#!/bin/bash

## Azilink Tether application launch script

## This script will initiate all necessary
## processes on your computer to enable the
## tether between your G1 and your PC.

## Tripp Holden - August 13, 2009
## --Updated - October 22, 2009--

## Variables
## Optional, and depends if you've added the
## Android SDK to your $PATH.

ANDROIDSDK=/apps/android_sdk_1.6
VPNCONF=/apps/tether/azilink.ovpn
RESOLVCONF=/etc/resolvconf/run/resolv.conf

## Functions

start_wrapper ()
{

   adb_service_start
   vpn_service_start
   add_ns

   i=1
   VPNSTATUS=`grep "Initialization Sequence Completed" /tmp/azilink.out | awk '{ print $8 }'` 
   while [[ "$VPNSTATUS" != Completed ]] && [[ "$i" -le 6 ]]; do
      VPNSTATUS=`grep "Initialization Sequence Completed" /tmp/azilink.out | awk '{ print $8 }'`
         if [ "$i" -eq 6 ]; then
            echo "==============================================================================================="
            echo "##WARNING:## VPN did not start successfully, check /tmp/azilink.out."
            echo "Ensure Azilink service is started on your G1 and that it is connected to your computer via USB."
            echo "==============================================================================================="
            
            ## Call stop functions
            adb_service_stop
            vpn_service_stop
            remove_ns
            exit 0
         fi 
      sleep 3
      (( i++ ))
   done

}

stop_wrapper ()
{
   adb_service_stop
   vpn_service_stop
   remove_ns
}


adb_service_start ()
{
	## Check for the adb server and make its process a variable.
   SRVPS=`ps -ef | grep "adb fork-server server" | grep -v grep | awk '{ print $2 }'`

   ## if the process does not exist, start the server
   if [ -z $SRVPS ]; then
      $ANDROIDSDK/tools/adb devices 1>/tmp/azilink.out &
   else
      ## if the process exists, kill it and re-start the server
      kill -9 $SRVPS
      $ANDRIODSDK/tools/adb devices 1>>/tmp/azilink.out &
   fi
   
   ## wait for the adb server to initialize
   sleep 5

   ## Forward the necessary local port to the G1 phone for VPN communication
   $ANDROIDSDK/tools/adb forward tcp:41927 tcp:41927 1>>/tmp/azilink.out &
   echo "VPN Port Forwarded."
   echo ""
   echo "ENABLE AZILINK TETHER SERVICE ON YOUR G1 PHONE NOW!"
   echo ""

   ##  This is usually instant, but allow time for the user to enable the azilink application on the phone
   sleep 10
}

vpn_service_start ()
{
echo "VPN Starting."

   ## Check for the vpn process if it is running and make the process a variable.
   VPNPS=`ps -ef | grep "$VPNCONF" | grep -v grep | awk '{ print $2 }'`

   ## if the process does not exist, start the server
   if [ -z $VPNPS ]; then
      openvpn --config "$VPNCONF" 1>>/tmp/azilink.out &
   else
      ## if the process exists, kill it and re-start the process
      kill -9 $VPNPS
      openvpn --config "$VPNCONF" 1>>/tmp/azilink.out &
   fi

   echo "Waiting for VPN to start..."
}

add_ns ()
{
	echo "Adding nameserver to $RESOLVCONF."

   ## check if nameserver entry exists and create a variable to test against
   NSENTRY=`grep 192.168.56.1 "$RESOLVCONF" | awk '{ print $1 }'`

   ## if the entry does not exist, add it
   if [ -z $NSENTRY ]; then
      echo "nameserver 192.168.56.1" >> "$RESOLVCONF"
   ## if the entry exists, exit
   fi
}

adb_service_stop ()
{
	## stop all processes for the tether
   echo "Stopping the tether service..."

   ## make the adb server process a variable
   SRVPS=`ps -ef | grep "adb fork-server server" | grep -v grep | awk '{ print $2 }'`

   ## if the server is not running, skip and move to the next process otherwise kill it
   if [ -z $SRVPS ]; then
      echo "ADB not running."
  else
      echo "Stopping adb server, process $SRVPS."
      kill -9 $SRVPS
   fi

}

vpn_service_stop ()
{

   VPNPS=`ps -ef | grep "$VPNCONF" | grep -v grep | awk '{ print $2 }'`
   ## if the vpn is not running, skip and move to the next process otherwise kill it

   if [ -z $VPNPS ]; then
      echo "VPN not running."
   else
      echo "Shutting down VPN, process $VPNPS."
      kill -9 $VPNPS
   fi

}

remove_ns ()
{
	echo "Removing nameserver entry if it exists."
   
   NSENTRY=`grep 192.168.56.1 "$RESOLVCONF" | awk '{ print $1 }'`

   ## Remove the namserver entry if it exists, otherwise exit
   if [ -z $NSENTRY ]; then
      echo "Nameserver entry does not exist."
   else
      cat "$RESOLVCONF" | sed "/192.168.56.1/d" > /tmp/resolv.conf
      mv /tmp/resolv.conf "$RESOLVCONF"
   fi
}

## Script

case "$1" in
'start')
   echo "Starting the tether service..."
   start_wrapper
;;
'stop')
   stop_wrapper
   echo "Exiting, you may shutdown Azilink tether service on your G1 now."
;;
esac