#!/usr/bin/env bash

TRANSUSER=your_transmission_username
TRANSPASS=your_transmission_password
TRANSHOST=192.168.x.xx

error( )
{
  echo "$@" 1>&2
  exit 1
}

error_and_usage( )
{
  echo "$@" 1>&2
  usage_and_exit 1
}

usage( )
{
  echo "Usage: `dirname $0`/$PROGRAM"
}

usage_and_exit( )
{
  usage
  exit $1
}

version( )
{
  echo "$PROGRAM version $VERSION"
}


port_forward_assignment( )
{
  echo 'Loading port forward assignment information...'
  if [ "$(uname)" == "Linux" ]; then
    client_id=`head -n 100 /dev/urandom | sha256sum | tr -d " -"`
  fi
  if [ "$(uname)" == "FreeBSD" ]; then
       client_id=`head -n 100 /dev/urandom | shasum -a 256 | tr -d " -"`
  fi

  json=`curl "http://209.222.18.222:2000/?client_id=$client_id" 2>/dev/null`
  if [ "$json" == "" ]; then
    echo Port forwarding is already activated on this connection, has expired, or you are not connected to a PIA region that supports port forwarding
    exit 0
  fi

  echo server returned $json

   #trim VPN forwarded port from JSON
    PORT=$(echo $json | awk 'BEGIN{r=1;FS="[{}\":]+"} /port/{r=0; print $3} END{exit r}')
    echo if successful, trimmed port is:$PORT

    #change transmission port on the fly

    transmission-remote $TRANSHOST --auth $TRANSUSER:$TRANSPASS -p "$PORT"
     echo remember to run no longer than 2 mins after reconnecting/connecting to vpn server.
}



EXITCODE=0
PROGRAM=`basename $0`
VERSION=2.1

while test $# -gt 0
do
  case $1 in
  --usage | --help | -h )
    usage_and_exit 0
    ;;
  --version | -v )
    version
    exit 0
    ;;
  *)
    error_and_usage "Unrecognized option: $1"
    ;;
  esac
  shift
done

port_forward_assignment

exit 0