#!/bin/bash
#
# Return the consolidated user´s memory usage (in megabytes).
# The user could be passed as the first argument, otherwise the $USER
# variable should be used.
#

function check_if_is_valid_user()
{
  if `id $1 >/dev/null 2>&1`; then
    return 0
  else
    return 1
  fi
}

function print_usage()
{
  echo "Usage: $0 [--help|-h|--all|-a|some_valid_user]"
  exit 1
}

function get_user_memory_usage()
{
  proc_mem=`ps -u $1 -o rss --no-heading`
  mem_usage=0

  for i in $proc_mem; do
    mem_usage=`echo $((mem_usage+$i))`
  done

  echo $((mem_usage / 1024))

}

function get_active_thinlinc_users()
{
  # Temporary solution...
  ps ax -o user --no-heading |sort -u | grep ^tw
}

# Dont touch that!
ALL_USERS_REPORT="No"

if [ $# -eq 1 ]; then
  case $1 in
    --all|-a)
      ALL_USERS_REPORT="Yes"
    ;;
    --help|-h)
      print_usage
    ;;
    *)
      if `check_if_is_valid_user $1`; then
        # Okay. You must be root to query another user...
        if [ $UID -eq 0 ]; then
          query_user=$1
        else
          echo "Hey, smart one! You must be root to query another user!"
          exit 1
        fi
      else
        echo "Ops... \"$1\" doesn´t seem to be a valid user. Exiting."
        exit 1
      fi
    ;;
  esac
elif [ $# -eq 0 ]; then
  query_user=$USER
else
  print_usage
fi

if [ $ALL_USERS_REPORT == "Yes" ]; then
  tl_active_users=`get_active_thinlinc_users`
  count=`echo $tl_active_users |wc -w`
  echo -e "\nThere are currently $count ThinLinc active users."
  echo -e "*============================================*\n"

  # Lets start by 0, ok?
  all_users_mem_usage=0

  for tl_user in $tl_active_users; do
    echo -en " $tl_user\t: "
    user_mem_usage=`get_user_memory_usage $tl_user`
    all_users_mem_usage=`expr $all_users_mem_usage + $user_mem_usage`
    echo "${user_mem_usage} MB"
  done

  echo -e "\n*============================================*"
  echo "Total user memory usage: ${all_users_mem_usage} MB"
  
else
  get_user_memory_usage $query_user
fi