
		              --extra-label "Save" \
		              --nocancel \
		              --backtitle "DNS Editor v1.0" \
			      --title "DNS server #2" \
			      --inputbox "Enter 2nd DNS setting" 8 40 2>/tmp/dnse/input2.$$
		       SEL=$?
		       NA1=`cat /tmp/dnse/input2.$$`
		       case $SEL in
		         0)
		           `echo "nameserver $NA" > /etc/resolv.conf`
		           `echo "nameserver $NA1" >> /etc/resolv.conf`
			   dialog --backtitle "DNS Editor v1.0" \
		                  --title "Copying DNS settings" \
			          --infobox "Copying new settings to /etc/resolv.conf. Please wait.\n$NA\n$NA1" 8 40
		           sleep 1s;;
		         3)
		           `echo "nameserver $NA" > $HOME/.dnseditor`
			   `echo "nameserver $NA1" >> $HOME/.dnseditor`
			   cp $HOME/.dnseditor /etc/resolv.conf
			   dialog --backtitle "DNS Editor v1.0" \
			          --title "Saving" \
			  	  --infobox "Saving and setting your current settings of \n$NA\n$NA1" 8 40
			   sleep 1s;;
		       esac
		   esac
		   edit_dns
	       fi
	       sleep 1s
	       edit_dns;;
	 Main)
	         main_menu;;
	 Exit)
	         clean_up;;
       esac;;
    255)
       clean_up;;
  esac
}

#
# View the current DNS settings
#
view_dns()
{
  CURRENT=`cat /etc/resolv.conf`
  dialog --backtitle "DNS Editor v1.0" \
	 --title "Current DNS settings" \
	 --infobox "Your current DNS settings are:\n$CURRENT" 6 35
  sleep 2s
  main_menu
}

#
# The main menu of the script
#
main_menu()
{
  dialog --nocancel \
         --backtitle "DNS Editor v1.0" \
         --title "Main Menu" \
         --menu "Use [UP] [DOWN] to move, [ENTER] to select and [ESC] to exit" 20 40 3 \
	 View "View the current DNS settings" \
	 Edit "Edit the DNS settings" \
	 Exit "Exit the script" 2>$TEMP
  OPT=$?
  SELECT=`cat $TEMP`
  case $OPT in
    0)
       case $SELECT in
         View) view_dns;;
	 Edit) edit_dns;;
	 Exit) clean_up;;
       esac;;
    255)
       clean_up;;
  esac
}

#
# Check if the user is running the script as root
#
mkdir /tmp/dnse
if [ $(id -u) != "0" ]; then
  dialog --backtitle "DNS Editor v1.0" \
  	 --title "Alert : Root Required" \
  	 --yesno "\nYou are currently not running as root! Some features in this script will not be usable. Would you like to continue anyway?" 8 60
  SEL=$?
  case $SEL in
    0) 
       main_menu;;
    1) 
       clean_up;;
    255) 
       clean_up;;
  esac
else
  main_menu
fi